wheel alignment jig

maylar · Jun 16, 2009

I'm considering making a fixture of some sort to hold the front wheel perfectly straight so I can align the rear wheel to it when adjusting the chain. My idea is to have something that will clamp to the front frame tubes and locate against the back of the forks. Have any of you guys done something similar? I want a quick and positive way to get the 2 wheels in perfect alignment each time I adjust the chain.

Jeandr · Jun 16, 2009

If you make something that clamps to the frame, then you have to assume the frame is aligned correctly at that precise point. Why not clamp rectangular or square aluminum tubes on both sides of the rear wheel, then the back wheel can be moved so that the front wheel is centered between the two tubes.

Another way is to have a smaller piece calmped to the rear wheel onto which a laser pointer is mounted, the the rear wheel is moved so that the laser beam is the same distance at two points on the front wheel.

More ideas anyone?

Jean

This picture http://www.pbase.com/jeandr/image/96424139 and the next few show how I did mine, I will recheck before going on the road.

swooshdave · Jun 16, 2009

ludwig said:
First you should make shure that the front wheel is EXACTLY in the middle of the front fork .
Mesure this relative to the fork stanchions , not the sliders .
Than clamp the front wheel ( without tire ) with 2 square alloy bars of +/- 1 meter to the centre frame back bone .
The WM2 rim is a bit wider than the frame tube , so you need 2 spacers of equal thichness .
(also need to remove front fender and coils) .
This is IMO the only way to make shure that the front wheel is in line with the frame .
In fact , you should do the same with the rear wheel .
If not clear , I'll make a drawing .

Isn't that a pain to remove both tires every time you adjust the chain? :shock:

swooshdave · Jun 16, 2009

ludwig said:
Wheel alignment ( on a Commando ) means aligning the engine craddle in the frame .

Yes but the original question was about maintaining the wheel alignment when adjusting the chain.

maylar · Jun 16, 2009

Jeandr said:
If you make something that clamps to the frame, then you have to assume the frame is aligned correctly at that precise point. Why not clamp rectangular or square aluminum tubes on both sides of the rear wheel, then the back wheel can be moved so that the front wheel is centered between the two tubes.

Jean

I was approaching the process from the other end.. get the front wheel straight, clamp angle stock to it, then align the rear wheel to that. Parallelism is my goal, not absolute alignment of both wheels to the frame centerline. I just want something more accurate than a Mark I Eyeball when moving the rear axle during chain adjustments.

Maybe your idea would work too. But that stuff on your web site is a bit extreme for a stock Commando.

BTW there's no guarantee that a disc brake Commando's front rim is exactly centered in the forks. The famous "offset" is a function of wheel lacing and has a tolerance. My 850's factory front rim was off to the left by almost 1/8 inch. It's much closer now after being laced by Buchannans.

Ludwig, thanks for that. I agree that the stock adjusters are terrible.

swooshdave · Jun 16, 2009

Here's the adjuster on a Bultaco. Some of them are serrated which is also nice.

Here's the adjuster on a Dick Mann frame. Hint, look at the swingarm pivot.

It doesn't seem like ludwig's has very much range of adjustment although it's a very sturdy arrangement.

swooshdave · Jun 17, 2009

ludwig said:
swooshdave said:

It doesn't seem like ludwig's has very much range of adjustment...

Click to expand...

I have more than one set of plates , but in practice I only une this one .
Each hole is a step of 0.5 mm . 4 adjustments + loose chain = 2.5 mm , or 0.1 inch , then I change the chain .
I also use 2 chains alternatively .

Can you send me your old chains? I think I can squeeze a little more use out of them. :mrgreen:

Coco · Jun 17, 2009

ludwig said:
I also use 2 chains alternatively .

