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Longer wearing tires for track

victorofhavoc

Autocross Champion
Location
Kansas City
Does anyone know how wide the 235 and 255 nt01 actually are? with my 245/40/17 Z3 I can probably go another 0.5" wider before rubbing on the strut. Those are 8.8" wide tires. The z2ss in a 245 were 9" I believe. I'm wondering if the 255/40 nt01 are less than 9.2" wide, but if not, I'd have to go for the 235.
 

Cliff

Drag Racing Champion
Location
San Francisco Bay Area
Car(s)
2015 Cayman GTS
Does anyone know how wide the 235 and 255 nt01 actually are? with my 245/40/17 Z3 I can probably go another 0.5" wider before rubbing on the strut. Those are 8.8" wide tires. The z2ss in a 245 were 9" I believe. I'm wondering if the 255/40 nt01 are less than 9.2" wide, but if not, I'd have to go for the 235.

I am running 235/40R18 NT01's with 18x9 et45 wheels on a car that is lowered about an inch compared to a stock R with -2.5 deg camber up front. I get very slight rubbing in front when the suspension compresses heavily. I would imagine the rubbing would be constant with this tire in a 255 width.
 

victorofhavoc

Autocross Champion
Location
Kansas City
I am running 235/40R18 NT01's with 18x9 et45 wheels on a car that is lowered about an inch compared to a stock R with -2.5 deg camber up front. I get very slight rubbing in front when the suspension compresses heavily. I would imagine the rubbing would be constant with this tire in a 255 width.

235 on 9 wide? That seems like a lot of stretch unless the true width of the tire is closer to 9". I wouldn't be surprised if it's really that wide since a 245/40 hoosier R7 is around 9.7" wide. You're closer to the strut than I am, though, so a 235 should clear just fine for me.
 

Cliff

Drag Racing Champion
Location
San Francisco Bay Area
Car(s)
2015 Cayman GTS
235 on 9 wide? That seems like a lot of stretch unless the true width of the tire is closer to 9". I wouldn't be surprised if it's really that wide since a 245/40 hoosier R7 is around 9.7" wide. You're closer to the strut than I am, though, so a 235 should clear just fine for me.

It's not stretched, but the sidewalls are under tension, which is what I wanted in going with a wide wheel like that. The car is pretty well loaded up on the right side in this photo.
 

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victorofhavoc

Autocross Champion
Location
Kansas City
ZII Star Spec. A 235/40R18 tire has a larger outer diameter than a 245/40R17 tire, the NT01 is a broad shouldered tire, and it's mounted to a 9" wide wheel, so it fills the wheel well more completely than the 245 tire.

I think the Z2ss is 0.2" wide than the Z3 in the same size, but with a barely smaller contact patch. I know the diameters are significantly different, but is the nt01 significantly wider on the tread (from top edge to top edge)? i'm not too concerned about mounting width since there's no way i can compare an 8" wheel to a 9" wheel on that, lol.
 

donefor

Go Kart Newbie
Location
usa
Hey it’s quite possible. I ran my white GTi in B-run group with Tarheel in September last year. I remember a dark colored Mk 6 in my run group. Was that you? I ran the stock Bridgestones and really struggled for grip while learning the car. I picked 5-secs going from the all seasons to the MPS4S.

I haven’t run R888’s. NT01’s are predictable.


Nah, couldn't have been, i checked and i actually haven't run with BMWCCA since late 2014... every event since then i've done with Trackdaze. The way things are going this year, i'll be satisfied if i get just one or two days in my "new" Mk7. Just got APR stage 1 and oh yeah :D gonna need better suspension and brakes :rolleyes:
 

victorofhavoc

Autocross Champion
Location
Kansas City
just an update on this...

after running the Z3 tires all of last year I noticed that around 4/32nds the tread compound changed drastically. The tires did not grip nearly as well, would heat up faster, but they would wear much more slowly. The first 2 weekends they wore down to the 4/32nds mark, and the next 3 they wore down to 3/32nds. I was not too happy with the performance and fast initial wear, so I spoke with a dunlop rep a friend introduced me to. He mentioned the Z3 is targeted specifically for autocross and if you exceed 140 degrees across the tire, they wear very quickly and lose a lot of their initial grip. I expect other recent, more focused, autox tires will act the same.

I went to a yoko a052 for this year. It starts at 6/32nds instead of 8/32nds so it's not autox legal as a street tire, but it does have a 200tw rating, so for some race classes it still qualifies as a street tire. Supposedly these tires have a higher temp range they like to be in, a lot closer to a slick than a street tire, so we'll see how they get on.
 

Cliff

Drag Racing Champion
Location
San Francisco Bay Area
Car(s)
2015 Cayman GTS
My set of ZIII's aren't wearing as quickly as yours did. I have 24 sessions on my tires (~6 days) and the tread depth is 6/32 on all 4 tires, which I rotate front to rear after every day.
 

victorofhavoc

Autocross Champion
Location
Kansas City
My set of ZIII's aren't wearing as quickly as yours did. I have 24 sessions on my tires (~6 days) and the tread depth is 6/32 on all 4 tires, which I rotate front to rear after every day.

very interesting. Do you use yours on the road? I had about 3k road miles on mine, some autox, and 18 sessions before they hit 4/32. Around 5/32 is when I noticed the compound started to get firmer and less resistant to heat.
 

Cliff

Drag Racing Champion
Location
San Francisco Bay Area
Car(s)
2015 Cayman GTS
very interesting. Do you use yours on the road? I had about 3k road miles on mine, some autox, and 18 sessions before they hit 4/32. Around 5/32 is when I noticed the compound started to get firmer and less resistant to heat.

Probably a similar amount of road miles and yes, these are my every day tires. For me, tire life is measured more meaningfully in sessions and not miles.
 
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