Rear Tire Rubbing

[DGXSER]

Yes, it is back...well...never really went away I guess.

So, here is what I know and have tried. I have a spare set up of complete swingarm, brake, torque plate, spacer, wheel, and FD. All assembled, tire in spare runs fine. No rubbing. Put the same tire in the setup on the bike frame, rubs. This is true for both wheels/tires. I do notice that when I go to put the axle in, it is very tight getting the larger diameter section to go in the swingarm. I have to lift and push on the tire to get it aligned. At rest, so to speak, the axle is low and to the rear of the opening.

OK, so I swapped out wheels, same problem. Swapped out torque plates, same problem. Swapped out brake bracket, same problem, Swapped out FD, same problem. I am at my wits end with this. I thought I was a decent mechanic but this is just killing me.

Only thing I can think of is the rubber gromet the torque plate mounts into. Anyone have a pic of their torque plate properly mounted on that rubber gromet? Mine is VERY tight, and actually elongates the rubber, and must be driven on with a mallot. That is why I suspect it could be twisting the set up enough to cause the wheel to rub.

Any thought appreciated.

[crazy steve]

Still fighting that eh....

...So, here is what I know and have tried. I have a spare set up of complete swingarm, brake, torque plate, spacer, wheel, and FD. All assembled, tire in spare runs fine. No rubbing. Put the same tire in the setup on the bike frame, rubs. This is true for both wheels/tires. I do notice that when I go to put the axle in, it is very tight getting the larger diameter section to go in the swingarm. I have to lift and push on the tire to get it aligned. At rest, so to speak, the axle is low and to the rear of the opening..

The axle misalignment can be addressed. If the axle is to the rear of the swingarm hole, the arm is too wide; use a block of wood and a BFH to knock the brake side closer to the FD side about 1/16". For the 'low' part, loosen the FD and rotate it slightly. When the alignment is right, the axle will push in by hand. Do this with the wheel removed.

You don't mention what size rear tire you're running. With a 130, you should have between .2" and .25" clearance. The 140s will run tight, if you have a tire on the 'fat' side of the spec for that size it might rub no matter what. I've also noticed that the 'cutaway' in the swingarm for the tire isn't always as deep depending on the individual swingarm. Again, this may be a place to use the BFH to gain the needed clearance, rechecking swingarm alignment after the 'persuasion'...

Worse case, you could install a spacer washer on the axle between the wheel and the FD. After finding a suitable size, I'd glue it to the FD with some superglue to hold it in place so you can install the wheel.

As to the torque arm grommet, just remove it. That's nothing more than an anti-rattle anyway, and has been missing on most of the bikes I've seen with no noted issues. But I doubt that's the problem in any case.

Lastly, the max torque on the pivot bolts is only 52 inch-lbs, or just a hair over 4 ft-lbs. As has already been noted, overtightening these will cause problems...

[DGXSER]

Thanks Steve, Both wheels have 130/90/16 tires on them. One is a Shin, the other is the GT501. I measured both and they are about the same width.

Yep, I discovered that error in Clymers and corrected the torque. Thought I had th rubbing corrected then, but not really.

The low part of the axle is not a real concern, that is easily overcome by lifting up on the wheel a little, the to the rear so far I have to seriously pull on the back of the wheel to get it to go in that is. I will try beating the swingarm back into position. Anyone know the correct dimension for the swingarm brake side from say the lip of the FD?

What I find insane is that the setup works when not mounted to the frame. But I just do not see how the frame can be bent such that it would cause this.

[crazy steve]

...Anyone know the correct dimension for the swingarm brake side from say the lip of the FD?

What I find insane is that the setup works when not mounted to the frame. But I just do not see how the frame can be bent such that it would cause this.

I don't know that there is a 'correct' dimension for the swingarm as these are put together rather sloppily IMO. As long as there's a space between the torque arm and the swingarm once everything is installed it will be ok.

I'll tell you what I'd try; if everything lines up up with the swingarm off the bike, loosen both swingarm pivots then reinstall the wheel, etc. After all that's on (and with proper clearance), then tighten/adjust the pivots. If doing that pulls it back out of alignment, then you have a swingarm bearing and/or frame problem.

I'll agree, I don't see how the frame could do this, but something is...

[DGXSER]

So, Steppenwolf came over on his 80SG. So we took measurement after measurement and found nothing off. So I pulled the rubber gromet off, and reinstalled the wheel, no rubbing...until I pulled the phillips head out of the hole in the axle that I was using to keep the axle fromspinning as I torqued the bolt. Then the swingarm moved about 1/8" out and the tire rubbed. Put the phillips back, no rubbing.

So, the solution I applied was to put the phillips back in place, ue it to push the swingarm inward, and set the pinchbolt. Now, no rubbing!! So, at the end of the day it would seem the swingarm is bent.

[DGXSER]

As an update, I found that as I ride the bike, that bent swingarm would overcome the pinch bolt, and move back out. The tire would start rubbing again. So I got this process started, wrench, ride, rub, repeat.

So I decided this needed a more permanent solution. Here is what I came up with.

The glare makes it a little hard to see, but I took a hex bolt and cut one side so it matched the distance from the center of the hole in the axle to where I wanted the swing arm to be. Drilled the hole in the swingarm a touch larger to let the shoulder bolt I had on hand slide through.


Then I measured the distance across the axle, and using my dremel I flatened a spot on the bolt threads 90 deg offset from the area I cut to mate against the swingarm. Drilled a hole for a cotter pin and used that to ensure the bolt does not slip out of position. The 90 deg offset was to ensure the cotter pin did not protrude toward the wheel, its vertical up and down.


Several thousand miles later, not problems with tire rub or the bolt.

[natemoen]

Have to say it but I think the solution for a bent swingarm is replacement. If thay isn't an option then straightening.

[trbig]

My opinion is if the swingarm is only slightly bent.. ehhh. Bending it back and forth trying to fix it will only make it weaker. When the pinch bolt was being overridden, you can get a little bit longer bolt for the pinch bolt, install a nut on the other side and get a lot more torque to squeeze onto the axle than the wimpy allen screw.