Mixing RFT vs NRFT

[uncle_sam]

Now time to change my rear Bridgestone RFT's 315/35x40 tho my fronts (also RFT) 275/40x20 still good for another year. Thinking of getting Michelin Lattitude 315's Non-RFT for the rear.

Question: Will there be any issue if i continue with RFTs upfront and non-RFT's at the rear? Any experience on running with this mix? Kinda too early if I change/dump the RFT fronts together with the rears.
Thoughts?

[mitch808]

There isn't a problem with mixing tires. But the tire circumfrence NEEDS to match within 1/8" front to rear. So typically the recommended response for most ALL AWD vehicles, and even from BMW themselves, is to replace all 4 tires at the same time.

Or else there could be issues with the center diff overheating and grenading itself by having to constantly deal with a front axle spinning at a different rate than the rear.

[jandref321]

Originally Posted by mitch808

There isn't a problem with mixing tires. But the tire circumfrence NEEDS to match within 1/8" front to rear. So typically the recommended response for most ALL AWD vehicles, and even from BMW themselves, is to replace all 4 tires at the same time.

Or else there could be issues with the center diff overheating and grenading itself by having to constantly deal with a front axle spinning at a different rate than the rear.

X2 Had a friend who did this and ended up having to replace a portion of the t-case after a week and had to rush and buy matching front tires also. Was his wife's car and she complained about the xdrive studdering awkwardly for about a week; when he got around to it was too late.

[uncle_sam]

@mitch808, @jandref321: appreciate the insights. If i go with the current tire sizes, the circum diff bet front & back are within 1/16. So minimal discrepancy. But I noted possible overheating and potential t-case problem you shared. Will consider these risks very carefully.
Cheers & thanks,

[omgboost]

Are there any warnings or lights on the dash indicating the transfer case is working in overtime?

[jandref321]

Originally Posted by omgboost

Are there any warnings or lights on the dash indicating the transfer case is working in overtime?

He said the car would studder as if hydroplaning and eventually they got some lights on the dash and took it to an Indy. The tires were new and a different brand. The difference was this was an X3 not X5. I imagine the tires had big wear in the front and the new brand had a different overall diameter because of tread pattern or something. There are probably a lot more options and variances with the X3 tires sizes since the are a square setup with large sidewall so many companies make them different ways.

[-c-]

Just replaced the rear tires and not the fronts and the difference in tread depth grenaded my transfer-case. No lights of any kind just crazy shuddering when turning hard left or right.

It wore out the clutches. Unfortunately the transfer-case where of a poor design in the E70's even BMW had to redesign it 4 times before getting it to be less touchy. Look it up, it was superseded at least 4 times with different design iterations.

[135ivert]

Originally Posted by uncle_sam

Question: Will there be any issue if i continue with RFTs upfront and non-RFT's at the rear? Any experience on running with this mix? Kinda too early if I change/dump the RFT fronts together with the rears.
Thoughts?

I'm not sure how applicable this is, but I did this exact thing with my 135i. I put non-RFT Michelin PSS in the rear and kept the Bridgestone RFT in front. It was very unstable and downright scary to drive. I got matching Michelin PSS in the front shortly thereafter.

[Suge206]

Ive always staggered replacong front and backs with zero issues. Same brand, diff brands, run flat and non

[Qarban]

Originally Posted by uncle_sam

Now time to change my rear Bridgestone RFT's 315/35x40 tho my fronts (also RFT) 275/40x20 still good for another year. Thinking of getting Michelin Lattitude 315's Non-RFT for the rear.

Question: Will there be any issue if i continue with RFTs upfront and non-RFT's at the rear? Any experience on running with this mix? Kinda too early if I change/dump the RFT fronts together with the rears.
Thoughts?

Here are some good information from Tire Rack

http://blog.tirerack.com/blog/make-d...ead-this-first

http://blog.tirerack.com/blog/make-d...?affiliate=FH8

[uncle_sam]

@ Qarban: thanks for the useful blogs. Appreciate it.