Wheel Alignment .... doing my head in.

[yokohama]

I took my rear wheel off yesterday to clean it up, clean and adjust the chain and attach Bibio's shiny new marker plates.
Now I just can't seem to get the alignment right. I thought I had it and took the bike out for a short ride to check. Everything felt fine but the wear pattern/road line on the rear was slightly off centre.
Trying again today - using the parallel string method - all this maths, physics and trigonometry is beyond me and I can't get the distances to match between the string and the front wheel.
Current measurements from the front tyre to string looking forward are:
1 5/8 inch 1 inch ( left and right front of tyre)
1 4/8 inch 1 inch (left and right back of front tyre)

Which chain adjuster do I need to turn in order to balance these out and which way?

[DJ123]

why not simply measure from the rear of the swingarm (where the chain adjuster plate goes into) to the centre of the bolt. Shorter distance and easier to do

[yokohama]

Originally Posted by daddyjob

why not simply measure from the rear of the swingarm (where the chain adjuster plate goes into) to the centre of the bolt. Shorter distance and easier to do

I tried that as a check earlier. It gave me almost identical measurements but I wasn't convinced the wheel was aligned

[DJ123]

Measure the distance between the rim and the inside of the swingarm on each side

[Craig380]

You can also measure from the round base of the nut on each end of the spindle to the end of the swingarm, which is easy to check. BUT BUT BUT you have to remember that the round base of the nut on the chain (left side) is 1mm smaller in diameter than the round base of the 'head' of the spindle on the disc side. So the measurement on the chain side should always be 1mm longer than on the disc side.

A simpler method is to carefully measure the length of the exposed thread from the chain adjuster nuts to the end of the bolts.

[Bibio]

is it a Michelin tyre by chance?

[yokohama]

Originally Posted by Bibio

is it a Michelin tyre by chance?

Nah. Roadsmarts.

I had another go today and got the alignment much closer. I'll take it out tomorrow in the dry to see how it handles.

[Bibio]

can you pop some pics up of the adjusters on the bike as this does not sound right. having measured the swingarm markers and knowing that my adjusters are pretty much spot on i'm surprised there is a discrepancy. also how do you know there is a different wear pattern (slightly off centre) to the tyre.

has your bike ever been crashed?

[johnnyrod]

I've never had a problem with the swingarm adjuster marks, however they're not so precise. Use them to get the wheel as close to being right as possible, then go for a ride. At 20-30mph, close the throttle and take your hands off the bars. If the rear wheel is out of alignment then the bike will consistently wander to one side (try it a few times). If it goes left, if means the left hand end of the rear spindle is too far back, so adjust by maybe half a turn, try it again. It doesn't matter if the forks aren't quite straight, this works.

[timwilky]

I use a more precise variation of the string method

I have two lengths of 1 inch box section with two pieces of threaded bar at one end. This enables me to clamp the box section either side of the rear wheel and allow the alignment to be projected forward around the front. I then adjust to alignment to be equal either side of the front.

Well that is how I did do it with the sv etc. with the GSXR, I just stick my vernier calipers on each side of the swinging arm machined sections for the adjuster slides.