Xbr rear wheel alignment

[welland99]

After fitting my new chain and sprockets at the weekend, I wondered about satisfactory methods of checking the rear wheel alignment.  For now, I have just used the markers on the end of the swinging arm, and aligned them with the same place on both adjusters. 

Has anybody used another method and verified the accuracy (Or not) of the swing arm notch method?

[timbo]

I have only ever used the marks on the chain adjusters, as you have just done.

[welland99]

I also looked along the line of the chain and it appeared to be in a straight line with both sprockets. 

[themoudie]

Aye welland99,

You can use 2 straight edges laid parallel with either side of the rear wheel once you have adjusted the chain tension and tightened the spindle nuts. Then measure the distance between the edges of the straight edges and the front wheel rim or tyre, these should be equidistant. This is the methodology used at MoT stations ( or should be!).

An alternative that I use is to connect every thing up and then push the wheel as far forward as is possible in the swinging arm. Now finger tighten the spindle nut so that there is resistance to the sliding of the rear wheel assembly. Now thread the adjusting nuts onto the adjusters so that the nuts are 'full' and the rear end of the adjuster is parallel with the rear face of the nut. Now tighten the nuts, whilst counting the number of flats that you turn each nut; because the pitch of the adjuster thread is constant, providing you tighten the nuts by an equal number of flats the spindle should be drawn rearwards in parallel and once the correct chain tension has been achieved and checked after torquing the spindle nut and any locking nut, your two wheels should be in alignment.

If you don't achieve alignment then maybe you need to check swingarm or frame alignment.

I hope this helps.

My regards, Bill

[CrazyFrog]

Yep, I use the 'counting' method too. I also put a dab of tipex at the top of the nut for visual reference....

[themoudie]

Aye CrazyFrog,

That Tipex is also good for marking up timing marks on gears and the alternator rotor; or counting sprocket teeth, same as you use for marking the flats. 

My regards, Bill

[Propellor]

Long sections of rectangular hollow aluminium. Takes a bit longer as you'll need to check and adjust a few times to get spot on, but well worth the effort. Once set up you can make one or two intermediate adjustments by equal turns on each adjuster. But every so often set to perfection with the straight edges. This method will often disagree with the swingarm markers but it is accurate. Imo.

[welland99]

Aye welland99,

An alternative that I use is to connect every thing up and then push the wheel as far forward as is possible in the swinging arm. Now finger tighten the spindle nut so that there is resistance to the sliding of the rear wheel assembly. Now thread the adjusting nuts onto the adjusters so that the nuts are 'full' and the rear end of the adjuster is parallel with the rear face of the nut. Now tighten the nuts, whilst counting the number of flats that you turn each nut; because the pitch of the adjuster thread is constant, providing you tighten the nuts by an equal number of flats the spindle should be drawn rearwards in parallel and once the correct chain tension has been achieved and checked after torquing the spindle nut and any locking nut, your two wheels should be in alignment.

If you don't achieve alignment then maybe you need to check swingarm or frame alignment.

does this method work on the assumption that when the rear wheel is fully forward on both sides, it is in alignment?

[themoudie]

Aye welland99,

This method assumes that the rear wheel spindle is parallel and that the forked or slotted ends (internal and external) of the swingarm are equidistant from the pivot of the swingarm, as they should be. If the rear wheel spindle is banana shaped outwith the manufacturer's specifications, and or the two arms of the swingarm are not in parallel with each other or of differing lengths from the pivot, then this method will mirror these discrepancies and the only way to reveal these is by using the parallel straightedges, as I wrote of in my initial reply; "You can use 2 straight edges laid parallel with either side of the rear wheel once you have adjusted the chain tension and tightened the spindle nuts. Then measure the distance between the edges of the straight edges and the front wheel rim or tyre, these should be equidistant. This is the methodology used at MoT stations ( or should be!)." and as Propeller describes in his 'Comment' earlier this evening.

