The Fingertight Racing Sidecar Project

[wildman]

[QUOTE=Pumba;1130721725]Well given all the discussion on here figured I would spill my guts on what I am thinking for the future, just encase some long lost aunt with all her millions (would probably settle for thousands, even hundreds would not go a miss) and has named me as benefactor of the estate (I did mention earlier about being allowed to dream).

Anyway, should I start from scratch I am thinking a short bike modelled on a modern F2. What I am pretty sure I will do is:


Seamless Steel Tube Frame (anyone got any clues on sizes?)
Length somewhere around the minimum wheelbase of 1300mm
Wheel Track around the 800mm mark (for no other reason than it looks in proportion on my sketch)
FXR powered (although if the cheater 85cc engines come in.........)


Wow, not a big list when I look at. The list of what I have questions about is much longer.

One of the big things I am changing my mind about is the wheels. Just because I really like the 10inch rims. But to be honest I am starting to reconsider this. kart rims just seem like the easier option from an engineering point of view. If I were to go down the 10inch wheel track you are talking the need to get customised hubs to accommodate disk brakes and a drive sprocket. Kart gear to a large extent like axles and hubs are available off the shelf. Just seems easier.

Hey Pumba have to agree best way to go for bucket sidecar is a simple frame and kart running gear, the only down side and reason i on sold the one i had to Henk and Rick :brick:is being a big guy my weight would upset the handling which doesn't seem to be an issuse with my current one. Although it doesn't seem to like doing more than a couple of laps.
Here's some tips for you if you go with go-kart running gear, use a 30mm or 50mm medium axle.
Run split rear sprockets which will make it easier if you want to change the gearing.
Treat it like a go-kart not a bike with reguards to gearing, i've changed the gearing on the one Henk and Rick own and Brentons one. Originally one of them had a 40 tooth rear sprocket and i think now their both around 24 or 27 tooth rear.

[jibberwobble]

Well given all the discussion on here figured I would spill my guts on what I am thinking for the future, just encase some long lost aunt with all her millions (would probably settle for thousands, even hundreds would not go a miss) and has named me as benefactor of the estate (I did mention earlier about being allowed to dream).

Anyway, should I start from scratch I am thinking a short bike modelled on a modern F2. What I am pretty sure I will do is:


Seamless Steel Tube Frame (anyone got any clues on sizes?)
Length somewhere around the minimum wheelbase of 1300mm
Wheel Track around the 800mm mark (for no other reason than it looks in proportion on my sketch)
FXR powered (although if the cheater 85cc engines come in.........)
20 and 25mm seamless is common in the uk. Bare in mind if you plan on bending it, bigger than that will be difficult without a hydraulic bender.

Agreed the smaller wheel base sounds fair to me on the agility front





One of the big things I am changing my mind about is the wheels. Just because I really like the 10inch rims. But to be honest I am starting to reconsider this. kart rims just seem like the easier option from an engineering point of view. If I were to go down the 10inch wheel track you are talking the need to get customised hubs to accommodate disk brakes and a drive sprocket. Kart gear to a large extent like axles and hubs are available off the shelf. Just seems easier.

Yep, kart gear can be pretty cheap second hand and most things are possible with regard to different sizes and methods of attaching things together.


Something else that I had not thought a lot about until today was the alignment of the drive and front wheels. Always thought I would put them straight in line, but given we have the 70mm allowance in the rules, the pictures from jibberwobble and the realisation that the big rigs run some offset I am thinking that not utilising some of this 70mm offset would be a lost opportunity. But what to make it?

My best guess would be to go for the max like Drew says


I think I would still run suspension. My gut tells me that there has to be some benefit to doing so. Leading link at the front with a swing arm at the back, although if I go with kart wheels there is probably a chance to have something a bit flasher at the front (I doubt that is needed).

Surely suspension is only going to be of some real benefit if it is quality gear with setup adjustability? given the cost and complexity of getting it working well and the fact that super karts are doing over 200kph with no suspension on the same type of tyre I'm not convinced it's worth it.

My front axle is a piece of 40mm ally bar, bored out for bearing spacer tube, bearing recess in each end and 8mm woodruff keyway all the way down. I can slide brake disc carriers and wheel hubs up and down and nip up where needed.

http://i88.photobucket.com/albums/k180/jibberwobble/Minimoto/Minimoto%20Sidecars/My%20outfit/IMAG2004-1_zpscf812bf9.jpg

http://i88.photobucket.com/albums/k180/jibberwobble/Minimoto/Minimoto%20Sidecars/My%20outfit/IMAG2003-1_zps4e963d46.jpg

You can also get wheel hubs with bearings in that carry brake disc carriers. And brake disc carriers with bearings that carry wheel hubs so thats two more methods to consider.

http://i88.photobucket.com/albums/k180/jibberwobble/Minimoto/Minimoto%20Sidecars/DSC00070.jpg

http://i88.photobucket.com/albums/k180/jibberwobble/Minimoto/Minimoto%20Sidecars/012.jpg

[jibberwobble]

Here's some footage of the little uk units let loose on a full size racing track, (mallory park) they are a bit lost on this somewhat featureless layout but after everyone whacked on their smallest rear cog they were stretching their legs ok and putting in better lap times than some of the older classic full size chairs. Richards was apparently going through the speed trap @96mph (155kph) which is quite amusing.

Shows that having no suspension isnt doing that much harm though I feel.

<iframe width="640" height="360" src="//www.youtube.com/embed/0BO_t9LawPw?feature=player_embedded" frameborder="0" allowfullscreen></iframe>

[Pumba]

Mate the photos that you have put up on here and the other thread have been awesome. Given me a bit to think about. Once I have collected my thoughts I will have to write another post.

[jibberwobble]

Thanks for the positive comments along the way guys.

