The Fingertight Racing Sidecar Project

[koba]

Inches, the obsolete imperial measurement you are looking for is inches.

It's not like I was a mile out.

[wildman]

Koba what do you reckon. Does the flex make the handling less harsh?

Problem with it all is that the top cap is binding on the steering tube before the top bearing is seated in place. I thought it was ok when I first put it all together, but it is now pretty obvious I was wrong.

Given I got the front end in pieces with all the bearings in an ice cream container I gave it my best shot. I will admit that there were some bits left over at the end, so tell what I should be trying next.

This is the way I had it together.

Attachment 294120

Here is a close up

Attachment 294121

In my bin of left over parts there was this seal

Attachment 294122

Which could go like this

Attachment 294123

Or there is this one

Attachment 294124

Which looks a bit like this

Attachment 294125

Opinions please, am I missing something else?

I guess the other option is to make up a spacer.

Sorry Carl should of taken photos for you before we pulled it apart and can't be sure we got all the bearings that fell out. But look on the bright side, we only cut through one bar before we realized how to make it fit in van, [note to self alcohol and good ideas don't always go together ]

[Pumba]

All good Warren. Maybe I should get drunk and reassemble it? Yea that can only end well.....

[Drew]

Is this the one that failed on you Drew

So your set up now is solid top and bottom with a pin as the steering steam (haven't been up close to any modern chairs while I was really interested in paying attention to the set up)

Yip, that bit of 12mm plate across the top is quite S shaped now. It would flex so much while riding, that the big arse nut on the top used to undo itself.

We built it that way so we could use taper roller bearings. Everyone else just runs deep grove ball bearings, but I thought I knew better...I was wrong.

It's replaced now with a piece of fixed steel plate, and the pin goes down through it and secures with a big nut on the bottom. We made it about 1mm bigger between the plates, than the outside measurement from bearing to bearing. Then just shimmed it to make it snug. Works pretty well, and is easy enough to replace bearings on. Only thing I'd like to do different, is locate the shims in some way to save a little pissing around. It's not that important though, it's not overly hard to do.

[Pumba]

.....We built it that way so we could use taper roller bearings.......

Interesting as that was my plan as. I have a triple tree and steering steem here that I was going to graft on. May have to rethink it, although I suspect that the forces that we are aciveing with our chairs is a little different to the full sizejobs

[Drew]

Interesting as that was my plan as. I have a triple tree and steering steem here that I was going to graft on. May have to rethink it, although I suspect that the forces that we are aciveing with our chairs is a little different to the full sizejobs

Fixed fork, swingarm front end is the only way to go. Pair of nice soft shocks, and brakes mounted on a torque arm rather than the swingarm.

This is the system that all other than hub center steering outfits have...and Windle short chairs are still made this way.

It's not even that much work to make from scratch. I've done it twice now.

[Pumba]

Cheers Drew. Will have to look into it a bit harder in a few weeks, when I can pull it all to bit again and do some measuring.

For now I can say I have the front end back together. Hope fully it stays that way, but I know what to keep an eye on now.

Now a few will know the carb issues I had over a few meetings (basically it feel off and had a huge hole in the mid range jetting). I don't have the cash to buy a new OKO so I have borrowed the carb off my FXR with he theory being I can swap it over Saturday night to run the bike on the Sunday. I am going to add into the fuel line a primer bulb which should make the bike a bit easier to start.

Once I get it running on the weekend it should be all ready to go for the GP.

[Pumba]

Right mental note to ones self, tighten banjo bolts before trying to bleed brakes.

Chair is pretty much all back together and ready to rock. Might even get time to put a number or two on it before the weekend.

[Pumba]

Well what an eventful event! Figured I shall record it here with a race report.

Arrived at the track Friday night and was introduced to Ieda who was jumping on to swing. All good we start looking over the Battletruck (as it has now been christened), the comments are interesting to say the least.

Saturday morning rolls round and I am feeling pretty good. After a few tweaks to replace a panel that was left on the bench at home and cleaning up a few odds and ends we are all go for practise one/qualifing.

