OEM 18" wheels with 275/40-18 upsized rear tires

Richbot · 08-04-2010, 08:03 PM

After getting 7600 mostly highway miles out of the factory 265/40-18's (which I suspect the dealer, who had the car on his lot for over 18 months, probably took off of a higher-mileage used car to give a customer the 19's this car was originally delivered with) I needed new tires. I chose the PS2's because A) they're great-performing tires in almost every situation 2) the original front tires are still good for a long time and I prefer to match and IV) I think they look cool.

I chose 275/40-18's because A) they're molded at 9/32" instead of 8/32" like the 265/40-18's, so they'll probably last about 12% longer just because there's more tread before you get to the wear bars 2) they're $27 cheaper per tire than the BMW ///Marketing "specially engineered" size and IV) wider is better

You can look up the specs relative to OE tires for yourself, but even though this is often mentioned as a common size to replace with on these cars I've never seen a photo of them mounted on OEM wheels, so here we go, another good thread for the archives. Check out the huge amount of clearance, especially on the inside of the fenderwells and the lack of pinched looking sidewalls. If there was a ~26.5" tall 285 or 295 18" tire there would be plenty of room.

For anyone in the St Louis, MO area, I used Bavarian for my mount/balance and they did a perfect job and gave me a good price. I dismounted the wheels and took them there because of time constraints and spent some time under the car last night while it was up on jackstands. It's pretty cool under there, those M engineers aren't screwing around.

Richbot · 08-05-2010, 07:51 PM

After driving around a while, no rubbing at all, no weird DSC issues, and the speedo is now only about 1mph low vs. GPS as opposed to 2-3mph low with the stock size.

flipm3 · 08-05-2010, 08:19 PM

thanks for sharing!! that sure looks beefy!

clubspec330i · 08-07-2010, 10:28 PM

Nice.

I have been running 265/35-18 and 275/35-18 NT05 on stock OEM for about a year now. It is noisier as mileage increases but cheaper and grippier.

schnell325 · 08-07-2010, 11:19 PM

Same setup as me!

tudernos · 08-09-2010, 08:51 AM

Are you still running the same size stock front tires? 245/40/18?

Richbot · 08-09-2010, 10:43 AM

Quote:

Originally Posted by tudernos

Are you still running the same size stock front tires? 245/40/18?

Yup. When they wear out I'll either replace them with 255/40-18's or the same size, depending on availability of a take-off set of OE tires. The narrower front tires are probably a little better for steering response and they're lighter, but I would imagine the bigger ones fill the wheel wells a little better.

One more pic:

tudernos · 08-09-2010, 06:08 PM

You think it's good to run 255/40/18 fronts and 285/40/18 rears or should I do your set-up with 255/40/18 fronts and 275/40/18 rears?

Richbot · 08-10-2010, 07:53 AM

Quote:

Originally Posted by tudernos

You think it's good to run 255/40/18 fronts and 285/40/18 rears or should I do your set-up with 255/40/18 fronts and 275/40/18 rears?

If you're going to do 285's on the rear you're probably going to want to use a 285/35-18. A 285/40 is a pretty tall tire, I'd be worried about rubbing the top of the fender liner or the corner of the bumper cover when the suspension is compressed. There's only one way to find out short of doing some pretty complicated modeling of the fender well, suspension, and tires and that's to try it and see! One of the reasons I didn't do anything bigger than a 275 on the rear is because I didn't want to go smaller in diameter (295/35-18 is 26.1") and I didn't want to go more than 0.5" larger in diameter than stock (26.3") to make sure I didn't freak out the DSC with a bigger wheel speed difference. There's already probably at least enough wheel speed tolerance for 1.1" of rolling diameter built in to the stability control programming to keep it working properly when the front tires are worn out (0.5" less diameter than new) and the factory 0.6" stagger. And obviously lots of people are running tires that are a lot closer to the same diameter, or the same size all around, with no problems either.

If I were going to try to put as much rubber as possible on the road on stock wheels for the street, I'd probably use a 265/35-18 and 295/35-18.

tudernos · 08-10-2010, 08:49 AM

Thanks Richbot. I don't know if I want to go that wide (265/295). That's crazy! LOL. I was thinking something more conservative such as your set-up 255/275. With personal preference, I don't like to do modifications to the fenders. I want everything to be simple, clean and stock. I'll just probably run the same set-up as yours.

