[ocN55]

Originally Posted by Liquidpaper

Okay so car went into the shop today for some upgrades (some show, some go):

4x18.5 ET 38 APEX ARC-8 in Hyper Black wrapped in 255/35/18 Direzza II rubber;

Challenge F22 Stainless Line Kit (with ATE 200 fluid);

Porterfield R4-S Pads (F&R);

M-Performance Exhaust and Stainless pedals (for fun).

Also, I got my Ground Control camber plates put in a few weeks ago. They're great. Have a "light race/aggressive street" setup at 2.25 F, 1.65 R, 1/16 Toe In.

AROSC has their school next weekend at streets of willow - already booked my slot. Super excited.

My next upgrade is going to me the M-Performance LSD, maybe in six months or so.

you fit a 255 in the front without rubbing issues? 18x18.5 all around I'm assuming?

[Liquidpaper]

Originally Posted by ocN55

you fit a 255 in the front without rubbing issues? 18x18.5 all around I'm assuming?

Yep. No rubbing. 255 fit just fine on 8.5 wheels (ET 38). Mind you, I'm running pretty aggressive camber (2.25) in the front.

[ocN55]

Originally Posted by Liquidpaper

Yep. No rubbing. 255 fit just fine on 8.5 wheels (ET 38). Mind you, I'm running pretty aggressive camber (2.25) in the front.

Do you think i would rub with 255 all around with stock suspension setup? I'm looking at the PSS but i heard that michelin tires are fatter and may require going down a size.

[Béhème]

Originally Posted by pikcachu

do they have those for the back too ?
where do you order them from?

I received the following e-mail from Pagid on February 5th:



Hi,

We do have the M235i pads in RS29, please contact one of our US distributors. http://www.pagidracing.com/service/distributors/

Thanks

Best Regards

Andreas
pagid@braketechnology.com

[Béhème]

I also received the following from HAWK on February 12:


We do not offer pads for your vehicle. The FMSI part numbers are D1609, and D1656. We have initiated production on pads for your M235i. Please check back with in April for updates.


Best regards,


Edwin Mangune
Hawk Performance Products Group
emangune@carlislecbf.com

[rwalker]

Originally Posted by ocN55

Do you think i would rub with 255 all around with stock suspension setup? I'm looking at the PSS but i heard that michelin tires are fatter and may require going down a size.

very unlikely. to clear the strut, the tire must poke a good bit. my test fit of 255s with stock camber showed clearly that compression would cause interference with the fender.

[Liquidpaper]

Originally Posted by ocN55

Do you think i would rub with 255 all around with stock suspension setup? I'm looking at the PSS but i heard that michelin tires are fatter and may require going down a size.

Yes, you would rub. You need a relatively aggressive offset to fit a 255 wide tire without hitting the strut. In order to do so, you'll have some poke, and in order to deal with that, you'll need camber plates.

[ocN55]

Originally Posted by Liquidpaper

Yes, you would rub. You need a relatively aggressive offset to fit a 255 wide tire without hitting the strut. In order to do so, you'll have some poke, and in order to deal with that, you'll need camber plates.

Was thinking 18x8.5 +38 all around with 255s, stock everything.

Shouldn't this work with no rubbing? Sorry I'm just reading different information and trying to find out whats right.

[rwalker]

Originally Posted by ocN55

Shouldn't this work with no rubbing?

no, sorry. these cars are hard to get rubber under, especially in the front.

[pikcachu]

Originally Posted by ocN55

Was thinking 18x8.5 +38 all around with 255s, stock everything.

Shouldn't this work with no rubbing? Sorry I'm just reading different information and trying to find out whats right.

safest bet is 245 if you are full stock

[Liquidpaper]

Originally Posted by pikcachu

safest bet is 245 if you are full stock

Absolutely right. You really can't fit 255 in the front on stock suspension.

[ocN55]

Originally Posted by pikcachu

safest bet is 245 if you are full stock

245/35/18 or 245/40/18?

[pikcachu]

Originally Posted by ocN55

245/35/18 or 245/40/18?

i think either one but maybe
Liquidpaper has more insight

what would be the advantages/disadvantages of 35 over 40 tire?

[ocN55]

Originally Posted by pikcachu

i think either one but maybe
Liquidpaper has more insight

what would be the advantages/disadvantages of 35 over 40 tire?

Liquidpaper, enlighten me

[pikcachu]

well i was browsing on Tirerack and there are almost no perf tire in 245/35-18 (or 17)...
so i guess it's 245-40...

Also found lower profile means less cushion so it acts like if you have a stiffer suspension and viceversa...

[Liquidpaper]

Originally Posted by ocN55

Liquidpaper, enlighten me

A few months back, I thought about going to a 245/40 tire on the rear (stock wheels) so I could move away from the PSS (no one makes 245/35/18 other than the Michelin in the PSS).