Glad to help spread the word and promote our sport whenever possible dude, just happy I'm not sticking my nose in where it's not wanted!:niceone:

[Grumph]

Seamless tube - other than hydraulic tube - is not that common in NZ. Hydraulic tube is also a tad expensive here...

i use ERW mild steel in appropriate diameters and conservative gauges for my solo frames. gauges range from 2mm to 1.6mm wall.
there is a DOM option available in mild steel too - but it doesn't have much ductility and is known to be prone to splitting. Ray Breingan who builds classic frames uses it but test bends each stick - tossing out any that fail. I can't afford that luxury so just use seamed tube.
When in doubt with ERW just go up in diameter - the weight penalty is very small and it pays off in stiffness.

[Pumba]

Cheers Grumph, was hoping some with some experience on that one. I was only guessing based on what I was reading and talking to some work mates with hot rod experience.

[Grumph]

[QUOTE=Pumba;1130723120]Cheers Grumph, was hoping some with some experience on that one. I was only guessing based on what I was reading and talking to some work mates with hot rod experience

Apples and Oranges....they're working in diameters and gauges we never use on bikes. Yes, big, thick wall seamless is about - but you'd only use it if you built a trailer for the chair.....

[jibberwobble]

Gotta admit after looking around my chassis most of it is seamed. The bits I've made are seamless in the imortant areas and whatever I can find for everything else. I only had to buy a few metres and yes it was expensive :(

[Grumph]

Gotta admit after looking around my chassis most of it is seamed. The bits I've made are seamless in the imortant areas and whatever I can find for everything else. I only had to buy a few metres and yes it was expensive :(

There are one or two areas I'd use something better too....dechromed fork stanchions for the legs on leading link forks comes to mind.

[Pumba]

Been having a harder than I have in the past at some of those rigs built in the UK and I am liking what I am seeing. I have concluded that kart wheels and hub are certainly the better option, if for no other reason than it limits the amount of custom fabrication.

Although I still like the idea of suspension I have concluded that it probably is not required.

Lots of thinking going on here. Now all I need is for numbers to come in on the weekend as I see Lotto is at a mere $23million. Yep, think I should be able to build something adequate with that.

[koba]

Been having a harder than I have in the past at some of those rigs built in the UK and I am liking what I am seeing. I have concluded that kart wheels and hub are certainly the better option, if for no other reason than it limits the amount of custom fabrication.

Although I still like the idea of suspension I have concluded that it probably is not required.

Lots of thinking going on here. Now all I need is for numbers to come in on the weekend as I see Lotto is at a mere $23million. Yep, think I should be able to build something adequate with that.

Look closely at a kart frame, I'm pretty sure it's designed to flex in the right places, could try and incorporate that idea but I have no idea how.

Yet.

[Drew]

Look closely at a kart frame, I'm pretty sure it's designed to flex in the right places, could try and incorporate that idea but I have no idea how.

Yet.Dunno if they're allowed suspension, but I imagine the whole point of not having it in the beginning would have had something to do with weight. If tyres could be made to effectively deal with surface imperfections, F1 cars wouldn't have shocks.

Not so much of an issue, when dealing with an outfit like Pumba's.

[wildman]

Some early seventies American karts had a crude form of suspension and i have seen it tried on a couple of Superkart frames but i don't think it really helped. Some modern karts have torsion blades which run across the front and rear of the chassis and can be set at different angles to alter chassis stiffness Or you could buy my sidecar rolling chassis which already has suspension.

[Gazzza]

Hi Warren, so are you saying you are going to sell your rig? :confused:

[wildman]

Hi Warren, so are you saying you are going to sell your rig? :confused:

Hi Gazzza, yeah thought about it and probably better to sell it than let it sit around for rest of year. Will look at building one similar to my first one i had years ago when i get back from South Sudan next year. Will give you a ring sometime over weekend.

[Pumba]

Its ok Warren. Your rig is a work of art, but would rather build me own before buying another. After doing that lap on yours it would require a few changes for me to be comfortable on.

[wildman]

Its ok Warren. Your rig is a work of art, but would rather build me own before buying another. After doing that lap on yours it would require a few changes for me to be comfortable on.

Haha that's okay, i've worked out what was going on with front end on mine. So are you going to rebuild your old one for now or concentrate on a new one?

[Pumba]

Haha that's okay, i've worked out what was going on with front end on mine. So are you going to rebuild your old one for now or concentrate on a new one?

Going to fix up my current one. Frankly the money is not there to race at the moment. Would really love to build one from scratch but not sure what the time frame on that would be.

[Gazzza]

Hey Warren, can see the logic in that, if some one buys the frame can wrangle an engine in we could have one more for the new season... There must be some one out there who would like the only hub centre steering bucket chair. I have also decided to finish off the frame I started and sell it as a rolling frame, good to go for some one who wants to put an engine in, I'll make it with plenty of room to mount any sort of motor. Will pull out what I have done so far this coming weekend and see what needs to be done to get it to a stage I can sell it on.

[jibberwobble]

Hows it going Pumba? Anymore thoughts on a new outfit? I've not been on for a while courtesy of life and it's many complications :( Still building my rig, it's consuming huge amounts of time which is always the case when you're inventinting shit from nothin.......... for every hour I spend on it I reckon only 15 minutes is actually tools in hand doing something, the rest is scribling, bollock scratching and imagineering. And for evry hour of work (15mins) there seems to be at least 2 hrs of research n part hunting.

Still aiming to do a thread on mine soon. Oh and shout if you lot want anymore pics of particular areas put up on my UK chair thread.

Do you guys change gear with right foot?

[Pumba]

Na nothing more has happened here. Apart from a lot google searching, thinking and formulating ideas. Really need to get the wife back into work so I can afford to go play again:crazy:

I have been spending a bit of time over on your forums and looking a bit harder at the photos that you guys have up. There are some beautifully crafted rigs over there.

I do have a couple of questions for you, no centre hub steering type rigs have been built? Reviewing your rules I see nothing stopping it. Another was in regard to the braking/gear change set up. I had concluded that all the photos I was looking at had the foot brake on the left and gear shift on the right which is a little unconventional, any reason? All ours (as far as I am aware) are the more standardised bike set up with gear sift on the left. Cant imagine it any other way, hell I still run road pattern on my solo for fear of getting confused between the road bike and race bike.

[Drew]

Brake goes on the left, so it's not in danger of another chair hitting it. At least, that's the only reason we swapped ours over.

