Actual rear wheel alignmet

[simi_ed]

OK, We've all read this, seen it & said "I should do this".  


But, has anybody done it?  Or maybe, "has anybody else done this? As outlined in numerous places (I used the Motorcyclist-online write up as a 'how to', http://www.motorcyclistonline.com/how-to/how-to-check-front-and-rear-motorcycle-wheel-alignment-mc-garage-tech-tips.

Let me start here: this was  pain!
 
About 20 ft of masons twine, tied to the front wheel, pulled up to almost the lower edge of the brake rotors


a
Pulled taut, to the rear wheel, on either side.


String is pulled tight, and attached to a pair of jack-stands, I had to weight the stands so they didn't topple (learned that quickly)
String never touched the centerstand.  Pull it tight and straight.  Measure the space from string to tire edge at the extreme from front wheel. I got the differential down to about 0.5 mm, close enough.  Initial error was about 5mm, since I knew I was going to check this.




The payoff:  The marks are pretty damn close on the swing arm!

Rotor side:


Chain side:


0.5mm 0r 0.020" vs 1/2 the thickness of the stamped line?  I guess it's close enough for me.  

So, has anybody else done this?  What did you find?

[movenon]

Been a while but I did mine when I did the rear and front wheel mod. I didn't find it to hard. I did learn that a very little adjustment on the rear makes a measurable difference.  Here is what I used as a "how to reference".

Align the forks first (check for twisting).  https://www.youtube.com/watch?v=vSunBRB6-r8

Then align the wheels:

https://www.youtube.com/watch?v=RBxK-OQ--fg



George

[X-Ray]

I really have to do this. Even with brand new tyres etc, chain aligned with motion pro aligner, steering still pulls to the right. I don't get it. Maybe the forks are slightly out, will check this first and then try the string alignment.

[ribbert]

.........So, has anybody else done this?  What did you find?

Let me start by saying the bloke that originally brought this antiquated idea to youtube should be strung up (by an 20' piece of string)

The notion that you can tell when a piece of string contacts a tyre 5 or 6 feet away, multiplied by the distance (length) factor to an accuracy of mm's is ridiculous.

Ed, not only does the tutorial you followed make hard work of it, I can't possibly see how it can be accurate (and I've never seen it done in reverse before, from the front wheel)

The guy in the link Fred posted nailed it up front, a couple of straight bars but then went on to dismiss it because of the difficulty in obtaining them.....Rubbish, they can be bought at any hardware store for pocket change.

I have tried all sorts of things, including lasers, but keep going back to the tried and proven method. It is the fastest, easiest and most accurate, what else does it need to be?



A couple of lengths of 1" tube clamped to the back wheel (near the centre), adjust back wheel until equal distance is achieved at 4 points, those being the front and back of front wheel on both sides, job done. 100% accurate and mm perfect.

The string method is a hangover from the days of cork clutches, friction knobs and bicycle chains on 20 hp motorbikes when accuracy wasn't an issue.

Noel

[X-Ray]

Noels method it is, and I must say a true solid straight edge just has to be accurate. Will still do the fork alignment first, and I noticed I have one fork tube about 1-2mm higher in the clamps than the other. so will sort that, head to Bunnings for a couple of lengths of 1" square tube steel and get measuring, 

[Arnie]

Noel,

You should warn those with gorilla strength to not overtighten the Fclamp on the rear wheel and tubes, otherwise the tubes will be diverging and not give a true reference. 
Also, make sure you use paint tins that are certified to a "standard" height.

[ribbert]

Noel,

You should warn those with gorilla strength to not overtighten the Fclamp on the rear wheel and tubes, otherwise the tubes will be diverging and not give a true reference.  
Also, make sure you use paint tins that are certified to a "standard" height.

Yes Arnie, I know, but my monitor ink doesn't seem to travel North of the equator anyway so I didn't bother with the detail.

However, for those enlightened souls who choose to act on this advice, yes, the clamp is best placed as near to the centre of the wheel (under the axle) as possible so the force is distributed evenly between the front and the back of the tyre to give a true reading.

It is also wise to not tighten the clamp any more than is necessary to hold the bars for the same reason.

The paint tins I sit the bars on are metric (as is the clamp) but imperial should work just as well.

Noel

[simi_ed]

Noel, I am glad you chimed in! I have some thoughts on your input.

.........So, has anybody else done this?  What did you find?

Let me start by saying the bloke that originally brought this antiquated idea to youtube should be strung up (by an 20' piece of string). Agreed!  How about 20' of rope, though?

The notion that you can tell when a piece of string contacts a tyre 5 or 6 feet away, multiplied by the distance (length) factor to an accuracy of mm's is ridiculous.  I disagree.  I watched carefully as I moved the string into the tire.  When it contacted the tire, it deflected.  Easy to spot!

Ed, not only does the tutorial you followed make hard work of it, I can't possibly see how it can be accurate (and I've never seen it done in reverse before, from the front wheel). Again, I agree ( too much hard work), but it 'appeared' to be accurate.  Since I don't have the needed items to test your method, we're at a (friendly) standoff, for now.  I'll see what I can scrounge up to test your method.

The guy in the link Fred posted nailed it up front, a couple of straight bars but then went on to dismiss it because of the difficulty in obtaining them.....Rubbish, they can be bought at any hardware store for pocket change.

I have tried all sorts of things, including lasers, but keep going back to the tried and proven method. It is the fastest, easiest and most accurate, what else does it need to be? The only cheaper method was my method, so you have a decent argument here.



A couple of lengths of 1" tube clamped to the back wheel (near the centre), adjust back wheel until equal distance is achieved at 4 points, those being the front and back of front wheel on both sides, job done. 100% accurate and mm perfect. Agreed

The string method is a hangover from the days of cork clutches, friction knobs and bicycle chains on 20 hp motorbikes when accuracy wasn't an issue. Agreed

Noel

Thanks again for your contrary points, makes me think I maybe can it do better & easier.  I'll report back when I do more tests.

Ed

[gumby302ho]

 Sorry for being daft but the rear wheel is wider than the front so what goes on up front with these straight bars that are used for measuring? Also, when I align my rear wheel using the markers on the swingarm that my bike could still be out of alignment and should I not be trusting the swingarm markers as it shows in Eds picture one side is way off compared to the other. Still learning here!

[simi_ed]

Sorry for the ambiguous pics of alignment marks. Try these:




The alignment marks on my swing arm appear to be ~100% on.  As far as the long bar method, I think you would try to center the front wheel between the bars, then adjust the rear wheel until the front can be centered between the bars.
Noel, you care to chime in?