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Top Case and Front tire cupping

2K views 8 replies 4 participants last post by  carldmd 
#1 ·
So I've noticed this slight squirrely motion of the front end lately. I've got 3000 miles on my GT. Had to replace the rear Bridgestone 020 tire at 700 miles due to a flat, and placed a Metzeler M1 on the rear while running the BT 020 on the front.
Now I carry my backpack, which weighs about 20lbs. in the topcase. I carry my Powerbook in the backpack. Could this weight account for the motion of the front end.
Also, here's a photo of the cupping of the front tire:
.
Anybody have any comments? I'm scheduled to have both tires replaced this afternoon to see if that helps.
Thanks,
Carl
 
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#2 ·
The weight in the topbox is not the issue. BT-020 front tires all cup like that at some level or another. That is why I changed to Avons. IMO, I don't think the B'Stone front 020 can take heavy braking, and that's what feathers them. (BTW..."feathered", not cupped.)

How many miles are on that front 020?
 
#3 ·
carldmd said:
So I've noticed this slight squirrely motion of the front end lately. I've got 3000 miles on my GT. Had to replace the rear Bridgestone 020 tire at 700 miles due to a flat, and placed a Metzeler M1 on the rear while running the BT 020 on the front.
Now I carry my backpack, which weighs about 20lbs. in the topcase. I carry my Powerbook in the backpack. Could this weight account for the motion of the front end.
Also, here's a photo of the cupping of the front tire:
.
Anybody have any comments? I'm scheduled to have both tires replaced this afternoon to see if that helps.
Thanks,
Carl

Hello Carl,

I had 020s on my departed '02 RT. I did not own that machine when the 020s were installed. The front cupped/feathered badly at or before half life. Not noticing any bad ride or handling issues because of the tire I rode 'em till I sold the bike.

Interestingly, I replaced the '02RT with a new '04GT. It came equipped with 020s as well.
I'm about to replace the tires on the GT for the first time. I have 9,700 miles on those original 020s. The tire pressures were always kept at or a bit above factory specification. 36 front / 42 rear. Only when returning home to Cleveland from Washington D.C. this month did the front tire finally give up and show some significant cupping/feathering.
In fact it looks alot like yours, except worn to the wear indicators.
It is now wasted, done, finished.

The 020s really performed quite well for me on the GT. Predictable , good in the rain, enough grip for my risk level, and quiet running.
Go figure...

For kicks and comparrison sake I now have a set of Avons for it (not yet installed).

DMilan
 
#4 ·
carldmd said:
So I've noticed this slight squirrely motion of the front end lately. I've got 3000 miles on my GT. Had to replace the rear Bridgestone 020 tire at 700 miles due to a flat, and placed a Metzeler M1 on the rear while running the BT 020 on the front.
Now I carry my backpack, which weighs about 20lbs. in the topcase. I carry my Powerbook in the backpack. Could this weight account for the motion of the front end.
Also, here's a photo of the cupping of the front tire:
.
Anybody have any comments? I'm scheduled to have both tires replaced this afternoon to see if that helps.
Thanks,
Carl
If you have your preload set to "one helmet", I'd suggest that you try setting it to "one helmet plus luggage". It sounds to me like you need a bit more suspension firmness?
 
#5 ·
Thanks guys. Joe, I've got 3200miles on these.
But can this movementof the front end be from the feathering? Or from the weight on the rear end? I know some you guys (I won't mention any names) have seen some triple digit speeds. Have you had any issues with feeling as if the front end is too light?
Carl
 
#6 ·
carldmd said:
Thanks guys. Joe, I've got 3200miles on these.
But can this movementof the front end be from the feathering? Or from the weight on the rear end? I know some you guys (I won't mention any names) have seen some triple digit speeds. Have you had any issues with feeling as if the front end is too light?
Carl
3200 miles? I would suspect that you're not keeping enough pressure in that front tire. I run 42 up front. 46 rear. But you have to experiment with what works for you. My 020 didn't really need changed at 6K, but I knew it would be going downhill soon, so I just changed it with the rear just to get it over with.

I have done 140+ with both the 'Stones and Avons, and the frontend feels very planted. And I did 140+ fully loaded . . . and I mean LOADED. No, the topbos is not the issue.
 
#9 ·
Joe
20 miles from the Pittsburgh stadiums, 8 miles from the Pa turnpike. If you're riding this way, let me know.
I reset the preload to 1up with luggage and that did the trick. The adjustment eliminated that squirrely feeling. Really knid of amazing. Of course, I feel rather stupid. I paid BMW to put ESA on my bike, and then I don't use it....DUH.
So there's a lesson here - use the ESA the way it was intended. I also had Z6's put on this afternoon. I'm feeling much better.
BTW, ESA should stand for 'EXTRA STUFF ADJUSTMENT'. Then I would always know to adjust it for ALL THE EXTRA STUFF I CARRY!!
Carl
 
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