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. :thumbsup:

[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. :underchair:

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]

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

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. :D

Does that help?

[gerno]

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?

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

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.....:poke:


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. :thumbsup:

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?

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:hairpullout:

[Flash68]

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

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. :D

:popcorn2:

[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.

[gerno]

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

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. :D

:popcorn2:

Good advice, I'm shocked...:sarcasm_smiley: For once in my life I probably should take the "easy" way out. At this point I think the "easy" way may also be the most competitive too.

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.

Good to know on the 275/335 setup as well as the 295 clearance.


At this point the idea of the 335 is gone from my choice because I don't want to cut up the front end to fit a 315 (yet) and I don't want a massive push on the track. I'm steering (pun intended) back to the 275/315 combo but will call Falken to see what the biggest rim I can run is for the front. I want to try to follow Ron Suttons advise on the front and stretch the tire so want to try for a 10.5 rim at least with possibly a 11" depending on what Falken says. With the smaller tire stretch I think the 11" will fit and give me room for more tire later. I am thinking this should increase grip and also reduce tire height to balance the profile front and rear.

I would love to go with the 19" rear for looks but I just can't find a tire that I'm comfortable with in that size. I'd take a little push for the look but I don't want to give up tire selection. Some reason I'm nervous to use the PS2's, supersports, Goodyears and the RE11 is under the 200TW rating. I'm not too concerned with Optima and Good guys but it would be nice to find something that worked.

[gerno]

Stopped by a local Vette specialty shop. They had stacks of worn out tires sitting beside their building. Picked up some 285/18, 285/19, 295/18 and 325/19 tires for free. Now hopefully I can finally make a decision.

[carbuff]

Sweet! Is that the shop on North Lamar by chance?

I picked up a worn out one from CL when I needed one, but the guy gave me the wrong one (front instead of rear), so it didn't help me... What aspect ratio are the ones you picked up?

[gerno]

Sweet! Is that the shop on North Lamar by chance?

I picked up a worn out one from CL when I needed one, but the guy gave me the wrong one (front instead of rear), so it didn't help me... What aspect ratio are the ones you picked up?

It was Corvette World off Mopac. They had a ton of tires and told me I could take as many as I want.

I picked up these 4

325/30/19
295/35/19
295/35/18
285/35/18

I also still had the Falken 275/35/18 and 315/30/18. Here's a pic of all of them so people can see the differences.

45802


Here is the 315/30/18 rear

45810

45811

45812

45813

325/30/19 Rear

45814

45815

45816

45817

45818

The 325/30/19 fills out the wheel well much better. It's tight but not unreasonable. I have over 1/2" on the inside and can compress the suspension all the way and it barely touches. When not compressed I could push the tire out another ~1/2" and still have plenty of clearance with the reduced lip. I may try to clearance the inner fender a little more, still deciding. Think I may be able to gain 1/8-1/4"

Pretty sure I'll be going 325/30/19 rear and 285/35/18 front.