Suspension Sag 2016 F86 52k

[m3fuz]

Originally Posted by 640ijims

I must apologize , went to garage and looked at car. Passenger rear tire flat as floor…evidently tire casing held it up for a while. When BMW assist arrives to put spare on; this 240# 74 year old could not budge one nut; I'll be interested to see what I picked up.

Update, tire changed. Spare had 20 # of air ( rated at 60# max), despite being checked by tech at each service.. so now trust & verify for my BMW dealer. Picked up what looks like a utility knife blade…no plug for this..have to it "adjusted" , tire has about 8K on it. Change one or both rears?

If the other tire is fine and has good tread left, then use it. If both tires had, for examples sake, 20K miles and they were rated for 30K, then I’d switch them both, but I don’t think 8K is going to have any appreciable bearing on the car’s AWD.

[640ijims]

You are probably correct .. I think I will use a tread depth gage to be safe

[///MCollection]

I think the tolerance is something like 5mm difference end to end and supposedly in pairs on an axle. The transfer case isn't the strongest thing in the world so I would put a pair on and keep the non damaged one in the garage as a spare if you get a puncture again and there close in wear.

[640ijims]

In measuring tires today both fronts are 8/32 all way across tread rears are 8/32 in center, 7 ½ at edges. In mm fronts are6 mm across treads, good rear is 6+ across tread. So literally no diff Currently front to rear or side to side same axle. One new rear will have 1/16" or 1.60 mm side to side rear and with just one new tire same front to rear same side ( passenger). Incidentally 39# is ideal front , based on pattern I think 42# at rear.

SO QUESTION IS ONE OR TWO NEW REARS?

[m3fuz]

Personally, I’d just replace the one tire.

[///MCollection]

So on the rears you will have your existing one at 6mm which roughly matches the 2 fronts and the new one will be 7.6mm in that case I think just one as the rest must be relatively new or wearing well as 1.6mm difference is nothing.

[640ijims]

Thanks, gentlemen