Tyre fouling on swingarm

Hi All
Just back from the MOT test centre and the old girl failed due to the sidewall of the tyre rubbing on the swingarm. The guys at the test centre can't come up with any explanation as to why this should be. The bike was parked up all winter and only brought out of hibernation to be tested. The fouling is on the drive shaft side and is quite severe and uniform all around the circumfrence. The tyre is the correct size for the bike and is also correctly inflated. The tyre has been on the bike for 3 years (I don't ride enough) without any problems. The wheel has not been out of the bike since the tyre was replaced. As I am totally and utterly inept with anything vaguely oily, I'll get my mechanic son to have a look at it.
Any ideas at all as to what the cause might be?
Any and all ideas gratefully received.

Many thanks in advance

Martin

What is the make & size of the tire ??

Hi JV
Avon of some sort. 160/70/17.

Could you have picked up some debris that got caught on the swingarm, and caused the rub, or can you actually see where it is rubbing?

Ride Safe
John

Others here will have to verify, but I do believe there is a spacer that can be installed wrong when the rear wheel is removed and replaced. It's been a while since I had an 1100 apart so my memory is quite vague.

If the tire never rubbed before, and now suddenly developed the rubbing after being stored over the winter, the first step in my mind would be to replace the tire. Not sure what would cause it to happen, but either the dimension of the swingarm changed, or the dimension of the tire changed, my money is on the tire.

Just had a quick look and my impression is that the area circled in yellow (not a photo of mine obviously) is the bit that is causing the problems. Not sure if it's gone as far as the example in the picture but I think the lower flange has "blown" out a little if that makes sense.

man you Brits really have some kind of corrosive environment over there, I'm at the opposite extreme, we don't even have humidity. Never gave it a thought that the swingarm could "grow" over the winter, so go figure.

BTW, if the swingarm had that kind of distortion wouldn't the guys at the inspection station been able to see that? You said earlier they had no clue what the cause was.

Time to pull the wheel off to get a good look at the swing arm. Then post us some pics. Swing arm bent out of shape from severe rusting seems the most logical answer, but why wouldn't the MOT guy have picked that up, so you have a real mystery on your hands that has probably never been seen here.

I guess another possibility could be extremely worn swing arm bearings?

I believe it's a swingarm swolen from rust inside. I had same symptoms on my 94'- actually that's how I found out that there are holes on bottom of swingarm. That never happened after I replace it with used one from eBay.

Mark

I think maximark has probably hit the nail on the head there. I'll have to wait until my son has time to whip the wheel out for me. As soon as he does I will take some photos.
Thanks for taking the time on this guys.

Like to see what U find out on that tire rub.
Never heard of RUST??? on the Swingarm, or ever had any trouble like that on my ST1100.
Hope U'r not looking at needing a new 1.
WHEEL Install issues?? B careful.
Good Luck.

Has to be the swingarm rusting away,I'll be interested to see what you find,don't understand though why the MOT tester couldn't see what was rubbing on the wheel.

Hi brock11
the tester knew it was fouling on the swing arm, he just couldn't.figure out why. I'm pretty sure it's going to end up needing a new swing arm or at least major repair work to the existing one, but I haven't totally given up hope that it may be something less expensive like a collapsed wheel bearing or the like. Fingers crossed.

I'm thinking a rotten swing arm too. However, before condemning the swing arm, when you take the rear wheel off, take a real good look at the wheel bearings, thrust washer, cush drive, etc....

Photos as promised. Rest of swingarm is solid.

Probably the combination of an Avon Storm II, known for a rather extreme wide tread-surface, plus the rust-deformation on the swing-arm...




I would however seek for a replacement swing-arm, as the grade on internal, structural damage is unknown...

I would however seek for a replacement swing-arm, as the grade on internal, structural damage is unknown...

Click to expand...

As someone who is usually pretty far to the risk-taking end of the "ride it or replace it" spectrum, I wouldn't ride on a swingarm that could potentially fail and lock up the rear wheel in the process. Whatever the replacement cost, its gotta be a lot cheaper than a crash.