[thejeremyman9]

I have been digging through several pages of threads in this section of the forum but did not see this specific questions answered. If it has been, sorry for the new thread and please point me to the correct one.

Basically, i want to know the max tire size i can run on stock 19'' rims with stock M-sport suspension

I have a 2015 335i RWD with stock M-sport suspension and stock 19''. Stock specs are:

19x8" ET36 225/40/R19 front = 26.1 ''
19x8.5" ET47 255/35/R19 rear = 26''

I saw a couple threads where people stated they have ran up to a 255/35r19 on all four corners on stock 19s, implying this would work on the front. Can anyone confirm that? I think that's even a bit wider than i would go up front.

For the rear, I haven't found much info on how wide/big people are going in the rear with stock 19s. Any info on this?

Considering:

265/35 = 26.3''
275/30 = 25.6''
275/35 = 26.6''

Thoughts and personal experiences with larger-than-stock tires on stock 19'' wheels?

[alohasurftoad]

the max recommended widths on 19x8 and 8.5 are 245 and 255 respectively. going wider than spec will reduce turn-in sharpness and be sloppier in transition. if you just want more grip for straight line acceleration i suppose it'd work but i'd rather get the best properly sized tires you can afford.

the comparison pics of the car below(not mine) has kept the rear at 255/35/19 and changed the front from 225/40/19 to 245/35/19. 245/35/19 up front will improve handling by reducing understeer with just a slight loss in turn-in sharpness.

it is the only tire size change on the oem wheels i'd recommend.

[thejeremyman9]

Originally Posted by alohasurftoad

the max recommended widths on 19x8 and 8.5 are 245 and 255 respectively. going wider than spec will reduce turn-in sharpness and be sloppier in transition. if you just want more grip for straight line acceleration i suppose it'd work but i'd rather get the best properly sized tires you can afford.

the comparison pics of the car below(not mine) has kept the rear at 255/35/19 and changed the front from 225/40/19 to 245/35/19. 245/35/19 up front will improve handling by reducing understeer with just a slight loss in turn-in sharpness.

it is the only tire size change on the oem wheels i'd recommend.

Thanks for the info - exactly what i was looking for (especially the additional consideration of turn-in). I am much more concerned with handling than straight line grip, and I'm sure BMW picked OEM sizes for a reason. I will consider the 245 front and do some additional research. I havent really noticed understeer in dry conditions and i have pushed the car hard in the canyons.

One other question:

On Costco (havent checked other websites yet), they are showing two different load index tires as recommended for rear. Both of these are different than front. This is for PS4S. One also has a "Z" in the tire size. I looked this up and my understanding is that its basically an optional label for the speed rating. Both tires are Y rated, but one lists the Z in the tire size. Prices are slightly different. For example:

Rear:
255/35R19/XL - Load index 96
255/35ZR19 - Load index 92

Front:
225/40ZR19/XL - Load index 93
225/40R19/XL - Load index 93

Front's with and without the Z label are the same load index, rear's are not. Everything else is exactly the same on these tires, including Y speed rating, treadwear, etc. All 4 of these are different item numbers and prices vary between them (albeit slightly). I'm sure the load index is not a big concern for a 3-series but I havent seen costco list these different nearly identical options for other cars/tires i have looked at.

Any experience with this?

EDIT: I am seeing the same thing on Big O Tires, but even more options, with and without the Z, etc. And some list mileage warranty as 20k instead of 30k?
https://www.bigotires.com/tires/by-v...e%3A2553519%29

[alohasurftoad]

compared to the 225, you'll be able to have a higher speed through "canyon carves" with the extra grip that 245 gives you up front.

regarding the different load index, I checked TireRack and believe the higher load indexed tires may be Star BMW spec for the M-cars. I am not sure of this, though.

[thejeremyman9]

Originally Posted by alohasurftoad

compared to the 225, you'll be able to have a higher speed through "canyon carves" with the extra grip that 245 gives you up front.

regarding the different load index, I checked TireRack and believe the higher load indexed tires may be Star BMW spec for the M-cars. I am not sure of this, though.

Yeah i know i might get some extra grip, i just don't want to have that lead to oversteer at the limit instead of understeer. I usually dont drive the car at 10/10 but i may just stick with the 225 since that is what i am used to.

I did some some research and i figured out that the tire sizes with a Z have a speed rating of (Y) instead of Y. Basically:

"But what about that "Z" rating mentioned earlier? "Z" means that the tire has been tested over 149 mph, but doesn't indicate how far over. The "Y" rating basically puts the cap at 186 mph. Except here, the designation is in parentheses, indicating that the tire has been tested above 186 mph. However, again it doesn't indicate how far over 186 mph that testing was done."