Works too. I've folded the gear lever and had to spend the race doing some awkward shifts. Would have had to pull off if it were the brake pedal.

Takes fuck all to get used to, but I admit that I made a hash of it when trying to run it race pattern. So it's right side normal shift on the chair, left side normal shift on the road bike, and left side normal shift on a solo on the track.

[Pumba]

Well looks like I have learnt somthing today.

[Drew]

Cocked that up. Left side race shift for a solo on the track.

[nodrog]

Brake goes on the left, so it's not in danger of another chair hitting it. At least, that's the only reason we swapped ours over.

Works too. I've folded the gear lever and had to spend the race doing some awkward shifts. Would have had to pull off if it were the brake pedal.

Takes fuck all to get used to, but I admit that I made a hash of it when trying to run it race pattern. So it's right side normal shift on the chair, left side normal shift on the road bike, and left side normal shift on a solo on the track.

On a modern its also far easier to mount all the masters cylinders and plumbing inboard.

On a classic the poms always had their gear levers on the wrong side.

If running left foot brake its common to run standard road shift as if their was some foot retardation, pushing down with either foot will slow you down one way or the other.

[Danger Dave]

I run race shift on my chair, right foot change and push back to change up but then i'm slow and don't really know what i'm doing :wacko:

[jibberwobble]

I take it you've been on MMS forum and FB uk mini sidecars page?

Re centre hub steering..... No I dont think there has been any yet. I dont know why, I imagine it's just a case of no one's got round to it. The new Filf and Emms outfits both have single side fork on the front but thats about as far as anyone has gone. I think the thinking behind it is for quicker tyre changes mainly.

My personal view that it has more potential to be damaged in a incident and wont necessarily be any lighter. I guess the same could be said for centre hub depending on how it's designed. Havent got a clue what is better about centre hub TBH, is it that the suspension can be better set up or something? If so it wouldnt provide a major leap forward on machines that dont have suspension (our rules dont allow it). At a complete guess I was under the impression that the rules for minimoto, mini sidecars and possibly karting didnt allow suspension to keep costs and complexity down but who knows.

As for brake/gear change..... I was told that on full size rigs they put the brake on the left so that if you get hit hard from the right rear corner and your foot/leg gets broken you can still stop because your braking foot is safe. Again dont know if thats all there is to it but it's something I've heard along the way.

Please clarify: race bikes - push down to change up where as road bikes push down to change down? I knew straight away when I first tried out my outfit prior to mods for our first season that shifting was going to be an issue unless I took a run up and drop kicked the pedal, the only way I could shift at all was to wear steel toe cap work boots due to the pedal being modelled around an elephants leg. At the time it was set up to change up by pushing down, great on the going with the natural forces front but given that it's much easier to push the pedal down I binned the original pedal, made something my foot could use and set it up to work the other way round. I figured the only time I would need to be going rapidly through gears was on the down shift so stamping down in rapid secession seemed like it was worth a try. As far as I know all the others change up by pushing down which is how a race solo is..... correct?? Got used to it in no time although I dont ride proper bikes very often, had a go on a pitbike the other day and surprisingly for someone with such a small brain I didnt have any issues at all using the other foot for shifting.

As far as uk mini's go there has been some weird shit going on in the past. The old school outfits run front brake on right bar as per normal road bike, rear brake on left bar as per normal bicycle. Then come the comedy bit, the clutch is also on the left bar so you have two levers to choose from and no amount on finger dancing is gonna deal with them both at once which makes the rear brake fairly useless in most situations, mine came to me this way and I didnt use the rear brake once in anger all last season, in fact the only time I ever pulled that lever was to test if it worked once when I was coming out the holding area. The brake pads also end up caked in chain grease when you dont use then so the whole arrangement is pretty crap really. It would seem that the rear brake was only ever introduced to accommodate the 'must have' two separate braking systems regulation. Personally in the situation of brake fail on the front there is not much time to think and I reckon dumping it down through the box would be just as effective, this is what I've been using as a rear brake all along anyway. just using a small front caliper alone we've been stopping very well indeed with no major issues.

I think some folk have linked the front n rear calipers to the same lever on the right bar and used bias valve for adjustment. Then putting an additional tiny little minimoto mechanical caliper on the rear disc as the emergency brake knowing that it will never be used.

The rigs you see with foot brake seem mostly to do a similar thing to the above or have a second hydraulic caliper on the front disc attached to a conventional front right bar mounted lever as the emergency.

Tamzine's Black n orange (posh) outfit has the addition of a chair wheel brake.

On mine I've now gone the whole hog and have hooked up a brake pedal (left foot) to a second front disc, rear disc and introduced a chair wheel brake too. This is an experiment so the jury will be out for a while yet. I had to go for a second front disc because there wasnt enough room to get another caliper on the other side, the frame is very close on my rig. The original front brake that we have been doing all our stopping on will remain in place as the emergency brake and for instant bias control if more front is needed mid braking zone. For those who are thinking this is gonne be a disaster for quick tyre changes, I have a plan. Three front axles already set up with tyre and discs so it'll be just the spindle to pull out, swap the whole assembly n spindle back in, so thats one nut to undo verses the three wheel nuts the single sided boys are running. And yes I had to buy quite a few brake discs for this lot.

Will do pics of the brake setup as soon as its all bolted back together and a bit more finished.

Now I've bored the living shit out of you all I'll go climb back under my rock! :whistle:

[Drew]

On a modern its also far easier to mount all the masters cylinders and plumbing inboard.

On a classic the poms always had their gear levers on the wrong side.

If running left foot brake its common to run standard road shift as if their was some foot retardation, pushing down with either foot will slow you down one way or the other.
Was easier to mount the master cylinders on the right hand side when we first built the brakes. Only changed it because Ian didn't like it.

Race shift on the right foot is just hard work I found. G forces seemed to be working against me when turning, what seemed like every time.

[nodrog]

...... G forces seemed to be working against me when OVERturning, what seemed like every time.

yeah its was a tough couple of months bro.

[Drew]

yeah its was a tough couple of months bro.You got beaten up at school a lot eh?

