Will fitting a square wheel setup to an M140i cause issues??

[FakeCarGuy]

Because the front and rear have different rolling diameters, I’ve been advised that fitting a square setup will throw-off the car’s calculations and computers and can hamper the driving dynamics of the car, with the traction/stability control becoming intrusive and confused.

However, is there actually any truth to this?

Reason I ask is because i’m in the market for a 340i m sport shadow edition - but they’re rare as fk - and i’m really struggling to find one that I like in my price range - so now i’m starting to look at the m140i now - but i’m only really interested if I can rock a square tyre setup.

[ARHarh]

No idea, But being old I do remember the development of the wheel, and the team soon gave up on the square one

[Pica-Pica]

ARHarh said:

No idea, But being old I do remember the development of the wheel, and the team soon gave up on the square one

To be expected. Lazy Sunday afternoon?

[thebraketester]

FakeCarGuy said:

but i m only really interested if I can rock a square tyre setup.

Why?

[danb79]

FakeCarGuy said:

Because the front and rear have different rolling diameters, I ve been advised that fitting a square setup will throw-off the car s calculations and computers and can hamper the driving dynamics of the car, with the traction/stability control becoming intrusive and confused.

However, is there actually any truth to this?

Reason I ask is because i m in the market for a 340i m sport shadow edition - but they re rare as fk - and i m really struggling to find one that I like in my price range - so now i m starting to look at the m140i now - but i m only really interested if I can rock a square tyre setup.

Utter bks

I run a square set up on my E81 130i and on my F31 touring - both should have staggered set ups; but prefer square as I find it better for handing, ride etc

Doesn’t matter if it s RWD or xDrive - as long as the tyres are the correct sizes, you’ll have zero issues

Plus you tend to find the dedicated winter wheels for the car(s) will always be a square set up too

Edited by danb79 on Sunday 6th July 16:28

[MitchT]

Tens (if not hundreds) of millions spent on R&D to design a car when all they had to do was ask some randoms on the internet what the optimum setup would be!

[bigdom]

FakeCarGuy said:

Because the front and rear have different rolling diameters, I ve been advised that fitting a square setup will throw-off the car s calculations and computers and can hamper the driving dynamics of the car, with the traction/stability control becoming intrusive and confused.

However, is there actually any truth to this?

Reason I ask is because i m in the market for a 340i m sport shadow edition - but they re rare as fk - and i m really struggling to find one that I like in my price range - so now i m starting to look at the m140i now - but i m only really interested if I can rock a square tyre setup.

Of course you can. Just seems a odd decision to give the car less rubber to put the power down, especially as you've mentioned on other threads of mapping a car to >400bhp and adding birds suspension/quaife diff.

[danb79]

bigdom said:

FakeCarGuy said:

Because the front and rear have different rolling diameters, I ve been advised that fitting a square setup will throw-off the car s calculations and computers and can hamper the driving dynamics of the car, with the traction/stability control becoming intrusive and confused.

However, is there actually any truth to this?

Reason I ask is because i m in the market for a 340i m sport shadow edition - but they re rare as fk - and i m really struggling to find one that I like in my price range - so now i m starting to look at the m140i now - but i m only really interested if I can rock a square tyre setup.

Of course you can. Just seems a odd decision to give the car less rubber to put the power down, especially as you've mentioned on other threads of mapping a car to >400bhp and adding birds suspension/quaife diff.

The lads that have 135i and 140i BMWs that my pals look after all have square set ups and they track their cars hard… Yes they’re aftermarket Apex and Protrack wheels; but all the same size all round and they never have any issues…

[InitialDave]

FakeCarGuy said:

Because the front and rear have different rolling diameters,

They shouldn't?

My Z4 has a staggered fitment, and the wider rears are lower profile to compensate. The difference is 0.4%, so in practical terms they're identical.

[4rephill]

danb79 said:

The lads that have 135i and 140i BMWs that my pals look after all have square set ups and they track their cars hard Yes they re aftermarket Apex and Protrack wheels; but all the same size all round and they never have any issues

Have they tried the same model aftermarket wheels with wider rear wheels and tyres? (my money is on they haven't )

They may never have had an issue - But they could be missing out on their cars handling even better than with their square setup.

[danb79]

4rephill said:

danb79 said:

The lads that have 135i and 140i BMWs that my pals look after all have square set ups and they track their cars hard Yes they re aftermarket Apex and Protrack wheels; but all the same size all round and they never have any issues

Have they tried the same model aftermarket wheels with wider rear wheels and tyres? (my money is on they haven't )

They may never have had an issue - But they could be missing out on their cars handling even better than with their square setup.

No idea but they’re seasoned track drivers and I’d say their judgement sits well with that side of things

For me personally my 130i on its current straight set of Protrack Ones drives and handles better than it did on its staggered Style 216s - that’s road driving though, not track

[PistonbrokePaul]

My winter wheel steelies are a square setup on my M140i and I have had zero issues with them over the years. From memory (I have been wrong before and will be wrong in future) its staggered to make them understeer (alongside the stock geo) before they oversteer to make them a bit safer on public roads for drivers who are not enthusiasts and are used to FWD handling characteristics.

[g3org3y]

danb79 said:

Utter bks

I run a square set up on my E81 130i and on my F31 touring - both should have staggered set ups; but prefer square as I find it better for handing, ride etc

Doesn t matter if it s RWD or xDrive - as long as the tyres are the correct sizes, you ll have zero issues

Plus you tend to find the dedicated winter wheels for the car(s) will always be a square set up too

Edited by danb79 on Sunday 6th July 16:28

WRT to your square set up, is that the recommended square set up as per the handbook (as you mention which is often smaller wheels for winter) or something else?

InitialDave said:

They shouldn't?

My Z4 has a staggered fitment, and the wider rears are lower profile to compensate. The difference is 0.4%, so in practical terms they're identical.

Indeed.

thebraketester said:

FakeCarGuy said:

but i m only really interested if I can rock a square tyre setup.

Why?

Sourcing tyres to match front and back can be annoying. Had that issue with my E91 (staggered) where I was unable to get Goodyear Eagle F1 RFTs in 255/35 R18 (which seems to be an annoying size) to match the fronts so had to get Hankook instead.