08-04-2010, 08:03 PM	#1
Richbot Major General 2759 Rep 5,484 Posts Drives: Jerez Black E90 Join Date: Sep 2007 Location: STL iTrader: (5)	OEM 18" wheels with 275/40-18 upsized rear tires - Pics inside After getting 7600 mostly highway miles out of the factory 265/40-18's (which I suspect the dealer, who had the car on his lot for over 18 months, probably took off of a higher-mileage used car to give a customer the 19's this car was originally delivered with) I needed new tires. I chose the PS2's because A) they're great-performing tires in almost every situation 2) the original front tires are still good for a long time and I prefer to match and IV) I think they look cool. I chose 275/40-18's because A) they're molded at 9/32" instead of 8/32" like the 265/40-18's, so they'll probably last about 12% longer just because there's more tread before you get to the wear bars 2) they're $27 cheaper per tire than the BMW ///Marketing "specially engineered" size and IV) wider is better You can look up the specs relative to OE tires for yourself, but even though this is often mentioned as a common size to replace with on these cars I've never seen a photo of them mounted on OEM wheels, so here we go, another good thread for the archives. Check out the huge amount of clearance, especially on the inside of the fenderwells and the lack of pinched looking sidewalls. If there was a ~26.5" tall 285 or 295 18" tire there would be plenty of room. For anyone in the St Louis, MO area, I used Bavarian for my mount/balance and they did a perfect job and gave me a good price. I dismounted the wheels and took them there because of time constraints and spent some time under the car last night while it was up on jackstands. It's pretty cool under there, those M engineers aren't screwing around. Attached Images __________________ Last edited by Richbot; 08-04-2010 at 08:10 PM..
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08-05-2010, 07:51 PM	#2
Richbot Major General 2759 Rep 5,484 Posts Drives: Jerez Black E90 Join Date: Sep 2007 Location: STL iTrader: (5)	After driving around a while, no rubbing at all, no weird DSC issues, and the speedo is now only about 1mph low vs. GPS as opposed to 2-3mph low with the stock size. __________________
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08-05-2010, 08:19 PM	#3
flipm3 E46 + E90 + F80 192 Rep 2,894 Posts Drives: E46 + E90 + F80 Join Date: Jul 2008 Location: Illinois iTrader: (1) Garage List 2009 BMW M3 [0.00] 2002 BMW M3 [0.00]	thanks for sharing!! that sure looks beefy! __________________ F80 M3 DCT\|Alpine White . Black Leather \| My Build Thread E90 M3 DCT\|Melbourne Red . Speed Cloth \| My Build Thread E46 M3 6MT\|Jet Black . Black Nappa Leather \| My Build Thread
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08-07-2010, 10:28 PM	#4
clubspec330i First Lieutenant 71 Rep 396 Posts Drives: MG F39, CB F86, MB 911T Join Date: Apr 2005 Location: So. Cal iTrader: (0)	Nice. I have been running 265/35-18 and 275/35-18 NT05 on stock OEM for about a year now. It is noisier as mileage increases but cheaper and grippier.
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08-07-2010, 11:19 PM	#5
schnell325 Bored at work.... 890 Rep 5,390 Posts Drives: 2016 F82 M4 GTS//2022 M235iGC Join Date: Aug 2007 Location: Comox Valley iTrader: (8)	Same setup as me! __________________ Grey Matter:2008 E92 M3:608/425. SG/PS SOLD! Dark Matter:2015 F80 M3:495/505. SOLD! Anti Matter :2016 F82 M4 GTS What next?!? A 2022 M235i GC- I must be getting old
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08-09-2010, 08:51 AM	#6
tudernos Private First Class 12 Rep 143 Posts Drives: 2008 E92 AW M3 Annabelle Join Date: Aug 2010 Location: Charlotte, NC iTrader: (1)	Are you still running the same size stock front tires? 245/40/18?
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08-09-2010, 06:08 PM	#8
tudernos Private First Class 12 Rep 143 Posts Drives: 2008 E92 AW M3 Annabelle Join Date: Aug 2010 Location: Charlotte, NC iTrader: (1)	You think it's good to run 255/40/18 fronts and 285/40/18 rears or should I do your set-up with 255/40/18 fronts and 275/40/18 rears?
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08-10-2010, 08:49 AM	#10
tudernos Private First Class 12 Rep 143 Posts Drives: 2008 E92 AW M3 Annabelle Join Date: Aug 2010 Location: Charlotte, NC iTrader: (1)	Thanks Richbot. I don't know if I want to go that wide (265/295). That's crazy! LOL. I was thinking something more conservative such as your set-up 255/275. With personal preference, I don't like to do modifications to the fenders. I want everything to be simple, clean and stock. I'll just probably run the same set-up as yours.
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