[nodrog]

You got beaten up at school a lot eh?


https://www.youtube.com/watch?v=YoPVC4YxDlI&feature=kp

[Kickaha]

Was easier to mount the master cylinders on the right hand side when we first built the brakes. Only changed it because Ian didn't like it.


What didn't he like? there's nothing in the rules which says they have to be mounted on the left

We run road pattern

Like Noddyrog said, pushing back slows you down, easy to have both sides the same

[swarfie]

Race shift on the right foot is just hard work I found. G forces seemed to be working against me when turning, what seemed like every time.

Seems better to me to have race shift on a modern sidecar, as when accelerating it helps to change up when you're being forced backwards in the knee trays and forced forward when under braking. I loved riding Pinky with Jo at Taupo but struggled with the gear changes as its forward for up. But then I'm an OLD bastard with too many old injuries to contend with, like broken ankles, legs, knees and arses :(:crazy:

Having said that my shed is full of all sorts from Pommy to European to Japa and I've got them all one down and the rest up, whether they're left or right change...never seem to get them ffff..mucked either.

[nodrog]

...... I loved riding Pinky with Jo at Taupo but struggled with the gear changes as its forward for up. .....

The shift rod was too short for men's legs, I managed one lap in first gear. Couldn't change up due to foot being already bent all the way forward just to fit in the stirrup.

was a good lap though.

[swarfie]

The shift rod was too short for men's legs, I managed one lap in first gear. Couldn't change up due to foot being already bent all the way forward just to fit in the stirrup.

was a good lap though.

Yeah mate....but you're a bit stretched out on one end tho ;) I couldn't use the lever with my toes in the stirrup, had to lift my toes from behind the rear bar to in front of the front one to get it to change. Could hardly walk afterwards. :whistle:

[nodrog]

..... I couldn't use the lever with my toes in the stirrup, had to lift my toes from behind the rear bar to in front of the front one to get it to change. ....

See that's why you are the smart one, I was too busy marvelling at how good it handles.

[Drew]

What didn't he like? there's nothing in the rules which says they have to be mounted on the left

We run road pattern

Like Noddyrog said, pushing back slows you down, easy to have both sides the same

The master cylinder push rods went through a guide. The lever was mounted on the swing arm. So at any given time the main push rod might not be in a dead straight line.

Any concern he might have had, was proven unfounded on the same day when we rolled it and the bike pivoted around with all it's weight on the pedal. Bit of a twist in the lever, no further damage.

[Pumba]

I take it you've been on MMS forum and FB uk mini sidecars page?

More the forum, for a quiet forum there is some great info. Well more great pictures that give a great insight into what you guys are doing.


Re centre hub steering.....

Yea I have a few vague ideas. No idea if it would be any better given the application was more curious if it had been attempted as I had not seen any examples


As for brake/gear change.....

Well all the other big chair racers have given me a good insight on that issue.


Please clarify: race bikes - push down to change up where as road bikes push down to change down?

You have got it.


As far as uk mini's go there has been some weird shit going on in the past.

Yea sounds like there are some interesting things that have happened in the past; however the brakes cant be any worse than my current rig. Even with new pads and good feel on the leaver the front felt like it was never really biting. The disk and calliper are one of the awesome Honda inboard ventilated jobbies from a VTR250. I dont they worked when they were new let alone 25 years later. The rear is a drum that actually has good bite, but has to be backed off so far to not bind that I need a double jointed foot for it to work. Dodgy as really.Think I would be inclined to just go for a standard type brake set up, front brake operating the front and a rear foot break operating the rear. I am not sure a chair brake would be of any benifit, although if I do get a chance to build one from scratch an the money is available I may be inclined to put one on just because it would be easier to do then than try and reto fit later.


Will do pics of the brake setup as soon as its all bolted back together and a bit more finished.

I really do like photos. If you have any more around the rear axles and hubs that you guys use on the rear that would be great. Particularry the ones that use (what I presume is a) 17mm solid axle and how they are attached to the frame. Almost looks like the sit inside a cup with a bolt in to hold it in place.


Now I've bored the living shit out of you all I'll go climb back under my rock! :whistle:

I wont lie it was a long rant that took me a couple of attempts to read. But all good, keep sharing

[Drew]

Those inboard disks work fucken great. They're just heavy. Have you got the right size master for it.

As for the drum, make it cable operated. Should work mint when the swingarm isn't effecting the linkage rod.

[Pumba]

swingarm

:killingme:killingme:killingme:killingme:killingme :killingme:killingme:killingme:killingme:killingme :killingme:killingme

[Drew]

:killingme:killingme:killingme:killingme:killingme :killingme:killingme:killingme:killingme:killingme :killingme:killingme

Oh right. In that case I'd pick the lever ratio is wrong.

[Drew]

You guys realise that compliance equals traction right, suspension is a good thing.

[Henk]

:killingme:killingme:killingme:killingme:killingme :killingme:killingme:killingme:killingme:killingme :killingme:killingme

Hey, you have front suspension at least you flash bastard.

[Henk]

You guys realise that compliance equals traction right, suspension is a good thing.

When you have all of 13 horsepowers suspension is a load of unnecessary heavy.

[Pumba]

Hey, you have front suspension at least you flash bastard.

It was useful while it was attached.

[Drew]

When you have all of 13 horsepowers suspension is a load of unnecessary heavy.

I don't agree, but I understand the opinion.

[Henk]

I don't agree, but I understand the opinion.

Quite happy to argue the point over a beer on the weekend. Of course my argument is going to consist mainly of "piss off you're wrong"

[Drew]

"piss off you're wrong"Gonna be a fucken funny argument for onlookers then..."You dunno what you're on about".

[Henk]

Gonna be a fucken funny argument for onlookers then..."You dunno what you're on about".

We could place bets on when the interested onlookers get bored and walk away or we start hitting each other.

[Drew]

We could place bets on when the interested onlookers get bored and walk away or we start hitting each other.
It isn't worth a punch up. I'd bet three minutes before they realised it wasn't going anywhere.

[Henk]

It isn't worth a punch up. I'd bet three minutes before they realised it wasn't going anywhere.

