Wheel width for 315mm squared?

[roguegeek]

Second gen Camaro with full Speedtech ExtReme subframe and rear torque arm. This thing is capable of doing 335 squared with no clearance issue, but I don’t see a reason to go beyond 315 on all four corners. At 18” wheels, what width should I be looking into?

[130fe]

315s and 11” wheels go well together.

[roguegeek]

315s and 11” wheels go well together.

And if for some reason I did want to push 335 in the rear at some point, would an 11” width cut it?

[Jonathonar89]

And if for some reason I did want to push 335 in the rear at some point, would an 11” width cut it?

For reference, the MINIMUM recommended width for BFG Rival is 11.5"...

BFGoodrich g-Force Rival S 1.5 | P335/30ZR18 (tirerack.com) (https://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=g-Force+Rival+S+1.5&partnum=33WR8GFRSV2&vehicleSearch=false&fromCompare1=yes)

[carbuff]

I used 11" from and 11.5" rear. Both worked well with BFG Rival 1.5's at 315. I think a 12" width would be better for a 335, but I'm not sure how many manufacturers are still making that width.

[68Formula]

I'd do the 11.5".

[roguegeek]

For reference, the MINIMUM recommended width for BFG Rival is 11.5"...

BFGoodrich g-Force Rival S 1.5 | P335/30ZR18 (tirerack.com) (https://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=g-Force+Rival+S+1.5&partnum=33WR8GFRSV2&vehicleSearch=false&fromCompare1=yes)

Ok. So the most likely 315 tires would be Falken Azenis RT660 315/30ZR18 (https://www.falkentire.com/tires/passenger-car-tires/azenis-rt660-tire) or BFGoodrich g-Force Rival S P315/30ZR18/LL 91W (https://www.bfgoodrichtires.com/tires/g-force/g-force-rival-s.html). The Falkens have a range of 10.5-11.5" with the BFGs at 10.9-11.5". If I were to ever move up to a 335, it would be something like a Rival S P335/30ZR18/LL 95W (https://www.bfgoodrichtires.com/tires/g-force/g-force-rival-s.html) which has a range of 11.5-12.5". It sounds like if I wanted to be flexible with the tire, I would want to go with a 11.5" width on the wheel. Correct? So if that was right, I would be pushing the upper limit of a 315 and lower limit of a 335. For all the people who know much more than I do, is that a concern?

[roguegeek]

I used 11" from and 11.5" rear. Both worked well with BFG Rival 1.5's at 315. I think a 12" width would be better for a 335, but I'm not sure how many manufacturers are still making that width.
How do you normally have your tires set up with the offset wheel widths? 315 squared?


I'd do the 11.5".
11.5 if sticking with 315 or 11.5 for 315 with the option of doing 335?

[dontlifttoshift]

I just mounted a bunch of 315s. Falkens look way better on a 12 than on an 11. Also, not much difference between the Falken 315 and BFG 335 on a 12.

Yokohama A052s always look stretched because they don't have a rim protector molded in but I can confirm that they mount easily on a 12.5" rim and have seen them on 13s.

I am pretty sure you can run 12" wheels square on that car with that suspension so I would.

[68Formula]

11.5 if sticking with 315 or 11.5 for 315 with the option of doing 335?

I was referring to the 315s with option to 335s. Originally I was thinking a 12" would be better, but interestingly Falken didn't recommend more than 11.5" on the 315. Based on dontlifttoshift's feedback a 12" setup would be more ideal even for 315s, and better especially if you went up to 335s later on. I prefer having the overall rim width (outside to outside) at least as wide as the overall tire width if possible. It'd be better if you really decide which size you want to go with first.

[Jonathonar89]

I would follow Donny’s experience here.

The advertised tread width for the BFG Rival 315 is 11.7”. I personally would strive to run a 315 on a 11.5-12” wheel mounting width to stay in line with the tread width. Doing so keeps the shoulders of the tire squared. A 335 on the same wheel would be “pulling over” the shoulders of the tire slightly.

[carbuff]

How do you normally have your tires set up with the offset wheel widths? 315 squared?

My front and rear offset were different, as were the widths. So while I had 315's at all 4 corners, I couldn't rotate anything without unmounting / remounting (if this is what you were asking).

