I have noticed that my rear tires get a build-up of residual rubber after track events. It almost looks as if the rubber was melted and was rolled over to form veins adjacent to the grooved in my tires. This used to happen when I ran Kumho SPT street tires. But it also is happening to my Nitto NT01 R-Compound tires. I have dealt with this problem by rotating the tires and adjusting the pressure between race days. Most of the time, I can burn off the excess rubber after a few laps on the front of the car. I was wondering if anyone else has this issue on their rear tire and will an increase in tire pressure minimizes or eliminates this effect?



Thanks
DJDport66

 

Are your tires picking up excess rubber from the track? This is fairly common - if it's the same thing. I just...Drive like I stole it - couldn't help it, and it comes off.

 

Hey Meb!

Interesting theory...Why would the rear tires pickup so much rubber from the track? I have got the car dialed in to the point that I really don't want to add more air to the rear tire to induce over-steer. Have you noticed rubber being picked up on your Toyos?

David

 

Getting the same thing on Hankook Z212's, it wears right off in a lap or so.

 

Yea, it's just rubber from the track that your picking up. It can really vary as to the amount due to track conditions and temp. I might be that there was some club or pro race just prior to your track time. Maybe there has been no rain for a while to clean up the track.
You will pick up more in the rear.

 

Thanks onasled! This kind-a makes sense since it happens at some tracks more than others. My last race was at VIR where there was a BMW club race the weekend before.

It's not my baby! Yeah!

David

 

I suspected that my rear tires pick up more because they aren't being turned...no scrubing.

Last year while running at an open event at LRP - between the NASA runoffs - a pro was watching me use a torch and putty scraper to remove a hell of a lot of buildup. He suggested that the air temps are in the 90s and that if I drive fast enough, the material will fall off. I took his suggestions and let it go...worked fine. I picked up a lot of debris during my previous event at Watkins Glen...that'l happen when you've got Ferraris, Nobels and Porsches behind you; I was constantly off line letting these guys go buy.

 

i, too, have had this issue w/ RA-1's and hoosiers. one little detail has helped me minimize the problem. stay on the racing line during your cool-down lap. your tires are hottest at this point, and driving off line is where most of the rubber lies....

 

Thanks Bean! Good Advice. It easy to go off line during a cool down after you been doing 30 laps like a bat out of hell!

David

 

It's normal, don't freak out. If you must the best way to get it off is hitting the skidpad before you take the tires off. most tracks have them. A couple minutes each way will knock them off but really, it's not a big deal they come off on the track your next run and you'll get some new ones. You might want to wipe the ones on the inside of your wheels off when you put the street tires back on just to prevent any balance issues.

 

Hi Guys,

Just finished a weekend at VIR North. Ran most of the weekend in the rain but got some dry time on Sunday. Ran 2:11 in time trials but had tire issues. I am currently running NT-01 tires with cold pressure at 32-33- front and 30 psi in the rear. I am getting 40-41 and 36 psi hot coming of the track. I find that the tires start to fade really bad after about ten laps. What are you guys running for cold/ hot pressures? Are you getting tire fade. What is your experience with Hoosier R-compound tires?

Thanks everyone for your thoughts!

David

02 MCS
-2 deg camber front 1/16 out toe
-1 deg camber rear 0 toe

 

I get the nitto's up to 38 hot and have no problem with getting sloppy.


I'm out doing 1 lap, may be a bit slow to respond.

 

I would like to revive this thread to ask a question:

I was at VIR over Thanksgiving weekend and got to run Saturday with my Nittos. I did one session and discovered the pressures were all messed up. Rears were too low. I reset and went out. When I came back in, both front and rear were just a little too high. I bled them to 39 psi hot at the end of the day (had just come off the track - the car felt great) The next day it was raining so I ran on my street tires.

I checked the nitto's pressures (cold obviously.. very cold) as I was packing up to go home and the rears were higher than the fronts. It seemed peculiar to me(they read something like this: 31 psi front, 33.5 psi rear... that's a big difference)

Any thoughts? Ambient temperature was about 40 degrees and I have stock suspension. And yes I get the same buildup on the inside rear.

 

That's normal. The front tires take more abuse, so get heated more during a session. The outside tires take more abuse, so get heated more during a session. Try to get to a consistent hot temp that feels good and produces even wear across the tire.

Alan

 

Thanks for the reply. I had read in Modern Mini that it was best to have the rear tires set at a lower pressure than the fronts. But higher rears actually makes sense now that I think about it. I'm getting a lot of wear on the outside of the tire (on both sides of the car). Is the only solution adding camber?

I couldn't go another day on the Nittos because of the rain. I wish I could have in order to test the pressures and get a consistent reading.

 

Either that, or drive slower.

 

Camber plates and rear control arms are cheaper than tires. you only need to buy them once.

snid's option will work too!

 

Sounds like camber plates and control arms to me!

 

Drive slower? How the heck do you do that in a Mini? The Camber Plates and a good alignment really help with tire ware. After getting the number right, my tire ware has been really good, plus I rotate the tires during a two day HPDE or Time Trials. The Nitto NT01 have been great and don't cost that much. I start off with about 30lbs cold on the front and 34-36 on the rears. I typically will test all four tires hot right off the track to see where I am at and make adjustments as necessary for track condition and my frame of mind. Generally they are in the low 40's (psi) Also checking lap times helps to figure out if your making the right adjustment or just sliding around the track scrubing speed. No problems now but finding the time to head to VIR.

Cheers,

DJDport66