You don't give them much credit for brains. I say a minute and a half.

[jibberwobble]

Well all the other big chair racers have given me a good insight on that issue.


I really do like photos. If you have any more around the rear axles and hubs that you guys use on the rear that would be great. Particularry the ones that use (what I presume is a) 17mm solid axle and how they are attached to the frame. Almost looks like the sit inside a cup with a bolt in to hold it in place.



I think I need to talk to more people that race big chairs too, there's a fair few areas I havent yet got a grasp on.

I'll have a dig for some pics of rear ends. I like the neatness of some of the axle arrangements but have not had a close inspection of any in the flesh. The other guys over here although helpful tend not to be very thorough with explanations and dont do much internet so it can be quite hard to get to the bottom of things at times and usually I end up going off and doing loads of research to make sure I know where I'm at.

[jibberwobble]

For the Guys on here that run big chairs:

What is your view on the usefulness of a chair wheel brake? The only time I've managed to have a chat with a team at a full size meeting they were of the opinion that it was a waste of time and was only there to cover the regs. Tamzine who's family are well known in big sidecars always ran a chair brake which makes me wonder as it contradicts what the other guys said. Also what sort of level of bias is common?

On big chairs how do you view the chair wheel in terms of tyre compound and pressure? On our rigs we run a hard tyre compound @ around 50 PSI, let it down to the same as the other two and it adds a second or two to a 1 minute lap time! Same on big stuff??????

[Drew]

For the Guys on here that run big chairs:

What is your view on the usefulness of a chair wheel brake? The only time I've managed to have a chat with a team at a full size meeting they were of the opinion that it was a waste of time and was only there to cover the regs. Tamzine who's family are well known in big sidecars always ran a chair brake which makes me wonder as it contradicts what the other guys said. Also what sort of level of bias is common?

On big chairs how do you view the chair wheel in terms of tyre compound and pressure? On our rigs we run a hard tyre compound @ around 50 PSI, let it down to the same as the other two and it adds a second or two to a 1 minute lap time! Same on big stuff??????

Chair wheel brake is important on ours for sure. If for nothing else but to set the slides up nicely into right handers.

Chair wheel gets the cast offs from the front. We run it between 15 and 19 psi depending on temp and track direction.

There's a cheat that people talk about, where you put suspension on the chair wheel, and a tie rod mounted on a downward angle. Suspension compresses, chair wheel tows in. Sidecar actually fucken turns right at last.

[Kickaha]

On big chairs how do you view the chair wheel in terms of tyre compound and pressure? On our rigs we run a hard tyre compound @ around 50 PSI, let it down to the same as the other two and it adds a second or two to a 1 minute lap time! Same on big stuff??????

Most people put any old rubbish on the side, at World Champ level they used to have a few different compounds and on right hand tracks considered it quite important to get it right

[Pumba]

...... On our rigs we run a hard tyre compound @ around 50 PSI, let it down to the same as the other two and it adds a second or two to a 1 minute lap time! Same on big stuff??????

Shit I dont know much about kart wheels. But that pressure sounds ridiculously high.

[Henk]

Kart wheels we run about 25 and that seems high on a cold day

[jibberwobble]

Thanks very useful indeed. We run 25 - 30 psi in front and rear but 50 ish on the chair with a hard as nails old tyre I've even run 60 on the chair which is the limit for the recommended operation written on the tyre. we once accidentally put 100psi in a front getting it to pop onto the bead :eek5: so I know 50 isnt going to be dangerous. karters are running them @ 8PSI.

Been told to adjust it forward with a touch of tow in) for twisty tracks and to the rear for bigger track with long straights. Which seems to be fair comment and kinda goes hand in hand with what Kickaha is saying. So basically it seems a good philosophy to get it as far out of the equation as pos unless you're chucking into a right hander.

Liking what Drew is saying about it helping set up the slide in rights. digging the front in to instigate a flick to the right and getting the rear sliding seems to work best for us and up until now it's all been on the front brake alone so good times ahead :2thumbsup

still got to do some more pics......

[jibberwobble]

I'm having a mare trying to get sodding links from online storage to here via my phone and cant find many showing anything more than the ones I've already put up so bare with.........

On a side note here's something else thats just turned up, GRC (Italy) make very good minimoto's but not sure if this is made by them or just has their stickers on it. GRC have shared it on FB though.

I know nothing about it at this stage.

https://scontent-b-lhr.xx.fbcdn.net/hphotos-xap1/t1.0-9/10405497_315621791936033_6050959580717159638_n.jpg

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xfp1/t1.0-9/10371728_315621985269347_6795625954763752411_n.jpg

[Pumba]

looks nice. Would be nice to see it with is clothes off.

Google translated the opening album comments as


After a strenuous work in the company of some crazy (like me) have completed the mini sidecar.

[wildman]

Shit I dont know much about kart wheels. But that pressure sounds ridiculously high.

I would agree with Pumba 50 psi seems a bit high. I know with my old gearbox kart running Dunlops or Bridgestones would run 15psi front and between 18-20 rear anything more and it would tend to make back end hop.
I think i got Brenton to run 15 psi in the front of his sidecar and 20 at rear but would have to check that with him. Over inflate a kart tyre and you loose grip real quickly , especially old compound ones.

[Gazzza]

Our way of setting pressure is to push on Rick and Henks rubber and get the same finger pressure to match, if it works for them it should work for us... I think we have gone really low a couple times, wouldn't mind betting we have gone close to single figures when I have no stick and am getting desperate. Thinkng about it I should have gone lower last weekend, the MG Red we had on the front just wasn't sticking like the old Vega's we had on before. We also run our chair wheel hard, 30-40 psi, haven't tried adjusting it, mind you maybe we could have a play and see if it makes any difference.

[Kickaha]

looks nice. Would be nice to see it with is clothes off.

RSR junior sidecar http://www.rsr-sidecar.de/junior/index.php


I would agree with Pumba 50 psi seems a bit high. I know with my old gearbox kart running Dunlops or Bridgestones would run 15psi front and between 18-20 rear anything more and it would tend to make back end hop.
I think i got Brenton to run 15 psi in the front of his sidecar and 20 at rear but would have to check that with him. Over inflate a kart tyre and you loose grip real quickly , especially old compound ones.

