[KingLT1]

Originally Posted by Msquared

If all someone is doing is drag racing, that may work fine. If someone wants good handling and grip while cornering, it's not going to work well.

Define cornering grip? Obviously, running a drag radial or oversize tire isn't ideal if you plan on road coursing the car. For street use the 305/35/20 555r2 is very stable and will handle some fairly aggressive cornering at high speed. Done it plenty of times at the end of a hard pull at my test spot that has a fairly aggressive left corner where I have roll through it around 90mph on decel. I have also been to the top of 6th gear on that wheel tire combo and it was 100% stable.

[White1SS]

Originally Posted by KingLT1

Define cornering grip? Obviously, running a drag radial or oversize tire isn't ideal if you plan on road coursing the car. For street use the 305/35/20 555r2 is very stable and will handle some fairly aggressive cornering at high speed. Done it plenty of times at the end of a hard pull at my test spot that has a fairly aggressive left corner where I have roll through it around 90mph on decel. I have also been to the top of 6th gear on that wheel tire combo and it was 100% stable.

I was thinking of going with a square set-up with 285/35/20's on factory SS 9.5" rims with 15mm spacers. The car is stock and will never be tracked or at the strip, so it's really just for the look of a wider stance. However, in the future I plan to go with something around 600-650whp. With the bulge of a 305 on a 9.5" rim , would a 285 on a 9.5" rim have almost as much contact with the ground?

[FlukeSS]

Originally Posted by KingLT1

I have had 305/35/20 555r drag radials on my stock SS 20x9.5 wheels for 8yrs. You ought to try reading outside this general section. Plenty of info on it being done over the years.

https://www.camaro6.com/forums/showthread.php?t=486613

Understood didn't know they would work that way.

[Msquared]

Originally Posted by KingLT1

Define cornering grip? Obviously, running a drag radial or oversize tire isn't ideal if you plan on road coursing the car. For street use the 305/35/20 555r2 is very stable and will handle some fairly aggressive cornering at high speed. Done it plenty of times at the end of a hard pull at my test spot that has a fairly aggressive left corner where I have roll through it around 90mph on decel. I have also been to the top of 6th gear on that wheel tire combo and it was 100% stable.

"Cornering grip" is defined as lateral acceleration of the car. That acceleration force is usually - but not always - generated by the front tires' steering angles, which cause front and rear tires to develop slip angles roughly perpendicular to the car's direction of travel. I mean, we can get into the weeds on this and I can reclaim my copy of the Milliken bible on vehicle dynamics, but I think everybody has a good idea of what "cornering (lateral) grip" actually means.

Yes, obviously a 305/35/20 on a 20x9.5 wheel will generate some lateral grip when asked, even enough to make the shutdown turn at a small drag strip. I mean, even a Top Fuel funny car can make the turn at the end of a run, despite having probably the worst cornering tire setup of any pavement-bound car. However, the 305/35/20 is both too wide on that wheel width and too tall in general to generate the best grip, and its handling characteristics will be very poor, in comparison to something like a 305/30/20 on a 20x11 wheel. "Handling characteristics" means things like steering response, linearity, slip angle vs lateral grip, etc. These tires will be very laggy and very mushy in steering response, but they also raise the CG and roll center height at the rear of the car, which reduces rear lateral grip and makes their response very non-linear. This is not stable unless matched by similar fitment at the front, in which case you have a whole car that is mushy, non-linear, and generally low in grip instead of just the rear. That instability and lower lateral grip will show up any time a driver is trying to autocross, do a track day, or just carve corners aggressively on a public street. Worse yet, it will be the most obvious in transient maneuvers like a slalom or emergency lane change, right when the driver needs stability the most. I also haven't addressed braking, but the extra tire diameter will also worsen braking performance.