P1/Qual

Well it was pretty loose. I think Ieda was strugling to figure out how to move in the limited room available, and where the handholds were. Add to that the new rear tyre that was taking a bit to scrub in. Oh and then was the small off track excursion when coming out of the bottom of the hill the left hand clip on moved as I loaded it up.

Managed to put a 58sec lap on the board. Good enough for second on the grid but a long way of the 52sec? of Rick and Henk, so we had some work to do.

P2

Another quick practise was called right before the GP. This was great as it gave me a chance to drop the rear tyre pressures and Ieda and I to have a chat over what was working and what wasn't. We only had about 3-5 laps and come back in actually thinking we were down a bit on speed but felt smoother on track. Well we did something right as we knocked another 2 sec off our qualifying time.

Race

Decided it was worth dropping the pressure in the rear another couple. I knew I had to nail the start because if Rick and Henk got away I didn't think we were going to catch them.

Flag dropped and I nailed it.

Felt I had out driven Rick and Henk off the line, as soon as I lost sight of the front wheel in my vision I made the move to shut the door on them before turn one; and HOLLY SHIT!!!! IT WORKED!!!!! WE WERE IN FRONT!!!!!

I just put my head down from this point on and gave it all I could. I was aware the Henk and Rick wouldn't be giving up without a fight, but was a bit surprised when I took a glance driving up the hill and saw the blue and pink of the Lawrence rig trying to stick its nose up the inside. He was not going to gain on that line so just continued to put my head down.

Then disaster struck. Lap 5? coming out of the hairpin I suddenly had no drive? Thrown chain!! FUCK!! In hindsight this probably was the fist sign that things were going wrong as it was quite easy to run back on.

Anyway we got the chain on and set about salvaging something from the race.

It was only a lap or so later that I noticed that the front wheel wasn't quite sitting right. First though was something had loosened off in the steering head again. Didn't seem to be slowing us down so I pushed on, we had places to make up!

Couple of laps later it was getting worse, but still wasn't affecting the handling to badly, so we pushed on.

A few laps after that I was really aware that something was not right (by this stage so was Ieda). Things were starting to get very loose up front. I really should have stopped but I was dead set on finishing.

Well we got 2 laps from the end and it finally gave up the ghost as the front end completely collapsed. Fortunately it was on the straight, slamming the frame into the track and sending us sliding off into the grass on the side of the track, coming to a stop about as close as I would want to get to the wall.

Race well and truly over



So Drew, in recommendations and the solution to this horrible looking mess?

[Drew]

That's a mighty effort!

Heavier box section would be the easy fix. If you do go to a swingarm front end though, the headstock can be made much stronger just by not being so far out.

I would have thought the forks would bend before the frame snapped though.

[Moooools]

Well we got 2 laps from the end and it finally gave up the ghost as the front end completely collapsed. Fortunately it was on the straight, slamming the frame into the track and sending us sliding off into the grass on the side of the track, coming to a stop about as close as I would want to get to the wall.

Race well and truly over



So Drew, in recommendations and the solution to this horrible looking mess?

That is just a classic failure. Very high stiffness section (welded in steel panels) meets very low stiffness section. It causes huge stresses on the unstiff section causing it to fatigue.

one solution could be to cut out the steel shear plate and replace it with a single piece of RHS on each side to triangulate it. It will be locally less stiff, because springs (and yes your frame is a spring) in series are mostly driven by the least stiff spring (in this case being the rest of the rig), the overall stiffness of the rig should barely change.

Or just more steel. That also works.

Also I currently have no tyres for you, as we left our worst set in Aus. But we have an engine again, so as soon as we have burnt up this set a bit I will let you know.

[Bert]

Funny things get recorded when you leave your camera lying around.

Here's Carl telling the story...

[Pumba]

Funny things get recorded when you leave your camera lying around.

Here's Carl telling the story...

Bloody hell! Secret squirl recordings, next thing I know the GCSB will be knocking on the door! (at which point I will ask what thier welding skills are like).

[NinjaNanna]

Funny things get recorded when you leave your camera lying around.

Here's Carl telling the story...

@Pumba

looks like you've been having fun though mate

[koba]

That is quite scary!

Thanks though, couldn't have got with your rig still going!