[jjmaine]

I put a new set of Diablo Rosso 2's on my bike about a month ago and noticed a good wobble on decel. At first I thought the front hadn't been balanced correctly so I took the wheel off and put it in a balancing stand and it was perfectly balanced. Then, I thought it had to be the steering head bearings even though it was strange that it started right after I had the tires put on. I installed tapered roller bearings and the decel wobble is still present. I can tighten the steering stem nut enough and it stops the wobble but it is obviously too tight because the bike wallows at slow speed and is impossible to drive in a straight line.
Also, while I had the wheel off to check balance, I noticed one of the wheel bearing was crunchy so I replaced those...
I've come to the conclusion that it has to be the Diablo Rosso 2 front tire, some kind of defect? I think I'll try a Rosso 3 and then when its time for a new rear, I'll put a Rosso 3 on to match.
Has anyone else experienced this? New tires causing a wobble? I know others have as there are examples of it with different bikes/tires on the internet. Just curious if it is a recent problew with the Pirelli's?
I've also verified my wheel alignment with the string method and they are dead on....

 

[jjmaine]

And when I lifted my bike up to do the steering bearings the there was no play in the forks and the bearings and races looked perfect. I could also tell that to my surprise someone (other than Kawasaki) had greased them in the distant past. I replaced them anyway with the tapered roller bearings since I had it apart and won't ever have to worry about them again... Also with 7000 miles, they were bound to fail soon...

 

[jjmaine]

I also verfied that my wheel is true when I had it on the stand and it is. Anyway in my mind it has to be that new front tire which is just my luck lol...

 

[jkv45]

Any chance the forks may be tweaked slightly?

You could try loosening the clamps and re-centering everything before re-tightening.

Other than that, I think it's the tire.

 

[jjmaine]

Thanks, I’d say I am 99% sure it is the tire as I think everything is aligned correctly but I’ll double check. I put a stand next to the front wheel with a wodden dowel taped to it and set it about a mm front the front of the tire and the is a the is definately a high spot in the tire. You can actually feel the front bounce slightly when decelerating at low speed as wheel.
The only question now is do I run it and get my moneys worth out of it or replace? Hmmm.

 

[Topaz]

Did you buy them new two months ago? If so, I would try to get a free or discounted replacement from the seller.

 

[jjmaine]

No, I bought them last winter from Motosport but only put them on recently. I never in the world thought there would be an issue with them. I did notice that these are made in Brazil now and all my previous Pirelli’s (and the Rosso 3’s I have now on my supermoto) were made in China. Maybe its a quality control thing or I just got a bad one.

 

[jkv45]

I'd contact the seller, and if that goes nowhere, contact Pirelli directly.

Seems to me, I've heard something about them like this before. Maybe it's a known problem with a certain production batch.

 

[jjmaine]

Good idea actually. Nothing to lose, maybe they'll replace it or even give me a discount on a new one.

 

[Rogue]

I've run multiple sets of DRIIs on the bike and I've never had that after a new set. With everything you've checked, I'd say it's definitely a bad tire. Pirelli also has a great warranty policy - if 50% or more of the tread is still on the tire, if it's defective, they'll cover it at 100%.

Warranty for motorcycle tires: terms and conditions | Pirelli

Discover what Is Warranted and who Is eligible for Pirelli warranty Coverage for motorcycle tires!

www.pirelli.com

 

[jjmaine]

Nice I'll check that out!