Again, will this fitment negotiate a turn at well below the limits of lateral grip? Will it do what a driver needs in normal street driving? Sure. Will "handle well" as the car approaches its lateral limit of grip? Nope. And neither will it provide the same overall level of grip as a properly-sized tire for cornering and braking. I'm not saying it can't be used. I'm just saying that drivers should know the pros and cons ahead of time and should consider their realistic use of the vehicle.

[Msquared]

Originally Posted by White1SS

I was thinking of going with a square set-up with 285/35/20's on factory SS 9.5" rims with 15mm spacers. The car is stock and will never be tracked or at the strip, so it's really just for the look of a wider stance. However, in the future I plan to go with something around 600-650whp. With the bulge of a 305 on a 9.5" rim , would a 285 on a 9.5" rim have almost as much contact with the ground?

First, stock SS rear wheels are 20x9.5 with 39mm of offset. Your plan to use 15mm spacers on a set of four rear SS wheels will push the rears out 15mm from stock, but will only set the center of the front wheels in the same place as the stock 20x8.5 et20 wheels (well...1mm further out). You may want a little more spacer thickness up front if "wider stance" is your goal. Also, understand that this tire size will be taller than any stock Camaro tire at 27.9" diameter. That may be what you want, but it's generally not the look the stance crowd is going for. 285/30/20 would be 26.8" in height with the same width, and it's what came stock on SS 1LE cars. That might be more appropriate for your goals, but you can be the judge of that.

The question about contact patch size has a lot of "it depends" in the answer. For a drag radial designed to be run at a pretty low pressure, and which generally has relatively soft carcass construction, the 305/35/20 may have significantly more contact patch size at low inflation pressures. Probably not so much more at typical radial pressures for street use (~35psi). High-performance tires designed for cornering and braking typically have stiffer construction and are designed to run closer to street pressures than drag racing pressures. In that case, for a 9.5" rim width, the 285 may have nearly as much contact patch area as the 305 on the same wheel. The difference would shrink even further if you compare tires with an aspect ratio of 30 as opposed to the taller 35s.

[digitalfutur]

If better cornering is the goal, why not just get stickier tires in stock size, rather than wider ones? Almost certainly cheaper, since new rims aren't needed.

[White1SS]

Originally Posted by Msquared

First, stock SS rear wheels are 20x9.5 with 39mm of offset. Your plan to use 15mm spacers on a set of four rear SS wheels will push the rears out 15mm from stock, but will only set the center of the front wheels in the same place as the stock 20x8.5 et20 wheels (well...1mm further out). You may want a little more spacer thickness up front if "wider stance" is your goal. Also, understand that this tire size will be taller than any stock Camaro tire at 27.9" diameter. That may be what you want, but it's generally not the look the stance crowd is going for. 285/30/20 would be 26.8" in height with the same width, and it's what came stock on SS 1LE cars. That might be more appropriate for your goals, but you can be the judge of that.

The question about contact patch size has a lot of "it depends" in the answer. For a drag radial designed to be run at a pretty low pressure, and which generally has relatively soft carcass construction, the 305/35/20 may have significantly more contact patch size at low inflation pressures. Probably not so much more at typical radial pressures for street use (~35psi). High-performance tires designed for cornering and braking typically have stiffer construction and are designed to run closer to street pressures than drag racing pressures. In that case, for a 9.5" rim width, the 285 may have nearly as much contact patch area as the 305 on the same wheel. The difference would shrink even further if you compare tires with an aspect ratio of 30 as opposed to the taller 35s.

Thanks for the response. I definitely prefer the look of a slightly taller tire, the factory tires are 27.7" and 27.6" , the 27.9" tall 285/35 is just slightly taller and closer to the correct speedo at stock, I think it's perfect for what I'm looking for. I understand the performance advantage of the shorter tires for the 1LE, but I just don't care for the look on the rim, or the gap in the wheel well.