I personally liked the fit of the 315 Rivals on the 11.5" width also.

Best suggestion I can make... Get one of the wheel fitment tools and the tire you plan to run and test very carefully to make sure you are getting everything correct in terms of fitment if you are going to squeeze a 335 under the car. The shape of the Camaro wheel openings make it a little tighter than the Firebird (which I had). And if/when in doubt on offset, I'd go a little conservative and use more offset (I think that's how it's stated) as you can always use a small spacer to push the wheel out if needed (as in a 1/4" size or so, don't go too conservative).

[roguegeek]

I just mounted a bunch of 315s. Falkens look way better on a 12 than on an 11. Also, not much difference between the Falken 315 and BFG 335 on a 12.

Yokohama A052s always look stretched because they don't have a rim protector molded in but I can confirm that they mount easily on a 12.5" rim and have seen them on 13s.

I am pretty sure you can run 12" wheels square on that car with that suspension so I would.
Thanks for the feedback. I'm less concerned with how they look on the car and am more concerned I'm running an optimal setup. The car will accept 12" all around, but in talking with the Speedtech guys, I'm finding everyone is moving away from 335 and sticking with 315, which is what I'm very likely going to do. I was just asking about 335 flexibility, but it's really not that important to me here. At 315 squared, you'd still recommend 12? Even though Falken doesn't recommend over 11.5?


I was referring to the 315s with option to 335s. Originally I was thinking a 12" would be better, but interestingly Falken didn't recommend more than 11.5" on the 315. Based on dontlifttoshift's feedback a 12" setup would be more ideal even for 315s, and better especially if you went up to 335s later on. I prefer having the overall rim width (outside to outside) at least as wide as the overall tire width if possible. It'd be better if you really decide which size you want to go with first.
I'm set on 315. I was just wondering about 335 compatibility, but it was just to gather info. 335 shouldn't be taken into consideration for this particular decision. Thoughts?


I would follow Donny’s experience here.

The advertised tread width for the BFG Rival 315 is 11.7”. I personally would strive to run a 315 on a 11.5-12” wheel mounting width to stay in line with the tread width. Doing so keeps the shoulders of the tire squared. A 335 on the same wheel would be “pulling over” the shoulders of the tire slightly.
Yup. Let's throw the 335 conversation away at this point then. I'm going to be running 315 squared.


My front and rear offset were different, as were the widths. So while I had 315's at all 4 corners, I couldn't rotate anything without unmounting / remounting (if this is what you were asking).

I personally liked the fit of the 315 Rivals on the 11.5" width also.

Best suggestion I can make... Get one of the wheel fitment tools and the tire you plan to run and test very carefully to make sure you are getting everything correct in terms of fitment if you are going to squeeze a 335 under the car. The shape of the Camaro wheel openings make it a little tighter than the Firebird (which I had). And if/when in doubt on offset, I'd go a little conservative and use more offset (I think that's how it's stated) as you can always use a small spacer to push the wheel out if needed (as in a 1/4" size or so, don't go too conservative).
Yes, I was asking for the purpose of rotation. Thanks for the details here. For this particular wheel purchase, I'm only considering 315. At this point, I'm leaning towards 11.5, but I'm all ears to hear more experience on this.

[Jonathonar89]

I don’t think you will miss much in either direction. 11.5” obviously gives you the all-around option here.

[roguegeek]

I don’t think you will miss much in either direction. 11.5” obviously gives you the all-around option here.
Yeah, that's what I'm thinking too.

[dontlifttoshift]

Yes, I would run 12" wheels with 315s. People are moving away from the 335 because it only exists in 18" in the Rival and it's not as fast as the A052 or the RT660.

Stretching the tire some (not talking about the hellaflush stance guys) supports the sidewall better which in turn allows you to dump some air pressure. Less air, more grip, more grip, more fast. Turn in is crisper and the rear of the car will break away cleaner as it is less likely to load up the sidewall and snap to over steer.

