275-35 front - 295-35 rear OEM Black wheels

[Palomequet]

OEM 275-35 rear tires mounted on front wheels and 295-35 on rear, Michelin PSS
What do you think? the car drives great!

Next step, H&R springs.

[RJVIII]

Looks good, love the meaty tire look.

[TahoeM3]

Nice...how is the traction? Any change in handling?

[CanAutM3]

Interesting and smart approach. Also interested about feedback on the handling. Any rubs?

My front tires are shot from a track weekend. So I am considering doing the same thing, moving my rears up front and buying a new set of rears.

Please share more driving impressions

[Vectors2final]

Wow, it looks good. It's not pudgy or anything.


I don't know what the contact patch difference is between the two is.

[WVUDrJay]

Looks great. This will be my next setup.

[kitw]

This will work fine with the OEM suspension and bump stops but any increase in travel will result in rubbing, due to the larger overall diameter. I wouldn't be surprised if you start to see some rubbing on the H&R sports but report back, as I'm not sure!

[CanAutM3]

Originally Posted by kitw

This will work fine with the OEM suspension and bump stops but any increase in travel will result in rubbing, due to the larger overall diameter. I wouldn't be surprised if you start to see some rubbing on the H&R sports but report back, as I'm not sure!

The rolling radius is only larger by ~¼". You think that is enough to cause rubbing?

[volkl23]

Very interesting post OP! Please share your experience once you have some time with the setup over stock. Am thinking about going this route..

[afadeev]

Originally Posted by CanAutM3

The rolling radius is only larger by ~¼". You think that is enough to cause rubbing?

By going from 255->275mm front and 275->295m rear tires, you are 20mm wider. Or 0.787".
Since the tire will be centered, it will stick out !0.39" on each side.

Another consideration is the tire vs. wheel width.
Front wheels are 9JX18 ET:29 or 9JX19 ET:29.
Rear wheels are 10JX18 ET:40 or 10JX19 ET:40.

Michelin recommends both 275/35-18 and 275/35-19 tires to go onto 9-11" wide wheels. So 9" OEM wheel is at the minimum acceptable width, but still OK.
Similarly, both 295/35-18 and -19 are good to go onto 10-11.5" wheels, so rear 10" wide wheels are minimally acceptable.

http://www.tirerack.com/tires/tires....ndard%20Brakes

a

[CanAutM3]

Originally Posted by afadeev

By going from 255->275mm front and 275->295m rear tires, you are 20mm wider. Or 0.787".
Since the tire will be centered, it will stick out !0.39" on each side.

Another consideration is the tire vs. wheel width.
Front wheels are 9JX18 ET:29 or 9JX19 ET:29.
Rear wheels are 10JX18 ET:40 or 10JX19 ET:40.

Michelin recommends both 275/35-18 and 275/35-19 tires to go onto 9-11" wide wheels. So 9" OEM wheels is at the minimum acceptable width, but still OK.
Similarly, both 295/35-18 and -19 are good to go onto 10-11.5" wheels, so rear 10" wide wheels are minimally acceptable.

http://www.tirerack.com/tires/tires....ndard%20Brakes

a

It is actually more than that. According to the Michelin site, the 295 are 1.2" wider than the 275 (271mm vs 301mm). So they would protrude 0.6" more on each side (15mm).

Some folks are running up to 20mm spacers front and rear without rubbing and 15mm spacers are very popular. Since the rear tires in the OP stick out by 15mm, it should not cause any rubbing IMO.

After further research, I might opt for a 265/285 /35R19 setup. The 295/35R19 are significantly more expensive than the 285/35R19. On the vendor sites I checked, the 295 are ~26% more expensive than the 275 while the 285 are only ~3% more expensive. However, that extra rubber on the road of the 295 sure is tempting.

[MatthewDavid]

This definitely fills out the rear wheel well better!

The M4 rear wheel looks a bit like a scrawny guy wearing a polo shirt where his bicep isn't big enough to fill in the arm hole so it looks awkwardly too large, flaps in the wind...

Originally Posted by Palomequet

OEM 275-35 rear tires mounted on front wheels and 295-35 on rear, Michelin PSS
What do you think? the car drives great!

Next step, H&R springs.

[rmedeir1]

There has been a lot of comments made by a lot of you on moving to 275/295, but how do any of us really know the width will provide better grip? Psychologically I would think that 295 rears would help, but what testing has been done to show this proves better grip? 1.2" increase in width on the rear can't cure 50% of the grip issues I would guess. I raise not to stir the pot, but hopefully become more informed about a future purchase.

[CanAutM3]

Originally Posted by rmedeir1

There has been a lot of comments made by a lot of you on moving to 275/295, but how do any of us really know the width will provide better grip? Psychologically I would think that 295 rears would help, but what testing has been done to show this proves better grip? 1.2" increase in width on the rear can't cure 50% of the grip issues I would guess.

See my thread here.

The 295 has a contact patch that is 18% (1.7") wider that the F8X specific 275. It is not negligible.

