Help please rubing hugger
 

Help please?
Just come in from the garage after fitting wheels back on bike with new Rensports, 180 rear instead of 190. I am running 94-link chain with a 14 front sprocket and 38 rear. Problem is tyre hits the hugger and I can’t adjust it to miss with chain adjusted right; it was fine with the 190 0n?
Gonna be running 36-rear sprocket for big tracks this year but want to keep 38 rear for Cadwell and Indy.
Not really possible to move the hugger and the hub is the right way as well
What you reckon longer chain?
:puzzled::puzzled:

Sounds like you may have shortened your wheelbase.

Someone with more of an idea will be along shortly ...

So where's your hugger rubbin' on the tyre? From your desription it sounds like it's at the front?

The 180 tyre is obviously narrower, but they tend to have a higher profile than 190's, so whilst the wheelbase won't be affected, the radius of the tyre will be.

Not sure on a solution, don't know what a longer chain would do to the handling other than slow the steering slightly, but if you do find a bit of clearance then bear in mind that when the tyre's spinning round it'll enlarge a bit more with the centrifugal effect!
I've followed a gsxr1000 once doing XXXmph when his back tyre ripped the hugger off and made a nice mess of his back end.

Tyre is just rubbing on the hugger were it's shaped on top to allow the pipes to clear

On my 748, I wore a hole in the hugger the first time I changed tyres. A different make tyre, with a slightly different rolling radius, was all that was needed for the hugger to foul the tyre. Clearance on the stock sprockets is minimal. It's not uncommon to see Dukes with holey huggers.

This is another good reason to drop the gearing a little and go with a longer chain, as Shazaam! suggests. I went up only one tooth, from 14/38 to 14/39, but with a longer chain, and the hugger now has plenty of clearance.

Don't know what your bike is, eric, but you seem to have a similar problem.

Yep...as you say eric...a longer chain is the answer.

You should always aim to have the spindle of the eccentric hub in the 4 or 5 oclock position (when viewed from the sprocket side) no matter what combination of gearing or ride height you are running.

The secret is to measure the rear ride height when you are happy with the bikes turn in etc, (loads of threads about this 'magical' ride height figure), either using the proper ducati ride height tool, or a couple of datums on your bike (ie the flat of the wheel nut and one of the exhaust bolts on the subframe).

Then make all of the alterations needed (new gearing etc) and then aim to get the hub in the 4/5 oclock position ...with the chain adjusted to the required tension. This may require adding/removing links to the chain.

When you are happy you have achieved that...then finally re-adjust your ride height using the tie bar, back to the figure you noted earlier.

The aim is to get the eccentric hub as far back in its rotation as possible (allowing for some stratching/adjustment of the chain) to add stability to the ride, and then acheive the desired turn in by adjusting the ride height using the tie bar (or steering head if you so wish).

[Edited on 14-2-2005 by Harv748]

This is a common problem when fitting a 180 rear tyre, happened on my bike without any changes to gearing etc.

Solution without fitting longer chain and/or adjusting the ride height is to drill a small hole in the bottom side of the hugger on the side away from the swinging arm, where the hugger has no support, then put a cable tie, or lock wire from this hole to the bracket on the exhaust where the pipe springs fit. This just lifts the huggewr enough and gives enough support to clear the 180 rear tyre and has worked for me.