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[Gr330zhp]

What's up everyone

So it's almost time to put my 19s back on and remove the winter wheels. Looking at some new tires. Most likely go with the Pilot Super Sport, my favorite tires. So, I have stock Competition package suspension and not planning on modifying that, had my suspension fun in my E46. What's the widest rear tire I can install and wheel spacer combination to not rub. Was thinking of maybe going up to 275? Or 285? Maybe I won't do spacers though. Just trying to see what my options are for sizes

Thanks!

[d0o0fy]

I run 255/35F-275/35R in PSS and it works perfectly, without spacers, on ZCP suspension and wheels.

[Ashley Schaeffer BMW]

295's in the rear look so much better.

[s85e90]

275/35 is perfect. There is no need to put a bigger tire on the car it just doesn't need it. IMO 295 is too big for a 10" wheel also.

[Gr330zhp]

So why does tirerack say I need to run a 255 front with a 275 rear? Is that really necessary? Not Awd obviously

[aus]

There's this tire/wheel section here that has all your answers.

[squartus]

295 looks fine on a 10 inch wheel. Some pics around with ZCP with 295 on back looks good, im running 315 on a 10.5 looks good as well.

[jphughan]

Originally Posted by Gr330zhp

So why does tirerack say I need to run a 255 front with a 275 rear? Is that really necessary? Not Awd obviously

Because things like DSC and ABS look at relative wheel speed and are programmed based on the expected difference in rolling diameter for the stock tire size setup -- so if you change that difference significantly, those sensors won't be as effective. Increasing tire width while keeping the same aspect rating makes the tire taller, which in turn increases its rolling diameter. Increasing only the rear size would also shift the handling balance of the car more toward understeer, which is already fairly pronounced on the stock setup -- most people try to REDUCE understeer. And increasing tire size in general (front and/or rear) also increases ride height and tire roar, and adds rotating, unsprung weight, the worst kind. That increased weight can mean reduced ride quality (though in this case the impact of the additional weight might be cancelled out by the added comfort from the thicker sidewall), and it will definitely mean REDUCED performance in all scenarios where the stock tire size would have provided sufficient traction. All of that is why I don't see the point of increasing rear tire size unless you either a) have a supercharger, b) care more about acceleration from a dead stop than anything else, or c) just want the looks. For anything else, you'd probably be better served by getting stickier tires rather than larger ones, and chances are you'd also want to adjust your front tire size in addition to your rears -- or perhaps even instead of.

But if you're determined, 255 PSS in the front will fit to match your 275 rear. However, tires that are known to run wide for their rated sizes might rub. For example, the Yokohama AD08 and AD08 Rs run roughly 10mm wider than their rating suggests. I actually ran a 255 PSS in the front with the stock rear because I thought that increasing just the front would dial out more of the built-in understeer at the track and reduce the premature sidewall wear I'd been seeing without unnecessarily adding more unsprung weight in the rear. I didn't encounter any DSC/ABS issues, and it did help a bit on the first part but not at all on the second, so I'm now on AD08 Rs in stock sizes front and rear, which in terms of size is essentially a 255/275 PSS setup. Too early to tell whether the stiffer sidewall on these solves my premature wear issue.

[jphughan]

Originally Posted by squartus

295 looks fine on a 10 inch wheel. Some pics around with ZCP with 295 on back looks good, im running 315 on a 10.5 looks good as well.

10" is the smallest wheel that is allowed for a 295 PSS, which means that in addition to potentially creating a "muffin top" look where the sidewall bulges out between the wheel rim and the top of the tire, you can end up with handling consequences from having a shifty sidewall. Of course if you're just going for looks, maybe the latter doesn't matter to you, but that's why you want your wheel size to fall roughly in the middle of a given tire's acceptable wheel sizes, not on one extreme or the other.

[rjd598]

this question never ceases to amaze me. like seriously WOW

[squartus]

Originally Posted by jphughan

10" is the smallest wheel that is allowed for a 295 PSS, which means that in addition to potentially creating a "muffin top" look where the sidewall bulges out between the wheel rim and the top of the tire, you can end up with handling consequences from having a shifty sidewall. Of course if you're just going for looks, maybe the latter doesn't matter to you, but that's why you want your wheel size to fall roughly in the middle of a given tire's acceptable wheel sizes, not on one extreme or the other.

Pics it runs almost flush, no bulge or muffin top at all.
Here is one guys pics with 295pss on a 10inch ZCP, fits fine.


Here is my 10.5 with 315 fits fine.

[Edward]

Originally Posted by jphughan

Because things like DSC and ABS look at relative wheel speed and are programmed based on the expected difference in rolling diameter for the stock tire size setup -- so if you change that difference significantly, those sensors won't be as effective. Increasing tire width while keeping the same aspect rating makes the tire taller, which in turn increases its rolling diameter. Increasing only the rear size would also shift the handling balance of the car more toward understeer, which is already fairly pronounced on the stock setup -- most people try to REDUCE understeer. And increasing tire size in general (front and/or rear) also increases ride height and tire roar, and adds rotating, unsprung weight, the worst kind. That increased weight can mean reduced ride quality (though in this case the impact of the additional weight might be cancelled out by the added comfort from the thicker sidewall), and it will definitely mean REDUCED performance in all scenarios where the stock tire size would have provided sufficient traction. All of that is why I don't see the point of increasing rear tire size unless you either a) have a supercharger, b) care more about acceleration from a dead stop than anything else, or c) just want the looks. For anything else, you'd probably be better served by getting stickier tires rather than larger ones, and chances are you'd also want to adjust your front tire size in addition to your rears -- or perhaps even instead of.

