What width size rims to buy? (135i coupe)

[457892345]

I'm looking at replacing oem 18 inch rims with 17 Inchers and I'm coming a bit unstuck on what size rims I need to do so.

Currently tyre sizes are 225 front 245 rear on 18 inch rims

I'm settled on goodyear asm 6 tyres for when I move to 17 however I'm not sure which of the following options is optimal for road performance.

1. 245 front and rear on 8.5 inch wide 17 inch rims.

2. 225 or 235 front, 245 rear 8.5 inch wide 17 inch rims

3. 225 front and 245 rear on 8 inch wide 17 inch fronts 9 inch wide 17 inch rears

Which of these 3 options if money is no object is best?

Edited by 457892345 on Friday 26th August 12:26

Edited by 457892345 on Friday 26th August 12:27

[helix402]

A factory sized square 17” set up would be 8x17” wheels with 225/45 17 tyres.

[Caddyshack]

9 sounds very wide. I would look up the sizes that bmw put on the earlier 1 series with 17’s, they will have done all the hard work for you.

I think my winters were 225 tyres all round.

[d_a_n1979]

ALL 1 series alloys are here:

https://www.auto-treff.com/wcf/index.php?tagged/63...

Use Chrome to translate to English

It's a superb website and has all the info needed on the alloys & also the factory tyre specs etc

A good way to see what alloys & tyres you need

[457892345]

helix402 said:

A factory sized square 17” set up would be 8x17” wheels with 225/45 17 tyres.

It would be bad to go 225 on rear when the current setup is 225 front 245 on rear would it not? I'm looking for optimal performance setup for road and will be changing out lots of suspension etc parts later on.

Is 245 all around not just outright better although more costly?

Caddyshack said:

9 sounds very wide. I would look up the sizes that bmw put on the earlier 1 series with 17’s, they will have done all the hard work for you.

I think my winters were 225 tyres all round.

I was going by a forum post where a guy downsized to 17s and he had 8 inch front 9 inch rear and ran 225 front 245 rear, this isn't for winters

d_a_n1979 said:

ALL 1 series alloys are here:

https://www.auto-treff.com/wcf/index.php?tagged/63...

Use Chrome to translate to English

It's a superb website and has all the info needed on the alloys & also the factory tyre specs etc

A good way to see what alloys & tyres you need

Awesome thanks very much will take a look

Edited by 457892345 on Friday 26th August 10:56

[Pica-Pica]

The front suspension will have designed clearance for the 225 size, it may be an issue on steering and suspension extremes to go to 245. I don’t know about BMW, but some are designed with adequate clearance for snow chains on top of standard tyre sizes. What does the door label say?
225 should take 8” rim and 255 8.5” rim.

[457892345]

Pica-Pica said:

The front suspension will have designed clearance for the 225 size, it may be an issue on steering and suspension extremes to go to 245. I don’t know about BMW, but some are designed with adequate clearance for snow chains on top of standard tyre sizes. What does the door label say?
225 should take 8” rim and 255 8.5” rim.

I should add i plan to change suspension heavily later but im on stock sport suspension atm.

I see thats a consideration i hadnt really made. I just spoke to a rim dealer and it seems the 8 inch wide can take 245 all around too so it seems to me the choice is between 8 inch wide all around with 225 front 245 rear or 8.5 inch all around 225 245 rear, giving me the option to go 245 all around when i later change suspension etc.

Which would you pick out of these two?

[d_a_n1979]

457892345 said:

Pica-Pica said:

The front suspension will have designed clearance for the 225 size, it may be an issue on steering and suspension extremes to go to 245. I don’t know about BMW, but some are designed with adequate clearance for snow chains on top of standard tyre sizes. What does the door label say?
225 should take 8” rim and 255 8.5” rim.

I should add i plan to change suspension heavily later but im on stock sport suspension atm.

I see thats a consideration i hadnt really made. I just spoke to a rim dealer and it seems the 8 inch wide can take 245 all around too so it seems to me the choice is between 8 inch wide all around with 225 front 245 rear or 8.5 inch all around 225 245 rear, giving me the option to go 245 all around when i later change suspension etc.

Which would you pick out of these two?