However, you're going to run into the issue of a larger rolling diameter. So, if you don't know, the three numbers in a tire rating (245/40/18) stand for three different things:

245=mm tread width
40=sidewall height as a function of % tread width
18=diameter of tire

So, if you are going from a 245/35/18 to a 245/40/18, you are ending up with a 5% increase in sidewall height. This is bad. It really screws up several systems in the car which rely on a certain rolling diameter for the wheel/tire (gearing, speedometer, TPMS, traction control). You want to stay as close to the stock rolling diameter as possible. Use willtheyfit.com as a good calculator.

Here, you'd end up with a speedo error of -3.75% (you're moving 3.75% faster than what your speedo says) moving to the 40 sidewall. This is very, very bad (you NEVER want to have an error over 3%, and anything over 1.5% is not so good).

If you want to keep the stock wheels, you're better off running 255/35/18 in the back and 225/40/18 in the front. Everyone makes those sizes, and although the manufacturer specs say that you need an 8.5"minimum to run a 255 wide tire, you'll be fine with an 8" wheel. I was running 255/35 Direzza II's on my stock rear tires, and they did just fine.

[ocN55]

Originally Posted by Liquidpaper

A few months back, I thought about going to a 245/40 tire on the rear (stock wheels) so I could move away from the PSS (no one makes 245/35/18 other than the Michelin in the PSS).

However, you're going to run into the issue of a larger rolling diameter. So, if you don't know, the three numbers in a tire rating (245/40/18) stand for three different things:

245=mm tread width
40=sidewall height as a function of % tread width
18=diameter of tire

So, if you are going from a 245/35/18 to a 245/40/18, you are ending up with a 5% increase in sidewall height. This is bad. It really screws up several systems in the car which rely on a certain rolling diameter for the wheel/tire (gearing, speedometer, TPMS, traction control). You want to stay as close to the stock rolling diameter as possible. Use willtheyfit.com as a good calculator.

Here, you'd end up with a speedo error of -3.75% (you're moving 3.75% faster than what your speedo says) moving to the 40 sidewall. This is very, very bad (you NEVER want to have an error over 3%, and anything over 1.5% is not so good).

If you want to keep the stock wheels, you're better off running 255/35/18 in the back and 225/40/18 in the front. Everyone makes those sizes, and although the manufacturer specs say that you need an 8.5"minimum to run a 255 wide tire, you'll be fine with an 8" wheel. I was running 255/35 Direzza II's on my stock rear tires, and they did just fine.

Thank you very much, this was all great information. Side note, my car came with the all seasons so I have 225/40/18 all around. If that's the case, wouldn't I be able to get away with the 245/40 in the rear since that is my stock sidewall rating?

[pikcachu]

Originally Posted by ocN55

Thank you very much, this was all great information. Side note, my car came with the all seasons so I have 225/40/18 all around. If that's the case, wouldn't I be able to get away with the 245/40 in the rear since that is my stock sidewall rating?

the 40 is a ratio... because you are increasing your width it means you are also increasing the sidewall height...

http://www.willtheyfit.com/index.php...et2=20#content

so your tire will actually be about 16mm taller so your speedometer will read 2.5% slower

[ocN55]

Originally Posted by pikcachu

the 40 is a ratio... because you are increasing your width it means you are also increasing the sidewall height...

http://www.willtheyfit.com/index.php...et2=20#content

so your tire will actually be about 16mm taller so your speedometer will read 2.5% slower

Darn, so it seems like either way I can't win. Whether if I go with the 245/40 I'll be off -2.45% and 245/35 will be off 1.35% (borderline acceptable from what liquidpaper explained to me)

[pikcachu]

245-35 i guess it's the best compromise...

[Liquidpaper]

Originally Posted by ocN55

Darn, so it seems like either way I can't win. Whether if I go with the 245/40 I'll be off -2.45% and 245/35 will be off 1.35% (borderline acceptable from what liquidpaper explained to me)

How wide are the wheels? 7.5 square? If so, stick with 225/40.

If you have an 8 inch in the back, move to 255/35 tire. The rolling diameter between a 225/40 and a 255/35 is almost exactly the same.

[Supernaut]

Originally Posted by Liquidpaper

A few months back, I thought about going to a 245/40 tire on the rear (stock wheels) so I could move away from the PSS (no one makes 245/35/18 other than the Michelin in the PSS).
...
If you want to keep the stock wheels, you're better off running 255/35/18 in the back and 225/40/18 in the front. Everyone makes those sizes, and although the manufacturer specs say that you need an 8.5"minimum to run a 255 wide tire, you'll be fine with an 8" wheel. I was running 255/35 Direzza II's on my stock rear tires, and they did just fine.

Tire Rack lists 16 different tires in the 245/35-18 range, 14 of which are in the same category as the PSS. Is there something I'm missing? I've been considering a square setup, so I've been looking at this size on an 8" wheel.