I have a tire shimmy on my 2009 cbr 600 rr, has about 5600 miles on it. it starts around 35 mph and works up on through to 65 plus. I had new Dunlops installed, the old ones which were on the wear bars were just fine. I had them rebalanced at a different shop and also had them install a new chain, but the shimmy is still there. Any help would be great!!

 

Normally, out of ballance tires have a range they cause issues. For example, if it shimmy's at 35, it would normally stop shimming around 45 or so, then start again at 55.....ect. out of ballance tires will become ballanced at certain speeds, then loose their ballance again. Also, out of ballance tires don't normally show up so low in speed. It usually takes 45-50 mph for it to reallly become noticable.

So, my first thought, since it only happened after the tires were changed, would be the tire itself is defective. If it has a broken belt or mis-shapened. It happens, some tires that should have been scrapped from the factory make it to the public. I'd suggest inspecting the tire very carefully to make sure the sidewalls are true, and also as you run your hand along the tread, make sure there are not any high or low spots. Sometimes, over inflating a tire can cause issues as well...

Can you tell if its the front or rear causing the shimmy?

My thought is still a out of round tire. But another thought... whats your tire pressure at?

 

tire pressure at 36psi. Im pretty sure its coming from the front of the bike, and am quite sure its a defective tire, I read an older post about someone having an issue like this with Dunlops. My friend has an 08 cbr we are gonna swap out the tires one at a time to try to narrow down which tire it is, he is running michilens with no problems. and of course, the store where I had the tires replaced said that the shimmy was extremely subtle, but its funny cause when the tires are cold the bike will almost shake me out of my seat. Im sure they are setting themselves up to tell me its normal so they dont have to help me out, not impressed with this particular store. but hey thanks for the helpful info, I will let you know what I find!

 

whoops, tire pressure, 36 psi front, 42 rear

 

Pressures are right so it can't be that! I can't help you with what it could be especially if you think its coming from the front! My guess for the rear would be that the wheel isn't in a true straight position, like when you adjust you're chain and not adjusted it the same on both sides but that is purely a guess.

 

ok I will go check that right now, I hate spending 400 dollars and getting results like this, its just not professional

 

I would try lowering the tire pressure to 32f and 36 r.If it changes your shimming then you know your problem.If not then take it to a different place and have them check the balance and if possible look to see if the wheels are true.