Running a 250 Superkart I didn't run more then 12 front 14-16 rear, sidecar and two fat bastards would weigh a bit more though

We'd normally run 12psi in the side on the F1 and the only time I run a higher pressure in the side is if I want it to slide more as I turn into rights

[Pumba]

RSR junior sidecar http://www.rsr-sidecar.de/junior/index.php

Yep fair call, same body work.

[Kickaha]

Yep fair call, same body work.

GRC one looks smaller to me although could just be the guys riding it are bigger

[Pumba]

GRC one looks smaller to me although could just be the guys riding it are bigger

No I am pretty sure it is at the very least the same RSR bodywork. Just camera angles and rider sizes playing tricks with the scale.

[Skunk]

Wasn't Speedpros chair a centre hub?


If it ain't smokin' - it's broken.

[Kickaha]

Wasn't Speedpros chair a centre hub?.

Pretty sure it was, rear engined and water cooled

[wildman]

Wasn't Speedpros chair a centre hub?


If it ain't smokin' - it's broken.

Yep still is, just got to stop killing engines in it. It's sitting in the naughty corner at the moment while i build up a new sidecar. Might bring it out again next year with a four stroke in it.

[Pumba]

Wasn't Speedpros chair a centre hub?

Yep

https://www.flickr.com/photos/sonscc/13121231963/in/set-72157642282552865/

https://www.flickr.com/photos/sonscc/13121408414/in/set-72157642282552865/ - I can never figure out embedded images from outside sources


Pretty sure it was, rear engined and water cooled

Yep and yep

[Skunk]

Yep still is, just got to stop killing engines in it. It's sitting in the naughty corner at the moment while i build up a new sidecar. Might bring it out again next year with a four stroke in it.

If I had money I'd buy it (if it was for sale at the time). Always wanted that one...


If it ain't smokin' - it's broken.

[Gazzza]

Any one know when Chris and Richie are back? Would be good to see their rigs back at the track.

[wildman]

If I had money I'd buy it (if it was for sale at the time). Always wanted that one...


If it ain't smokin' - it's broken.

Was thinking about selling it as havn't had much luck with it. But decided i'd probably regret it, so have parked it up for now.

[jibberwobble]

I would agree with Pumba 50 psi seems a bit high. I know with my old gearbox kart running Dunlops or Bridgestones would run 15psi front and between 18-20 rear anything more and it would tend to make back end hop.
I think i got Brenton to run 15 psi in the front of his sidecar and 20 at rear but would have to check that with him. Over inflate a kart tyre and you loose grip real quickly , especially old compound ones.

Well it's only the chair wheel that gets that pressure and I think the name of the game on these little things IS to reduce grip on the chair wheel as it goes. It must just average out better to be faster on the straights and pay a small penalty somewhere else. Either way when ever we have an unexplained slow session it's generally because the chair wheel went a bit flat or we didnt check it. dropping to 20psi really does add over a second on our units.

As you say Kickaha at over 250kg's all up we are putting a lot more load on less tyre than a karter so running the same pressures as them isnt going to work out the same. Our tyres are proper puddings if we run them @15 and the brake disc sees as much tarmac as the tyre. with the minimoto's I just give em a poke with my finger but I find it a bit harder to tell on the 7-8 inch wide slicks. Our setups must work a little different, even with the rear at 30 it never hops or skips just spins up a bit sooner, nearer 25 is favored mostly on front n rear

[jibberwobble]

I forgot about that RSR rig, seen it ages ago on the Steve English sidecar site, sure it was a fair few grand which kinda makes it a non starter when you could buy a 2nd hand F2 for similar.

Yeah GRC one's got to be copied from the RSR one hasnt it, its so damn similar from the left but from the right it looks like a small land speed car with it's longer back end and the little wheel poking out the back.

http://www.rsr-sidecar.de/images/rsr-junior3_lbb.jpg

Liking the back of the GRC better on the wheel cut out front

https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-xfp1/t1.0-9/10402642_309077985923747_392498592904268222_n.jpg

Now got a photo of the GRC naked but brace for disappointment..... it's only got a 40cc polini water cooled minimoto engine in it (around 9 - 10 hp 4.5ft/lb torque usually) so must struggle to even pull away. Those minimoto engines only have tiny little centrifugal clutch, on a 12+hp 50cc super (open class minimoto) that same clutch is fairly near the limit with one adult and a 25kg bike!!!

https://scontent-b-lhr.xx.fbcdn.net/hphotos-xpa1/t1.0-9/10485030_317120488452830_1264408551819835073_n.jpg

[Pumba]

Now got a photo of the GRC naked but brace for disappointment.....

Well if it is not a modified RSR then it is a copy as even with the limited photo angle the look very simular

http://www.rsr-sidecar.de/images/rsr-junior1_lbs.jpg

[jibberwobble]

Yes agreed, it's remarkably similar in most respects. Must be scaled down a touch though.

[wildman]

Here's some photos of the hub steering bucket sidecar

[jibberwobble]

I like the centre hub steering. Great photos, can't fully work out how the steering works there though. The brakes are neatly tucked away in there ain't they!

It all looks quite strong though.

[swarfie]

Here's some photos of the hub steering bucket sidecar

All very cool but I can't help thinking someone has lost the plot a bit. Haven't you guys heard that 3kg is a HP? How on earth you expect a little engine to drag all that ironmongery around at speed is beyond me ( and then you have to stop it too! ). My home built "Matchless" engine probably doesn't make THAT much more horsepower than my competitors hotted up Triumph and Norton engines, but the whole plot is a HEAP lighter than all the extra shit their old bangers have to drag around...it's all about power to weight ratio. Make them light and they will go:msn-wink:

[Skunk]

I like the centre hub steering. Great photos, can't fully work out how the steering works there though. The brakes are neatly tucked away in there ain't they!

It all looks quite strong though.

Full floating disc. Not sure if you can see it properly. The disc is held in place by lugs. Remove the wheel and the disc comes out.


