[moldcad]

OK guys - so I have decided I'm NOT going for 19" (even though the F22 does really look beautiful on larger wheels), but I AM definitely going for a set of BC Forged 18" with wider rubber (235/255).

Since BC Forged can machine the wheels to the user's specs, I have a nice request to those of you who tried and experimented with various wheel widths/offsets: please tell me which size to order for the above mentioned rubber, so that:

- the setup is more aggressive than the OEM, but
- the wheels/tires are flush with the fenders and do not poke at all
- the tires are not stretched on the wheels too much, so that there is some rim protection by the rubber against curbs etc.
- no spacers needed
- no need for any fender rolling
- no plans for lowering the car

I guess I should go with something like 18x8 ET 40 front, 18x9 ET 45 rear to achieve my goals - but please help me decide on even more specific sizes.

Here is a picture of my favorite model - RS43 - finished in brushed metal:

[x233]

First off, do not go 235/255. Go the factory 225/245. Or, at least don't go 235 front.

Wheels: Front 8.0x18 ET_38 (or, IF possible, 7.5x18). Rear 9.0x18 ET_45. Don't go wider either in terms of ET or the wheels width. There's a lot of reasons to choose these particular specs, looks and function, AND practicality. Don't try to "re-invent the wheel" and just stick to these specs.

[Drpoomanchu]

Originally Posted by x233

First off, do not go 235/255. Go the factory 225/245. Or, at least don't go 235 front.

Wheels: Front 8.0x18 ET_38 (or, IF possible, 7.5x18). Rear 9.0x18 ET_45. Don't go wider either in terms of ET or the wheels width. There's a lot of reasons to choose these particular specs, looks and function, AND practicality. Don't try to "re-invent the wheel" and just stick to these specs.

Why not 255 in the rear might i ask or even 265 for that matter..?

[Drpoomanchu]

In my opinion the wheel specs are fine the way they are with ET40 front and ET45 rear. Very similar to my setup and looks more aggressive without poking. As far as tire specs, i think if you go a 235 in the front at least with MPSS you may have to roll fenders depending on if your lowered. 235 MPSS lowered may cause rub. As for the rears, if your making any more power than stock, i would strongly consider a 255 or 265 depending on brand. 255 with MPSS to avoid rubbing. To add to the above, the specs from bbs wheels maybe CIR and CHR would allow you to run a 235 front and 265 MPSS rear with Dinan lowering springs. Someone else may be able to chime in on this as i know the original Dinan 235 ran this aggressive setup

[moldcad]

Thanks Guys; I supplemented my OP with 2 more important assumptions (no need for any fender rolling, no plans for lowering the car). With this in mind, I might stay with 225 front - even though 235 would be more like it to not introduce understeer; as to the rears I indeed am making some more power and definitely need wider rubber, so 255 is my minimum.

I can see (from both the 2 answers in this thread as well as from reading all so many other threads in this forum) that 255 at the rear should not pose any problems; is 235 at the front really so risky? Since I read many people use 235 but - with some fixed front wheel width/ET - some must use some spacers (to avoid rubbing inside) or roll the fenders (to avoid rubbing the fenders), I was hoping for a recipe of very exact front wheel width /offset that would allow 235 tires w/o any of the mentioned mods (I mean like e.g. 18x8 ET 41, or 18x7.5 ET 39 - something I can easily order from BC forged while it's not available from "fixed sizes" wheel manufacturers...).

Also, If I had to stay with 225 at the front, I'd probably go for 18x7.5 wheels in order to avoid stretching the tires too much; to make them (and the 225 tire) flush with the fender, which specific ET would bee needed? Please remember I can order any offset, not limited to popular ET values of 38 or 40 mm..

Tia

Piotr

PS. Also, in the BBS CI-R thread, I can see even less aggressive sizes of the wheels (but not tires):
265/30/19 rear 235/35/19 front, Wheels :19 by 9 ET48 rear, 19 by 8 ET45 front on stock suspension. I realize they are 19", but perhaps I should go towards those sizes?

[x233]

Originally Posted by Drpoomanchu

Why not 255 in the rear might i ask or even 265 for that matter..?

