Going nuts picking tires and wheel sizing - help?

[gerno]

I've done a lot of work to my 72 Camaro and am eagerly awaiting driving the car. Unfortunately I'm hung up with picking the perfect tires and wheel combo. I know the style of wheels I want, its the best sizing to match the tires that is getting me.

If you check my build thread you will see I'm moved to 100% Speedtech suspension front and rear using ride tech shocks and the ATS spindles. My goal for the car is to be a street car but I want to do lots of track days and some auto crosses. goal being more aimed at track days than autocross. I'm spent extra money with this specific goal in mind so I don't want to negate the advantages of some suspension changes by getting a bad tire combo. I don't know the details for all the suspension parameters but assume Blake or Roger could help provide them if it's critical for the tire choice.

Originally I was thinking to go with the 275/315 x18 combo using 10" and 11.5" rims. I was then talked up to the 335 rears using a 12.5" rim due to the larger sidewall mainly (looks do still matter with sidewall). I made the 335/12.5 sizing fit the car but then became worried the front tire was too small and I would have to tune out rear grip.

I tried to fit 315's on the front but it's too much tire without flares and the largest reasonable rim is really a 10.5. Looking at the 10.5 I can fit a 295x18 on it without issue. Only concern is since it's the front tire I should try to stretch it in order to stiffen the sidewall based on reading Ron Sutton's advise (hopefully I got that right). I feel the 295 better balances the 335 rear but I'm not sure if any gains would be lost with the 10.5 rim. Would a 275 on a 10.5 be better and a different rear tire?

This thinking has lead me to a state of total confusion. At this point I don't know what size tires/wheels to get. I'm now also thinking to change the rear to a 325x19 and find a 285x18 front using 12' and 10.5" rims.

Anyone have any advice?


Next issue comes to the tires themselves.

I was thinking the Falkens at first since I had them before and liked it. Issue is the sizes are limited basically to the 275/315 x 18.

I then moved to the Rivals for the 335/295 combo. I see lots of hype for these tires but have also heard mixed reviews.

If I go with the 285/325 I 'm not sure which tire to use but am steering towards the RE-11. Issue here is I don't have any feedback on these.

Anyone have any real world opinions on these tires or any other tires that may first my car/application?

[Sieg]

FWIW IMO -Too much tire creates unnecessary clearance issues, escalates $, and adds stress to driveline and chassis components........personally I have more fun driving a car that gets a little lose vs one that sticks like glue. If you need that much tire to be competitive in a class that would change my opinion.

[glassman]

I'm going with a 275/315 combo on mine, but yet to do the tubs/rear (still aquiring data for that)....I want the Forgeline ZX3's, but have to wait, budget and rear fitmant....

[carbuff]

You're overthinking it in my opinion... And probably listening to Dave and Greg and Rob.

Go with the known quantity: 275/315. You'll have more choices in tires, and it's a guaranteed fit. After my first track day last weekend, my car felt very balanced on that combo. I still have a way to go on the learning curve of driving, but even with the instructors driving the car, it again felt very balanced.

Is there a reason you feel you 'need' to go bigger?

If I had it to do over, the only change that I might make would be to step up to a 19" rear wheel. But that would be purely for aesthetic reasons, as the Firebird wheel well opening is bigger than the Camaro, and the rear wheel/tire feels a little lost in there. I may have gone with a 325 on it, but that's just because that's the only size readily available I think (305 being the other option). But I'm very happy with my choice other than that...

Again, if you need to borrow my wheels/tires again now that you have things assembled, I can get one to you next week. The car is going to Eric tomorrow for some work, and I have the auto-x on Sunday. But it will be free after Monday...

[gerno]

Originally Posted by carbuff

You're overthinking it in my opinion... And probably listening to Dave and Greg and Rob.

Go with the known quantity: 275/315. You'll have more choices in tires, and it's a guaranteed fit. After my first track day last weekend, my car felt very balanced on that combo. I still have a way to go on the learning curve of driving, but even with the instructors driving the car, it again felt very balanced.

Is there a reason you feel you 'need' to go bigger?

If I had it to do over, the only change that I might make would be to step up to a 19" rear wheel. But that would be purely for aesthetic reasons, as the Firebird wheel well opening is bigger than the Camaro, and the rear wheel/tire feels a little lost in there. I may have gone with a 325 on it, but that's just because that's the only size readily available I think (305 being the other option). But I'm very happy with my choice other than that...

Again, if you need to borrow my wheels/tires again now that you have things assembled, I can get one to you next week. The car is going to Eric tomorrow for some work, and I have the auto-x on Sunday. But it will be free after Monday...

I am definitely over thinking this. I am leaning towards the 325/19's mainly due to the appearance and the fact that the tread is close to the same as the 315/18 Falken for balance. I just have no clue which 325/19 tire I would select.

[71RS/SS396]

I'm using Rivals so the 295 is only available in a 35 series which is pretty tall. I actually had more clearance problems with the 295 on the front than with the 315 because it's so much shorter.

[Flash68]

Stuff the biggest and baddest you can in there. And if that don't work, start cutting sh!t out.

Does that help?

[gerno]

Originally Posted by 71RS/SS396

I'm using Rivals so the 295 is only available in a 35 series which is pretty tall. I actually had more clearance problems with the 295 on the front than with the 315 because it's so much shorter.

Good to know. I'm pretty sure you're running the DSE subframe unlike me but do you know how much steering angle you have with the 315's?

Originally Posted by Flash68

Stuff the biggest and baddest you can in there. And if that don't work, start cutting sh!t out.

Does that help?

Helpful as always. I'd like to finish my updates some time this year, not continue to "improve" it like some people.....

Originally Posted by Sieg

FWIW IMO -Too much tire creates unnecessary clearance issues, escalates $, and adds stress to driveline and chassis components........personally I have more fun driving a car that gets a little lose vs one that sticks like glue. If you need that much tire to be competitive in a class that would change my opinion.

Good points. I'd like it to be reliable and easy to drive but also want it to stick like glue. Is it too much to ask for both?

Originally Posted by glassman

I'm going with a 275/315 combo on mine, but yet to do the tubs/rear (still aquiring data for that)....I want the Forgeline ZX3's, but have to wait, budget and rear fitmant....

Tubs aren't that bad, I was surprised. I'm really leaning back to the 275/315 combo if I stay with the 18's all around. Good luck with the budget, we all know it's never going to be there. You simply have to make it happen

[Flash68]

Seriously, most of us have been where you are. Where to stop and just Many (most?) have failed.

The 275/315 plan is obviously the safest.... most clearance... you know the tires already (Falkens)... but the real question can only be answered by you.... what effort you are willing to undertake (cost/time/headache) to achieve what you think you want. Do the bigger tires look better? Well yeah. Are they going to outperform the smaller ones by a substantial margin? Likely not, but depends on what you are shooting for. I know you are a pretty competitive guy from talking and see you. That's what makes me wonder if you'll be okay with taking the "easy" way out.

Okay, is that better? Probably not.

[71RS/SS396]

Yes I have a DSE sub. I do get some rub on the inside at full lock but the interference was worse with the 295. I have never checking how much steering angle I have but the turning radius is not as tight as a stock sub. I'm using a 10.5 wheel but was told by BFG that it was an acceptable width for the 315. Fwiw I've used a 275/335 combo and the car had a horrible push, I had to brake early and throttle the exit late to deal with it.