[ddotffoeg]

225 on an 8.5 is perfectly fine and what I would do. 235\40 is a very tall tire and will kill your torque delivery. And if I am being honest there isnt any torque to spare. It would result in performance loss without a doubt. After I supercharge, if
traction in 1st gear becomes a problem I might do a 235\40 just to intentionally lose that wheel torque by essentially changing the final drive ratio with the tires. Added bonus is also better highway MPG. 😆

I'm torn between a 225/40 and 235/40 for an 18x8.5 +38 wheel (already purchased). I know the offset isn't perfect and I want to avoid potential rubbing.
I have camber bolts in the front and everything else is stock. Alignment is -1.4 all around.

Do you think it will rub in the rear or on full lock with with this set up?

I have RLCA in a box in the garage that could put on to help with the rear if needed. Nothing planned for coils yet due to managing the car budget.

 

[Briansshop]

☝ From what I've seen researching online,Id go with the 225.

 

[ddotffoeg]

☝ From what I've seen researching online,Id go with the 225.

I am also leaning that direction. a 225 isn't a stretch on an 8.5 and will be a little thinner than the 235 providing some extra clearance. I've seen posts on Fitment Industries of people running the 18x8.5 with 235/40 and no mods required, but I've also heard people say minor rubbing.

From my research too, I think 225 is the right choice.

EDIT: adding that I'll be going with Conti Extreme Contact Sports too.

 

[ddotffoeg]

Just a quick update. I put on my 18x8.5+35 with 225/40 Conti ECS this weekend. It fits perfectly without any rubbing. Rears have maybe a 2mm poke but otherwise it’s flush all the way around. I love the ride quality, handling and it’s quieter and smoother on the road.

if you lower it without adding camber, it will likely rub depending on the drop.

I plan on lowering it next year with coils and RLCA. About -3 in the front and -2 in the rear and about an inch total drop. i don’t foresee it rubbing at all. There should be plenty of space. Now if you slam it, then yes, you’ll need more camber and probably trimming.

Hope that this helps others. I’ll post a couple photos too.

I’ll post a lot on my Instagram too which is @projectneptune86 - i need to get high res photos for the wheel company first, which is SuperSpeed Wheels. They are flow formed and about 18.1lbs each. Highly recommend them and have a discount code if anyone is interested 🫡😂🙂

 

[adrian393676]

Would a 18x8.5 +30 and a 235/40 tire would be good ?

 

[ddotffoeg]

Would a 18x8.5 +30 and a 235/40 tire would be good ?

+30 is definitely pushing it and i wouldnt go with that. It'll poke alot and rub if you ever lower it. 225 tire if you do go with that.
It'll poke, side wide and have a thick tire at 235

 

[TRU-BOOST]

+30 is definitely pushing it and i wouldnt go with that. It'll poke alot and rub if you ever lower it. 225 tire if you do go with that.
It'll poke, side wide and have a thick tire at 235

Agree. Way too much poke.

 

[adrian393676]

+30 is definitely pushing it and i wouldnt go with that. It'll poke alot and rub if you ever lower it. 225 tire if you do go with that.
It'll poke, side wide and have a thick tire at 235

So what kind tire should I go with ?? I want it to be I little aggressive.

 

[ddotffoeg]

So what kind tire should I go with ?? I want it to be I little aggressive.

It depends on the wheel size you want. If you're going for an 8.5in wheel (+1 in over stock), a +35, +38 or even a +44 would work with a 225 tire.
If youre going a 9 or 9.5in wide tire, i think a +35 or +38 would work with a 235 tire.

Check out fitment Industries gallery, it's really helpful for looking at the various fitment and what is required (coils, RLCA, trimming, tire and wheel size, etc.)

 

[Eracles]

Just a quick update. I put on my 18x8.5+35 with 225/40 Conti ECS this weekend. It fits perfectly without any rubbing. Rears have maybe a 2mm poke but otherwise it’s flush all the way around. I love the ride quality, handling and it’s quieter and smoother on the road.

if you lower it without adding camber, it will likely rub depending on the drop.

I plan on lowering it next year with coils and RLCA. About -3 in the front and -2 in the rear and about an inch total drop. i don’t foresee it rubbing at all. There should be plenty of space. Now if you slam it, then yes, you’ll need more camber and probably trimming.

Hope that this helps others. I’ll post a couple photos too.

I’ll post a lot on my Instagram too which is @projectneptune86 - i need to get high res photos for the wheel company first, which is SuperSpeed Wheels. They are flow formed and about 18.1lbs each. Highly recommend them and have a discount code if anyone is interested 🫡😂🙂


View attachment 13509
View attachment 13510

Looks really nice, they don't stretch at all, if you were to say the wheel is 8x18, not 8.5, I would believe it.
But the wheels are 8.5 ET38 or ET35? You have said both in posts

 

[ddotffoeg]

Looks really nice, they don't stretch at all, if you were to say the wheel is 8x18, not 8.5, I would believe it.
But the wheels are 8.5 ET38 or ET35? You have said both in posts

+35 on my set

 

[SheperdX]

I'm planning on buying a set of 18x8.5 +45 Advan TC4s. I'm a little torn on what size of Michelin PS4S's to pair them with.

