Cali rider
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Re: Crisis takes to chattering, brakes that is.. .. ..
I ran Bridgestone 023, 016 and 002, both matched sets and mixed models. I ran Michelin Pilot Powers and Pilot Road 2. I had a set of Dunlop Qualifiers at one point way back, as well as the OEM Dunlops. I don't remember if the problem was critical way back but it was common for the last 2+ years. The range of sidewall strength was softest with the PR2, and by far the stiffest sidewall tires were the 002. I agree with the possibility that sidewall strength is interacting with the suspension to initiate the pogo effect as it would explain the specific frequency of the shaking at any given road speed. I did experiment with extreme pressure differences in the front, as low as 25 and up to 38 PSI. Never made a noticeable change.
I changed out the FZ forks for a R6 setup with different spring rates, damping values and shorter overall length. I moved the fork tubes up and down in the triple clamps, altering the rake/trail values across a wide range. Still no change in feel and shaking. With all of the recent reports of frame cracks I'm starting to think that my frame had damage that I was unable to locate.
Hope this helps move the discussion along.
[MENTION=681]Cali rider[/MENTION]
I didn't research all your post to find "what" tires you ran on the bike but here is what I am finding.
Of the Sport Tires Bridgestone makes, the S20 which I'm currently running is the softest ply sidewall & carcass they have released thus far. I've been speaking with a NW rep who said some bikes have this issues and its a product of the sidewall interaction with the suspension.
I saw in one of your posts you ran 023's. Was that both front and rear? These do have a stiffer carcass than the S20 I'm on now and what I'm finding is NEW, the tire only had this woodp@cker issue at speeds greater than 60 mph and as the tires looses tread off center it will hammer at speeds as low as 20 mph. Do note its the same rate of hammer, but we're at a different speed.
The rep suggested try stiffer sidewall tires and so I'm real curious what all tires you had on the bike and if you could tell the difference in rate of occurrence from a new tire to used up tire. i.e. did it get worse??
Observation: the S20 with no air in it is so pliable it feels as though one could stick their thumb right through the tread off center. Its VERY soft in the tread area.
I may go back to the 016 PRO or Maybe a T30 but thoughts go towards the 16 if I can find one.
Bridgestone Battlax Hyper Sport S20 Front Motorcycle Tire
Size: 120/70ZR-17,
Tire Construction: Radial
Load Rating: 58 (520 lbs.)
Speed Rating: W (168 mph)
Max PSI : 42
Load Range: B
Tread Plies: 2 Rayon 1 Steel
Sidewall Plies: 2 Rayon
Position: Front
Weight: 9.35 lbs.
==========================
FWIW: M-Spec tires are tires that a motorcycle manufacture will have modified from the original design to meet the needs of "their" production bike.
==========================
Time for some more reading I guess and find a new tire to try.
Edit: added S20 pic's as they near the end. And yes, the rightside is missing more tread!
I ran Bridgestone 023, 016 and 002, both matched sets and mixed models. I ran Michelin Pilot Powers and Pilot Road 2. I had a set of Dunlop Qualifiers at one point way back, as well as the OEM Dunlops. I don't remember if the problem was critical way back but it was common for the last 2+ years. The range of sidewall strength was softest with the PR2, and by far the stiffest sidewall tires were the 002. I agree with the possibility that sidewall strength is interacting with the suspension to initiate the pogo effect as it would explain the specific frequency of the shaking at any given road speed. I did experiment with extreme pressure differences in the front, as low as 25 and up to 38 PSI. Never made a noticeable change.
I changed out the FZ forks for a R6 setup with different spring rates, damping values and shorter overall length. I moved the fork tubes up and down in the triple clamps, altering the rake/trail values across a wide range. Still no change in feel and shaking. With all of the recent reports of frame cracks I'm starting to think that my frame had damage that I was unable to locate.
Hope this helps move the discussion along.