If it ain't smokin' - it's broken.

[Skunk]

All very cool but I can't help thinking someone has lost the plot a bit. Haven't you guys heard that 3kg is a HP? How on earth you expect a little engine to drag all that ironmongery around at speed is beyond me ( and then you have to stop it too! ). My home built "Matchless" engine probably doesn't make THAT much more horsepower than my competitors hotted up Triumph and Norton engines, but the whole plot is a HEAP lighter than all the extra shit their old bangers have to drag around...it's all about power to weight ratio. Make them light and they will go:msn-wink:

Talent built it. It was a top chair. Weight or not.


If it ain't smokin' - it's broken.

[Pumba]

Full floating disc. Not sure if you can see it properly. The disc is held in place by lugs. Remove the wheel and the disc comes out.


If it ain't smokin' - it's broken.

VTR250 inboard jobbie same as on mine

[Skunk]

VTR250 inboard jobbie same as on mine

I had been told but couldn't remember. You should build a centre hub steer rig.


If it ain't smokin' - it's broken.

[Pumba]

I had been told but couldn't remember. You should build a centre hub steer rig.


If it ain't smokin' - it's broken.

That is my plan. And I will start when some steel, wheels, hubs, oh and a pipe bender falls off the back of a truck:weep:

[Skunk]

You and me both.


If it ain't smokin' - it's broken.

[jibberwobble]

All very cool but I can't help thinking someone has lost the plot a bit. Haven't you guys heard that 3kg is a HP? How on earth you expect a little engine to drag all that ironmongery around at speed is beyond me ( and then you have to stop it too! ). My home built "Matchless" engine probably doesn't make THAT much more horsepower than my competitors hotted up Triumph and Norton engines, but the whole plot is a HEAP lighter than all the extra shit their old bangers have to drag around...it's all about power to weight ratio. Make them light and they will go:msn-wink:

I agree with the concept that weight is very bad. Having said that my outfit when last together was weighing in at 110kgs and 270kg's all up with the idiots on board so that gives us -70hp going on the 3kg per hp theory.

[swarfie]

I agree with the concept that weight is very bad. Having said that my outfit when last together was weighing in at 110kgs and 270kg's all up with the idiots on board so that gives us -70hp going on the 3kg per hp theory.

I actually meant that if you remove 3kg off your machine, it is the equivalent of gaining one horsepower. :rolleyes:

[wildman]

I actually meant that if you remove 3kg off your machine, it is the equivalent of gaining one horsepower. :rolleyes:

While the hub centre bucket sidecar looks heavy the framing is very small funiture tube and when it;s set right it does fly or it did with the watercooled mb engine. the weight of passenger also doesn't affect the handling like on the go-kart derived ones [ i know because i've run them both and weigh 115 kg :facepalm:] It's also survived 24 years of abuse considering it was built in 1990:banana::banana:

[Rick 52]

Well it's one strange thing to drive and swing on !
Fitting the FXR motor was much trickier than I thought it might be but after many hours and Henk driving two hours a day to my place to help every weekend and lots of tea and biscuits we sorted it and got it to run properly,
a trip down the driveway made us a little concerned, it would not turn !
At the track on the Saturday first few laps confirmed it needed lots of work to make it handle anything like as well as the old rig, the front shock was so soft that when driving hard the front was very vague and braking it bottomed out and swerved across the track, Henk had a great idea to pre load the spring and srap the coils together with thick cable ties, this made a huge difference .

The race day was dry and that was a big relief as even damp patches made the rig uncontrollable, big difference than the old rig, that loved the wet !
After qualifying we were both worn out, it's so physical to drive and swing on, Brenton qualified on pole but we were not far of his pace.

Our start was a cracker and we led the race, we have a little more power but lost lots of ground around the horse shoe, even sliding in sidways the rig will not turn right under power, even with Henk as far upfront working his arse off with bruises to show for it, over driving the rig we had a massive slide and Brenton passed us only to have a big crash himself, glad to see you both ok !

Two very lucky wins from its first outing as a diesel but not happy! We have a new wide rear 10"slick and rim to go in, we have fitted a Kart wheel to the chair 180mm further back with adjustable front to back and toe in, we have moved the tank and given Henk more room to swing forward, The front spring has been changed for a much stiffer one .

Let's hope this makes a big difference and we can enjoy rather than being scarred of pushing the rig.
On a much more positive note, we have enjoyed working on the rig and a lot more confident to make it much much better, big thanks to Henk for all the hard work :Punk:

I think knocking 1second off the lap record in either direction before the end of the year!
Come on fellas get in your sheds and get building ..

[Kickaha]

Two very lucky wins from its first outing as a diesel but not happy! We have a new wide rear 10"slick and rim to go in, we have fitted a Kart wheel to the chair 180mm further back with adjustable front to back and toe in, we have moved the tank and given Henk more room to swing forward, The front spring has been changed for a much stiffer one .
Not sure how you'd scale it down from the full size Long Sidecars but they normally run around 3mm toe in measured over a metre on the sidewheel

You can change the front to rear weight bias by moving the chair wheel forwards or backwards

Front suspension is normally much softer than the rear and rear ride height is about 10mm higher than the front

Chair wheel runs slightly negative camber and rear drive wheel slightly positive

http://www.steveenglish.com/forum/download/file.php?id=3506&mode=view/G-Chassis-1.JPG
http://www.steveenglish.com/forum/download/file.php?id=3507&mode=view/G-Chassis-2.JPG
http://www.steveenglish.com/forum/download/file.php?id=3508&mode=view/G-Chassis-3.JPG

[mr bucketracer]

when i had a go at the gp apart from the crazy gear change witch i could never get used to , it steard way to fast for my liking but something you would get used to , felt like the front wheel would turn 90 deg if you did not hold on to it

[Drew]

Having seen photos of the hubcenter chair in action, no amount of set up is going to fix it till there's some lateral rigidity up front. If it isn't twisting the way it looks to be, someone has set the castor up backwards and it cambers the wrong way when you turn.