In order to run this setup square, you start with the front. So that's 18x12 and I believe the backspace number is 8ish inches. Confirm that number with SpeedTech!! Then you build your rearend to the width that properly locates the wheels in the wheel house. In the theoretical case of 8" backspace on a 18x12, your rear end width would be approximately 65" from wheel mount surface to wheel mount surface.

[roguegeek]

Yes, I would run 12" wheels with 315s. People are moving away from the 335 because it only exists in 18" in the Rival and it's not as fast as the A052 or the RT660.

Stretching the tire some (not talking about the hellaflush stance guys) supports the sidewall better which in turn allows you to dump some air pressure. Less air, more grip, more grip, more fast. Turn in is crisper and the rear of the car will break away cleaner as it is less likely to load up the sidewall and snap to over steer.

In order to run this setup square, you start with the front. So that's 18x12 and I believe the backspace number is 8ish inches. Confirm that number with SpeedTech!! Then you build your rearend to the width that properly locates the wheels in the wheel house. In the theoretical case of 8" backspace on a 18x12, your rear end width would be approximately 65" from wheel mount surface to wheel mount surface.
Ok. A lot of really good info here. I'll give Speedtech a call and see what they say in terms of backspace. My Dutchman rear-end is 56".

[roguegeek]

I'd like to expand the scope of my questions here. Let's say I go with 18x11.5, that will allow me to run all of the available 315/30ZR18 tires out there. What I haven't thought about is tires for when I'm daily driving. Yes, I could get a set of wheels that will better accept tires for the street, but what kind of smaller sizes could I fit on the 18x11.5? Could I fit a 295/30R18 like ones found in the Falken Azenis KF510 (https://www.falkentire.com/tires/passenger-car-tires-light-truck-suv-cuv-tires/azenis-fk510-tire) or comparable tire? Sizes where I can get higher UTQG ratings and are more mannered for daily driving. Would an 18x11.5 be capable of running something like that?

[dontlifttoshift]

Do you have the ability to mount and balance your own tires? The time and money spent swapping tires all the time gets old......hell, it gets old when you have your own equipment.

I just mounted a 295/30 A052 on an 11.5. It fit fine.

I will readily admit that I don't understand the willingness to stretch the DD tires past the recommended specs for no advantage while at the same time unwilling to stretch the race tires.

[68Formula]

295/30s are really short on a 2nd gen. I'd look at the 295/35s.

[roguegeek]

Do you have the ability to mount and balance your own tires? The time and money spent swapping tires all the time gets old......hell, it gets old when you have your own equipment.
I will probably not be doing the mounting myself. Moving tires around depending on usage is something I'm going to want to try before spending another $6k on additional wheels, though. To your point, I could easily see myself being annoyed with the time and cost, but I'll probably try it for the first year before grabbing a dedicated set of wheels.


I just mounted a 295/30 A052 on an 11.5. It fit fine.
How did it look? The last thing I'd want is for it to have that way too stretched look. Any other feedback you can offer on this would be much appreciated.


I will readily admit that I don't understand the willingness to stretch the DD tires past the recommended specs for no advantage while at the same time unwilling to stretch the race tires.
Well that's not my intention. My intention is to find a wheel width that works well for 315 squared on track days, but can also fit a tire that is more streetable in terms of tread wear and cost. I don't care what tire size is used for the street as long as it's safe. I picked 295/30 because I saw it being a more widely available, but I'm an idiot and I'm guessing there's better options? If you know something else that fits that criteria, I'd love to hear it. Would a 285/35 be better with the large sidewall? Is there something larger out there? Or... would it be better to drop down to 18x11 without sacrificing notable performance from the 315 and opening up options for the street? Whatever feedback you have, I'm all ears.

[roguegeek]

295/30s are really short on a 2nd gen. I'd look at the 295/35s.
That's absolutely possible. The only initial problem I'm seeing (https://www.tirerack.com/tires/TireSearchResults.jsp?filtering=true&width=295%2F&ratio=35&diameter=18#allTitle) is cost and options. Thoughts?

[68Formula]

That's absolutely possible. The only initial problem I'm seeing (https://www.tirerack.com/tires/TireSearchResults.jsp?filtering=true&width=295%2F&ratio=35&diameter=18#allTitle) is cost and options. Thoughts?

