Ok, heres the deal, I have an 06 cbr 1000rr. I am 6ft 5 in @ roughly 275. (big guy I know) Ever since I put my race compounds on (pirelli super corsas) I have notice a shudder in my front braking. It doesn;t do it all the time, which scares me, and I seem to notice it the most in right hands going about 30 or so.....it does NOT do it at over 55 just when coming to a moderate slowing or stop. What could this be...? I have taken off the calipers and inspected them as well as the pads for anything. A buddy says it might be I am compressing the forks too much and given it a "suspension wobble"? Any ideas? Maybe the tire or possibly a warped rotor? But why only at slowing down speeds?

 

err im just a 15 year old (no joke) and my guess is its just because it is sports compound. they tend to work better under high temperature since you said that braking at low speeds starts the shudders it MAY be why.. i have never driven a bike above 150cc (because legal age limit here is 18 anyways). so this is based on what i read

 

set up the suspension properly and see if that cures your problem, because it's definitey not the tires. I've got Supercorsas on my bike, and I had a shudder (with a set of Avons, not the Pirellis), but when I set my suspension properly it cured the shudder.

Get some springs for your weight (the stockers are sure not up to the task of 275[:-]) and dial in the settings properly. The fork may be bottoming out on the tracel and causing an issue. Trysetting the preload a little tighter and diaing in a little more compression damping for the time being.

 

wouldn't there be more G when he is braking from high speed? O.o so if he is NOT shuddering above 55km/h its probably not the suspension grounding right? or am i wrong ? @_@

 

I had the same issue - I'm 225 lbs and I have an appt. with Traxxion on Tuesday to get some beefier springs for my boyish figure!

Just searched on the net and didn't realize Traxxion was only 30 minutes away...sweet!

 

Blackrr1:

I do not think it has anything to do with suspensions. Wasn't the bike fine BEFORE the Pirellis? Something must have happened during the installation of the new tires. Are you sure the brake pads are being actuated equally and constantly? There is a technical concept called "natural frequency" in any machine. If a machine, in this case your bike, is excited by an external force at a certain constant interval (frequency) that happens to match the natural frequency of your bike, it will vibrate.

In your case I am guessing that the brake pads are not squeezing down evenly and/or constantly on the front rotors. The cause could be a slightly warped brake rotor(s). Did you mess with the brake cylinders at all when you removed/installed the new tires? If you messed with the brake lines, there may be air in the lines that would keep the pads from squeezing evenly and constantly.

The fact that there is no vibration above 55, but there is vibration as you slow down is a pretty clear sign to me that the vibration is caused by some form of external force as I mentioned above. This transient vibration occurs because natural frequency phenomena is dependent on the frequency of the external force. In your case, the frequency of the external force is dependent on your front tire rotation speed.

 

The 2006 CBR 1000's have thin rotors that are prone to warping. If you can feel it pulsing I'd bet that you have a warped rotor.
Charlie