I was mostly stressing not to use 235 in the front.

As for everything else... 255 in the rear is OK but... when you gain somewhere you lose elsewhere. e.g, when you go wider (and taller) in the rear you do gain in traction but you lose in responsiveness and the car gets yet more prone to understeer and handling isn't that great (kind of like that of a school bus). Same about making the rear track wider with more offset than that of the front wheels. Same about wider (and taller) fronts - you get a bit better braking but you don't really improve handling or responsiveness, quite the opposite. When you get nice wider than reasonable wheels such as 8.5 or more for the fronts or 9.5 for the rears you get wheels that are significantly heavier, less responsive, don't improve handling, and are more prone to damage. etc, etc, etc.

My recommendations are based on practicality (he's trying to save those wheels from damage) and on what you get in terms of handling/responsiveness/balance of the car.

[moldcad]

Yep - your advise is very sound, x233 !

That said - if I was solely after responsiveness and great cornering, I'd go with 19" and ultra-low profile in the first place. So no - a balance of as many advantages as possible is my goal

Piotr

[moldcad]

What do you think on such an extreme fitment - will there be rubbing? How to fine-tune the ET to avoid it?

A profile like this would benefit cornering and the width - traction; still on 18" so ride should not suffer much...

[Joe240]

If staying stock suspension, 235/265 setup works 100% fine without rubbing with a 8.5x19et39 front, 9.5x19et44 rear. Rear pokes about 10mm, so to compensate you'd go a higher offset (which there's still room to bring the wheel in).

Like someone mentioned, the BBS wheels offered by Dinan allow a 235/265 setup without rubbing, rolling fenders, or spacers even when lowered. I'd highly go with their specs since you can custom order your wheel width and offset.

Those specs are 19x8et45 front, 19x9et48 rear. Since you're going 18s, do the same width and offset and you'll be fine.

[moldcad]

Thanks, however one thing in your answer makes me wonder: regarding 235 front, the greatest danger of rubbing is inside (against the strut). Your mentioned 8.5x19 ET 39 wheel size seems to consider it, as the 38mm offset moves the wheel ouwards; has is then possible that there also will not be any rubbing against the strut with the Dinan's setup of 19x8 ET 45 at the front, and with the same 235mm rubber width?

Are those Dinan's settings 100% confirmed, or just guessed at or speculated? TIA

Piotr

[moldcad]

The bolded-out question is valid, but pls disregard my doubts in the first part of the above message; just compared the 19x8.5et38 vs. 19x8et45 and indeed, the inner position of the rim is almost the same..

[x233]

dear moldcad, please, do not make it more difficult than it is.
just go with 8x18 et38 front and 9x18 et45 rear and run 225/40/18 front and 245/35/18 rear (or 255/35 if you think it'll somehow be better) and be done (and happy) with it.

[Joe240]

I'm running 19x8.5et39 in the front with 235/35. There's about 2-3mm of poke on stock suspension, but under compression it tucks under. If I was lowered, I'd have to roll my front fenders. Going to an 8in width with the 40-45 offset would clear the strut and also the inner lip under compression with zero poke (exactly what you were looking for) even with a 235 size tire.

Not sure what x233's problem is with a 235 front, but there's no issues running 235 in the front when you have the right width wheel with the right offset.

And like you said, 8.5et39 sits almost identical to 8et45 in reference to the strut. The 8.5in wheel is 12.7mm wider than the 8in wheel, and since my wheel (again, 8.5et39) has about 10mm of poke, that means the 8in wheel will be 2mm inside the fender, zero poke.

[moldcad]

Thanks guys, I guess I'm settled as far as fitment is concerned!

One last question: what do you think of my wheel brand/model choice? I realize BC Forged makes budget forged wheels - but have you hear any bad opinions about their quality? And, how do yoy like the RS43 model's design/finish?

Piotr

[Joe240]

Haven't heard anything bad about them. Finish and style looks nice in the picture, might be a different story once put on the car. Never know how they will look until they're put on the car.

[x233]

Originally Posted by Joe240

Not sure what x233's problem is with a 235 front

Handling and balance of the car. First and foremost. Same for wheel width front and rear and ET ratio front/rear. The ones recommended in my post are the ones that I found to be the best from my numerous try and fail experiments with tire and wheel widths and offsets for my street car. The looks are great, too, but that's not the point.

PS: something else, as long as you're ready to splash some cash on forged wheels, and if their strength and longevity are top concerns, you might want to take a look here: http://www.weldwheels.com/ccwheel/corsair/c140/ (other other corsair series).

[AlpsRider]

Originally Posted by Drpoomanchu

In my opinion the wheel specs are fine the way they are with ET40 front and ET45 rear. Very similar to my setup and looks more aggressive without poking. As far as tire specs, i think if you go a 235 in the front at least with MPSS you may have to roll fenders depending on if your lowered. 235 MPSS lowered may cause rub. As for the rears, if your making any more power than stock, i would strongly consider a 255 or 265 depending on brand. 255 with MPSS to avoid rubbing. To add to the above, the specs from bbs wheels maybe CIR and CHR would allow you to run a 235 front and 265 MPSS rear with Dinan lowering springs. Someone else may be able to chime in on this as i know the original Dinan 235 ran this aggressive setup

My setup is BBS CI-R wheels with MPS4 S tires, 235/35/19 x 8" et45 and 265/30/19 x 9" et48. The car is dropped with Dinan springs. The rear tires don't rub but the front tires rubbed twice on the inside of the wheel well. I think the new MPS4 S tire may be bigger than the MPSS. It was a slight rub which just made a black mark on the inside of the wheel well that easily wiped off. Both times it rubbed it was under extreme conditions. Rolling the lip would probably eliminate the issue. Overall I'm happy with the setup.
The stock 245 rear tires in my opinion just don't have enough traction for the M235/M240 power and torque. The only way to keep the car from spinning the tires is to use the traction control all the time. The traction control in the 2 series is really not very smooth, it hunts and jerks in turns while trying to keep the car on the road. The Porsche 911 in comparison, which really needs traction control, is utilized seamlessly. The bigger tires have made my car much more stable, the drop along with the lower profile tires have also made the steering more sensitive. After installing the Dinan springs, the alignment specs came out at 1 degree negative camber in the front which will hopefully help the tires last longer. I've dropped the air pressure down 2 psi front and rear to 33/34 at 65 degree cold pressure for everyday driving, they heat up quickly to 36/37 and higher if pushed or if
it's a hot day. Now the car rarely has to resort to traction control trickery to keep the car from sliding unexpectedly, it just sticks to the road. Comfort is my preferred mode now unless I'm on a race track like smooth surface.

All that being said this 235/265 setup would be without issue on stock suspension, the specs on the BBS CI-R is close to perfect for the 2 series if you want to run bigger tires. The scrub radius is also still at 0 with this setup. Anyone with the desire to run 235/35 MPS4 S tires in the front while dropping the car had better be prepared to get 8" wheels with around et45 offset or be ready to install camber plates etc.

[Drpoomanchu]

Originally Posted by AlpsRider

My setup is BBS CI-R wheels with MPS4 S tires, 235/35/19 x 8" et45 and 265/30/19 x 9" et48. The car is dropped with Dinan springs. The rear tires don't rub but the front tires rubbed twice on the inside of the wheel well. I think the new MPS4 S tire may be bigger than the MPSS. It was a slight rub which just made a black mark on the inside of the wheel well that easily wiped off. Both times it rubbed it was under extreme conditions. Rolling the lip would probably eliminate the issue. Overall I'm happy with the setup.
The stock 245 rear tires in my opinion just don't have enough traction for the M235/M240 power and torque. The only way to keep the car from spinning the tires is to use the traction control all the time. The traction control in the 2 series is really not very smooth, it hunts and jerks in turns while trying to keep the car on the road. The Porsche 911 in comparison, which really needs traction control, is utilized seamlessly. The bigger tires have made my car much more stable, the drop along with the lower profile tires have also made the steering more sensitive. The alignment specs came out at 1 degree negative camber in the front which will hopefully help the tires last longer. I've dropped the air pressure down 2 psi front and rear to 33/34 at 65 degree cold pressure for everyday driving, they heat up quickly to 36/37 and higher if pushed or if
it's a hot day. Now the car rarely has to resort to traction control trickery to keep the car from sliding unexpectedly, it just sticks to the road. Comfort is my preferred mode now unless I'm on a race track like smooth surface.

