I just did two 20-minute track sessions on a set of 215/45/R17 Dunlop Direzza Sport Z1 Star Specs last weekend. The tires are still new and had about 1400 street miles on them before I took them to the track for the first time. I drove the car pretty hard on the track. After I got home, I took my track tires off and put on my regular street tires. Upon close inspection of my track tires, I noticed a thin layer of rubber with rippled edges on my rear driver side tire. The rippled edge is kind of loose and I can peel small parts off of this thin rubber layer. Anyone knows what I am talking about? I guess the tire could not take the extreme heat on the track and melted a bit and caused this. Will it be safe to use this tire on my next track session?

 

That is common and normal. Your tires are fine.

 

Throw a picture on here if you can. It's not uncommon for tires (and the track) to heat up, and then for your tires to pick up rubber from the track; often it's kind of balled up and peels right off. Hard to tell from your description, but the Star Specs should hold up for a couple of 20 minute sessions; even driving hard that's not going to stress the tire THAT much. It may simply be rubber you picked up rather than losing something from the tire itself. The thing is, a rear tire won't heat up nearly as much as your front tires, so if only one tire was going to overheat, that one would be the last one I'd pick...

 

OK thanks! My front tires are actually looking good. I am not sure why the rear driver one came out looking like that. I will try to post a picture of it later today or sometime tomorrow.

 

Maybe because you had the tail hanging out around some turns?

 

Sounds pretty much like what my Z1s looked like at then end of a track day. And my RT615s... And my XSs...

 

OK, here is a picture of my rear driver side tire after the track adventure. If you look closely on the inner edge of the tire, you will see the thin layer of rubber on top of it which I described in my first post. Also, my car has the JCW suspension kit, so there is a bit of a negative camber in the rear. I think I will put this tire on the front next time to wear off the loose rubber.

 

Nothing wrong with your tire. Thats pickup of the r-comp rubber other folks left on the track.

Alan

 

Thanks, that's good to know!

 

this star spec dunlop was specifically developed for AutoX purposes so it can heat up quicker. I personally wouldn't run these tires on track for more than couple laps. They're not a track tire.
But it seems that you're fine.

 

Tirerack recommends the Star Spec tire for the track.

Can you please quote the source of your information. Thanks.

 

This dunlop was first developed without Star Spec. About year later the star spec came out as Dunlop addressed concerns that the tire did not heat up fast enough during autox use. it was engineered specifically to address this issue so that tire can reach the full temp in less than a minute.

So now you see all these folks who have them at autox event, spraying them with water after couple runs to cool them down. If the tire gets hot after couple of minutes at autox, I think it would be waaaay too greassy for the track.
But the good side is that with every heat cycle it will get harder thus
more suitable for track.

 

The people at the track who autox as well tell me the exact opposite that they are great for the track but wear down quite quickly on the outside edge for autox.

 

Based on that picture, you didn't even work them that hard, that's just clag you collected at the end of the session pulling into the pits. When you destroy a tire by overheating it, they usually get really greasy feeling behind the wheel, and if you really kill them they'll delaminate or chunks of rubber will rip off, and then next session they won't have the same kind of bite. Depending on the compound they'll also turn a nasty blue/purple color, but that can be kind of normal too, so it's tough to generalize.

I hope you enjoyed your track day! Was it your first time?

FYI next set of new tires: they usually need to be heat-cycled before going full-bore on the track. This could be as simple as doing a couple of 7/10ths "warm-up" laps and then parking the car for an hour or so.

Cheers,
Ryan

 

Thanks Ryephile! Yes, it looks like I got worried over nothing!

That was my second time at the track, but it was my first track experience with the Dunlop Direzza's. On my first track day, I was running on my regular street set (205/40/18 Pirelli P-Zero runflats).

I just had another track day at Sebring yesterday. My Stage 1 JCW MCS with JCW suspension and the Dunlop Direzza's was eating the Corvettes and the Mustangs on the track for lunch!

 

come down to Homestead miami April 18-19 for NASA!!! Would be fun to play! I'm always the only R56 mini out there!

 

I cannot make a promise but I will try to make it if I can!

 

uzun,

Are you running the 215/40ZR17 on the stock rims? I would like to run the Dunlop Direzza Sport Z1 Star Specs on my 17" web spokes on the road, but the tirerack configuration page does not include the 215/40ZR17 in the results for the '07 MCS/JCW with metal stem.

I run Nitto NT01 on the standard MINI rims for track day.

Would love to go with the NT05 for the road but no matching sizes.

Thanks for any help here.

 

You can use 215 45 17 on a R56.

 

I was instructing passanger seat with Ali, Excellent job hustling around sebring. I was impressed that lacking camber and with as much roll as it had the direzza's held up. The outside edges didn't show near the wear I was expecting to see.
Ali, come down to Homestead next weekend. Should be a few mini's there. Plan to have ours in TTC down there.

 

Actually I am running 215/45/17 and not 215/40/17 on my stock 17-inch crown spokes. You should be fine with either 215/45 or 215/40 on your 17" web spokes too.

 

Hey Ian, thanks again for everything! I definitely learned a lot from you and feel very fortunate to have met you! I wish we had some photographic evidence of us riding on the tails of those Corvette's so I could post them on here!!!

I am not sure if I can make it to Homestead next weekend but I will do my best to make it! Hope to see you there!

 

No thank you for letting me have those couple laps. The 07 is much more tame then our 03. Very pleasant to drive. I really like that chassis.

 

Thanks! I'm going to pick up a set of 215/45ZR17 Dunlop Direzza Sport Z1 Star Spec from Tire Rack. I appreciate your help.