Dirt bike tower thingy

[pete-blen]

I needed a way of getting the dirt bikes around..
No room for a trailer & the cars not big enough for
a bike rack across the back...
So I put this togeather at work...
The only real pain is takeing the chain off/on the bike..
there will be 4 tie downs & 2 wheel straps to hold it in..
The pull is on the wheel as it fits down in the frame...

http://imageshack.us/a/img24/390/9xr3.jpg

http://imageshack.us/a/img35/4828/yzp1.jpg

http://imageshack.us/a/img713/6909/6ki0.jpg

It just plugs into the fitting bolted to the tow bar with 2
1" bars with 10mm cross pins to hold it in... 1min to put
it on/off...
http://imageshack.us/a/img809/9442/nzr9.jpg

[Gremlin]

Surely rear tyre wear is fast enough already? Guess it depends how far you need to move it.

Have you ever considered a slightly heavier BMW GS adventure bike? It's road legal, so you can ride on the road too. :laugh:

[fridayflash]

pretty trick bit of engineering there :cool:
ya reckon itd be no good running the chain on it..as in spinning the counter shaft?

[scott411]

i can't imagine thats wonderful on the gearbox either, having it spinning that quick behind a car, tyre wear would have to be an issue as well, knobblys dont like tarseal

[pete-blen]

Surely rear tyre wear is fast enough already? Guess it depends how far you need to move it.

Have you ever considered a slightly heavier BMW GS adventure bike? It's road legal, so you can ride on the road too. :laugh:

Was waiting for the tyre wear comments..... :nya:
Now here's how I veiw the tyre wear issue...
Rideing the bike under it's own power would wear more rubber than towing it with out any drive force
or rider weight on the tyre... ..... They are Dot rated tyres as the bike has rego & wof...



pretty trick bit of engineering there :cool:
ya reckon itd be no good running the chain on it..as in spinning the counter shaft?

I wouldn't like to try... the chain slack would also be on the top instead of the bottom..

[haydes55]

..... They are Dot rated tyres as the bike has rego & wof...


That was going to be my question, being basically a trailer in the eyes of the law, this could only be done with a WOF'd bike.

[Jay GTI]

Was waiting for the tyre wear comments..... :nya:
Now here's how I veiw the tyre wear issue...
Rideing the bike under it's own power would wear more rubber than towing it with out any drive force
or rider weight on the tyre...



But the tyre would also be put under quite a different load than it is designed for. When cornering at speed, there will be a lot more lateral load and as the bike will be upright, it's not going to put the same forces on the tyre as a leaned over bike being held at constant throttle. Not saying it's going to suddenly start lurching sideways and tearing knobs off the tyre, but it won't be the load you'd imagine just because there's no drive or weight on it.

[pete-blen]

But the tyre would also be put under quite a different load than it is designed for. When cornering at speed, there will be a lot more lateral load and as the bike will be upright, it's not going to put the same forces on the tyre as a leaned over bike being held at constant throttle. Not saying it's going to suddenly start lurching sideways and tearing knobs off the tyre, but it won't be the load you'd imagine just because there's no drive or weight on it.



I think you are grasping at straws a bit here...
But the real good thing is..they haven't stoped makeing tyres..

[Motu]

There will some forces acting on it for sure. Many years ago (mid '70's) we tried to tow a husky behind a Mini - first we put the front wheel in the boot, then took the front wheel off and tried with just the forks. But no matter how tight we wrenched it down, soon as we turned a corner the bike fell over....we ended up taking the wheels off and the seats out of the Mini and putting it in the back. That won't happen with this rack because the bike is being held tight, but those forces will still be there twisting the bike where it was never designed to be twisted.

[pete-blen]

There will some forces acting on it for sure. Many years ago (mid '70's) we tried to tow a husky behind a Mini - first we put the front wheel in the boot, then took the front wheel off and tried with just the forks. But no matter how tight we wrenched it down, soon as we turned a corner the bike fell over....we ended up taking the wheels off and the seats out of the Mini and putting it in the back. That won't happen with this rack because the bike is being held tight, but those forces will still be there twisting the bike where it was never designed to be twisted.


I realize there are forces at play...
I couldn't design them all out...
If yer look at it you will see the up/down pivot point of the front axle
& tie down lower mounts are in line.. to stop the tie downs wanting to change
length / forks compressing , exspanding as the bike moves up/down

It would be possable to make the bike lean into the corners...
muliply the body roll of the car in the oppisite direction..
But really how complex do yer go ?

