optimal street tire size for RTR on 17x7

[Aznsky]

Yeah I'm also leaning towards 225 Rival's instead of 235 Z2's now based on the latest back to back testing I've seen.

First autox huh? I'd almost suggest going out on the stock tires just so you can feel the car sliding around. That way you'll appreciate the grip later.

[7thgear]

i'm very tempted at going 215's on an aftermarket 17X7 rim but one that is much lighter.

hmmmmm

[SVThis]

Originally Posted by Aznsky

Yeah I'm also leaning towards 225 Rival's instead of 235 Z2's now based on the latest back to back testing I've seen.

First autox huh? I'd almost suggest going out on the stock tires just so you can feel the car sliding around. That way you'll appreciate the grip later.

I'd get the grippier tire. Kind of like having sex for the first time. Why do it with an ugly women when there are hot ones available.

[Ranatsu]

Originally Posted by Gearhd79

Well, I just ordered my ZII's in 225 45 to go on OEM rims. Ill see how this goes

They'll fit no problem
225/45 Z1's on stock wheels.

[fishek]

Originally Posted by Aznsky

Yeah I'm also leaning towards 225 Rival's instead of 235 Z2's now based on the latest back to back testing I've seen.

First autox huh? I'd almost suggest going out on the stock tires just so you can feel the car sliding around. That way you'll appreciate the grip later.

I did 5-6 track days with the stock tires last season so I had quite a bit of sliding around, and they don't look pretty

[Gearhd79]

Originally Posted by Ranatsu

They'll fit no problem
225/45 Z1's on stock wheels.

well..just picked up my 225 45 ZII's on my stock wheels and let me tell you..they look meaty. I used your pic as a reference for my final decision to buy these tires and they actually look wider than i thought. i cant wait to try these out on the car but its only 40deg. today

ill try to throw some pics up here directly

[Ranatsu]

Originally Posted by Gearhd79

well..just picked up my 225 45 ZII's on my stock wheels and let me tell you..they look meaty. I used your pic as a reference for my final decision to buy these tires and they actually look wider than i thought. i cant wait to try these out on the car but its only 40deg. today

ill try to throw some pics up here directly

Oh they are definitely meaty.

[chucky12012]

Originally Posted by 7thgear

i'm very tempted at going 215's on an aftermarket 17X7 rim but one that is much lighter.

hmmmmm

That's actually what I am running, which is certainly not the more common approach. I've found that because it fits the 7" rim so well, I can run lower pressures than the folks with wider tires while maintaining the sharp response this car should have. I'm not sure it's a complete win though and I would consider going to a 225 for my next set of autocross tires.

[7thgear]

Originally Posted by chucky12012

That's actually what I am running, which is certainly not the more common approach. I've found that because it fits the 7" rim so well, I can run lower pressures than the folks with wider tires while maintaining the sharp response this car should have. I'm not sure it's a complete win though and I would consider going to a 225 for my next set of autocross tires.

what were you times compared to the competition?

[chucky12012]

Originally Posted by 7thgear

what were you times compared to the competition?

So far they have been good. I won the last local RTR class with 13 cars in the class. We had about 120 cars total at the event, and when you add in a .975 multiplier for the RT class (which the Houston region doesn't currently do, our PAX results for RT just use the base class multiplier), I would have finished 5th out of 120. I'm running the Z1's btw, got them last fall, so they have seen 4 events to date.

The better results will be from the national tour next weekend. After playing around with pressures a couple of events ago with an experienced codriver, I ended up settling on around 30/31 psi rear and 35/36 psi fronts. I don't think I would run pressures that low if I went with a wider tire, but I don't have any first hand experience at this point to validate that statement.

[7thgear]

Originally Posted by chucky12012

So far they have been good. I won the last local RTR class with 13 cars in the class. We had about 120 cars total at the event, and when you add in a .975 multiplier for the RT class (which the Houston region doesn't currently do, our PAX results for RT just use the base class multiplier), I would have finished 5th out of 120. I'm running the Z1's btw, got them last fall, so they have seen 4 events to date.

The better results will be from the national tour next weekend. After playing around with pressures a couple of events ago with an experienced codriver, I ended up settling on around 30/31 psi rear and 35/36 psi fronts. I don't think I would run pressures that low if I went with a wider tire, but I don't have any first hand experience at this point to validate that statement.

that's an excellent result!

do you think then that moving up in width would give you that edge?

also did you run your 215's on the stock wheels or did you source a lighter wheel of same size/ (for RTR)

[chucky12012]

Originally Posted by 7thgear

that's an excellent result!

do you think then that moving up in width would give you that edge?

also did you run your 215's on the stock wheels or did you source a lighter wheel of same size/ (for RTR)

I'm actually running Kosei K4R's, so it's a lighter wheel. Another local BRZ will be getting some similar wheels with 225 ZII's or Rivals, so I'll probably run an event sometime soon where I swap between the two for some comparison. It won't be the same tire though, so we'll see how conclusive it really is.

[Getagrip]

Is anyone using 245/40-17 on 17x7" (stockers) ie SP1 or ZII etc and if they will even fit?
I'm thinking of going th RTR route this summer and I will need new tires. I have 245/40-17 on 17x8 right now.
Maybe 225 would be a better choice as the 245 would be pinched too much thus negating the extra width?

[Gearhd79]

all i can say soo far about the "pinch" is that my 225 ZII's look a bit pinched already..i can not imagine what a 245 would look like. I am no expert my any stretch, but I think the 225 is plenty of tire for RTR. If I make any major changes (CS),I think I might try going with the "purple crack" in a 235 40 series. Based on some times I've just read about these cars are fast on hoosiers