Vibration Banking Right

[Ves]

Anyone have any ideas what could cause a vibration when turning right that isn't there when upright or turning left? I feel it through the bike... Hard to describe. It's like the difference between going over a rough road surface vs smooth. I checked the wheels... they seem tight and roll freely... the rear tire is evenly worn... I'm wondering if it's the start of some sort of drive problem...

[NoRRmad]

Welllll....

The load on the final drive bearings is different when you're turning... If there's a rough spot on the race, it may get loaded only when the tire is on one side or the other.

Just a theory.

[Ves]

I guess that's as good a theory as any. The thought did occur to me. Only one way to find out... Guess I need to go order some bearings... .

[Ves]

Whew ... glad to say it wasn't a drive problem. It was my tire. Don't ask me how? The tire was pretty worn, but I didn't see any difference between left and right side of tread... but after putting on a new rear Pilot Road... no more vibration. And man, does the thing turn now ... it feels like it lost 100 lbs. The difference is unbelievable.

[NoRRmad]

Hm. Another thing that's changed -- besides your tire -- is that you've had the rear wheel off, and retorqued the lugnuts putting it back on. I wonder.

[Ves]

Hm. Another thing that's changed -- besides your tire -- is that you've had the rear wheel off, and retorqued the lugnuts putting it back on. I wonder.

Don't think that had anything to do with it. I checked the wheel earlier. Everything was tight and true. My old front tire, replaced last year, was cupped, that one vibrated, but you could see the cupping, so it made sense. I didn't see anything unusual in the rear tread... I'm just glad it wasn't something serious. After all the spline and final drive problems I keep hearing about I'm just praying mine isn't one of bikes that's going to have that problem.

I talked to a guy at a local BMW shop that specializes in repairing vintage BMW's. They also work on the modern bikes. Guy said he's never heard of a bearing that would be rough only when turning in one direction. Either it's rough or it's not.

Moral of the story. If you have an old tire on your bike and you get directional vibrations... could be the tire...

[NoRRmad]

Just theroretically, now...

I think there are two bearings in the final drive; an inner and an outer. (I could be wrong on this.) When you bank the bike, the contact patch moves, producing a moment change on these bearings, reducing the load on one bearing, and increasing it on the other. If one's rough, that will be felt as an increase in vibration with lean angle.

Concerning the lugnuts, if, say, two, adjacent nuts are loose, the wheel will shift slightly when you bank, and it will no longer be running straight-and-true to the frame, producing a side-to-side force with each turn of the wheel, which would be felt as a low-frequency vibration.

But I'm glad the tire change worked. For whatever reason.

[RGuy]

Sleep well Ves. My Pilot Roads with 12k miles on them do the same thing. Go a bit faster and they will howl too. The OEM Macadams were worse. I think you notice it more on the right turns because they are typically tighter turns than left turns.
Neal

[Ves]

Sleep well Ves. My Pilot Roads with 12k miles on them do the same thing. Go a bit faster and they will howl too. The OEM Macadams were worse. I think you notice it more on the right turns because they are typically tighter turns than left turns.
Neal

The tire that was doing it was a Metzler. Pilot will do it too, huh? Well, it must be a form of "wear indicator"...