[DrunkenMistake]

http://i.imgur.com/Cv84T9I.jpg


My mate recently went to a big ride with his bike and car..

[BMWST?]

I like the other idea better,exhaust fumes will come in the car

Sent from my ST27a using Tapatalk 2

[Jay GTI]

I think you are grasping at straws a bit here...
But the real good thing is..they haven't stoped makeing tyres..

No grasping at straws, just trying to explain the laws of physics, which you seem oblivious to.

[pete-blen]

No grasping at straws, just trying to explain the laws of physics, which you seem oblivious to.

nice come back..:lol:

[Jay GTI]

nice come back..:lol:

Interesting, you seem to think I'm having a go at you.

[bogan]

I realize there are forces at play...
I couldn't design them all out...
If yer look at it you will see the up/down pivot point of the front axle
& tie down lower mounts are in line.. to stop the tie downs wanting to change
length / forks compressing , exspanding as the bike moves up/down

It would be possable to make the bike lean into the corners...
muliply the body roll of the car in the oppisite direction..
But really how complex do yer go ?

Interesting invention you got there!

I reckon a bike designed for all the knarl of off road and hill traversing lateral forces and the like, will have no issues holding itself together through the rigors of a Hyundai Lantra's cornering ability :laugh:

Was just thinking if tyre wear did become an issue, you could get a rim and just swap it out for travel, I mean you have to unclip the chain anyway...

[nallac]

Was just thinking if tyre wear did become an issue, you could get a rim and just swap it out for travel, I mean you have to unclip the chain anyway...


if ya had to go to all that bother a trailer would be a hell of a lot easier.

[bogan]

if ya had to go to all that bother a trailer would be a hell of a lot easier.

So would a van, but there's a lot of enjoyment in the doing of such things.

[nallac]

So would a van, but there's a lot of enjoyment in the doing of such things.

Building traliers is fun too, have built two bike trailers myself... a while ago now tho.

[Blagger]

OP - you might want to blur your numberplate - some scrotes trace plates back to houses and nick bikes

And yes I know that the bike is in a lockup - just sayin'


Nicely made unit by the look of things, easier on the towbar than the "across the back" type.

[nzspokes]

My concern with this is there is no pivot point for the back of the bike. Yes there is the head bearings but that is at an angle.

[gwynfryn]

My concern with this is there is no pivot point for the back of the bike. Yes there is the head bearings but that is at an angle.

Now that could be a problem.

[Gremlin]

Crazy suggestion I know, but have you considered of them there 4 wheeled vehicles with a big flat area on the back? No trailer required? :lol:

http://i210.photobucket.com/albums/bb236/_Gremlin/th_20130221_114820_zps2f8d3511.jpg (http://s210.photobucket.com/user/_Gremlin/media/20130221_114820_zps2f8d3511.jpg.html)

[pete-blen]

My concern with this is there is no pivot point for the back of the bike. Yes there is the head bearings but that is at an angle.


Now that could be a problem.

It would be if the forks were locked ridged... but they can pivot foward & arft
at the axle.. yer can pick the rear of the bike up it will pivot at a line though
the axle..tie downs fix on the same line so they can pivot aswell..
in fact what it dose do is give a castering effect... the bike always wants
to be directly in line with the car.. dueing most normal driveing the rear wheel will
only ever be a few degrees off straight in line with the car...
I have done tight 180* turns around the storage units where it's kept.. no issues.


anyways time will tell... I will know on sunday as I maybe useing it...

[FlangMasterJ]

I'm more interested in the two-tone seat. Who sells those?

[fridayflash]

I'm more interested in the two-tone seat. Who sells those?

the 'ring of fire' curry house may be able to help there...

[barty5]

Interesting I'm living in the states at the moment and you can buy this very idea of the shelf.

http://www.ebay.com/itm/Motorcycle-trailer-carrier-tow-dolly-hauler-hitch-rack-/130989186457?pt=Motorcycles_Parts_Accessories&hash=item1e7f905d99&vxp=mtr

Tow bars here are all the square box insert type so easily removed you can also get the more common rack that has the bike across the vehicle as a double cheap too.

http://www.ebay.com/itm/DUAL-MOTORCYCLE-CARRIER-RACK-RAMP-TRAILER-HITCH-HAULER-/200953184795?pt=Motorcycles_Parts_Accessories&hash=item2ec9be421b&vxp=mtr

[Buddy L]

The lazy man's jump starter? for people that just can be bothered? Or the smart.

