The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: a101960 on 25.03. 2009 16:10
-
I have just adjusted my rear chain and conventional wisdom says that a board or a taught piece of string should be used to check wheel the alignment after the chain has been adjusted. However, from all that I have read on this subject it says that the wheels and tyres should be the same size to ensure accurate alignment. This is all well and good, but very few bikes have the same size tyre front and back. A10's having 325X19 on the front and 350X19 at the back. Anyway, I opted for using the taught string method for checking the alignment because the centre stand would have got in the way if I had used a solid straight edge. How much error if any would have be introduced due to the fact that tyres are slightly different in size? The string is taught with no discernible evidence of it running other than true and straight. The string touches both tyres on the tyre walls and there is no evidence of any bending of the string. The rear tyre looks as if it is central in the mudguard when viewed from the rear. I am just a little concerned though because the drive side adjuster is screwed out just a little bit more than the timing side adjuster. I have not tightened every thing up yet, because I thought it prudent to check weather the method I have used is satisfactory and reliable. For the record the string is stretched across the wheels about 6" from the ground.
-
Hi
Using one piece of string is not going to be that good as logicaly the rear tyre is bigger than the front so by getting the string to touch on both walls of the rear tyre and holding it against the front wheel at the front wall by turning the handle bars slightly you can get it to touch on the rear part of the front tyre wall and you would not see any bend in the string.
By far the best way is to use two solid straight edges touching both walls of the rear wheel each side then straighten the front wheel and the gap at both points each side of the front wheel will be the same.
This is how they check it at my MOT station
Richard
-
This is how I do it... http://www.ljswain.btinternet.co.uk/lining-up-wheels.htm (http://www.ljswain.btinternet.co.uk/lining-up-wheels.htm)