João, I too am really interested in what Tod comes up with as we seem have a couple of twins.
My bike has 38000km on the clock and the first 10000 km belonged to the original owner. That first tyre was an Angel GT exhibiting scalloping so I replaced it with GTII , same result.
Blaming poor dampening and general bike setup I rebuilt the forks, got a decent shock blah, blah, blah.
Happened again, now if the tyre is clearly exhibiting fault it maybe the choice of tyre but .......it's made worse by that whopping great 180 wide, 55 low profile on the back.
The back resists lean angle due to its width having to raise the bike whereas a scalloped front tyre worn to a Vee presents an extremely high profile narrow contact patch that simply wants to fall over.
So low speed cornering resembles a low frequency oscillation of the rear saying no and the front saying "hell yes" and the rider reacting a split second behind all of this trying to correct each different problem in turn.
At high speeds the oscillation is at a higher frequency and moves out of the critical phase and of course cornering forces start to dominate and take over.
Still believe it's a combination of dampening settings and/or poor servicing with forks, the tyres pick up on so choose ones that don't and a lack of trail that allows the oscillations to enter a critical phase.
Can't prove any of that and I don't think that anyone can either as the problem seems to be so specific and unique, and even if it could be it would probably be denied by the owners as " just having a bad day" or "I must have got the pressure wrong" etc.
Back to the back tyre choice, I believe that a 170 wide rear would suit this bike far better as it doesn't lift the rear as far in cornering and would more closely resemble the behaviour of the front.
Remember the "matching pairs" quotes in all the preceding posts.......
Chris.
My bike has 38000km on the clock and the first 10000 km belonged to the original owner. That first tyre was an Angel GT exhibiting scalloping so I replaced it with GTII , same result.
Blaming poor dampening and general bike setup I rebuilt the forks, got a decent shock blah, blah, blah.
Happened again, now if the tyre is clearly exhibiting fault it maybe the choice of tyre but .......it's made worse by that whopping great 180 wide, 55 low profile on the back.
The back resists lean angle due to its width having to raise the bike whereas a scalloped front tyre worn to a Vee presents an extremely high profile narrow contact patch that simply wants to fall over.
So low speed cornering resembles a low frequency oscillation of the rear saying no and the front saying "hell yes" and the rider reacting a split second behind all of this trying to correct each different problem in turn.
At high speeds the oscillation is at a higher frequency and moves out of the critical phase and of course cornering forces start to dominate and take over.
Still believe it's a combination of dampening settings and/or poor servicing with forks, the tyres pick up on so choose ones that don't and a lack of trail that allows the oscillations to enter a critical phase.
Can't prove any of that and I don't think that anyone can either as the problem seems to be so specific and unique, and even if it could be it would probably be denied by the owners as " just having a bad day" or "I must have got the pressure wrong" etc.
Back to the back tyre choice, I believe that a 170 wide rear would suit this bike far better as it doesn't lift the rear as far in cornering and would more closely resemble the behaviour of the front.
Remember the "matching pairs" quotes in all the preceding posts.......
Chris.
