Is my rear wheel straight? Can I trust the marks on the swingarm?

**Oakie** · 5th October 2008, 18:50

I adjusted the chain on my bike today and the thought occured to me that it would be nice to really know if my rear wheel is straight. I know there are adjustment marks on the side of the swingarm but I've never really trusted them. Are they trustworthy? When I adjust I just tighten each side up by the same amount and the theory is that if was was straight originally then it'll still be straight.
Can you tell please of an easy way to check that my wheel is pointing straight ahead and is not a few degrees off true? There's nothing to indicate that it is ... no odd wear patterns and the bike seems to track straight ... it would just be nice to know is all.

**Ocean1** · 5th October 2008, 19:01

Originally Posted by Oakie

I adjusted the chain on my bike today and the thought occured to me that it would be nice to really know if my rear wheel is straight. I know there are adjustment marks on the side of the swingarm but I've never really trusted them. Are they trustworthy? When I adjust I just tighten each side up by the same amount and the theory is that if was was straight originally then it'll still be straight.
Can you tell please of an easy way to check that my wheel is pointing straight ahead and is not a few degrees off true? There's nothing to indicate that it is ... no odd wear patterns and the bike seems to track straight ... it would just be nice to know is all.

They're usuall good. Simple check is to hold a straight-edge along the side of the rear tyre, (as high up as possible) forward to the front wheel. Hold the front straight and check both sides, should be the same gap between the straight-edge and the front wheel both sides.

**Oakie** · 5th October 2008, 19:10

Originally Posted by Ocean1

They're usuall good. Simple check is to hold a straight-edge along the side of the rear tyre, (as high up as possible) forward to the front wheel. Hold the front straight and check both sides, should be the same gap between the straight-edge and the front wheel both sides.

Yeah that's what I have tried in the past. Unfortunately the only straight edge I've got that has any length to it is a clamp which is about 1.8 metres long but is really too heavy to be able to hold in place.
I've tried measuring the distance between the side of the swingarm and the rim of the tyre but I guess there is no guarantee that the swingarm is the same distance from the tyre on both sides anyway.

**Ocean1** · 5th October 2008, 19:23

Dude, how can you survive without a straight-edge?

Don't have to be good for a thou or less, piece of nice timber would do.

**Sam I Am** · 5th October 2008, 20:09

You can use string ....

**laRIKin** · 5th October 2008, 20:27

Originally Posted by Sam I Am

You can use string ....

As he said use a string line or you can measure from the swing arm
pivot to the center of the wheel axle.

**laRIKin** · 5th October 2008, 20:34

Here you, that is if you have never done it before.
http://www.motorcyclistonline.com/ho...els/index.html

**MSTRS:Me** · 6th October 2008, 07:46

The other way to get a good idea of straightness, is to (remove the chainguard if necessary) sight along the chain. With the rear up on a stand, spin the wheel - you will soon see if the chain is tracking straight between the sprockets.

**Oakie** · 7th October 2008, 20:42

Originally Posted by lemans

Here you, that is if you have never done it before.
http://www.motorcyclistonline.com/ho...els/index.html

Thanks for the link. I'll give that a crack.

**laRIKin** · 7th October 2008, 21:25

Originally Posted by Oakie

Thanks for the link. I'll give that a crack.

I sometimes use to put a bit of box steel or wood on each side of the rear wheel tire to make it easier to make align the wheels as you get a bigger gap and are not touching the front wheel as much.

**Blackbird** · 8th October 2008, 06:48

Or you could build yourself a simple laser alignment rig as I did, mainly because I was curious as to how well it would work. You could build an adjustable one for a whole range of tyres but my simple one works perfectly and I've used it for a good few years now.

See: http://www.kiwibiker.co.nz/forums/sh...nment#post6141

**Ocean1** · 8th October 2008, 17:30

Originally Posted by Blackbird

Or you could build yourself a simple laser alignment rig

Nice work dude.

**Oakie** · 8th October 2008, 20:17

Originally Posted by Blackbird

Or you could build yourself a simple laser alignment rig as I did, mainly because I was curious as to how well it would work. You could build an adjustable one for a whole range of tyres but my simple one works perfectly and I've used it for a good few years now.

See: http://www.kiwibiker.co.nz/forums/sh...nment#post6141

That is quite remarkable! Quite cheap and fairly easy to manufacture. I might give that a crack just for a laugh. Thanks

**puddytat** · 8th October 2008, 21:06

Dont trust your swingarm marks....mine are 15mm out of true using the stringline system. This came to my attention after seeing the damage it did to my new PR2's....

**Oakie** · 9th October 2008, 07:02

Originally Posted by puddytat

Dont trust your swingarm marks....mine are 15mm out of true using the stringline system. This came to my attention after seeing the damage it did to my new PR2's....

Ouch! Yeah I had a feeling from when I was a biker in my youth that you shouldn't trust those marks without question. Cheers