Wider tyres on OEM BMW alloys
Wider tyres on OEM BMW alloys
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Discussion

d_a_n1979

Original Poster:

13,899 posts

103 months

Thursday 27th December 2018
quotequote all
I love the Style 149 alloys on my 730D but the rear tyres are 275/35/20 and the sidewall slants up/away from the alloy rim edge and leaves it open to being 'nicked' or curbed (more so when reversing to park up etc)

Never have I curbed an alloy since learning to drive/owning my first car (2000) but since owning the 730D; I've caught the rear NS alloy twice since having them refurbed)!

I am a careful parker, so no need for the 'be more careful' comments biggrin

Anyways; having looked at a tyre calculator, I can go up to a 285/35 tyre with no issues, still well within the parameters etc

They're a more expensive tyre, but they'll give me that straighter sidewall I'd like...

What I'd like to know is will this cause any other issues, they won't rub, even with the 12mm spacers I'm running. Plenty of room under the arch and between the tyre and upright etc

Has anyone else done this to save alloys being marked etc?

My previous 530i ran 19" alloys, OEM sizes for the rears were 265/35/19s but I ran 275/35/19s and they looked much better and offered that bit more protection as well smile

E-bmw

13,566 posts

183 months

Thursday 27th December 2018
quotequote all
I would just run those sizes through tyresizecalculculator.com to check, but would expect they are within you ABS sensor limits.

I have fitted tyres that were outside normal limits before and had ABS errors.

What happens is the ABS ECU looks at all wheel speeds & looks for them to be within certain limits of each other over all wheels.

If they are outside your systems limits, as soon as you get up to the relevant speed you will get errors until you slow back down.

Ninja59

3,691 posts

143 months

Thursday 27th December 2018
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find a tyre with a rim protector. some do....i know my sportmaxx gt's do.

Prinny

1,669 posts

130 months

Thursday 27th December 2018
quotequote all
Dan, I run 255f and 285r in summer on mine, no issues at all.

Currently running MPS4S, and there’s about a 3mm ‘edge’ of tyre proud of the rim.

A further upside is the speedo becomes more accurate (pretty much spot on from 40mph upward).

No comment on spacers though as I don’t run them.

This shows the rear & the tyre lip on 285 - I reckon your spacers might still be fine.


d_a_n1979

Original Poster:

13,899 posts

103 months

Friday 28th December 2018
quotequote all
E-bmw said:
I would just run those sizes through tyresizecalculculator.com to check, but would expect they are within you ABS sensor limits.

I have fitted tyres that were outside normal limits before and had ABS errors.

What happens is the ABS ECU looks at all wheel speeds & looks for them to be within certain limits of each other over all wheels.

If they are outside your systems limits, as soon as you get up to the relevant speed you will get errors until you slow back down.
As per my post, tyre calculator already checked and well within parameters

d_a_n1979

Original Poster:

13,899 posts

103 months

Friday 28th December 2018
quotequote all
Prinny said:
Dan, I run 255f and 285r in summer on mine, no issues at all.

Currently running MPS4S, and there’s about a 3mm ‘edge’ of tyre proud of the rim.

A further upside is the speedo becomes more accurate (pretty much spot on from 40mph upward).

No comment on spacers though as I don’t run them.

This shows the rear & the tyre lip on 285 - I reckon your spacers might still be fine.

Cheers pal... That’s what I needed to see/read

Fronts are fine in all honesty, it’s the rears that just look a bit stretched for me and could do to be more ‘squarer’

I’ll get this sorted closer to the time I look to take the winters off

E-bmw

13,566 posts

183 months

Friday 28th December 2018
quotequote all
d_a_n1979 said:
E-bmw said:
I would just run those sizes through tyresizecalculculator.com to check, but would expect they are within you ABS sensor limits.

I have fitted tyres that were outside normal limits before and had ABS errors.

What happens is the ABS ECU looks at all wheel speeds & looks for them to be within certain limits of each other over all wheels.

If they are outside your systems limits, as soon as you get up to the relevant speed you will get errors until you slow back down.
As per my post, tyre calculator already checked and well within parameters
I saw that, but you didn't say what parameters (could still be fine for speedo as mine were & not for ABS) & don't forget (as per my post) you are only changing one end so if the rears are then slower than the fronts as soon as they misread by a couple of mph (not sure of the exact number) you stand the chance of ABS errors.

d_a_n1979

Original Poster:

13,899 posts

103 months

Friday 28th December 2018
quotequote all
E-bmw said:
I saw that, but you didn't say what parameters (could still be fine for speedo as mine were & not for ABS) & don't forget (as per my post) you are only changing one end so if the rears are then slower than the fronts as soon as they misread by a couple of mph (not sure of the exact number) you stand the chance of ABS errors.
The difference on the tyre calculator is 1%, so well within parameters of the +/- 2.5% recommendations of changing up/down tyre sizes

E-bmw

13,566 posts

183 months

Friday 28th December 2018
quotequote all
d_a_n1979 said:
E-bmw said:
I saw that, but you didn't say what parameters (could still be fine for speedo as mine were & not for ABS) & don't forget (as per my post) you are only changing one end so if the rears are then slower than the fronts as soon as they misread by a couple of mph (not sure of the exact number) you stand the chance of ABS errors.
The difference on the tyre calculator is 1%, so well within parameters of the +/- 2.5% recommendations of changing up/down tyre sizes
I get what you say & you are probably fine but that recommendation is written from the perspective of the speedo accuracy only.

What you are doing is changing size for one end of the car which will make your ABS sensors read different front to rear.

Worst case scenario part worn on the wheels you keep the same & new on the other end & you may have enough difference to trigger errors.

d_a_n1979

Original Poster:

13,899 posts

103 months

Friday 28th December 2018
quotequote all
I'll be going up a tyre size on both front and rears; so 255 front, 285 rears.

My OCD doesn't work well with non-matched pairs of tyres (front / rear etc).

I'll just sell the current Nexen tyres off on eBay or similar smile

E-bmw

13,566 posts

183 months

Friday 28th December 2018
quotequote all
You will definitely be fine then, just you only mentioned rears & I did have an issue with an insignificant change a few years ago on an e39.