I trust this clarifies this point.

My regards, Bill

[Propellor]

Someone I know bought a bike years ago and on his first proper ride on it he called in at my house. He said it steers like a dog. A quick squint down the length of the bike told me the wheels were bang out. Yet the swingarm marks lined up to perfection. We got the long straight edge (rect hollow section) on it and set the rear wheel by this method, ignoring the markers. When we'd done we checked the markers. They were bang out. I mean 15/20mm out, that order of magnitude. He took it for a spin and came back grinning. Perfect transformation. I've ridden that bike a couple of times myself and it steers and handles well. Just ignore the markers! Obviously the bike has had a knock at some point in a past life. We checked fork stanchions. Perfectly straight. The yokes perfect. Probably these components were not original. Probably the headstock out of line.

We contemplated the implications of riding the bike. The main issue will be the sprocket alignment not being parallel. Next, the centre of gravity won't be quite where the manufacturer wanted it, but this will be very slight. Whatever, the bike rides perfectly well, so long as you set up with straight edge.

Even on brand new factory bikes it makes logical sense not to place 100% trust in the markers. There are simply too many other tolerances and a very convoluted path involved. A small error at the headstock, maybe within manufacturing tolerances, is bound to have an effect on wheel alignment.

When you think about it, a bike will self correct and ride straight even with bad rear wheel alignment. It'll just ride with the wheels parallel but offset. You really notice this when steering on corner turn in. The bike feels inaccurate. It really screws up the steering. You'll also notice the yokes and bars not in proper alignment as you're traveling straight, again slight though.

I recommend obtaining a decent straight edge (you only need one if you're by yourself) it's amazing what it shows up!

[JOOLZ]

You could use a laser pointer or a laser level 100 % accurate

[richardeblack]

Hello All
I use a laser pointer with some brackets I made which clamp to the rear wheel rather than against the tyre. I then use a magnetic laser spirit level and drop it onto my bracket on one side.  I take measurements at the front wheel and put the level on the other side and do the same . After a small amount of fiddling with the steering I can then quickly swap he level from side to side and take measurements as I adjust the wheel. I can get it bang on in about 1/4 hour where I used to spend ages with straight edges against the tyres and never get repeatable readings.
I did try to buy a second, apparently identical laser spirit level from eBay to speed it up even more but it was quite a way out from my first, better quality one. I will probably buy a couple of good quality ones in the future when I can bring myself to spend some money.
I will try and take some pictures at the weekend as I'm probably not going to Stafford now.
Cheers
Richard

[timbo]

Must admit, I've never really bothered with any of this 
I just match the markers up on each chain adjuster, and I've never had any need to do anything else.

[CrazyFrog]

I did try it once about thirty years ago with lengths of wood and stuff but the thing I could never work out is how you make sure the front wheel is perfectly aligned down the axis of the bike to begin with. Measuring from the centre of the swinging arm spindle to the centre of the rear axle on each side seems to be a reasonably accurate compromise to me but to be honest I don't even bother with that usually. I slacken everything off, push the axle as far forwards as possible, advance the adjusters till the just nip, Mark with tippex and count the turns I'm winding them out. Admittedly this is useless if the swinging arm is out of true, but in practice I've never had a problem.

[iansoady]

Slightly O/T, but a few years ago I took my Triumph Tiger to me MoT'd and they did check wheel alignment. Apparently it was a new requirement at the time (and due to ham-handed work by the dealer I bought it from, the Tiger's wheel was indeed off - as some people will know, that model had eccentrics in the swinging arm to adjust the chain, which should never be slackened off when removing the rear wheel. Of course, that was exactly what the dealer's workshop had done.

When I went back for the next MoT, the alignment stuff was lying in a corner. When I asked, the tester reckoned that so many bikes with single sided swinging arms (which of course can't have the alignment changed) had failed that the DVLA scrapped the requirement.......

He may of course have made the whole lot up.