Does all 4 tires need to match? otherwise you damage the transmission!

[ducati2242]

Originally Posted by JCL

The splines that are at risk are on the output shaft of the transfer case, where the front driveshaft connects.

If you changed one tire and then had repeat DSC problems, then yes, you would need to change all of them. If you didn't have DSC warning lights, then you could try it out, and see if the front driveshaft gave any problems.

This isn't anything to do with BMW, it is with all AWD/4WD vehicles with different tire circumferences, and the problems just show up in different failure modes.

Well Ive had them for over 6 years now and it has never happened to me . Got a front wheel puncture last april changed 1 tyre and its still going strong,even towing, There is no way I would consider changing all tyres for one puncture . Never heard of anything so stupid . A full set of tyres, 4 , in the U.K. is over £1000 ( $1650 ) and people would change them all for one puncture that needs replacement. I`d sooner change the car.

[Nik]

So, If DSC doesn't give warning then you can try to get lucky (at least for a while)?

[ducati2242]

Originally Posted by Nik

So, If DSC doesn't give warning then you can try to get lucky (at least for a while)?

Dont think luck has anything to do with it I think that too many home mechanics have got more money to waste then sense.

[BlackX54.4i]

Originally Posted by JCL

Weasel is a BMW tech, and has previously posted here that he likes to see no more than 4 revolutions per mile difference. I would look for no more than 2% difference, not sure how that compares to the 4 revolutions per mile.

Thanks, I'll look at the specs per the tires that I am looking at...I have 1 tire which will have 8/32's remaining and then 3 new ones on a staggered set up, sport 19's. The mismatched tires will be on the front, 255/50 19's.

FYI for everyone...Tire Rack offers tire "shaving" to match treads in the instance of flats...etc...

[JCL]

Originally Posted by ducati2242

Well Ive had them for over 6 years now and it has never happened to me . Got a front wheel puncture last april changed 1 tyre and its still going strong,even towing, There is no way I would consider changing all tyres for one puncture . Never heard of anything so stupid . A full set of tyres, 4 , in the U.K. is over £1000 ( $1650 ) and people would change them all for one puncture that needs replacement. I`d sooner change the car.

First thing to do with a puncture is to repair it, not replace it.

If you have to replace one, then just calculate the difference in rolling diameter. There are lots of tire size calculators on line. 30% worn is about the limit, but it depends on the specific tires. Another thing you could do is get the one new tire shaved down to approximate the size of the worn tires, if that service is available locally.

IMO it is a bit ridiculous to say that because you never had a problem that nobody ever will. That is as bad as saying that if you did have a problem, then everyone will. What you are doing is stressing the driveline, and buying some risk. Some problems show up quickly with mismatched tires (DSC lights coming on in the first block). Others take longer (output shaft splines on pre x-drive, or clutch plates in the transfer case on x-drive models). Glad your tire replacement worked out OK for you.

[ducati2242]

Originally Posted by JCL

First thing to do with a puncture is to repair it, not replace it.

Agree with you there but if theres a hole in the side wall 20 mm long theres little chance of that .
My x5 was still under warranty when it went in for a new tyre . Ring them up and they will fix anything when under warranty in England .
They fitted the new tyre when the others were about 30% worn , I had to pay for that one though , Never even mentioned that there could be a problem, which there wasnt , And its still going strong now with another 6k miles on it. They are very particular having changed the camshaft rattle that came on and the actuator on the transfer box without even being asked . So I believe in them Im afraid .

[admranger]

Originally Posted by CTSportX5

Sounds made up.

Sounds uniformed.

I'm with JCL (and Weasel) here. Both know their stuff and I have had nothing but good luck listening to their advice.

Get 4 tires of the same diameter. Or don't. It's not my money that's going to be buying the new drivetrain parts...