[rmedeir1]

I get the 18% increase in contact surface and I read your post and liked the analysis you did! It helped. What I am really trying to figure out is how much better the grip is in "butt-testing" with the OP and ultimately in real-world measurement/testing. The increase is radius does concern me though for the 275/295 35 widths. The 265/285 scenario only adds 5% increase in contact. Do straightline 0-60 and 1/4 mile times increase by 1/10th (or whatever) of a second? Do they not? Lateral acceleration improve? If so by how much? The answers to these questions are good to have, but if no one tests then I'll have to go buy and test on my own. It would be nice if BMW did an in-depth article like they have on other topics on why they chose the tire sizes and what they tested and why?

[kitw]

Originally Posted by CanAutM3

It is actually more than that. According to the Michelin site, the 295 are 1.2" wider than the 275 (271mm vs 301mm). So they would protrude 0.6" more on each side (15mm).

Some folks are running up to 20mm spacers front and rear without rubbing and 15mm spacers are very popular. Since the rear tires in the OP stick out by 15mm, it should not cause any rubbing IMO.

After further research, I might opt for a 265/285 /35R19 setup. The 295/35R19 are significantly more expensive than the 285/35R19. On the vendor sites I checked, the 295 are ~26% more expensive than the 275 while the 285 are only ~3% more expensive. However, that extra rubber on the road of the 295 sure is tempting.

I think you are forgetting the measurements for width are mounted and mounted on different width wheels. If you measure those tires on the stock wheels, you will find the width to be much more similar,

Also remember contact patch doesn't change in overall size, rather shape for a given air pressure.

[kitw]

Originally Posted by CanAutM3

The rolling radius is only larger by ~¼". You think that is enough to cause rubbing?

25.4mm in an inch.

275/35 vs 255/35 vs 295/35

You have 20mm * 35% = 8.89mm or .35" which is yes enough to rub

By the actual specs on Tire Rack:

255/35r19 is 26" overall
275/35r19 is 26.6"
295/35r19 Is 27.1"

Divide by 2 to get radius and still similar and yes, I suspect you will rub. Let me know what you find, might be more clearance than I think. Definitely if you end up with coilovers that increase suspension travel. (Ie if you get the Dinan 435i bits that increase travel)

[m4 java green]

We really need the track guys posting their tire setups and lap time comparisons... Can anyone who has this info post it and help us guys looking to buy a good wheel and tire track setup? Street setup you can go crazy as far as I'm concerned. Whatever looks cool and doesn't rub

[CanAutM3]

Originally Posted by kitw

25.4mm in an inch.

275/35 vs 255/35 vs 295/35

You have 20mm * 35% = 8.89mm or .35" which is yes enough to rub

By the actual specs on Tire Rack:

255/35r19 is 26" overall
275/35r19 is 26.6"
295/35r19 Is 27.1"

Divide by 2 to get radius and still similar and yes, I suspect you will rub. Let me know what you find, might be more clearance than I think. Definitely if you end up with coilovers that increase suspension travel. (Ie if you get the Dinan 435i bits that increase travel)

Check you math :

20mm * .35 = 7mm = 0.275" (pretty darn close to a 1/4", isn't it )

The dimension in inches on the Tire Rack website are rounded off. From the Michelin website:

255/35r19 is 661mm
275/35r19 is 675mm
295/35r19 Is 689mm

There is the same 14mm difference in dia between each, so 7mm in radius.

But I get what you are saying. Wider tires combined with increased radius does increase the probablity of rubs with a lowered suspension.

[CanAutM3]

Originally Posted by kitw

I think you are forgetting the measurements for width are mounted and mounted on different width wheels. If you measure those tires on the stock wheels, you will find the width to be much more similar,

I doubt so. While the wheel width does have an impact on the resulting section width, IMO, the thread width would not change drastically.

EDITED to correct eroneous info

Originally Posted by kitw

Also remember contact patch doesn't change in overall size, rather shape for a given air pressure.

Agreed.

[kitw]

Originally Posted by CanAutM3

I doubt so. While the wheel width does have an impact on the resulting tire width, the tires structure has much more influence (unless you go with crazy stance nation wide wheels ). IMO, the overall tire width would not change drastically.

Incorrect.

I've stacked a set of 275/35r18s next to an identical set, 1 mounted on 18x9 and 1 mounting on a set of 10s and the difference was HUGE. They looked slightly pinched on the 9s and pretty straight up and down with the 10s and there was over 4" of difference in the total stack height. I was shocked. That's why it is key to keep in mind the width of the wheel.

[CanAutM3]

Originally Posted by kitw

Incorrect.

I've stacked a set of 275/35r18s next to an identical set, 1 mounted on 18x9 and 1 mounting on a set of 10s and the difference was HUGE. They looked slightly pinched on the 9s and pretty straight up and down with the 10s and there was over 4" of difference in the total stack height. I was shocked. That's why it is key to keep in mind the width of the wheel.

You are correct. I was mixing up two conversations. Total section width will vary significantly with wheel width. It is thread width that does vary much with tire width.