Rear wheel centered in frame?

Just finished putting the chain adjusters in, set the chain, made sure same gap on both sides, about 1" play in the chain. I'm just wondering if the wheel is supposed to sit dead center in the cradle arms. Mine has like 3/8" clearance between the frame arm on the left and 1 1/8" on the right. Just seems strange. If I made it so it sat dead center, the right adjuster not be anywhere in synch with the left.

Robb2013 said:

Just finished putting the chain adjusters in, set the chain, made sure same gap on both sides, about 1" play in the chain. I'm just wondering if the wheel is supposed to sit dead center in the cradle arms. Mine has like 3/8" clearance between the frame arm on the left and 1 1/8" on the right. Just seems strange. If I made it so it sat dead center, the right adjuster not be anywhere in synch with the left.

Click to expand...

I think it is more important that you run a straight edge, like a long piece of aluminum angle, from along the front wheel through to rear wheel, that is of course if both front and rear rim are the same width, to get the alignment.
Check the chain during this process. I do this everytime I adjust the chain or remove the rear wheel.

Althoiugh the gap at my adjusters were never the same when alignmnet was correct, now that my front wheel offset is corrected, they are much more equal than before.

I never assume that notches or marks are correct at the chain adjusters. The straight edge does not lie. Although this is not an exacting science, getting it as close as possible is all we can do, which is pretty darn good.

Mine doesn't sit dead centered either - I tried to ensure it was centered and in-line with the main frame tube. Then if the front is in the middle of the forks you should be good.

pvisseriii said:

Robb2013 said:

Just finished putting the chain adjusters in, set the chain, made sure same gap on both sides, about 1" play in the chain. I'm just wondering if the wheel is supposed to sit dead center in the cradle arms. Mine has like 3/8" clearance between the frame arm on the left and 1 1/8" on the right. Just seems strange. If I made it so it sat dead center, the right adjuster not be anywhere in synch with the left.

Click to expand...

I think it is more important that you run a straight edge, like a long piece of aluminum angle, from along the front wheel through to rear wheel, that is of course if both front and rear rim are the same width, to get the alignment.
Check the chain during this process. I do this everytime I adjust the chain or remove the rear wheel.

Althoiugh the gap at my adjusters were never the same when alignmnet was correct, now that my front wheel offset is corrected, they are much more equal than before.

I never assume that notches or marks are correct at the chain adjusters. The straight edge doed not lie.

Click to expand...

My front rim is an inch narrower than the back. Maybe I could shim it out and measure from there with a 6' drywallers straight edge. So you're saying you don't pay any attention to whether the wheel is centered in the cradle or not?

I would calculate a spacer to add to the straight edge.

It's not that I do not pay attention if the rear is centered or not in the swing, but the front and rear wheel NEED to run on center. I think that if all is trued (front and rear wheel offset and aligned) with all bushing and spacer in their proper place, the wheel will still be off center to some extent. Althoug the isolastic system is forgiving in some respects, A Norton running true on the wheels is a beautiful thing.

Hang on, with me sticking my neck out here someone will either validate, correct or both.

pvisseriii said:

I would calculate a spacer to add to the straight edge.

It's not that I do not pay attention if the rear is centered or not in the swing, but the front and rear wheel NEED to run on center. I think that if all is trued (front and rear wheel offset and aligned) with all bushing and spacer in their proper place, the wheel will still be off center to some extent. Althoug the isolastic system is forgiving in some respects, A Norton running true on the wheels is a beautiful thing.

Hang on, with me sticking my neck out here someone will either validate, correct or both.

Click to expand...

Makes sense. I ran my 6' straight edge down the center of the main frame tube, and as far as the eyeball can gage it's balls on. Tomorrow I'll measure both rims, subtract the front from the back, cut that in half and add two spacers that length to two spots in the rim, then put the straight edge on front and back wheels and see how close it lines up.

Robb2013 said:

Just finished putting the chain adjusters in, set the chain, made sure same gap on both sides, about 1" play in the chain. I'm just wondering if the wheel is supposed to sit dead center in the cradle arms. Mine has like 3/8" clearance between the frame arm on the left and 1 1/8" on the right. Just seems strange. If I made it so it sat dead center, the right adjuster not be anywhere in synch with the left.

Click to expand...

You have used the term "cradle arms" and "frame arm". Then you say that you can't get it dead center with the adjusters. Did you mean "swing arm" in both cases? Words matter, make an effort. Find the names of things in a parts list with pictures like Old Britts online. That's what everybody else does.

You can not use the chain adjusters to align the wheels. It will screw up the alignment of the rear sprocket with the front.

http://www.nortonownersclub.org/support ... el-offsets

Read the last post. The Commando has a series of offsets that end up with the rear rim centered on the main backbone tube.

Since no-one has mentioned the engine and cradle offset I will. Engine cradle and swingarm etc is offset 3/16" to 1/4" (depending on who did the welding) to the left (primary). Wheel therefore has to be offset that much to the right in the swingarm to align with the front. That gets you the starting point. Check for centreing in the forks, forks centred on backbone and rear wheel centred on front. Your measurements are giving 5/8" wheel offset to the left which is way out. It depends on tyre size but with a 110 x 18 AM26 mine is 0.7" on left and 0.45" on right measured on an 11" radius with the wheel axle centre 15/16" from the outer end of the swingarm. That tyre is 4.49" wide at the 11" radius. I'd suggest you get the back wheel as equal in the swingarm as you can with the adjusters equally set then remeasure. If its still way out then you'll have to let the tyre down and start loosening and tightening spokes in equal measures to pull the wheel across to the right. Oh and in case you were wondering why Norton offset the whole engine and cradle caboodle to the right I was told it was to give chain and guard clearance to the tyre.........it makes sense.