I'd prefer going with a thinner/shorter tire to keep more of the stock characteristics, but I'm worried 225/40 will be too much stretch on a 8.5 inch rim. 235/40 seems a little too tall (and more speedometer error than I'd like). I guess 245/35R18 is also an option to keep the stock wheel diameter, but a 245mm width honestly seems like overkill and is starting to edge into fitment limits on stock suspension.

My car is daily driven with 1-2 AutoX events a year, if that matters. Any advice?

you won’t have any fitment issues on +45 with an 8.5 width. There have been a few that have already ran this on a stock suspension.

mine is 245, and if you want to keep with OEM tire diameters, that’s the one to get.

 

[thomason2wheels]

I'm planning on buying a set of 18x8.5 +45 Advan TC4s. I'm a little torn on what size of Michelin PS4S's to pair them with.

I'd prefer going with a thinner/shorter tire to keep more of the stock characteristics, but I'm worried 225/40 will be too much stretch on a 8.5 inch rim. 235/40 seems a little too tall (and more speedometer error than I'd like). I guess 245/35R18 is also an option to keep the stock wheel diameter, but a 245mm width honestly seems like overkill and is starting to edge into fitment limits on stock suspension.

My car is daily driven with 1-2 AutoX events a year, if that matters. Any advice?

you should go to tire rack and see their test on different size tires on different size wheels, surprisingly enough a wider wheel like your 8.5 with a 225 would probably be close to optimum. TR actually stretch a set of 225s on 9 inch rims and tested those and they were rated very highly but deemed 'track use' only. their test car was an 86 so the results are very relevant.

 

[itsthemetho]

If your after performance and not looks, the following article is relevant: https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=296

It was done on a 2022 Subaru BRZ Limited. The following Tyres and rims:

Tires Tested
215/45R17 Bridgestone Potenza RE-71RS
225/45R17 Bridgestone Potenza RE-71RS
245/40R17 Bridgestone Potenza RE-71RS
Wheels Tested
17" x 7" Enkei Racing RPF1 (Black Painted)
17" x 8" Enkei Racing RPF1 (Bright Silver Painted)
17" x 9" Enkei Racing RPF1 (Gold Painted)

The results are below:

There is also a video:

 

[Xed32]

Stock shocks and springs, 18X8.5 +40, 245/35/18 tires, -3.2 Camber up front (5mm spacer). No rubbing anywhere.

Got her a while back and had parts from my Gen 1 that I put on. Occasional HPDE use.
Current mods:

• Tux Mats
• Ceramic Coat + tint
• MCA Traction mod
• Pedders offset top hats
• Camber bolts plus stock bolt swap ( -3.2 Camber up front)
• 245/35/18 Yokohama Advan APEX V601
• 18X8.5 +40 SuperSpeed RF06RR
• 5mm 73.1mm OD 56.1mm ID hybrid spacer up front (extended bolts going on soon as lugs need lots of tightening after a few laps) View attachment 22815 View attachment 22816 View attachment 22817 View attachment 22818 View attachment 22819

 

[chopsticksguru]

you won’t have any fitment issues on +45 with an 8.5 width. There have been a few that have already ran this on a stock suspension.

mine is 245, and if you want to keep with OEM tire diameters, that’s the one to get.

I've ordered the same wheel same spec🤘
So you went with 245/35 I assumed, Are you running on stock suspensions?

 

[SheperdX]

I've ordered the same wheel same spec🤘
So you went with 245/35 I assumed, Are you running on stock suspensions?

I am not. Since then, Ive gotten on coils. You should be fine, but I would suggest getting camber bolts.

 

[kimcheetos]

To finally update this thread, I did end up going with 225/40. There is some stretch for sure, but since the stock wheels were already a little stretched, this didn't feel too bad in comparison. On PS4S's. Don't mind the hole in the garage wall; that was left there by a previous tenant

Only problem with having aftermarket wheels is it makes me want to lower the car. When funds become available, I guess haha

 

[anthonyt654]

I have 235/40/18 ps4s’s on 18x8.5 +42 ne24’s.
I highly recommend them the 235/40’s. View attachment 11028

Hi, I am also thinking of going 235/40/18 18x8.5 with a 45+ offset wheel on my 23 brz, also with a stock suspension. Is your set up on a stock suspension? or is it lowered?

 

[lagging.brz]

Hi, I am also thinking of going 235/40/18 18x8.5 with a 45+ offset wheel on my 23 brz, also with a stock suspension. Is your set up on a stock suspension? or is it lowered?

Thinking of going similar route, 235/40R18 with 18x8.5 +42mm (Motegi MR147 CM7 wheels)
stock suspension, maybe coilovers in a few years

Let me know how yours works out.