"Gummies" on PR tires

[Gxsr_Sarge]

I finally ran my first CCS race last month at HS after a year of finding excuses not to.  I ran PRC/PR5's for two races on Sunday after running 4 practice sessions on Sat (didn't change tires before the race but I will next time).  I noticed that I had a substantial amount of "gummies" built up on the tires after the races.  My suspension guy told me that it was because I was slow (I won't argue with that - mid to high 1:40's - but I'm workin on it!) and wasn't "cleaning" the tires on the turns which is something that comes with speed.   I was on "stock suspension" on my '07 gixxer 600.  I have since installed Penske shocks and installed the GMD 20mm cartridge units (a Xmas gift to myself for the next 5 years!) and went through the "sweet numbers" deal. 

My question is:  Are the "gummies" a function of the tire, speed, suspension or "all of the above"??

I'd also like to throw this "hot topic" out there for anyone running PRC/PR3 or PR5's:  How often do you change tires??  Fresh set for race day?  If so, do you use the same set for practice sessions on the following race weekend?

Any input for this "newbie" would be greatly appreciated!  Thanks in advance....

[Toy Store]

Let me start off by saying that I have not conducted a comprehensive study on the causes of tire gum, but here's my humble knowledge of the matter in a nut-shell.

1.) The gumming is a process of the tire in which it "sheds" the  outer rubber and exposes the "fresher" and more sticky rubber.
2.) When I started out, we all had very little shedding. As we got faster, we heated the tires more and the gummies were more prevelant.
3.) With that said, there are patterns to look for in the tire wear that will indicate a poor suspension set-up. I would recommend GMD get you setup, or at the very least, buy Traxxion Dynamics "Suspension for mortals" DVD. I watched it and it gave me alot of insight into what was going on under the saddle.

I hope this helps you a little.

[Gxsr_Sarge]

Interesting that your experience was the opposite of mine in that you got the gummies as you got faster.   That is contrary to what GMD said.   After Homestead's race last December, I did have them set me up w/ both front and rear suspension (as well as an ohlins steering damper).  I guess I'll see how the tires react this weekend at Homestead. 

Also, I do have that DVD and it is very good.  In fact, you'll note that Max does say that the fastest guys have very smooth tires after the races (he says "like they never left the paddock").  That's what go me thinking that GMD was right on. 

Thanks!

[Toy Store]

There you go, I didn't remember that part. I'm sure those guys are more knowledgeable than me. Standby though, I'm call the Michelin Race tire distributor....

[theQman23]

Hello guys, Quentin of MizeMobile.com here, the NE Michelin race tire distributor.  Gummies themselves are not a tell all indicator of much, other than the fact that the tire is in fact, "shedding" which is a good thing.  Often you'll hear new guys say, "I have three weekends" or "I have fifteen heat cycles" or some such thing and then they'll say, "and my tires still look good."  This is almost always a cause of either A) new riders going slow and not taxing the tire, which is a good thing, and there's absolutely nothing wrong with that, and B) they are on a closeout sale tire, or the wrong compound tire, and it's either too hard or too old to be working effectively.  If you see boogies you're generally okay.  The reading of the tire comes from looking at how the wear patterns look in the contact patch itself.  In other words, which way do the grains go, is there cold tear?  If it looks like cold tear but it's really hot outside is the shock fading and causing compression tear?  These are what tire guys look for when they "read" a tire.  Sometimes boogies roll all the way off of the edge and fly off, and sometimes boogies work out to the edge, and then hold onto the tire for dear life and never fall off.   Either way is okay, as long as the tire is working properly and the chassis functions properly.  I agree that in most cases the really fast guy's tires look smoother when they come off of the track, provided the compound was set correctly, and the race wasn't too short.  Often, a super fact guy will go out on a new tire and spin-tear it a little when it's fresh, then after only eight laps there's evidence of tear marks.  If he's a money pro and puts another brand new one on , so be it,but often, if he runs it a second time that very minor surface stuff will smooth out, and the tire actually looks more attractive after 16 laps than after 8.  Not always, but just food for though.  Ride Safely, and enjoy.-Quentin

[Toy Store]

Thanks for chiming-in, I had made numerous calls to two other distributors, but they were boycotting the telephone 

[dylanfan53]

+1. Thanks for the info.
I also find that some tracks scuff the tire differently.  Here in the midwest Gingerman is rough on the tires.  If I leave the same tires on the bike and the next outing is at Autobahn they're nice and smooth again after a few sessions.