[Ejryan10]

Originally Posted by Wgosma

Tire shop wants to sell you 4 tires; buy 2. Put the (new) ones with 10/32 on the rear and your existing 8/32 tread depth tires on front, done.

That's what I was thinking when they told me I should get 4 new ones. So keeping the "old new two" (the ones that are 8/32) on the front and the new ones on the back won't mess anything you with my drivetrain at all? I didn't think it was that big of a difference either, but this one shop I'm dealing with is freaking out saying X3's are the most sensitive to different tread depths.

[Wgosma]

Originally Posted by Ejryan10

That's what I was thinking when they told me I should get 4 new ones. So keeping the "old new two" (the ones that are 8/32) on the front and the new ones on the back won't mess anything you with my drivetrain at all? I didn't think it was that big of a difference either, but this one shop I'm dealing with is freaking out saying X3's are the most sensitive to different tread depths.

Read again what the BMW TIS (Technical Information Systems) manual has to say about tires on X-drive cars:

From BMW TIS:
36 12 ...Notes and specifications for tyre / wheel exchange
General:

The tyre size, manufacturer and tyre tread must be the same on one axle
To meet the BMW standards, the vehicle should be equipped with tyres from the same manufacturer and with the same tyre tread (tyres approved by BMW) on all 4 wheels
The difference in tyre tread depth on one axle must not exceed 2 mm (control quality of suspension control systems and wheel alignment requirement)
The tyres with the higher tread depths must be mounted on the rear axle


So BMW is stating that the maximum allowable difference in tread depth on tires mounted on front vs. rear axle is 2mm. 2mm = 0.0787" which equals 2.5/32". Your four tires (2 will be new, two are existing ones) are within that spec as front/rear vary by 2/32", correct?

Buy two tires, install the brand new tires on the rear of the car, other 2 on the front, done.

(tires on these X3 cars wear pretty equally when comparing fronts to rears; rotation is almost not necessary...just keep an eye on the tread depths every 6 or so months and you'll be fine).

[Ejryan10]

Originally Posted by Wgosma

Read again what the BMW TIS (Technical Information Systems) manual has to say about tires on X-drive cars:

From BMW TIS:
36 12 ...Notes and specifications for tyre / wheel exchange
General:

The tyre size, manufacturer and tyre tread must be the same on one axle
To meet the BMW standards, the vehicle should be equipped with tyres from the same manufacturer and with the same tyre tread (tyres approved by BMW) on all 4 wheels
The difference in tyre tread depth on one axle must not exceed 2 mm (control quality of suspension control systems and wheel alignment requirement)
The tyres with the higher tread depths must be mounted on the rear axle


So BMW is stating that the maximum allowable difference in tread depth on tires mounted on front vs. rear axle is 2mm. 2mm = 0.0787" which equals 2.5/32". Your four tires (2 will be new, two are existing ones) are within that spec as front/rear vary by 2/32", correct?

Buy two tires, install the brand new tires on the rear of the car, other 2 on the front, done.

Gotcha, sorry man, math has never been my friend. And my local tire shop (who was recommended by master tech here) has got me all freaked out that I'll f*ck up my drivetrain if I don't replace them all. But I understand they're trying to make money as well, so I just want to be as close to 100% that I won't f*ck anything up by just getting two new new tires. Thanks for your help! I do believe that'll be the route I go now.

[Wgosma]

👍
Car will be fine- just measure tread depth every 6 months or so, so that you know you are within or close to max allowable tread depth difference.