I do this religiously with all of my high end bicycles. Ever price out chain rings on high end bicycles? As Ludwig said......chains are cheaper. If you keep your drivetrain clean and swap chains, the chainrings will last a very long time.

swooshdave · Jun 17, 2009

Didn't say I'd use them on a Norton. Dirt bikes are awful tough on chains. :mrgreen:

Brewer · Jun 18, 2009

Hey Guy,
Many years ago I worked in a motorcycle shop and one of the mechanics at the time, used a string line that was wrapped around the front rim including the tryre then he proceeded to bring this string back towards the rear wheel to check the alignment of both wheels in relation to each other after the chain ajustment.
Is anyone familiar with this technique of aligning the front to back wheel! And can shed a little light?
I have not tried this method myself , however obstruction from the centre stand may pose a problem.

Brewer.

Paul · Jun 18, 2009

Brewer said:
Hey Guy,
Many years ago I worked in a motorcycle shop and one of the mechanics at the time, used a string line that was wrapped around the front rim including the tryre then he proceeded to bring this string back towards the rear wheel to check the alignment of both wheels in relation to each other after the chain ajustment.
Is anyone familiar with this technique of aligning the front to back wheel! And can shed a little light?
I have not tried this method myself , however obstruction from the centre stand may pose a problem.

Brewer.

That's indeed a simple and efficient method but you should take in account the difference in tyre width (if any) so use a spacer such as a piece of board, as thick as half the tyre width difference and place it between front tyre and string. The centre stand indeed is a problem though (I tried it last week) so I used a hoist to lift the back of the bike. Once the wheels are alligned, measure up the position of the adjusters (for my bike: 3,5 mm difference) and in the future, you'll only have to ensure that the adjusters keep the same deviation of position.
(I hope you can understand my English... :? )

BillT · Jun 19, 2009

A string is just the same as a laser.

I work in construction, and strings are used all the time (in skilled trade work, that is) as a reference to keep things straight and aligned. Now that lasers are so cheap, they've replaced many strings, but there's a reason why that sturdy yellow string one finds at home centers is called 'mason's twine'.

rbt11548 · Jun 19, 2009

BillT said:
A string is just the same as a laser.

Capatain Kirk says it's not!

Jeandr · Jun 19, 2009

rbt11548 said:
BillT said:

A string is just the same as a laser.

Capatain Kirk says it's not!

Click to expand...

Only because Kirk hadn't studied string theory :lol:

Back to wheel alignment: why not clamp a board or aluminum piece onto which a laser pointer is mounted and use that to make sure the back wheel is in line with the front? Remember, a laser doesn't droop as long as there are no black holes near the bike of course.

Jean

79x100 · Jun 19, 2009

The use of a string line is a time-honoured technique for aligning Norton wheels.

Of course, it helps if both tyres are identical 3.25x19s and if there is a handy rear wheel stand, which is why my current project has...3.25 tyres and a rigid frame (and only 12bhp so if I get it wrong, it won't tie itself in knots anyway

)

Paul · Jun 19, 2009

Very nice and appropriate picture ! And with 7 assistants, it should be a bit easier to do than on your own ...

maylar · Jun 20, 2009

ludwig said:
I think that this string or laser method is not precise enough on a Commando , unless you first make shure that the engine craddle + swingarm are straight in the frame . It is perfecty possible to line out the wheels but have them both in an angle relative to the frame . Then you ride a little bit sideways , crab style ..

That's true, but it may be the lesser of evils. Adjusting the rear wheel so that it's inline with the front can have a dramatic effect on eliminating the infamous "Commando Left Lean Syndrome" where the bike wants to turn left if you take your hands off the bars.

Brewer · Jun 20, 2009

Yes! Mylar.

The string line method , to me! seems to be a tried and true "simple" Idea... even judging by the old image army image.
It does seem that it may not be as accurate as other methods already mentioned.... However it seems to be such a simple and better than nothing solution.
It would give you a indication that your front and back wheels are out of alignment with each other. If used correctly It could enable you to correct this wheel alignment problem when you adjust the drive chain tension.

One!, has also to consider that under power acceleration and heavy braking... the frame would also have some degree of flex and distortion to contend with, which would throw the wheels out of alignment to some degree anyway !

Brewer.

wheel alignment jig

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