But if you're determined, 255 PSS in the front will fit to match your 275 rear. However, tires that are known to run wide for their rated sizes might rub. For example, the Yokohama AD08 and AD08 Rs run roughly 10mm wider than their rating suggests. I actually ran a 255 PSS in the front with the stock rear because I thought that increasing just the front would dial out more of the built-in understeer at the track and reduce the premature sidewall wear I'd been seeing without unnecessarily adding more unsprung weight in the rear. I didn't encounter any DSC/ABS issues, and it did help a bit on the first part but not at all on the second, so I'm now on AD08 Rs in stock sizes front and rear, which in terms of size is essentially a 255/275 PSS setup. Too early to tell whether the stiffer sidewall on these solves my premature wear issue.

Smart responses like yours never win here because people want fat tires broooooo. shake my head

[81bear]

Originally Posted by jphughan

Because things like DSC and ABS look at relative wheel speed and are programmed based on the expected difference in rolling diameter for the stock tire size setup -- so if you change that difference significantly, those sensors won't be as effective. Increasing tire width while keeping the same aspect rating makes the tire taller, which in turn increases its rolling diameter. Increasing only the rear size would also shift the handling balance of the car more toward understeer, which is already fairly pronounced on the stock setup -- most people try to REDUCE understeer. And increasing tire size in general (front and/or rear) also increases ride height and tire roar, and adds rotating, unsprung weight, the worst kind. That increased weight can mean reduced ride quality (though in this case the impact of the additional weight might be cancelled out by the added comfort from the thicker sidewall), and it will definitely mean REDUCED performance in all scenarios where the stock tire size would have provided sufficient traction. All of that is why I don't see the point of increasing rear tire size unless you either a) have a supercharger, b) care more about acceleration from a dead stop than anything else, or c) just want the looks. For anything else, you'd probably be better served by getting stickier tires rather than larger ones, and chances are you'd also want to adjust your front tire size in addition to your rears -- or perhaps even instead of.

But if you're determined, 255 PSS in the front will fit to match your 275 rear. However, tires that are known to run wide for their rated sizes might rub. For example, the Yokohama AD08 and AD08 Rs run roughly 10mm wider than their rating suggests. I actually ran a 255 PSS in the front with the stock rear because I thought that increasing just the front would dial out more of the built-in understeer at the track and reduce the premature sidewall wear I'd been seeing without unnecessarily adding more unsprung weight in the rear. I didn't encounter any DSC/ABS issues, and it did help a bit on the first part but not at all on the second, so I'm now on AD08 Rs in stock sizes front and rear, which in terms of size is essentially a 255/275 PSS setup. Too early to tell whether the stiffer sidewall on these solves my premature wear issue.

Did you measure the spacing with these wheels mounted to determine that they are closer to 255/275 (PSS's) vs the actual rated 245/265? Or are you basing that on a general consensus of the forum (additional 10mm)? I ask because several tire professionals are saying the PSS's are a wider tire than the AD08R's when mounted.

[jphughan]

Originally Posted by 81bear

Did you measure the spacing with these wheels mounted to determine that they are closer to 255/275 (PSS's) vs the actual rated 245/265? Or are you basing that on a general consensus of the forum (additional 10mm)? I ask because several tire professionals are saying the PSS's are a wider tire than the AD08R's when mounted.

I rolled an unmounted 255 PSS up to an unmounted 245 AD08R. They were almost identical.

[Gr330zhp]

So maybe run 275 and smaller spacer or just keep the 265 and do 10-12mm spacer all around?

[chitown18]

If you want 255/275 PSS on ZCP wheels + suspension, get 12f/10r spacers.

If you get stock 245/265 PSS, then you can do 15f/12r spacers or even 18f/15r according to some people.


See this thread where many asked the same question, responded to by EAS:
http://www.m3post.com/forums/showthr...262054&page=24

[81bear]

Originally Posted by jphughan

I rolled an unmounted 255 PSS up to an unmounted 245 AD08R. They were almost identical.

Yeah I've seen pics of these two tires in the same size unmounted and the AD08R's definitely look bigger. That's why I'm finding it hard to believe that the PSS's are the wider tire when mounted... I wonder if the weight of the car on the PSS's cause them to bulge more than the AD08R's and thats why, when mounted, they are considered a wider tire...

[drewnel22]

Originally Posted by 81bear

Yeah I've seen pics of these two tires in the same size unmounted and the AD08R's definitely look bigger. That's why I'm finding it hard to believe that the PSS's are the wider tire when mounted... I wonder if the weight of the car on the PSS's cause them to bulge more than the AD08R's and thats why, when mounted, they are considered a wider tire...

You can't really compare the tires unmounted. The sidewall and tire construction between the 2 tires is different and will behave slightly differently when mounted.