So the (Y) means the tire has been tested over 186mph, compared with a cap of 186mph for Y.

Regarding the XL, generally this is a higher load index (tire can handle more weight when inflated to a higher pressure) and stiffer sidewall tire. However, for the fronts, they are both load index 93, so i am not sure if the XL is actually making a difference; perhaps the sidewall on the XL is stiffer.

[alohasurftoad]

i have a 245/255 18" setup on my car. although i don't have any canyon to carve (here on oahu) i can tell you it's way better. where 225's start scrubbing in a fast corner the 245 stays on the line longer and the trajectory of the car seems more balanced. while 245 is less understeer than a 225, it'll still be understeer at the limit.

i hear ya, tho. stay with what you're comfy with. more understeer is definitely safer albeit a bit slower.

[visionaut]

I concur with Aloha. I switched to the 35-series 245/255 combo (PS4S) on my staggered 19” 442Ms. I also have X-Drive, so it’s good for the 1% diff too. Much better feel/grip (less push/understeer) up front. I too thought the OEM 225 up front was okay, but the 245 is so much better, you can easily feel it cornering.

You almost always want the higher load rating tire for a 3/4-series. BMW Star rating is also a plus IMO (the 255/35-19 can have it, it’s not available on the 245/35-19).
I suspect BMW put 225 up front to aid gas mileage...

[thejeremyman9]

Originally Posted by visionaut

I concur with Aloha. I switched to the 35-series 245/255 combo (PS4S) on my staggered 19” 442Ms. I also have X-Drive, so it’s good for the 1% diff too. Much better feel/grip (less push/understeer) up front. I too thought the OEM 225 up front was okay, but the 245 is so much better, you can easily feel it cornering.

You almost always want the higher load rating tire for a 3/4-series. BMW Star rating is also a plus IMO (the 255/35-19 can have it, it’s not available on the 245/35-19).
I suspect BMW put 225 up front to aid gas mileage...

I think you might have just convinced me

I have the OEM 19'' 442 also, in orbit gray. Also, based on what i see on Costco's website, the 245/35ZR19/XL are actually cheaper than the 225/40 by about 20$ each... they are also the XL, load index 93, and speed rating (Y). Seems like the best decision for me. I will probably continue to over-research it as i do everything, lol.

Plus, i missed Costco's Michelin promotion for December, so i may be waiting until the next time they do that (hopefully Jan since they usually alternate Michelin and Bridgestone promotions) unless i find a good deal elsewhere.

[thejeremyman9]

FYI incase anyone else searches this thread:

Below are attachments for the tires i went with from Costco including the prices. This was with a $150 off promotion on a set.

Of note is that there are 3 options for the exact same size tire on the rear and 2 options for the front. For the rear, the two alternatives are a Star BMW certified option which is "R" instead of "ZR" and Y instead of (Y) [Y being a lower speed rating] and a ZR (Y) that is not XL and only a 92 load index. The option i went with was combination of highest speed rating and highest load index, for the cheapest price. For the front, the option i did not go with was the exact same spec as the one i ordered but it was MO1 Mercedes certified option, and it was more expensive for the same exact tire.

[IAmATeaf]

I placed an order for the same rear tyres from Costco, also went with the non BMW/Mercedes option as not only was it cheaper but it had a better fuel efficiency rating, C versus E.

[thejeremyman9]

Originally Posted by IAmATeaf

I placed an order for the same rear tyres from Costco, also went with the non BMW/Mercedes option as not only was it cheaper but it had a better fuel efficiency rating, C versus E.

Mine have been a little slow to ship, just got an email estimated delivery is Jan 13. I will report back with impressions and photos after i get them installed.

Did you already have PS4S on front and just needed new rears?

[IAmATeaf]

Yes already have 4S on the front. Mine aren’t due in until the 22nd, decided to get them swapped out as the Conti 5 tyres have let the back end slide out a few times when it’s slightly damp. Brown trouser moments for sure.

[thejeremyman9]

Bumping this because i just got my PS4S installed. Some pictures are below with before/after. I went from stock sized RFT to the sizes noted in my post above. As expected, the PS4S are bettery in every way. Cornering, straight line grip, noise, comfort, etc, all improved.

Before pictures album:

View post on imgur.com

After pictures album:

View post on imgur.com

[mholder]

Does anybody know why the BMW dealerships (in the DFW area) won't sell or install the Michellin Pilot Sport 4S tires. They are still pushing the Pilot Super Sports. No matter how many times I tell them that the PS4S has replaced and is a better tire than the older PSS they will not budge.

