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I just completed a 2500 mile trip on my 1977 R100S with Lester mags.

The last stretch home from Vegas to Los Angeles was a hair raising one. The drivers in cars were A-Holes, the roads were straight and HOT, massive head winds, and I tractor Trailer's tire blew up in front of me throwing scraps all over the road.

But the thing that had me concerned the most was that the back end started to feel loose when making turns.
I rode VERY cautiously the last few miles. At first I thought my tire pressure was low. Then I thought my axle or swingarm was loose. Upon inspection, everything is still OK.
I do know that my final drive splines have very little left to them. I tried to replace before I left them with a donor final drive, but the guy doing the welding mis-managed his time, thus leaving me without my rebuilt final drive.
I'm not sure about the wheel bearing condition. I was going to inspect that upon swapping final drives and I never got around to it before my departure.

I took all the bags off and went for a test ride today and it isn't as bad as I thought (i think the loaded saddle bags made it worse), but something is still a bit wobbly back there.

The only thing I can find that seems odd is this - The center tread of the tire is more worn on one part of the tire and fine elsewhere. This is the first time I ever used Avon Roadriders and up until now, I love them. They are the first tire that does not catch the wavy rain grooves in the freeways.

I'm guessing that this is the problem. But how did this happen? did the tires become unbalanced somehow?
I have tubes in these tires. And I did go from sea level, to 5000', to 7000', to 5000', to 11000' and then back to sea level so I was constantly checking tire pressure.




And here are photos from my trip:



Looks like I need a new tire? This one probably only has about 3300 miles on it.

I guess first thing is to take the wheel off and mount it on a wheel balancer and check for wheel/tyre buckles.
Tread depth variation shows wheel out of balance?
Could this be the front end causing this?
Chech frame/subframe for loose bolts or frame cracks.....perhaps.

The bike is going on the lift today and the rear wheel is coming off. I'll take it to a buddy's shop and check for true/balance tomorrow.
I did go through my front brakes before my trip (Bled, new piston seals, etc..). I noticed that occasionally, the front wheel felt like it was dragging, i'd adjust the calipers so the wheel would turn smooth, and then it would start dragging a bit after a few hundred miles. Nothing too terrible but not as free as a bicycle tire. There are no signs of the brake disks being warped.

I had taken my bike with ATE brakes to the BMW dealer where they have an airhead specialist. After I got the bike back, the brakes still rubbed some. I'm pretty sure he would have checked that little vent hole in the under tank master cylinder but it wasn't actually discussed. If you find out what cooks with your brakes, I'll be watching to try to learn from it.

I'm glad you didn't have the same result as I did from your bike's quirks. You are right to try to find it. Make sure you don't test ride in without wearing all the safety gear.

Chuey

Before you pull the rear wheel off, grab it and work it see if there is any movement side to side from the swing arm pivot area.

jagarra wrote:Before you pull the rear wheel off, grab it and work it see if there is any movement side to side from the swing arm pivot area.

That was the first thing I did. Nothing is loose. I am starting to think this was a severe balance issue which will cost me a new tire.

With a severe balance issue you would think you would feel the imbalance through the seat of your pants. It would give you a vibration not the elastic feeling you describe. You mentioned you are running tubes on the Lesters, they work tubeless, is there a reason you are doing this? I run Roadriders on my Connie, on my 2nd set, they work pretty good.

gg

No vibration throughout my ride. Not until I hit some curves and felt the uneasy feeling I described. And that wasn't until my last 200 miles or so.
Ever since I assembled this bike back in 2003, the mechanics who mounted my tires used tubes. I just stuck with it.
I'm willing to go tubeless... considering I have to get a new tire, I might as well give it a try.

jagarra wrote:With a severe balance issue you would think you would feel the imbalance through the seat of your pants. It would give you a vibration not the elastic feeling you describe. You mentioned you are running tubes on the Lesters, they work tubeless, is there a reason you are doing this? I run Roadriders on my Connie, on my 2nd set, they work pretty good.

gg

jagarra wrote:With a severe balance issue you would think you would feel the imbalance through the seat of your pants. It would give you a vibration not the elastic feeling you describe. You mentioned you are running tubes on the Lesters, they work tubeless, is there a reason you are doing this? I run Roadriders on my Connie, on my 2nd set, they work pretty good.

gg

Last year I was out on a ride and the bike became squirmy in the corners, but felt fine on the straights. The rear tyre pressure was 38psi. The problem was the axle nut was loose. When the rear brake lost it's usual firm feel, my light went on!

I have read about problems with Lesters concerning the bore that the wheel bearing sits in being sloppy. I used the Roadriders one time and found the rear tire was cupping. That has never happened before or since when running other brands.
I never bought them again.