The 285/35s have a lot more choices and are virtually the same diameter. Could still run it on a 11.5 if you wanted to (a little bit of stretch), but a 11" wide would be a better choice. Most people I know that occasionally track their daily driver, have dedicated rims and tires for each setup. Usually their track rims give up a little bit of styling for lighter weight. And the street tires are a little harder compound (300+ treadwear rating) for longevity.

[Jonathonar89]

For the price-point, I would just stick with the Falken Azenis tires and run it for now. Concentrate on other things to get the car going. Even if you wear them down quicker than a BFG Rival, $277 tires are a big cost savings over $377 tires. Some of the other more street oriented 315 tires run $400-$500 a tire.

[dontlifttoshift]

Trying to make a decision/compromise based on a hypothetical situation that may happen in the future is difficult. Side story, somewhat related. Every manufacturer makes an "all season" tire. They work in all seasons, just like it says. But they don't work the best in any season so I call them no seasons.

Picking a wheel width that will work with 315s and 285s is easy. Buy the 11s, they will work with both tires but they won't be the best for either. You spent a lot of money on go fast parts and it seems that go fast is what it is all about. Buy the wheels that optimize the go fast and deal with the street side later. There are several ways to do that. A set of Forgestars would run $1,500 or less, you could run 10s all around with 275-295 or whatever.......but long before I did that, I would see how many "street" miles the car actually sees and if there is even a problem running the "race" rubber all the time and deal with it then.

[roguegeek]

The 285/35s have a lot more choices and are virtually the same diameter. Could still run it on a 11.5 if you wanted to (a little bit of stretch), but a 11" wide would be a better choice. Most people I know that occasionally track their daily driver, have dedicated rims and tires for each setup. Usually their track rims give up a little bit of styling for lighter weight. And the street tires are a little harder compound (300+ treadwear rating) for longevity.

That could work. Just as long as the stretch isn't so extreme that it's visually looking like that weird ass stanced tire stretch thing some people do. So you think 285/35 would be a bit better than a 295/30?

[roguegeek]

Trying to make a decision/compromise based on a hypothetical situation that may happen in the future is difficult. Side story, somewhat related. Every manufacturer makes an "all season" tire. They work in all seasons, just like it says. But they don't work the best in any season so I call them no seasons.
Point taken. I would say these aren't hypotheticals, though. Purpose isn't a question for me. I know what the usage of the car will be when all is said and done. I do understand what you're saying though and it does make sense. I appreciate the perspective.


Picking a wheel width that will work with 315s and 285s is easy. Buy the 11s, they will work with both tires but they won't be the best for either. You spent a lot of money on go fast parts and it seems that go fast is what it is all about. Buy the wheels that optimize the go fast and deal with the street side later. There are several ways to do that. A set of Forgestars would run $1,500 or less, you could run 10s all around with 275-295 or whatever.......but long before I did that, I would see how many "street" miles the car actually sees and if there is even a problem running the "race" rubber all the time and deal with it then.

Go fast is part of the equation, but it isn't the whole equation. If you check out the link in my signature, you can get some insight into how I'm planning this project.

That being said, I haven't compromised in many places so far and I don't know why I'd compromise as much as everyone is making this seem right now. I spoke with Forgeline this morning to see if it was possible to order just an inner barrel so I could effectively make the 18x11.5 I'm initially buying into something like a 18x10 for daily driving. They said no problem, that people do it all the time, and that I'll want to use their gasket seals instead for quicker changes. So that's an option right there. Run the 315 on an 18x11.5 (or hell, 18x12 now), then change out the inner barrel so they're 18x10 and run a more streetable tire. So this isn't the no compromise solution of just getting two sets of wheels, but it's not far off either and it's saving me $5500 in parts.

Thoughts on this?

[vette427-sbc]

Something to consider... Ill assume weather is not of concern. Most of us arent driving in the rain (intentionally) or snowy weather (waiting for AndrewB to reply to this :lmao:). So the only concern is tread wear. Is the wear from street miles worth the additional set of tires, barrels and time to swap out? I also like getting seat time with the car as it would be on the track, while I drive on the street. Makes familiarizing yourself with the car far easier.
As you can tell, Im in the group of "just run your track setup on the street" Ive got 18x13's and stretched Toyo R888R's that will probably get more street miles than track time.