Different car; but for my E39 V8 I'll be running a straight set of 17x8 Style 66s for winter wheels and fitted with all season tyres (235/45/17)

If they were summer tyres I'd consider 245s, but absolute max; 235 are wide enough TBH - it can be down to the tyres too as some have straighter sidewalls than others (ie Michelin PS4 sidewalls are very square, whereas the likes of Nexen, Kumho etc are more slanted)

It's all down the offsets of the alloys (IIRC the 1 series needs around 45, so you could push that to 35 offset, maybe a bit more with either spacers or aftermarket alloys with more aggressive offsets) and tyres ideally you want to keep within the specs of OEM recommendations, or a size wider if you want, but no more

The 'willtheyfit' website is very good for this; you can mess with tyre sizes and alloy wheel offsets

If you look at these as an example (17x7 and 17x7.5): https://www.auto-treff.com/wcf/index.php?article/1...

Tyre recommendations ate 205 and 225, you could push that and go 215 and 235; which would give you better rim protection and a straighter sidewall etc

[457892345]

d_a_n1979 said:

Different car; but for my E39 V8 I'll be running a straight set of 17x8 Style 66s for winter wheels and fitted with all season tyres (235/45/17)

If they were summer tyres I'd consider 245s, but absolute max; 235 are wide enough TBH - it can be down to the tyres too as some have straighter sidewalls than others (ie Michelin PS4 sidewalls are very square, whereas the likes of Nexen, Kumho etc are more slanted)

It's all down the offsets of the alloys (IIRC the 1 series needs around 45, so you could push that to 35 offset, maybe a bit more with either spacers or aftermarket alloys with more aggressive offsets) and tyres ideally you want to keep within the specs of OEM recommendations, or a size wider if you want, but no more

The 'willtheyfit' website is very good for this; you can mess with tyre sizes and alloy wheel offsets

If you look at these as an example (17x7 and 17x7.5): https://www.auto-treff.com/wcf/index.php?article/1...

Tyre recommendations ate 205 and 225, you could push that and go 215 and 235; which would give you better rim protection and a straighter sidewall etc

i see, i just had another talk with a live support agent about "sparco ff1" wheels which are 17x8.5 and 40 offset and he said it might be tight squeeze at front, its a shame because i was pretty much dead set on buying these as they seem to tick all boxes but maybe going 8 inch wide is smarter? what are your thoughts?

EDIT: This ''willtheyfit'' seems very useful, how might i find my current setup parameters? i dont see where offset is written on the car

Edited by 457892345 on Friday 26th August 14:01

[d_a_n1979]

457892345 said:

d_a_n1979 said:

Different car; but for my E39 V8 I'll be running a straight set of 17x8 Style 66s for winter wheels and fitted with all season tyres (235/45/17)

If they were summer tyres I'd consider 245s, but absolute max; 235 are wide enough TBH - it can be down to the tyres too as some have straighter sidewalls than others (ie Michelin PS4 sidewalls are very square, whereas the likes of Nexen, Kumho etc are more slanted)

It's all down the offsets of the alloys (IIRC the 1 series needs around 45, so you could push that to 35 offset, maybe a bit more with either spacers or aftermarket alloys with more aggressive offsets) and tyres ideally you want to keep within the specs of OEM recommendations, or a size wider if you want, but no more

The 'willtheyfit' website is very good for this; you can mess with tyre sizes and alloy wheel offsets

If you look at these as an example (17x7 and 17x7.5): https://www.auto-treff.com/wcf/index.php?article/1...

Tyre recommendations ate 205 and 225, you could push that and go 215 and 235; which would give you better rim protection and a straighter sidewall etc

i see, i just had another talk with a live support agent about "sparco ff1" wheels which are 17x8.5 and 40 offset and he said it might be tight squeeze at front, its a shame because i was pretty much dead set on buying these as they seem to tick all boxes but maybe going 8 inch wide is smarter? what are your thoughts?

Which wheels do you have now?

If the average 1 series offset is around 45; then an offset of 40 will move the tyre away from the suspension but closer to the arch

But that's only 5mm, so it shouldn't really make too much of a difference

You could do to find out really what other 1 series owners run; are you on the likes of the BabyBMW forums etc?

[helix402]

Quote:

It would be bad to go 225 on rear when the current setup is 225 front 245 on rear would it not? I'm looking for optimal performance setup for road and will be changing out lots of suspension etc parts later on.

Going from 18s to 17s on an E8/9x platform probably won’t give the “optimal performance setup”. The correct 245 size would be 245/40 17. Afraid I don’t know what you’d need in a 235 17. (Checked-there isn’t one that keeps a close enough circumference to standard)

Edited by helix402 on Friday 26th August 14:09

[457892345]

d_a_n1979 said:

Which wheels do you have now?