I believe the 8.5" rims are et25 ? I'm looking to bring the outside of the rims out equally in the front and back, with just enough clearance in the front to clear the strut. What size spacer(s) would be necessary for the 9.5" et39 rim with a 285/35 to clear the strut in the front, and to bring the rear out equally ?


Thanks,
Joe

[Msquared]

Originally Posted by White1SS

Thanks for the response. I definitely prefer the look of a slightly taller tire, the factory tires are 27.7" and 27.6" , the 27.9" tall 285/35 is just slightly taller and closer to the correct speedo at stock, I think it's perfect for what I'm looking for. I understand the performance advantage of the shorter tires for the 1LE, but I just don't care for the look on the rim, or the gap in the wheel well.

All valid points, and it seems like a reasonable choice for your priorities.

I believe the 8.5" rims are et25 ?

Oops, you're right. Sorry about that! I don't know why I typed that, because I was on target about the 15mm difference. The 20x10 SS 1LE front wheel (with 285/30/20 tire) has an offset of 20mm, which I guess is where my brain faded to.
[quote]I'm looking to bring the outside of the rims out equally in the front and back, with just enough clearance in the front to clear the strut. What size spacer(s) would be necessary for the 9.5" et39 rim with a 285/35 to clear the strut in the front, and to bring the rear out equally?/QUOTE]
I'm assuming you don't have MRC dampers on your car, right? You probably have more room on the inside than you think. Although I don't have experience with that size tire on these cars, I bet 15mm (net offset of 24mm) will clear the strut. I'm sure it would clear with a 20mm spacer, as that would give you a net offset of 19mm which is 1mm further to the outside than a stock SS 1LE front wheel. I would expect that to still clear the outside fender edge and liner, too.

If you're definitely ordering 15mm spacers for the rear, what you could do is just order two of them and try one on the front and one on the rear with the new wheels and see how you like them. If they work well for you in front, order two more. If you still want to push the fronts out a little more, then use the two 15s on the rears and buy 20s for the front.

[White1SS]

[QUOTE=Msquared;11472492]All valid points, and it seems like a reasonable choice for your priorities.


Oops, you're right. Sorry about that! I don't know why I typed that, because I was on target about the 15mm difference. The 20x10 SS 1LE front wheel (with 285/30/20 tire) has an offset of 20mm, which I guess is where my brain faded to.

I'm looking to bring the outside of the rims out equally in the front and back, with just enough clearance in the front to clear the strut. What size spacer(s) would be necessary for the 9.5" et39 rim with a 285/35 to clear the strut in the front, and to bring the rear out equally?/QUOTE]
I'm assuming you don't have MRC dampers on your car, right? You probably have more room on the inside than you think. Although I don't have experience with that size tire on these cars, I bet 15mm (net offset of 24mm) will clear the strut. I'm sure it would clear with a 20mm spacer, as that would give you a net offset of 19mm which is 1mm further to the outside than a stock SS 1LE front wheel. I would expect that to still clear the outside fender edge and liner, too.

If you're definitely ordering 15mm spacers for the rear, what you could do is just order two of them and try one on the front and one on the rear with the new wheels and see how you like them. If they work well for you in front, order two more. If you still want to push the fronts out a little more, then use the two 15s on the rears and buy 20s for the front.

Thanks again for the response. Yes, non MRC. I know a lot of guys use the 10" MRR 1LE wheels as well, which are et23, and they don't have clearance issues, but I'm not sure if anyone is using a 285/35 instead of the standard 285/30. It looks like I can get 15mm-16mm-or even 17mm spacers from American Muscle. I'm not sure how the factory set-up is aligned front to back, meaning if I drove through the snow, would the front 245 be in the center track of the rear 275,or would they be aligned on the outside, or in some other manner? Visually it looks like they are both tucked in the wheel well pretty much identical, but it's hard to tell. If I could put the 9.5" rim in the front and use say the 17mm to clear everything, and then use a 17mm in the rear, I'm thinking the tires would be lined up front to rear and essentially leave one set of tracks in the snow. If I have it right, I would basically have the same stance as a 1LE in the front, and the same outer stance as a 1LE in the rear ?