[gwynfryn]

It would be if the forks were locked ridged... but they can pivot foward & arft
at the axle.. yer can pick the rear of the bike up it will pivot at a line though
the axle..tie downs fix on the same line so they can pivot aswell..
in fact what it dose do is give a castering effect... the bike always wants
to be directly in line with the car.. dueing most normal driveing the rear wheel will
only ever be a few degrees off straight in line with the car...
I have done tight 180* turns around the storage units where it's kept.. no issues.


anyways time will tell... I will know on sunday as I maybe useing it...

I didn't realise that. Should all work ok then, will the back of the bike jump around (off the ground) a bit?
Looks well made good on you, have you tried it with a passenger lol.

[gwynfryn]

Interesting I'm living in the states at the moment and you can buy this very idea of the shelf.

http://www.ebay.com/itm/Motorcycle-trailer-carrier-tow-dolly-hauler-hitch-rack-/130989186457?pt=Motorcycles_Parts_Accessories&hash=item1e7f905d99&vxp=mtr

Tow bars here are all the square box insert type so easily removed you can also get the more common rack that has the bike across the vehicle as a double cheap too.

http://www.ebay.com/itm/DUAL-MOTORCYCLE-CARRIER-RACK-RAMP-TRAILER-HITCH-HAULER-/200953184795?pt=Motorcycles_Parts_Accessories&hash=item2ec9be421b&vxp=mtr

That double rack is mad, are they for real.

[Jay GTI]

Interesting invention you got there!

I reckon a bike designed for all the knarl of off road and hill traversing lateral forces and the like, will have no issues holding itself together through the rigors of a Hyundai Lantra's cornering ability :laugh:

Was just thinking if tyre wear did become an issue, you could get a rim and just swap it out for travel, I mean you have to unclip the chain anyway...

Yeah I don't think it's going to cause any catastrophic failures or quickly destroy the tyre or anything, I would just be interested in the condition of the tyre after a reasonable journey, say Auckland to Taupo and back (which I do a couple of times a year for the Epic rides). But, as you say, if wear does become an issue, a spare rim with a decent road tyre on it would be perfect as an in-transit solution.

The only other possible concern is if you're unclipping the chain on a regular basis, you should carry a spare join link with you when you go riding, as they don't seem to like being unclipped and reclipped too often.

[barty5]

That double rack is mad, are they for real.

Yeah they are not sure id be putting two full size bike on it lol.

I was thinking bout one of these tow racks and getting a spare wheel with a road tire fitted easy to change at track.

[pete-blen]

Interesting I'm living in the states at the moment and you can buy this very idea of the shelf.

http://www.ebay.com/itm/Motorcycle-trailer-carrier-tow-dolly-hauler-hitch-rack-/130989186457?pt=Motorcycles_Parts_Accessories&hash=item1e7f905d99&vxp=mtr



Looking at that one in the link :crazy:.... Think I over engineered mine ....

[raglanash]

How about a small dolly strapped on under the rear wheel like the tow truck guys use when they piss off with your car.

[glukasil]

hi guys. dont think there will be any problems with handling. will weld the rig once back to nz. if you disconnect the chain there is not much of wear. only problem i see is legal aspect of towing it.

[haydes55]

hi guys. dont think there will be any problems with handling. will weld the rig once back to nz. if you disconnect the chain there is not much of wear. only problem i see is legal aspect of towing it.



If it has a wof and rego the cops cant complain (unless it's unsafe).

[pete-blen]

It just towed my bike for 140km up to 100kmh... no issues or drama's..
yer don't know its there... even on gravel road with the bike running on
the gravel mound in the centre the bike stayed straight , no wandering

[andy mac]

To save removing the chain, could you load the rear wheel and tow backwards? The front wheel should follow like a giant caster wheel?

[barty5]

To save removing the chain, could you load the rear wheel and tow backwards? The front wheel should follow like a giant caster wheel?

Any bumps in the road / pot holes could make it want to turn ???

Maybe couple a 10" wheels and some sort a clamp on dolly system as suggested before maybe better be easy to make with a couple of those trailer rims that just have the single nut to the axle.

[pete-blen]

To save removing the chain, could you load the rear wheel and tow backwards? The front wheel should follow like a giant caster wheel?

front wheel turning backwards... maybe the mileage will wined back...;)

[F5 Dave]

What if it winds back to before you bought it? Space time continuum impasse?

I still don't know why you just didn't make an East West mount (oh, like one shown on Ebay link). Fine for a light dirtbike.

[F5 Dave]

What if it winds back to before you bought it? Space time continuum impasse?

