Manky Monkey Motors

Hi all

I am busy converting a Honda ST1100 to a trike.

It has a 120/70 R18 front tyre fitted at present.

I have read about a sidecar tyre being fitted to reduce, or at least help with, wobble amongst other benefits.

My question is can I fit a 4" tyre to a 3" rim. The only tyre I seem to be able to find is a Metzler Block K sidecar tyre, which is 4.00 18.

All replies are very much appreciated to this novice.

Paul

I put a side car tyre on my gl1000 and to be honest it didn't do much. so I reduce the trail down from 4.5" to just under 2" and now there's no steering wobble or shaking.

On my gl1500 didn't need any alterations to the trail. and it running on the original spec bike tyre

I would work on getting the steering trail down to about 2" as I don't think a side car tyre will work for this setup

Thanks for that Terry, interesting stuff.

Have you had any experience with steering dampers?

No I haven't. personally I don't like them 

Check out the tyre and rim size chart at the top of bike tech.
Main reasons for changing to sidecar tyres is the different road contact patch afforded by the flatter profile and the stronger sidewalls.
Some bike tyres have a very narrow contact area in the upright position.
You may find lowering the tyre pressure a little will help. Then again it might not.

I have a massive amount of trail (about 6") Steady as a rock but the steering does get a tad heavy at speed.

Thank you Olds

I am probably jumping the gun with this as I have not had it out to play yet.

Just like to try and foresee any possible challenges.

It seems I could fit a sidecar tyre, will try with lower tyre pressure

The trail is 4" on the Pan ST1100.

I reduced the head shaking on my GT550 trike by lowering the tyre pressure to about 25, and letting all the air out of the air-assisted forks - guess you could do something with changing the amount or viscosity of the fork oil.

But the thing that made a HUGE difference was getting custom-made extended yokes fitted, to change the trail.  Not only stopped the headshake but made the steering much lighter too.

Thanks Biker Gran, interesting stuff, do you have a pic?

Not particularly helpful ones, but this album shows roughly what was done.  It's on Facebook but you don't have to be a member to see it, just follow the link.

https://www.facebook.com/media/set/?set=a.873110349373097.1073741890.100000224199684&type=1&l=a366d1596d (https://www.facebook.com/media/set/?set=a.873110349373097.1073741890.100000224199684&type=1&l=a366d1596d)

Thanks for that Bobbi, I get it.

Once I've got the Pan put together, I will see how the handling goes and take it from there. A few ideas to try thanks to all you good folk.

I've used a steering damper on a trike which was well worth doing and helped a lot with front end shake..( springer front end ) and a cheaper option than new yokes ? My advice is try starting with tyre pressures first then fork oils,then a damper etc ?

Thanks Stinkey, really appreciate the advise.

Yes but the yokes are so pretty!   ;)

Very pretty.

Nice job on your yolks Bobbi.

They were made by a bloke who used to post on here - I've forgotten his handle now.  Irrelevant though cos he moved to the middle of nowhere...........

They where made by ByzMax at choppit customs

I had my gl1000 rake altered I went for the ezi steer setup and had these made to suit my trike setup

Thanks for the pics Terry T, as they say a picture paints a thousand words.

Interesting ? ???

Cheers Terry - it's me age you know!

Just a number, just a number.

The problem is the number's too high!    ;D ;D ;D

That puts you in the wise sage category ;D

Those weird looking things should be easy to make ? Any decent engineering company could help ?

I remember filing out a set of yokes to accept Norton forks. Roadholders ?

Yes they can. and they look better then leading link or girder type

thats debatable ? Definitely better than leading links at least ? ::)

They may look better, but they won't work as well. I'm not sure if it would be just as easy to make some offset yokes - (+4 inches?). The trike looks good on them though how does it ride?

It handles fine no handle bar shake or tank slap at any speed from pulling away up to 70mph or back down again rides corners well. and in a straight line. you can ride one handed with no force from the bars affecting your control. there fully adjustable for ride height. in my opinion there better then doing offset yokes you go out +4" the trike drops down app 2"

Terry, I take it that they are wider at the top and taper in?

No all three slabs are the same. with the hole size the same as the gl1000 fork tubes and extended out about 2 3/4" to give a trail of 2".

they are not the same as the 4degree raked

Thanks Terry, with the angle of the pic, it looks like there is an angle.

Much clearer now.