Wheel alignment.

[nato674]

Have seen a few tips here and there but wondered how everyone else does theirs?

[Volvi]

often thought of doing it with a long string, but havent bothered, just measured space on rear axle(where the measuring marks are) to make sure that both ends are equal distance.

[nato674]

often thought of doing it with a long string, but havent bothered, just measured space on rear axle(where the measuring marks are) to make sure that both ends are equal distance.

I have been told those marks are not always accurate?

[BUSGO]

I think that they are more accurate than some believe.
Both of my busas have had good accurate markings.
I suppose all may not be so lucky though.

[jzbusa]

Im told gsxr's are often inaccurate with those marks, not sure about busa's. This is something ive been planing to check for a while now, just never got around to it. Maybe a job for the weekend.

[busakid08]

All bikes are not 100% but they are close and certainly close enough for the road rider, exact; use string or measuring device takes time though for a few mils gain

[Volvi]

one would assume that the 2 arms of the whatchmacallit would be exact in length and made from a preset mould. Therefore irrespective of those marks (which i for one believe theyre pretty accurate) if you measure from the end to the adjuster block and make them equal distant then shud stand to reason the rear wheel is correctly aligned. Bearing in mind theres no aligning the front wheel, but just to the front wheel.

[#CAS#]

Yes Volvi, one would assume that the 2 sides are of equal length, that doesnt mean the wheel will be straight in relation to the rest of the bike (as a wise man showed me) if you measure from the swingarm pivot centre to the rear axle centre you will have a true measurement for each side. And in my case there was 5mm difference.

[Volvi]

ermm where the swingarm pivot centre, anyway of illustrating the correct way to measure?

[steventh]

Folks,

As a tinkerer I have wasted many hours aligning the back wheel with string and straight edges on a variety of bikes and I proved that the markings on the back are wrong - until I had a cuppa and remeasured to find out that it was me (no shit!).

While there may be some where the markings are incorrect I wuold think they are rare.

In most cases all you will gain is a minor improvement that is of no consequence.

The worst thing that will happen if the back wheel is way out of alignment is increased chain and sproket wear as the chain will not be straight on the sprocket. But I think that will require a large misalignment. Is your chain/sprocket showing signs of this?

As bikes only have two wheels which track each other it will not affect tyre wear.

I dont think the string method would be particulary accurate when you have bikes with a narrower front tyre as it relies on you measuring the offset of the string from some point of the front tyre. For fine accuracy this assumes you measure the offset at the same place on each side and have the front wheel facing exactly ahead.

Cheers

Steven

[Madmax]

If you string line the back and front wheels to ensure they are running parallel, and your front wheel isn't off-set like some of the smaller older Yamahas, it's very effective. If you have front tyres scalloping one side or the other, this can be a cause - that is, not parallel.
No bike I have ever string lined has been straight, and the little marks on the swing arm can be out to blazes. Results are increased tyre wear and very high speed instability.

I'll publish a "how to string line your back wheel" in the How To area.
It's not difficult and makes a difference when done correctly.


Max

[steventh]

Max,

I agree with your view that string lining can be effective.

My comment about it not being particularly accurate is that you may still be a few degrees out from true because it relies on you measuring the gap between non parallel string lines and the front wheel (if you are using the string method of wrapping the string around the front and back tyre). I guess my point is that you will not get a "perfect alignment, nor is "perfect" neccessary.

I have never found this an easy or reliable thing to do and have had to resort to all types of "tricks" for limited improvment if any. In the end my swingarm marks have always been as accurate as my string lining. I am not saying that this is the same for every bike.

I now use parallel lines (either string or straight edge) as I find this much easier and quicker.

I dont understand how the rear wheel not being aligned will add to tyre wear. Irrespective of the rear wheel alignment - for the bike to go straight the wheels must be parallel (the bikes body may be going "sideways" though). Unlike a car when if the wheels are not aligned they fight against each other increasing wear.

       

[Madmax]

Max,

I agree with your view that string lining can be effective.

My comment about it not being particularly accurate is that you may still be a few degrees out from true because it relies on you measuring the gap between non parallel string lines and the front wheel (if you are using the string method of wrapping the string around the front and back tyre). I guess my point is that you will not get a "perfect alignment, nor is "perfect" neccessary.

I have never found this an easy or reliable thing to do and have had to resort to all types of "tricks" for limited improvment if any. In the end my swingarm marks have always been as accurate as my string lining. I am not saying that this is the same for every bike.

I now use parallel lines (either string or straight edge) as I find this much easier and quicker.

I dont understand how the rear wheel not being aligned will add to tyre wear. Irrespective of the rear wheel alignment - for the bike to go straight the wheels must be parallel (the bikes body may be going "sideways" though). Unlike a car when if the wheels are not aligned they fight against each other increasing wear.

I'll post it tonight. And will include photographs for ease of interpretation.

The back wheel is the driving wheel and will tend to push the out of alignment front wheel sideways. In your picture you show both bike tyres tracking in the same direction. Out of alignment will have one straight and the other not on the same track. I'd love to know the physics behind the driving and driven wheel when the rear is pushing, and the front wheel being pushed out of parallel.


Cheers

[steventh]

Hi Max,

Im not a mechanic or mathematicion so any explanation is helpful.

To go straight ahead both wheels need to point in the same direction but not necessarily in the same track.

The rider adjust for out of aligned rear wheels by automatically "re-aligning" the hadle bars. i noticed this when I had a HD that had an out of alignment rear wheel. On a long trip on the freeway I noticed the handle bars were a few degrees off straight (about 5) ahead even though the bike was going straight. Later investigation showed that the rear wheel was off alignment by quite a margin - fixed this and the handle bars were became straight.

By the way this is a good on the road test - if your bars are "straight" when your are going straight your rear is probably "reasonably" aligned. Note that I didn't feel the bars weren't straight, I compensated for it automatically - I had to see they were out of alignment.

re tyre wear. Thinking about it, if wheels were as in my picture I could see that the rear wheel would push the front a little to the left. In real situations the amount of out of alignment is much smaller than in my pic (a couple of degree at most). If I remember my vector diagrams I dont think the force would be so great to cause excessive wear, but if thats your experience I accept that.

Anyway, its great fun postulating. As I said Im not a mechanic etc. The point is the wheels should be aligned especially for chain and sprocket life and in your experience tyre life but its no drama if they are not "perfect"

Aligning wheels is a good thing to know - especially as you can not rely on all mechanics to do it properly. I still do it but only to check the accuracy of the calibration marks (the HD had none so had to be done each time an with a seperate gear box was an absolute pain).

Looking forward to your How to.

Cheers

Steven

[black13]

excellent info here, i have felt the bars were off a few degrees on past bikes. I asked a service manager about this once & the guy said you cant align
the wheels on bikes, which i thought was a strange comment.
so, max & steven bravo for the informative post,& nato for asking the ?
cheers