[thejeremyman9]

Originally Posted by mholder

Does anybody know why the BMW dealerships (in the DFW area) won't sell or install the Michellin Pilot Sport 4S tires. They are still pushing the Pilot Super Sports. No matter how many times I tell them that the PS4S has replaced and is a better tire than the older PSS they will not budge.

They probably have a contract or inventory they need to finish off. Lots of places still offer MPSS. Costco has the best deal for the PS4S when you get them on sale, the dealship is probably overpriced anyways.

[ChicaneKing]

Originally Posted by thejeremyman9

Bumping this because i just got my PS4S installed. Some pictures are below with before/after. I went from stock sized RFT to the sizes noted in my post above. As expected, the PS4S are bettery in every way. Cornering, straight line grip, noise, comfort, etc, all improved.

I have a 335I RWD with 442s, and I am looking at running 245/35/19 up front as well. Have you experienced any ABS issues with this setup considering it is slightly smaller in diameter to the rear 255/35/19? How are the MP4S in the wet compared to the RFTs?

[thejeremyman9]

Originally Posted by ChicaneKing

I have a 335I RWD with 442s, and I am looking at running 245/35/19 up front as well. Have you experienced any ABS issues with this setup considering it is slightly smaller in diameter to the rear 255/35/19? How are the MP4S in the wet compared to the RFTs?

No ABS issues and i have autocrossed the car (with FBO + tune) and otherwise pushed the brakes very hard.

MPS4S are great in the wet. Miles ahead of the bridgestone summer s001 RFTs that come stock (in both wet and dry). All around the MPS4S are my #1 summer tire choice, as were the MPSS before them; just dont get them if you need to drive in freezing temperatures. But dry/wet roads they are fantastic.

I highly recommend both the change in tire size front to 245/35/19 and the PS4S as the summer tire of choice.

[ChicaneKing]

I definitely plan to go with 245/35/19 MPS4S up front now. Thanks for the info. Hopefully Costco has a Michelin sale in the next month or two.

[John.K]

Thank you all for this thread. Was very informative, and insightful. I too am due replacement. Actually past due (my SA was very concerned while showing me all the balding on my fronts yesterday as I was having my oil changed)

I too would like to go up on size on the fronts with PS4S'es. But I was leaning more towards on 235s (vs 245). Didn't want to have too big a change from stock and wanted to be a bit more conservative.

I'm having a hard time deciding between 235/35 vs 235/40. Any recommendations as to which one would be a better pick? And why?

Much appreciated.

[alohasurftoad]

Originally Posted by John.K

But I was leaning more towards on 235s (vs 245). Didn't want to have too big a change from stock and wanted to be a bit more conservative. I'm having a hard time deciding between 235/35 vs 235/40. Any recommendations as to which one would be a better pick? And why?

235/35/19(25.5") smaller sidewall will have less impact protection and firmer ride. the front wheel gap will increase 0.25" (compared to oem) and become more unsightly. front vehicle height will be 0.25" lower and cause a slight forward rake which may not be noticeable unless pointed out.

235/40/19(26.4"), larger sidewall, better ride and impact protection with slightly less sharp turn-in. front wheel gap will be reduced 0.2" and front height will increase 0.2". the reverse diameter stagger will cause slight reverse rake though likely unnoticeable unless pointed out.

245/35/19 is the the best size for the oem 19x8 front wheel as shown in the posts above.

[John.K]

alohasurftoad thank you for this. I had picked up on the height issue for 235/35 would cause yes. But not on the reverse diameter stagger that would come with 235/40. From a diameter & height perspective (which i think is really important to keep as close to stock as possible, as the suspension & front axle geometry would have been designed for that), yes 245/35 seems to be the optimal configuration.

Originally Posted by alohasurftoad

235/35/19(25.5") smaller sidewall will have less impact protection and firmer ride. the front wheel gap will increase 0.25" (compared to oem) and become more unsightly. front vehicle height will be 0.25" lower and cause a slight forward rake which may not be noticeable unless pointed out.

235/40/19(26.4"), larger sidewall, better ride and impact protection with slightly less sharp turn-in. front wheel gap will be reduced 0.2" and front height will increase 0.2". the reverse diameter stagger will cause slight reverse rake though likely unnoticeable unless pointed out.

245/35/19 is the the best size for the oem 19x8 front wheel as shown in the posts above.

[thejeremyman9]

Originally Posted by John.K

alohasurftoad thank you for this. I had picked up on the height issue for 235/35 would cause yes. But not on the reverse diameter stagger that would come with 235/40. From a diameter & height perspective (which i think is really important to keep as close to stock as possible, as the suspension & front axle geometry would have been designed for that), yes 245/35 seems to be the optimal configuration.

Just get the 245/35 for the front, you won't regret it. This is one place you dont need to be 'conservative'