[roguegeek]

Something to consider... Ill assume weather is not of concern. Most of us arent driving in the rain (intentionally) or snowy weather (waiting for AndrewB to reply to this :lmao:). So the only concern is tread wear. Is the wear from street miles worth the additional set of tires, barrels and time to swap out? I also like getting seat time with the car as it would be on the track, while I drive on the street. Makes familiarizing yourself with the car far easier.
As you can tell, Im in the group of "just run your track setup on the street" Ive got 18x13's and stretched Toyo R888R's that will probably get more street miles than track time.

Yeah, weather isn’t a concern here in California. My only concern is daily driving tread wear, cost associated with it, and safety. I’ve budgeted my tread wear cost for track days already, so I’m only dealing with the daily driving aspect of it.

You bring up very legitimate points. I’ll need to do a proper cost analysis to see how much these options are. I am someone who will pay for convenience and, if I were to guess, I’m probably going to get pretty tired of the man-hours needed to maintain the countermeasure of multiple inner barrels and converting of the wheels, particularly if I’m doing the conversion 20-24 times a year.

Writing that out helps put it into perspective for me. I might very well discover NOT running a my track configuration on the street is cost prohibitive. If that’s the case, then safety might be my only concern.

[dontlifttoshift]

I would collect stamps before I swapped inner hoops and tires 24 times a year. You have two options.

Four extra inner hoops arent really much cheaper than the forgestars. Even using racer math I can't make the barrels make sense. Buy cheap wheels, run street tires, easy swaps.

Drive the race rubber. How many daily driver miles are you looking at? If you are talking about 20 track days, your tire budget is significant, and I don't think the street miles will add up to a large percentage of the wear anyways.

[Jonathonar89]

Yeah, weather isn’t a concern here in California. My only concern is daily driving tread wear, cost associated with it, and safety. I’ve budgeted my tread wear cost for track days already, so I’m only dealing with the daily driving aspect of it.

You bring up very legitimate points. I’ll need to do a proper cost analysis to see how much these options are. I am someone who will pay for convenience and, if I were to guess, I’m probably going to get pretty tired of the man-hours needed to maintain the countermeasure of multiple inner barrels and converting of the wheels, particularly if I’m doing the conversion 20-24 times a year.

Writing that out helps put it into perspective for me. I might very well discover NOT running a my track configuration on the street is cost prohibitive. If that’s the case, then safety might be my only concern.

I gave you a cost analysis before. $277 for the 200TW Falken tires is much cheaper than the other 315 tires and they fit 11.5” recommended wheel mounting width.

[roguegeek]

I would collect stamps before I swapped inner hoops and tires 24 times a year.
Don't trigger the stamp collectors. Those guys are maniacs.


Four extra inner hoops arent really much cheaper than the forgestars. Even using racer math I can't make the barrels make sense. Buy cheap wheels, run street tires, easy swaps.

Drive the race rubber. How many daily driver miles are you looking at? If you are talking about 20 track days, your tire budget is significant, and I don't think the street miles will add up to a large percentage of the wear anyways.
At this point, I'm looking at around 3-5k DD miles a year. I've budgeted 10-12 track days/year. Yes, the budget is significant, but I'm set there. As for the conversion, 10-12 days/year means 20-24 conversions/year. I agree. It doesn't make sense a lot of sense.


For the price-point, I would just stick with the Falken Azenis tires and run it for now. Concentrate on other things to get the car going. Even if you wear them down quicker than a BFG Rival, $277 tires are a big cost savings over $377 tires. Some of the other more street oriented 315 tires run $400-$500 a tire.

I gave you a cost analysis before. $277 for the 200TW Falken tires is much cheaper than the other 315 tires and they fit 11.5” recommended wheel mounting width.
Well to be fair, that isn't an actual cost analysis. That's just a comparison of two tires, which is definitely one piece of the puzzle, but I get what you're saying.

To do it properly, the questions I would need to answer are... How many 200TW sets would I go through over 5k DD miles/year? How many 300TW sets? Estimated costs for installation and balancing? Estimated man hours for conversions? Cost of inner barrels? Cost of entirely new set of wheels? Etc... Sorry, I'm just thinking out loud here. Not looking for a response on this.