The straight edge sure does lie! It is possible to have the straight edge line up by cocking the rear wheel. See previous posts by ludwig on this. It is only a valid measurement if the front wheel is perfectly straight (in line with the frame backbone) and tire centered in the forks. The rear adjusters should be equal. If the front wheel is straight and the adjusters are even then the two wheels can be brought into the same plane by changing the rear rim offset. Keith has it right.

I bought two 8 foot 1/4" thick steel strips to use as straight edges a long time ago but this technique is flawed.

It isn't all that critical anyway.

Russ

I personally don't think the rear wheel alignment is all that critical. Just take a pry bar and put it between the swing arm and the z-plate and wedge the swing arm back and forth. Even if you have your iso's set at 0.01, there is quite a bit of play back there.

Anyhow, I like the method of aligning the rear wheel with the main tube and steering head, Ala ludwig. Several ways to do this. Probably easiest if things are pretty much apart, remove the shocks, push the rear wheel/rim up as far as it will go and use a long straight edge to gauge both rim sides with respect to the steering head. Make your own marks or measurements on the adjusters. It's amazing how much just 1/8 of a turn on one side or the other throws it out though. I think most will agree that the rear wheel should align to the steering head and in line with the main tube. Pretty much irrelevant if it's centered in the swing arm or not. Spokes can be adjusted for a bit of offset too.

Dave
69S

Well this is disturbing like you can't F'ing believe. Here are the pics:



This is with the rear axle set via equal distance on the adjusters.



This is what the wheel looks like when it's centered in the swing arm.



A straight edge set across the rim to get an idea of rear wheel offset.

You seem to have the R/H lower shock mounting on the wrong side of the swingarm axle pad?

Robb,
Try the straight-edge method on both wheels and see what you come up with.Also,your speedo drive is not in the correct
position.Cable connects underneath the axle.Make sure all your rear axle parts are assembled in the proper order.You can
see pictures under the speedo drive threads.
Mike















a

Robb2013 said:

My front rim is an inch narrower than the back.

Click to expand...

Both front and rear rims would have been the same (WM2) width originally, so the rear wheel may have been rebuilt to the wrong offset measurement?

It sure does look like that right shock is mounted INSIDE the swingarm lug... (that's not going to affect the problem at hand)

Looks like the swingarm is crooked, or the cradle, or both. Was this a previously wrecked bike?

Looks WAY tweaked left at the end of the swingarm...

Quick easy tire alignment tools: 8' fluorescent bulbs!

Ugh, that looks pretty mis-aligned, but hard to tell from the pics. First get the right shock correct, that shouldn't mess with offset. Then get wheel/rim parallel with backbone. Next is adjusting offset. It should be close enough once parallel with backbone that you can get it centered on backbone with spokes, that's if you have all the correct spacers on the spindle. Someone with a newer bike than mine will have to help you with the spacers.

Also don't assume rear loop is straight/centered. Run a straight edge down the main tube center and mark the rear loop at "center" (rear most point) and see if it lines up.

Dave
69S

You need to make sure the drive sprocket lines up with the rear sprocket first.

Dave
69S

L.A.B. said:

Robb2013 said:

My front rim is an inch narrower than the back.

Click to expand...

Both front and rear rims would have been the same (WM2) width originally, so the rear wheel may have been rebuilt to the wrong offset measurement?

Click to expand...

When I had the wheels built, I brought the old ones in and had them measure the offset. The front is narrower than stock and it lines up perfectly as far as the disk caliper etc. The rear wheel offset is a big concern right now. I can already hear the denial of culpability speech in my head if I bring that wheel back saying he got the offset wrong.

I'm going to take a break and go clean the damn garage while it's still somewhat cool out. It's been so fricking hot the past few days... like over a hundred one day... that I just started dropping tools when I got done with them due to lack of energy. (As you can see in the pics). This is pissing me off and I need to relax.

Someone asked if this bike was ever in an accident. I don't have any information on it's history. Here's a pic of it the day I got it. Pretty much a rolling basket case.

Call up the people at the INOA chapter in Chicago. If anybody ever needed 'boots on the ground' help, it's you. It's what they love to do, let'em help you out.


You didn't follow the link in my post, so here it is. Read it.

This is Vern Fueston:

"I have the definitive answer as to what is offset, how much, and which way!

I set up a 1973 850 on the frame table and verified it was straight. I then put together a dummy engine and installed it with new isolastics, new washers, Hemmings adjusters, and a Norvil head steady. I put both adjusters on the left side, checked the swinging arm in my fixture and then installed it in the frame. I took all the play out of the adjusters and started measuring:-

The frame is symmetrical
The engine/gearbox cradle is offset 1/8" to the left.
The swinging arm is offset 1/8" to the right so the axle pads end up centred in the frame

I then installed the rear wheel:-

The spoke flanges are offset 1/8" to the left as mounted in the arm, so the rim is laced off 1/8" to the right to put the tyre in the centre
The centre of the rim is 3.3/8" from a straight edge laid across the brake drum (not the backing plate

With the stock Dunlop rim, if you sight across the rim on the brake drum side you will see about 1/16" of hub when it's in the right place. In my opinion, front and rear adjusters should be on the same side. Otherwise as things wear and you take up the slop you angle the engine and gearbox in the frame. Since the swinging arm mounts to the cradle, a little one way in the front and a bit the other way in the back and the rear wheel is out of line considerably. The chain will still line up but the wheels will not.