[Drew]

Oh yeah. Putting a bigger and better drive tyre on it will compound the steering deficiencies, rather than improve them.

[Kickaha]

someone has set the castor up backwards and it cambers the wrong way when you turn.
Which would go along with the below quote, although looking at the pic it looks like the whole front is twisting sideways


when i had a go at the gp apart from the crazy gear change witch i could never get used to , it steard way to fast for my liking but something you would get used to , felt like the front wheel would turn 90 deg if you did not hold on to it

[Drew]

Which would go along with the below quote, although looking at the pic it looks like the whole front is twisting sidewaysIt would have to have so much castor to get the angle seen in the pics, that you couldn't turn the bars without doing six months of arm work at the gym. So I think your second quote refers to a different bike or set up. Lots of castor gives heavy steering, not light/twitchy.

Pretty sure the front end is flexing. How the gantry is mounted is not clear in the pic though, so no idea where it's happening.

[Kickaha]

It would have to have so much castor to get the angle seen in the pics, that you couldn't turn the bars without doing six months of arm work at the gym. So I think your second quote refers to a different bike or set up. Lots of castor gives heavy steering, not light/twitchy.

Pretty sure the front end is flexing. How the gantry is mounted is not clear in the pic though, so no idea where it's happening.

I don't believe the castor it is running has much to do with the camber angle it is getting as the wheel still looks to be at 90 degree to the front suspension arms, I notice it doesn't have the vertical bar on the front cross link that we run, when Dave fitted it he said it made the front feel more rigid

[Moooools]

It would have to have so much castor to get the angle seen in the pics, that you couldn't turn the bars without doing six months of arm work at the gym. So I think your second quote refers to a different bike or set up. Lots of castor gives heavy steering, not light/twitchy.

Pretty sure the front end is flexing. How the gantry is mounted is not clear in the pic though, so no idea where it's happening.

From a quick 'nudge it with the knee' test at the track, it is definitely flexing. It would also explain the flicking to one side problem mentioned.

The wheel, when turned creates a friction force that is 90 degrees to the tyre. Because the wheel is not pointed straight ahead, some of this acts longitudinally. When the contact patch deviates away from the king pin axis along with this longitudinal force. You are left with a force and a lever arm, which creates a torque, that wants to turn the bars in the direction you are already trying to push them. The system is now unstable and so wants to pull the whole way to 90 degrees steering angle.

[Gazzza]

Hmmmm Rick taking a second off the lap record either way will take some doing, but could it be we are headed for the first sub 34 second sidecar lap. I'm not sure what we have up our sleeves re getting quicker times, I was tinkering with a leading link front end but it started to weigh in pretty heavy and I wasn't too sure it would have any benifit, I think just working out the best combination of riding and swinging is our best bet to lop off a bit of time.

I have a question that maybe Drew or Kichaha may have some ideas on... Say I was looking at a new build but was say limited to engine (my Loncin 150) and a hub front end was just a wee bit beyond my engineering what would you think would be the best sort of approach to take. Would you go kart rims and tires or 10 inch rims, conventional front end or maybe leading link? The other thing is short or long rig, bearing in mind Mt Wellington would be the track it spends most of its time, any ideas/advice much appreciated.

[Rick 52]

Hmmmm Rick taking a second off the lap record either way will take some doing, but could it be we are headed for the first sub 34 second sidecar lap. I'm not sure what we have up our sleeves re getting quicker times, I was tinkering with a leading link front end but it started to weigh in pretty heavy and I wasn't too sure it would have any benifit, I think just working out the best combination of riding and swinging is our best bet to lop off a bit of time.

I have a question that maybe Drew or Kichaha may have some ideas on... Say I was looking at a new build but was say limited to engine (my Loncin 150) and a hub front end was just a wee bit beyond my engineering what would you think would be the best sort of approach to take. Would you go kart rims and tires or 10 inch rims, conventional front end or maybe leading link? The other thing is short or long rig, bearing in mind Mt Wellington would be the track it spends most of its time, any ideas/advice much appreciated.

Kart wheels are the way forward and sub 34sec is on the cards, the front end is not twitchy or hard to turn, the under steer problem was the chair wheel toeing out 10mm over 1200mm and being way to far forward, the driveway test feels much better already, having the wide slick on the back will push the front again so we need a new front tyre to cope.
Moools knee test did reveal a little more stiffness is needed in the front end but if it steers rather than scrubbing it might not be needed !

[Kickaha]

I have a question that maybe Drew or Kichaha may have some ideas on... Say I was looking at a new build but was say limited to engine (my Loncin 150) and a hub front end was just a wee bit beyond my engineering what would you think would be the best sort of approach to take. Would you go kart rims and tires or 10 inch rims, conventional front end or maybe leading link? The other thing is short or long rig, bearing in mind Mt Wellington would be the track it spends most of its time, any ideas/advice much appreciated.
Haven't ever had anything to do with Bucket sidecars, but I'd be using Kart wheels and wouldn't bother with suspension on the rear anyway, undecided if I would on the front but would probably do leading link for ease of manufacture if I did and front engine

Most of how fast an outfit goes just comes down to the crew riding it

[Pumba]

So I have been thinking about this for a little while. My chair insist getting any use and it might still be a bit before I do get to use t on a consistent basis and I know you guys are struggling for numbers in Auckland. So is there anyone out there that want to buy my rig?

Comes less an engine, but is plumbed and ready for an FXR. The front end has been tacked back on, but still requires dome reinforcement.

Just an idea if anyone is interested let me know.

Oh and on another note, picked these up the other day

307222

[racer40]

how much i know someone who may buy it

[Pumba]

how much i know someone who may buy it

Hey Chris, Warren sent me a PM first so we will see how that goes. I was thinking around the $300 mark price wise.

[wildman]

Okay so after watching the bucket sidecars running at Mt Welly on saturday and chatting with people it looks like the Battle Truck will be back in action for the GP in March. new old front end is back on and chassis is under going some weight reduction [ nearly as heavy as the Agip bike ] will post some pictures in a week or so when chassis is finished. And it looks like Pumba is going to have another go at taking out the GP on it so watch out Rich and Henk:banana::banana: