Max tire size for square set-up

[Finneganistan]

Can anyone tell me what size tire I can fit on the front with stock wheels, 2013 135Is? And can that same size be fitted to the backs?

[jwolf]

https://apexwheels.com/fitment-guide...-fitment-guide

Lots of variables. Springs? Stock M-Sport or lower? Camber plates? Aftermarket Coilovers? Wheels? Spacers?

I run 245/35ZR18XL with the Apex wheels and some 5mm spacers up front. Dinan fixed camber plates. Stock shocks.

[Finneganistan]

Originally Posted by jwolf

https://apexwheels.com/fitment-guide...-fitment-guide

Lots of variables. Springs? Stock M-Sport or lower? Camber plates? Aftermarket Coilovers? Wheels? Spacers?

I run 245/35ZR18XL with the Apex wheels and some 5mm spacers up front. Dinan fixed camber plates. Stock shocks.

Stock suspension: no coilovers or camber plates. No spacers and stock 135Is wheels. I don't know if 245s will fit my car up front. And I'd prefer to keep the stock wheels.

[mkeiser]

https://www.1addicts.com/forums/showthread.php?t=213306

OE wheels, what are the biggest tires that will fit them?
225/40/18 is the widest size that will correctly fit the front 7.5"wheels and 255/35/18 is the widest correct fitting size for the rear 8.5". The sizes both fit the vehicle with no rubbing.
235/40/18 and 265/35/18 are sizes that will fit the vehicle but they will require a minimum of an 8" wheel in the front and a 9" wheel in the rear.

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not sure what size 135is wheels are but hopefully that's some helpful information for ya.

[Finneganistan]

Originally Posted by mkeiser

https://www.1addicts.com/forums/showthread.php?t=213306

OE wheels, what are the biggest tires that will fit them?
225/40/18 is the widest size that will correctly fit the front 7.5"wheels and 255/35/18 is the widest correct fitting size for the rear 8.5". The sizes both fit the vehicle with no rubbing.
235/40/18 and 265/35/18 are sizes that will fit the vehicle but they will require a minimum of an 8" wheel in the front and a 9" wheel in the rear.

~~~~

not sure what size 135is wheels are but hopefully that's some helpful information for ya.

Yes, thanks! According to Mr. Google: Front 18″ diameter, 7.5″ width; rear 18″ diameter, 8.5″ width. Will 225s fit both the front and the back?

[mkeiser]

Originally Posted by Finneganistan

Yes, thanks! According to Mr. Google: Front 18″ diameter, 7.5″ width; rear 18″ diameter, 8.5″ width. Will 225s fit both the front and the back?

Yes but I'm curious why you are wanting to go with a square tire setup on different width wheels? Having the same size tire on 1" difference width will have differences in the tire profile and rotating them around will cause weirdness in handling...

[tracer bullet]

Originally Posted by mkeiser

Yes but I'm curious why you are wanting to go with a square tire setup on different width wheels?

Agreed. For a truly square setup I'd switch the wheels as well.

I'd also consider swapping front and rear wheels as they sit now, on one side of the car perhaps as an experiment. You might find the offsets to be such that the whole idea of square with stock just doesn't even work.

Have to also ask why? Is it to limit rear traction, to slide a little more when racing, or something similar? Or is it purely for like tire rotation and longevity?

[Finneganistan]

Thanks everyone! This was what I was wondering. It sounds like if I want to have a square set-up I'd need to switch out the wheels and I'm not interested in doing that. I was looking into this as a way to dial back the car's natural understeer; I've read that a square set-up would be more 'neutral' in handling.

[jwolf]

With a square setup on Apex wheels, Dinan plates, and M3 control arms, the car does feel more neutral.

[cerealwars]

You could also see if you can find two more stock wheels (preferably rears) in your style. I went square (E90 style 285, 17×8 ET+34) for both easier rotations and more neutral handling and I'm happy with it.

To reduce understeer, I've found increasing front camber helps.

For $0 you can knock out the camber pin in your struts and shove the tophats inboard. Careful with how you do this, if it's uneven your alignment might suffer a little. Recommend measuring with a level at minimum or a camber gauge.

For $120ish you can add Dinan fixed camber plates. Both of these together nets you about 1.5⁰ of camber, significantly increasing steering feel and reducing the washing out effect in the front end.

[Olgeezer1]

Originally Posted by Finneganistan

Yes, thanks! According to Mr. Google: Front 18″ diameter, 7.5″ width; rear 18″ diameter, 8.5″ width. Will 225s fit both the front and the back?

Yes , you can use 225's on both your 7.5" fronts and your 8.5" rears but you can only rotate them side to side not front to back. Did it for a few years with no weird handling including short track sessions. More front tire and less rear does reduce understeer however while square 225's work great on my 128i , they're probably not enough tire for a 135i. You could look for another pair of 8.5 rears to put on the front and go 245/35/18 all around. Camber plates, spacers may be needed for front clearance.

[rackhenry]

Is there an faq on recomended wheel square setup for a track car? what wheel size? etc?

[mkeiser]

Originally Posted by rackhenry

Is there an faq on recomended wheel square setup for a track car? what wheel size? etc?

Apex has a good one on their website. There's some good threads in the wheels/tires section of this forum too.

[rackhenry]

Originally Posted by mkeiser

Apex has a good one on their website. There's some good threads in the wheels/tires section of this forum too.

Thanks much for the fyi.