[Luistinoco]

So im having an issue hooking and putting down power 1st, 2nd and sometimes 3rd gear.

I have an m sport brake kit on my car but I was planning on trying to put a 17 inch rim in the back to accommodate more sidewall. Would 17 inch wheels clear the rear brakes that are 345mm? From what ive been reading the rear brakes are smaller than the front which are 370mm but please correct me if im wrong.

My intention is to put a 17x8 wheel in the rear and cover it in 255/45/17 or 255/50/17 so I can grip better. If anyone has any experience with this than your response is greatly appreciated!

Thank you

[Maynard]

You need a LSD.

[rvtrcr]

I just happen to have one from an M235 for sale...

[morphomeman]

There are a number of 17" rims that fit these brakes. I have used a set in the winter since I bought the car and recently abandoned my 18" rims in favor of the 17" rims year-round, because my rim and tire insurance had run out and I wanted peace of mind.
I am not sure, though, about running different size rims on the front and rear on this vehicle.

[Dylan86]

Get an LSD, problem solved

[MerlinMc]

Get the LSD and 17s all around. That's the set up I have on my M240i.

[c-m]

Originally Posted by rvtrcr

I just happen to have one from an M235 for sale...

An LSD or 17" wheels?

[msej449]

When I got my winter 17" wheels & tyres from an independent, they said that they always test-fit a new wheel on the M BMWs first, before fitting a tyre. This is because even reliable manufacturers sometimes get it wrong, and a 17" wheel they say will fit doesn't. Wheel manufacturers won't take one back if a tyre has been fitted (even if they got it wrong).

Some 17" BMW wheels will be certified to fit 'round the M Performance brakes. But if it's not one of these, then be careful: you need to be able to check that it fits for real, before you commit to buy. Or go to / buy from an outfit who will take responsibility for the wheel not fitting on a M Perf brake setup if they make a mistake.

Oh, and I have retro-fitted the M Performance LSD. It's a pricey option but for me, it proved worthwhile in improving the handling.

@luistinoco Youdont' say what your existing setup is? Is it

7.5Jx18 225/40 R18 92Y front
8.0Jx18 245/35 R18 92Y rear

? This is the standard setup ex-factory in the UK - basically a 'summer' staggered configuration. I ask because optimising tyre & wheel configuration is quite a complex equation and changing you tyre brand might do more good than changing the wheels. For example, all other things being equal, if you increase the tire width and thus the contact patch area, the car doesn't get any heavier, so the weight per in² on the contact patch is actually less, not more. Making it more prone to aquaplaning in the wet. And so on.

[morphomeman]

In North America, TireRack is super-reliable. If they say a wheel fits, it will fit. If it doesn't they will take it back. Other dealers may also be good, but I have been dealing with TR for 25 years without a single problem

[Maynard]

^^this, plus keep in mind that some of the small suppliers with superlow prices will tell you it fits on a guess, and then deal w/ it via returns if it doesn't (sometimes refusing b/c the 'tire has been driven on' even if just moving around in the shop parking lot). Fortunately this comes to me second hand via 3 different similar stories, I've always used TRack myself.

[Sportstick]

+1 for tirerack.com

They helped me identify which 17" wheels fit over my MSport brakes, both for winter and other season use.

[cristo]

Me too.
Get some really nice BBS SR 17x7.5 inch
wheels from them for our 2020 M240i
(with the blue M brakes) for winter tires.

[rvtrcr]

Originally Posted by c-m

An LSD or 17" wheels?

An LSD.

[Pray for Mojo]

BMW Style 159s fit, they are 17x8 and are abundant and cheap.

[dradernh]

Originally Posted by cristo

Me too.
Get some really nice BBS SR 17x7.5 inch
wheels from them for our 2020 M240i
(with the blue M brakes) for winter tires.

If weight isn't a major concern, I think the BBS SRs are the wheels to get. It isn't that they're especially heavy (they're not); it's just that they're not in the very light category.

They fit over the brakes, they look pretty good, and, best of all, they're BBS-quality.

Full disclosure: I own a set with winter tires on them; I purchased them from another 2addicts member.

Given how mild our winters are here now, when the winter tires are done, I'm going to replace them with square 225/45-17 Vredestein Quatrac Pros. For me, those will do double-duty: winter tires (I hardly use the car in the winter), and long-distance travel tires (225 17s will kill two birds with one stone: low rolling resistance (i.e., better fuel economy), and the 45-series aspect ratio will offer improved protection against poor road surfaces).

[cristo]

I put 215/50r17 Michelin X-ice Xi3
winters on mine.

[c-m]

Originally Posted by rvtrcr

An LSD.

How much and which one?

[msej449]

M Performance LSD retro-fitted by my local dealer, so preserving the vehicle warranty. About GBP £2000, USD $2500. I get the impression that in the US, you have a much bigger and more established aftermarket, so I'd read up on some of the LSD threads on this forum, which cover 3rd-party products well.

It's pricey, but I drive a lot of cross-country 60mph-limit roads here in the UK and loads of Alpine switchback roads in the summer, where the benefit is noticeable. The cost is probably harder to justify if your main use is freeways but even then, many LSD owners still say they feel it's worthwhile.

Personally, I feel that with RWD and 330bhp the M235i/M240i should have come with an LSD as standard - BMW could probably have done this for around an extra $1K on the price. But that it was a marketing decision not to fit it to distance the M-Lite from the M2 in terms of what you get for the M2 price premium.

[c-m]

Originally Posted by msej449

M Performance LSD retro-fitted by my local dealer, so preserving the vehicle warranty. About GBP £2000, USD $2500. I get the impression that in the US, you have a much bigger and more established aftermarket, so I'd read up on some of the LSD threads on this forum, which cover 3rd-party products well.

It's pricey, but I drive a lot of cross-country 60mph-limit roads here in the UK and loads of Alpine switchback roads in the summer, where the benefit is noticeable. The cost is probably harder to justify if your main use is freeways but even then, many LSD owners still say they feel it's worthwhile.

Personally, I feel that with RWD and 330bhp the M235i/M240i should have come with an LSD as standard - BMW could probably have done this for around an extra $1K on the price. But that it was a marketing decision not to fit it to distance the M-Lite from the M2 in terms of what you get for the M2 price premium.

I’m pushing 500whp now and definitely need an LSD.

[Hpirx]

I can confirm fit of Apex Arc-8 17x9 wheel over M-sport brakes.
255-40-17 Bridgestone Potenzas square. No rub. Stock suspension and alignment.

[este]

Originally Posted by Hpirx

I can confirm fit of Apex Arc-8 17x9 wheel over M-sport brakes.
255-40-17 Bridgestone Potenzas square. No rub. Stock suspension and alignment.

Glad to hear that, any pics? No spacers needed up front? Going to try same setup this week 17x9 et 42 squares 255/40/17 but on hankook rs4 tires. On H&R springs and m4 lcas/ts.

[PDM5]

Originally Posted by Hpirx

I can confirm fit of Apex Arc-8 17x9 wheel over M-sport brakes.
255-40-17 Bridgestone Potenzas square. No rub. Stock suspension and alignment.

ET 42, correct? Man I wish I would have gone with a 17" square setup!