Wheel alignment - how do you do it?

AtomicBanana · 9 Aug 2012 at 23:10

Part way through changing my chain and sprocket, thought I was just about done when I realised I'd put a spacer in the wrong way round in my wheel and so it won't turn

Got to take it off and this made me think about how I was going to check alignment. I've heard all sorts of method from string to just lying down level with the front wheel and seeing how much rear tire is on each side...

So, how do you guys do it?

wazza300 · 10 Aug 2012 at 00:19

the spacers are marked with lines for adjustment as you take up tension on the chain,count each line(the one on the spacer and the one on your swingarm) and have both sides matching,then your rear wheel and sprocket wont be misaligned

idk if thats what you meant?

agnes · 10 Aug 2012 at 08:29

What Wazza said. On double sided swing arms, you will have spacing markouts, normally done in groups of 2mm or 1mm spacing. When you pull the rear wheel taught enough for your chain, count the shortest run of marks (from the back or front of the swingarm) to the location of the nut. This is pretty vital stuff, so you really don't want to rush it.

A missaligned wheel can cause all mayhem, VERY fast trye wear, uneven riding, dangerous cornering, increased wear in bearings, damage to sprockets and chain and many more.

Good luck.

Hector · 10 Aug 2012 at 09:13

Those markers are good on some bikes, others not so.

Best way if you have access to the swingarm spindle is to measure from the swingarm spindle to the wheel spindle on both sides. Some folks make their own tool for the job:
http://www.4strokes.com/tech/wheel_align_tool.asp
http://www.youtube.com/watch?v=mjXpV7cpe8Q

Dogbreath · 10 Aug 2012 at 09:15

Swing arm markings are pretty useless for accurate alignment IME. On cheaper bikes especially the markings can be way off and they don't give enough resolution anyway (you typically only need to move the wheel back a fraction of one mark to tension the chain if you adjust it regularly.)

One very easy way to get things aligned pretty close is to rest the edge of a steel rule on the side of the rear sprocket, pointing along the length of the chain, and then visually check the chain and rule are running parallel. This only works if you don't have loads of chain guards etc in the way. You can get a laser based system that does the same thing, sticks onto rear sprocket with magnets and projects a line down the chain. This should get you pretty close, assuming the frame is straight and the engine is mounted correctly!

Last time I did a full alignment I put the bike on it's rear paddock stand and used a long length of alloy box section held against two points on the rear tyre and measured the distance between two points on the front, and then repeat on the other side. You really do need an assistant for this however. The string method I don't find very reliable - it's difficult to set up the string without introducing a kink and it's difficult to measure to the string from the front wheel without touching and moving the string.

AtomicBanana · 10 Aug 2012 at 12:28

I did start doing it using the swing arm markers, but then I remembered that these aren't meant to be that accurate. Just curious if there were any other methods that worked out ok. I'll give this a go tonight when I hopefully finish the new chain + sprocket job!