Triumphrat

Bodger · 07-23-2006

I read in a post or two a while ago that the Tbirds triple tree's have a slight bias to wards the right to compensate for the single rotor set up.

Is this true? and if it is then would that account for the uneven tyre wear on the front of the bike?

I have put TBS forks straight onto the tree's of my Tbird and the tyre wear is noticeably more on the right side of the tyre, about an inch over from the centre line ( as you sit on the bike).

I have also replaced the front wheel with a Trophy one, so i might not have the correct spacings which might have compounded the tree problem, or might be the problem its self, but the bike seems to ride upright and straight with no deviation when i let go of the bars.

Any other factors for uneven tyre wear?

Ballacraine · 07-23-2006

Well I just went out and crudely measured the ones on my Legend and it seems plumb. They seem equidistant to stancion centres from the steering head nut.

I have had the TBS front end on for about 6 years and not noticed any abnormal wear.

Check that you have the forks evenly through the top yokes.

A friend of mine always has this problem. It is down to his riding posture. He doesn't sit square on the bike.

hope some of this helps.

Nige.

Ballacraine · 07-23-2006

Might be worth checking the rear wheel is evenly set in the swing arm to.

That might cause a 'crabbing effect' too?

Nige. :???:

TBSstunta · 07-23-2006

No bike has uneven fork offset. There are several reasons why your tires wear more on the right. Most obvious is the crown on the road. If roads were perfectly flat then rain would pool in the center; roads are raised at the center so the rain runs off it. You ride on the left which means that the right side of your tire gets more wear. In the end, having a single rotor doesn't do anything significant to the handling of the bike. I don't think your wheel is off center as there are no clearance issues with your rotors and calipers.

[ This message was edited by: TBSstunta on 2006-07-23 08:02 ]

shortys · 07-23-2006

My Thunderbird definately does not have "offset" forks. Offset actually refers to the relative position of upper and lower triple clamps, resulting in more or less trail.

Adjustables are available for the (excuse me for saying it on this forum "Racing Community")

Regarding your cupping or tire wear: You are riding in england. therefore your tire travels farther on the right side than on the left. The reason: your right turns require at least twice the distance to accomplish. Here in the U.S. and other countries as Germany, France etc. we experience more wear on the left side of our tires. It's just farther around, and turns are under stress, and thats where the wear happens. http://www.rattlebars.com/valkfaq/tirewear/

[ This message was edited by: shortys on 2006-07-23 09:17 ]

Slinky · 07-23-2006

My money's on the road camber theory.

Another thing, although it may not be relevant. On the standard Thunderbird wheel the rim is offset to the left.. Your Trophy wheel might be centred in the forks.

Ballacraine · 07-23-2006

TBH I don't know if the cambering issue totally explains it.

I have always got even wear on the tyres, where friends on occasion have not.

Maybe the camber on the roads I typically ride are not so severe?

Or maybe it is because I tend to ride near the crown of the road?

Nige. :???:

shortys · 07-23-2006

Camber Schamber, It's the mileage that wears 'em out, and cross traffic turns are twice the mileage. :razz: Read this article

[ This message was edited by: shortys on 2006-07-23 21:51 ]

Bodger · 07-24-2006

Thanks for all the input. Hears some pictures to illustrate the wear.

Its not that clear from the pictures, but i think the wear is too far over to be riding position.
The rear tyre has normal wear and i think its as central as i could hope for.
Again the camber theory might explain some wear just off centre.
The forks are the same in the yokes and they measure the some length when stood together.
The wheel is about half a millimetre to the left (sat on bike).

I bought the forks on ebay and was wondering weather the springs are shot or uneven. Also i has to change one of the fork legs as the compression adjuster was knacked. There couldn't be a difference in the fork legs could there?

Or it maybe that I'm just more aggressive on right turns and bends than left!

Bodger · 07-24-2006

Apologies to all!
It seems like the wisdom of the rat has prevailed again.
I took a tyre depth gauge to the rear tyre and found that the right side is 1mm more worn than the left. So it seems i am either sat acock on the bike or the camber theory is good or i like right turns and bends more than left. Or it is a combination of all three.
At least it is not a wheel or fork issue.