If the average 1 series offset is around 45; then an offset of 40 will move the tyre away from the suspension but closer to the arch

But that's only 5mm, so it shouldn't really make too much of a difference

You could do to find out really what other 1 series owners run; are you on the likes of the BabyBMW forums etc?

the 18 inch oem ones (style 261), i think they are 49 offset from research, i've looked on some of those forums but tbh i'm learning as i go and didnt see any that were trying to go for same as me except this forum post https://www.1addicts.com/forums/showthread.php?t=1...

[457892345]

helix402 said:

Quote:

It would be bad to go 225 on rear when the current setup is 225 front 245 on rear would it not? I'm looking for optimal performance setup for road and will be changing out lots of suspension etc parts later on.

Going from 18s to 17s on an E8/9x platform probably won’t give the “optimal performance setup”. The correct 245 size would be 245/40 17. Afraid I don’t know what you’d need in a 235 17.

You mean staying 18's would be better? honestly i feel like the ride quality is god awful with them (one of the rim is bent a bit since i bought the car though according to pre-purch inspection) and its on michellin ps4's so its not the tyres. I feel like the weight reduction and increased compliance is the right move for me but i'd be interested in hearing your thoughts as to why its not.

yes i would be going 225/45/17 front 245/40/17 rear, but with 235 on front or even 245 on front also being possible choices if that would be better (i'm not so sure it would be)

Edited by 457892345 on Friday 26th August 14:12

Edited by 457892345 on Friday 26th August 14:17

[helix402]

Maybe try a Birds suspension kit. I’m half way through fitting one to my E91 335d in the quest for decent ride/handling. A lot of people find non run flats better too.

[457892345]

helix402 said:

Maybe try a Birds suspension kit. I’m half way through fitting one to my E91 335d in the quest for decent ride/handling. A lot of people find non run flats better too.

Ill be spending a lot of time looking into suspension after, im really just trying to do wheels first because tyres on their way out and a bent rim.

I will be doing all the m3 underpinning swaps and coilovers and godknows what else so this is really just the first step. i have about 10-12k to put into the car to make it how i want.

[helix402]

Sounds like a great project. There are quite a few E8/9x threads on here which may give you some ideas.

[Court_S]

Is the car on stock suspension?

Just wondered because my other half’s 125i is in 18 inch 261’s on none run flats with Eibach springs and Bilstein B4 dampers and the ride is more then acceptable. It was bloody awful on RFT’s though.

[457892345]

Court_S said:

Is the car on stock suspension?

Just wondered because my other half’s 125i is in 18 inch 261’s on none run flats with Eibach springs and Bilstein B4 dampers and the ride is more then acceptable. It was bloody awful on RFT’s though.

It has the sport plus trim level but I think it's just standard sports suspension so idk if it's the bent rim or what but my old 118d lowest possible spec coupe with 16 inch wheels equipped with ps4s handled like a dream compared to this. Had bags of confidence when throwing it into turns + out of roundabouts that absolutely isn't there in this. Doesn't help with the hydraulic steering that you feel everything either adding to that uncertainty.

Everything I've read about wheels tells me 17s are best so going with this first but will do suspension shortly after also anyway.

Honestly I love this platform of car but all that it takes to research and buy best possible pieces is a lot. I wish there was some shop I could take it to that would help me because its difficult to get into when you are starting from scratch to know what to buy.

Edited by 457892345 on Saturday 27th August 16:11

[Court_S]

457892345 said:

It has the sport plus trim level but I think it's just standard sports suspension so idk if it's the bent rim or what but my old 118d lowest possible spec coupe with 16 inch wheels equipped with ps4s handled like a dream compared to this. Had bags of confidence when throwing it into turns + out of roundabouts that absolutely isn't there in this. Doesn't help with the hydraulic steering that you feel everything either adding to that uncertainty.

Everything I've read about wheels tells me 17s are best so going with this first but will do suspension shortly after also anyway.

Honestly I love this platform of car but all that it takes to research and buy best possible pieces is a lot. I wish there was some shop I could take it to that would help me because its difficult to get into when you are starting from scratch to know what to buy.

Edited by 457892345 on Saturday 27th August 16:11

How many miles has the car done? Could be shagged springs / dampers / bushes not helping.

18’s in my old 130i we’re fine too albeit with Birds B1 suspension and M3 LCA’s.

[457892345]

Court_S said:

How many miles has the car done? Could be shagged springs / dampers / bushes not helping.

18’s in my old 130i we’re fine too albeit with Birds B1 suspension and M3 LCA’s.

Its at 67k, my old 118d I had from 13 to nearly 90k.

Its a mixture of both no doubt , I like how 17s look and they better in nearly every way so I will do both but wheels are highest prio.