I still don't know why you just didn't make an East West mount (oh, like one shown on Ebay link). Fine for a light dirtbike. Or maybe even that:shifty:

[bogan]

What if it winds back to before you bought it? Space time continuum impasse?

I still don't know why you just didn't make an East West mount (oh, like one shown on Ebay link). Fine for a light dirtbike.


What if it winds back to before you bought it? Space time continuum impasse?

I still don't know why you just didn't make an East West mount (oh, like one shown on Ebay link). Fine for a light dirtbike. Or maybe even that:shifty:

Woah, speaking of time parabolas... :shifty:

[Jay GTI]

They really need a heavy duty tow bar with a higher than standard tongue weight, I had one built especially for my bike carrier and even then it flexed a lot more than I was comfortable with. I used to run an additional strap from the bike frame to the back of the car, clipped in to the back lip of the boot, which then just wore all the paint off the boot where the strap touched it. Stopped the bike moving forward and backwards as the tongue flexed though.

I also used mine on an old E32 7 series Beemer with uprated suspension, but even then it was pretty low at the back when loaded and all my gear in the boot. The Hyundai should cope with the additional load, but they really are better off on the back of a decent 4WD. The tower thingy would put a lot less load on the back of the car and as it sounds pretty stable under speed, I reckon it's a winner.

[pete-blen]

I still don't know why you just didn't make an East West mount (oh, like one shown on Ebay link). Fine for a light dirtbike.

You need to read my first post in this thread.... all that info is contained in it...

[F5 Dave]

Hmm, Pay attn to text in a post that has pictures? Meh, over-rated.


How about lay off the pies & buy a YZ80?

[doddzee]

Like the outside the square thinking but have you looked into the legalities of this?

Its not classified as a trailer, you will exceed the maximum dimensions for projecting loads, you wont meet the requirements for a recovery vehicle nor do you have flags or warning panels that overdimensional vehicles require.

[pete-blen]

Like the outside the square thinking but have you looked into the legalities of this?

Its not classified as a trailer, you will exceed the maximum dimensions for projecting loads, you wont meet the requirements for a recovery vehicle nor do you have flags or warning panels that overdimensional vehicles require.


So how would/dose all this apply to a rego'd / WOF car being towed on a "A" frame...
Is there some sort of diffrents because it's a rego'd/WOF motorbike being towed on a frame ?
Is quite common in the camper bus community..

just type "A" frame into TM..see how meany hits yer get...

[doddzee]

See link "you may not tow a motorcycle unless mechanically disabled" and "the maximum speed for towing a motorcycle is 30km"
http://www.aa.co.nz/cars/ask-jack-forum/legal-advice/show/4314/
Technically if you remove the chain you have disabled it but you are still exceeding the projections if it is classified as a load on the vehicle, safety chain and rear lights.

You have come up with something that runs on the edge of the wrong side of the law if not over the edge of it, I would look a little further into it and no be surprised if you get pulled for it.

[pete-blen]

See link "you may not tow a motorcycle unless mechanically disabled" and "the maximum speed for towing a motorcycle is 30km"
http://www.aa.co.nz/cars/ask-jack-forum/legal-advice/show/4314/
Technically if you remove the chain you have disabled it but you are still exceeding the projections if it is classified as a load on the vehicle, safety chain and rear lights.

You have come up with something that runs on the edge of the wrong side of the law if not over the edge of it, I would look a little further into it and no be surprised if you get pulled for it.

there are 2 sections that could apply.... towing a motorbike... or towing with a dolly system...
towing a motorbike 30kph... " by rope with a rider siting on it"... I think this would be
the assumption when thinking of towing a motorbike...
or maybe towing on a frame/dolly... no rider.. max 90kph..
saftey chains..the frame infact has 2 to the car... though I did not have them connected on the week end...
did you read the very last reply from the AA.... A towed vehicle dosn't have to have rego or WOF ..just must
be in a safe condiction...

I just ask the question... it's at the bottom of the link you posted.... the reply will be interesting... fingers crossed...
towing it seems to be legal... how fast yer can tow it seems to be the issue...30 or 90kph ?
Or wait and see if PC plod takes an interest...

[pete-blen]

Got a reply from the AA... It seems it is legal to tow up to 90kph..
Because it's a tow dolly... the towed vehicle dosn't need a rego or WOF...

Link below...
http://www.aa.co.nz/cars/ask-jack-forum/legal-advice/show/5648/#post15108

[glukasil]

hurray...............good news :) thanx pete

[pete-blen]

Think I will set up another rear wheel...
If I was to get a flat while rideing... So I
don't have to fix it before I tow the bike home...