Run flat tires

[master1917]

This is a follow up on my post 3 years ago with a concern of excessive tire wear on e70 X5M. I followed the specs that Ard recommended vs. the ones from BMW (an my technician) and put 50k kms between 2 sets of summers and winters Continentals - both still look great. Thank you Ard for your advice!

[ard]

Sweet!!! Thanks for the feedback.

[andrewwynn]

having JUST replaced all my suspension and tires i'm interested in those specs. I already had my alignment done but curious how it compares.

[ard]

Over on bimmerfest it is in my signature....


Alignment here: The Definitive Alignment Thread



Basically you want the least amount of TOE on each tire. Then camber and caster set at mid spec, but importanly BALANCED side to side on each axle. (dont set toe to 0.00, as it will tend to wander, but 0.01 0.02 toe in)


Pretty simple.


If you are tracking the car, well, then you know how to set up a car for track and dont need my advice.


The thread is a bit long, but it is kind of a 'teach a man to fish' thread...WHY we have the specs from BMW, WHY there is so much BS and mystique around the specs. etc etc

[andrewwynn]

Nice. Apparently my alignment guys read the same info. They did very much like you described.

Little enough toe I can feel it try to wander when I cross over a crown ( I can feel one or two caster wiggles, but I am hyper sensitive to it).

I have been using more toe my shop set up and the fronts have worn more on the outside as would be expected.

This is the first set of new tires I've had in six years. I've been getting 70% tread at 30% of normal price. This time 100% tread at 60% normal price.

[ard]

^ nice.


When I was spending time setting up my other car for handling and track, I realized that the numbers from a car manufacturer arent some holy grail. Indeed, it is simply a quick and dirty way for them to pump out cars that arent horrible. (They track OK, and importantly, BMW can set a spec such that cars rolling off the line dont need to be carefully aligned. Likely 90-95% fall 'in the green'.)


But people treat their numbers like they were derived from countless hours of track and performance testing- to be obeyed unless you want to risk 'not getting the performance BMWs are known for"


Anyway, I run more PSI in the fronts on my front engine cars. Reduces edge wear and roll.

[andrewwynn]

I have started doing the same. What PSI are you using ?


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[ard]

38F/36R... Mich Lattitude HP ZP.




Oh, and no, I dont have a spreadsheet of tire tread depths to 0.01" every 3 days....

[icicles9]

Agree 100% with the alignment specs
I run the Michelin non run flats
42 front 40 back.
Tyres last great


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[BGM]

+1 for RFTs. I'm at 105K miles. Had the OEM Dunlop Sport Maxx RFTs but being summer tires, compound was too soft only lasted 15K miles. Switched to the all-season OEM Bridgestone Dueler RFTs and been getting 40K a set.