+5 Tire Sizes for M550i comfort?

HiSport · 09-08-2023, 11:31 AM

Anyone tried using 20" tires with slightly taller (+5) sidewalls?

My current setup tends to hammer on rough roads:

New to me 2019 M550i; 20" 668M wheels with non-runflat Toyo Proxes A/S in stock 245/35 and 275/30 sizes. Car was delivered with Pilot Sport 4S summer tires and factory mini spare in trunk.

Believe contemporary 7 series with these wheels? uses 245/40 and 275/35 tires?

Oh, and my speedo is off ~ 3+ MPH at 70 mph. The ~ 1" larger diameter would, mathematically, seem to just about compensate for this...

Joe-BMW33 · 09-08-2023, 12:29 PM

Quote:

Originally Posted by HiSport

Anyone tried using 20" tires with slightly taller (+5) sidewalls?

My current setup tends to hammer on rough roads:

New to me 2019 M550i; 20" 668M wheels with non-runflat Toyo Proxes A/S in stock 245/35 and 275/30 sizes. Car was delivered with Pilot Sport 4S summer tires and factory mini spare in trunk.

Believe contemporary 7 series with these wheels? uses 245/40 and 275/35 tires?

Oh, and my speedo is off ~ 3+ MPH at 70 mph. The ~ 1" larger diameter would, mathematically, seem to just about compensate for this...

No direct experience here, but have read a lot of stories of people going bigger. Seems you can go to 255/35/20 front and 285/30/20 rear pretty easily with no rubbing. Possibly 295 out back if you aren't running spacers, but 255/35/20 front and 285/30/20 seems to be the sweet spot for most.

BMW's speedo is off +2-3 mph by design from the factory.

HiSport · 09-08-2023, 10:20 PM

tks Joe

My interest is softer, vs bigger. As in, taller sidewall.

Has anyone tried 7 series tire sizing on M550 with 20" wheels?

NGT2 · 09-09-2023, 12:54 AM

Quote:

Originally Posted by HiSport

tks Joe

My interest is softer, vs bigger. As in, taller sidewall.

Has anyone tried 7 series tire sizing on M550 with 20" wheels?

If you search the forum then I think you’d find some posts and threads on this. I have read others doing this, so I’m pretty sure it’s possible.

JoeFromPA · 09-09-2023, 05:00 AM

Your issue is partly your tires - those are not soft tires. If you went up in sidewall size with the same tire, you'd experience pretty similar crashing.

Look up peoples wider tire profiles as well as plus size wheel combos and look at overall tire height, since wider at the same tire sidewall ratio = taller tire. Most people don't go to taller sidewall aspect ratio (which is what the 35 is = 35% of the width of the tire), but they go wider, so the information exists on the forum to help you answer your question.

09-08-2023, 11:31 AM	#1
HiSport Stealth Traveler 6 Rep 3 Posts Drives: '19 M550i '01M3 '11XKR '07XJR Join Date: Sep 2023 Location: Beautiful Pilot Mt, North Carolina iTrader: (0)	+5 Tire Sizes for M550i comfort? Anyone tried using 20" tires with slightly taller (+5) sidewalls? My current setup tends to hammer on rough roads: New to me 2019 M550i; 20" 668M wheels with non-runflat Toyo Proxes A/S in stock 245/35 and 275/30 sizes. Car was delivered with Pilot Sport 4S summer tires and factory mini spare in trunk. Believe contemporary 7 series with these wheels? uses 245/40 and 275/35 tires? Oh, and my speedo is off ~ 3+ MPH at 70 mph. The ~ 1" larger diameter would, mathematically, seem to just about compensate for this...
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09-08-2023, 10:20 PM	#3
HiSport Stealth Traveler 6 Rep 3 Posts Drives: '19 M550i '01M3 '11XKR '07XJR Join Date: Sep 2023 Location: Beautiful Pilot Mt, North Carolina iTrader: (0)	tks Joe My interest is softer, vs bigger. As in, taller sidewall. Has anyone tried 7 series tire sizing on M550 with 20" wheels?
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09-09-2023, 05:00 AM	#5
JoeFromPA Colonel 1796 Rep 2,997 Posts Drives: '15 AW M3 6MT Stripper Join Date: Aug 2013 Location: SE PA iTrader: (0)	Your issue is partly your tires - those are not soft tires. If you went up in sidewall size with the same tire, you'd experience pretty similar crashing. Look up peoples wider tire profiles as well as plus size wheel combos and look at overall tire height, since wider at the same tire sidewall ratio = taller tire. Most people don't go to taller sidewall aspect ratio (which is what the 35 is = 35% of the width of the tire), but they go wider, so the information exists on the forum to help you answer your question.
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