Triumph Rat Motorcycle Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
252 Posts
Discussion Starter #1
Did a chain tightening and lube a few weeks back, but I was a bit pressed for time, and didn't put the same painstaking effort into getting the rear wheel alignment marks in just exactly the same position on both sides. They're close, but they're not perfectly the same.

How much tolerance do we have on this? The difference on mine right now is probably between one quarter to one eighth of one alignment mark. I get the strange sensation that the bike is floating a little on curves, but this could easily be my imagination.
 

·
Registered
Joined
·
117 Posts
I have a theory. My mate has a Ducati Diablo and the front tyre is bald on the right hand side only. The left side is good. So I figure that the rear wheel is not straight and that big tyre is pushing straight ahead causing my friend to compensate and negative steer causing the wear on the one side. This could only happen with the huge rear tyre. I don't think a little offset on normal sized tyres would cause too much trouble. If you had a huge rear tyre like my friend there would be an issue. Straighten it up anyway but measure to the centre of the swing arm as the marks may not be accurate on the end of the swing arm.
 

·
Registered
Joined
·
147 Posts
The wheel alignment marks on the swingarm are pretty rough measures of alignment.

Use the old method with a long string (monofilament fish line is ideal). Set the bike on a stand, or get as vertical as you can get with the sidestand (watch out it doesn't go over!). I sometimes put the sidestand on a 2x4 block. Then wrap the string around the rear tire and rim once, toward the rear. Pull the two ends of the string to the front, put weights on each end (heavy enough to get the strings tight), and hang them over something like a toolbox. The string should only be contacting the bike at the rear of the rear tire, and at the front of the rear tire; no contact at the frame, sidestand, front tire, etc.; turn the front wheel straight so the string passes by on both sides. You want the string as high as possible while still not touching any frame or engine piece in order to get a more accurate measurement. Now get a flashlight and look closely at the two points of contact on each side of the front of the rear tire. Adjust the position where the weight hangs over the toolbox so that the string JUST BARELY contacts the front of the rear tire. Now you have the two string ends in parallel. Look at the front tire. Each string end should pass by the front tire (turn front so it is even) at equal distances. The distance should be equal on the left side, on the right side, and between left and right. If the latter is not equal, you have to loosen the rear axle and turn the adjusters until you get equal spacing up front (you have to re-adjust the weights each time). Once you get everything right, snug up the adjusters on both sides of the axle, and from that time on always make equal adjuster changes on both sides (by counting flats) so you never have to mess with the string again ideally...
 

·
Registered
Joined
·
301 Posts
By far the easiest wheel-alignment method IMHO is to use one of the gizmos that clamps on the rear sprocket and has a pointer along the chain - the theory being that the chain will always be aligned with the axis of the bike. I've seen laser pointers too, but they aren't worth the extra dosh I think.

timbo
 
1 - 5 of 5 Posts
Top