All that being said this 235/265 setup would be without issue on stock suspension, the specs on the BBS CI-R is close to perfect for the 2 series if you want to run bigger tires. The scrub radius is also still at 0 with this setup. Anyone with the desire to run 235/35 MPS4 S tires in the front while dropping the car had better be prepared to get 8" wheels with around et45 offset or be ready to install camber plates etc.

If the Ci-R's would have been available when i made my purchase on the HRE's i may have opted for the CI-R's to run your more aggressive tire spec. I am FBO running JB4 map 2 and absolutely agree that the intervention of traction control is too abrupt, erratic, and cuts too much power at inopportune moments. Even with 255's the car wants to break traction fairly easily. I would like to run a 265 if i could. The only thing that held me back from Ci-R's was the weight.

[AlpsRider]

Originally Posted by Drpoomanchu

If the Ci-R's would have been available when i made my purchase on the HRE's i may have opted for the CI-R's to run your more aggressive tire spec. I am FBO running JB4 map 2 and absolutely agree that the intervention of traction control is too abrupt, erratic, and cuts too much power at inopportune moments. Even with 255's the car wants to break traction fairly easily. I would like to run a 265 if i could. The only thing that held me back from Ci-R's was the weight.

Yes they are not the lightest, but for 19" they are not bad at 24 pounds, they are also supposed to be strong. Many people have talked about bent wheels which I wanted to avoid. I think the HREs are pretty strong also but as you say the size and offsets weren't ideal for big tires.

[RotorOver]

Originally Posted by AlpsRider

My setup is BBS CI-R wheels with MPS4 S tires, 235/35/19 x 8" et45 and 265/30/19 x 9" et48. The car is dropped with Dinan springs. The rear tires don't rub but the front tires rubbed twice on the inside of the wheel well. I think the new MPS4 S tire may be bigger than the MPSS.

I've been looking at this. Data from TireRack.com. It actually looks like the MPSS has a wider tread width by 0.5", but that's the only difference.

MPSS 235/35ZR19 (91Y)XL
MPS4S 235/35ZR19 (91Y)XL

.............................MPSS.....MPS4S
RIM WIDTH RANGE...8-9.5"...8-9.5"
MEAS. RIM WIDTH....8.5".......8.5"
SECT. WIDTH...........9.5".......9.5"
TREAD WIDTH...........9".........8.5"

[moldcad]

This is an alarming news for me that with "Dinan fitment", the PS4S may scrub - as I'm in the course of ordering both wheels and tires exactly to this specs, and the tires are going to be PS4S. So I have 2 questions:

- as I'm not about to lower my car, is there really nothing to worry about even with the PS4S being 0.5" wider than PSS?

- or, just to be on the safe side, should I order my custom size of BC Forged front wheels with slightly higher ET than 45mm, like e.g. ET48 (the same as in the rear)? But then - wouldn't rubbing against front struts become a possible problem?

Please comment asap, as I held my order. Thanks!

Piotr

[Joe240]

Originally Posted by moldcad

This is an alarming news for me that with "Dinan fitment", the PS4S may scrub - as I'm in the course of ordering both wheels and tires exactly to this specs, and the tires are going to be PS4S. So I have 2 questions:

- as I'm not about to lower my car, is there really nothing to worry about even with the PS4S being 0.5" wider than PSS?

- or, just to be on the safe side, should I order my custom size of BC Forged front wheels with slightly higher ET than 45mm, like e.g. ET48 (the same as in the rear)? But then - wouldn't rubbing against front struts become a possible problem?

Please comment asap, as I held my order. Thanks!

Piotr

Think you read the post wrong. The MPS4S are .5" smaller tread surface than the MPSS. so you would be less likely to scrub with the MPS4S than the MPSS.