[KingLT1]

This is what 20x9.5 ET25 275/35/20 front and 20x10.5 ET38 305/35/20 looks like.

https://www.camaro6.com/forums/showp...5&postcount=26

[Joshinator99]

Originally Posted by KingLT1

This is what 20x9.5 ET25 275/35/20 front and 20x10.5 ET38 305/35/20 looks like.

https://www.camaro6.com/forums/showp...5&postcount=26

Looking good my man!

[White1SS]

Originally Posted by KingLT1

This is what 20x9.5 ET25 275/35/20 front and 20x10.5 ET38 305/35/20 looks like.

https://www.camaro6.com/forums/showp...5&postcount=26

That's a great look, just the right height and stance ! It's nice to see others like a bright wheel on these cars as well. Are the rims chrome or polished ?

[Msquared]

Originally Posted by White1SS

Thanks again for the response. Yes, non MRC. I know a lot of guys use the 10" MRR 1LE wheels as well, which are et23, and they don't have clearance issues, but I'm not sure if anyone is using a 285/35 instead of the standard 285/30.

I have three sets of the 19x10/11 ZLE replicas. They are also 23mm in front, and they fit fine even with a 305/30/19 and no spacer. But that doesn't help with the extra diameter of a 285/35/20. There's an extra 1/2" of radius to worry about.

I'm not sure how the factory set-up is aligned front to back, meaning if I drove through the snow, would the front 245 be in the center track of the rear 275,or would they be aligned on the outside, or in some other manner?

The front and rear track widths are the specs you're looking for here. Track width is measured at the centers of the wheel widths, so offsets factor in here and wheel widths don't. I can't find any specs for Camaro track width that make sense, including the factory brochures:


However, if you search for "2022 Camaro LT1 track width," you'll keep seeing 62.5" front and 63.7" rear, which is consistent with the LS and LT models from 2016 (i.e., all the "base" cars with equal wheel offsets front and rear) - basically the all the versions that came with equal offsets front and rear. when you plug in the offsets from the various versions' wheels, the math doesn't work out, so I don't know what to think...maybe there suspension links and hub/knuckle designs are that much different between the various models too? I don't know. And you can't jack it up to measure the from one hub face to the other, because the track width changes when the wheels droop. So the best way I think is to measure the distance between inside sidewalls (at the widest part) and the outside sidewalls and average the two distances. Then you'll know the actual track widths front and rear for your car with the stock wheels.

If I could put the 9.5" rim in the front and use say the 17mm to clear everything, and then use a 17mm in the rear, I'm thinking the tires would be lined up front to rear and essentially leave one set of tracks in the snow. If I have it right, I would basically have the same stance as a 1LE in the front, and the same outer stance as a 1LE in the rear ?

In that case, you'd be going from 25mm offset stock to net 22mm offset at both ends, and also increasing wheel width by 1" (1/2" either side of the hub) and tire section width by 40mm. So in this case, the outsides of the tires at the widest part of the sidewalls would sit 23mm further to the outside front and rear than they do now, but they'd have the same front-to-rear difference in track width than they do now. IOW, if the current tires follow exactly each other's paths in the snow, then so would the new set. The tracks would just be 1" wider and their centers would be 3mm further apart than your stock setup. Whether the front and rear are really perfectly in line with each other? I think you're going to have to measure that. The stock specs say they are not.

[KingLT1]

Originally Posted by Joshinator99

Looking good my man!

Thank you sir!

Originally Posted by White1SS

That's a great look, just the right height and stance ! It's nice to see others like a bright wheel on these cars as well. Are the rims chrome or polished ?

Thanks. Yeah, I am old school...I like shine! The finish is called Vacuum Chrome which is slightly darker than Bright Chrome at different light angles. It's a pretty cool finish imo.