How critical is equal tread depth?

jpm5150 · 02-16-2017, 02:35 PM

So, Im just curious...recently had a run-flat go flat. I'm not going to debate whether the run flat could have been patched as they claim you can't, I know that topic has been covered in length everywhere. My question is more around what dealership service claimed was critical to replace all 4 tires since the tread was ~3mm on the other tires. I get it that its good to have even tread, but, their claim was that it would damage the transfer case and cause the x-drive system to malfunction. Is that really true? If yes, is that a corner case?
I'm not here to argue one way or another or say anything bad about the service department, Im just trying to learn what's what.

FYI: This is a 435xi.

Cheers, Jeff

MrF30 · 02-22-2017, 11:55 PM

You should replace at 3mm. Wear bars are at 2mm. Tires wear faster below 5mm.

Rudy@tirerack · 02-23-2017, 09:48 AM

On X-Drive vehicles, it would be recommended to match tread depth within 2/32nd of an inch.
Example: If the new tire is 10/32 and your current tires are 8/32 or better, it is okay to replace one tire.
If your current tires are 7/32 or less, it would be best to replace all 4 tires or have 1 new tire shaved down to match the tread depth of the other 3 tires. If Tire Rack sells the tire you are looking for, we can shave it down to match the tread depth of the other 3 tires, saving you from having to replace all 4 tires.

This is a very common issue on AWD vehicles. BMW's are not traditionally AWD, so it may not be common knowledge to everyone here. Although, if you hop onto an Audi or Subaru forum, it is very common knowledge.

02-16-2017, 02:35 PM	#1
jpm5150 Private 58 Rep 62 Posts Drives: 2021 X5 M50 Join Date: Jan 2017 Location: Seattle iTrader: (0)	How critical is equal tread depth? So, Im just curious...recently had a run-flat go flat. I'm not going to debate whether the run flat could have been patched as they claim you can't, I know that topic has been covered in length everywhere. My question is more around what dealership service claimed was critical to replace all 4 tires since the tread was ~3mm on the other tires. I get it that its good to have even tread, but, their claim was that it would damage the transfer case and cause the x-drive system to malfunction. Is that really true? If yes, is that a corner case? I'm not here to argue one way or another or say anything bad about the service department, Im just trying to learn what's what. FYI: This is a 435xi. Cheers, Jeff
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02-22-2017, 11:55 PM	#2
MrF30 Second Lieutenant 58 Rep 248 Posts Drives: 335i Join Date: Dec 2015 Location: CA iTrader: (0)	You should replace at 3mm. Wear bars are at 2mm. Tires wear faster below 5mm. __________________ EXTERIOR: M Sport front bumper/side skirts, M3 rear bumper/fenders, black M3 kidney grilles, cf M3 mirror caps, cf MP trunk spoiler, ACS roof spoiler, side blades, black roof, Grigio Telesto, STANCE: Rotiform SPF 19"s, BC Racing BR coilovers, UUC front end-links, orange calipers, ENGINE: PS1, Wagner FMIC, Borla S-Type exhaust, quad ti tips, VRSF dp/cp, JB4, INTERIOR: ACS pedals, WeatherTech floor & BMW trunk mats
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02-23-2017, 09:48 AM	#3
Rudy@tirerack Moderator 123 Rep 281 Posts Drives: rudy@tirerack.com Join Date: Feb 2016 Location: 1-800-428-8355 EXT 4664 iTrader: (0)	On X-Drive vehicles, it would be recommended to match tread depth within 2/32nd of an inch. Example: If the new tire is 10/32 and your current tires are 8/32 or better, it is okay to replace one tire. If your current tires are 7/32 or less, it would be best to replace all 4 tires or have 1 new tire shaved down to match the tread depth of the other 3 tires. If Tire Rack sells the tire you are looking for, we can shave it down to match the tread depth of the other 3 tires, saving you from having to replace all 4 tires. This is a very common issue on AWD vehicles. BMW's are not traditionally AWD, so it may not be common knowledge to everyone here. Although, if you hop onto an Audi or Subaru forum, it is very common knowledge.
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