The rough math and knowing my tolerances points to couple of realistic options.

Run my optimal track configuration on the street (18x12 with 315/30 at 200TW), but compromise a bit on safety (we get enough rain here that I need to consider it) when daily driving.
Have two sets of wheels/tires with no performance compromise and except the added initial cost.
Run a wheel like an 18x11 that can do a 315/30 200TW and 295/30or35, but compromise on track performance (speaking with all the autox guys this week, it sound extremely minimal) and the added cost/time.

3 will take time away from having fun with the car and the entire point of this project is to have fun, so I'm pretty sure it's out. Now I just need to figure out if I value safety more or initial cost more in this scenario. I'll probably just do what I'm guessing most people do. I'll run my track configuration on the street and feel that out until I get to the point where I feel I'll benefit from an extra set of wheels/tires.

[68Formula]

3-5K/year daily driving, you'll barely burn out a street-dedicated set before they age out (6 years recommended) even with 200TW. You'll be wearing out your track tires way faster than that. Just run the track tires if they're street legal.

[Jonathonar89]

Don't trigger the stamp collectors. Those guys are maniacs.


At this point, I'm looking at around 3-5k DD miles a year. I've budgeted 10-12 track days/year. Yes, the budget is significant, but I'm set there. As for the conversion, 10-12 days/year means 20-24 conversions/year. I agree. It doesn't make sense a lot of sense.



Well to be fair, that isn't an actual cost analysis. That's just a comparison of two tires, which is definitely one piece of the puzzle, but I get what you're saying.

To do it properly, the questions I would need to answer are... How many 200TW sets would I go through over 5k DD miles/year? How many 300TW sets? Estimated costs for installation and balancing? Estimated man hours for conversions? Cost of inner barrels? Cost of entirely new set of wheels? Etc... Sorry, I'm just thinking out loud here. Not looking for a response on this.

The rough math and knowing my tolerances points to couple of realistic options.

Run my optimal track configuration on the street (18x12 with 315/30 at 200TW), but compromise a bit on safety (we get enough rain here that I need to consider it) when daily driving.
Have two sets of wheels/tires with no performance compromise and except the added initial cost.
Run a wheel like an 18x11 that can do a 315/30 200TW and 295/30or35, but compromise on track performance (speaking with all the autox guys this week, it sound extremely minimal) and the added cost/time.

3 will take time away from having fun with the car and the entire point of this project is to have fun, so I'm pretty sure it's out. Now I just need to figure out if I value safety more or initial cost more in this scenario. I'll probably just do what I'm guessing most people do. I'll run my track configuration on the street and feel that out until I get to the point where I feel I'll benefit from an extra set of wheels/tires.


Man, by the time you think/mull this over, you could buy another set of tires by working. “Most people” is a very generic statement. Tire wear also varies significantly by how you drive a vehicle. Even “street tires” wear faster with aggressive alignment and/or aggressive driving added into the mix.

[roguegeek]

3-5K/year daily driving, you'll barely burn out a street-dedicated set before they age out (6 years recommended) even with 200TW. You'll be wearing out your track tires way faster than that. Just run the track tires if they're street legal.
This is what I was thinking as well. Thanks for the feedback.


Man, by the time you think/mull this over, you could buy another set of tires by working.
I respectfully disagree. Preplanning nearly always saves time, cost, and rework.


Tire wear also varies significantly by how you drive a vehicle. Even “street tires” wear faster with aggressive alignment and/or aggressive driving added into the mix.
I understand there are a lot of factors that determine tire life. I'm not arguing that. That doesn't mean I can't determine estimated life for me and my driving style, though. Deep diving into nearly anything can reveal predictability. That being said, those were rhetorical questions I posted for context to show what and how I'm thinking about it. I'm not looking for those answers here because only I'm really the only one who could answer them.

Ok, so it basically back to Donny and your's suggestion of just do 18x12 all around. It's a good suggestion and it was helpful to hear why. I'll probably just go with that and run whatever 315 tire as my street tire as well. Ok, thanks everyone!