Hi. Found a nice 5 last week with plenty of extras but had already sold, found another but it’s a 4 wheel drive one. Are these like older 4 wheel drive cars regarding tyres having to be all same tread depth etc or is that issue solved with electronics now. I replace my tyres in pairs anyway but just thinking in case I have a puncture or anything. Do they wear the tyres quicker too!
There are tolerances issued by BMW as to the difference in tread depth between front and near and between tyres on the same axle. BMW also recommend that tyres are "star" marked ,....ie approved by BMW The tyres on my G30 X drive are wearing much slower than on my wifes X1. Mine have done 23k and still got 5.5mm tread depth
From NewTIS: Gives a good idea of BMW's stance on tyre wear. There is a feature called "Tyre Tolerance Logic" on xDrive, which does the technical part of giving a bit of slack within xDrive. But we must remember wrong tyres can cause extra wear within the transfer box. The closer we keep the RC 'front to rear' to accepted tolerances, the less stress on any components. https://www.newtis.info/tisv2/a/en/...s/36-wheels-with-tyres/36-12-tyres/1VnYEE2taP 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 The DOT age difference must not exceed 4 years The tyre pressure must be adjusted when the tyres are exchanged Wheel exchange between the axles The wheels may be exchanged between axles to achieve even abrasion. However, BMW does not recommend switching the front wheels to the rear or vice-versa. The wheel exchange may lead to the following customer complaints: complaints regarding acoustics Risk of increased lane groove sensitivity Compliance with the following requirements is required when exchanging wheels between the axles: Assess the wear pattern The tread difference between the front and rear wheels must not exceed a maximum of 2-3 mm Exchange the wheels between the axles every 5000 Km Additionally for all-wheel drive vehicles: The tyre size, manufacturer and tyre tread must be identical on all wheels; different tyre sizes between front and rear axles are only permissible if mixed tyres are fitted. The tyre tread difference between tyres in all wheel positions must not exceed 2 mm (normal quality of the wheel control systems and wheel alignment requirement) Peter
is the issue of different tyre depths specific to BMW's do Audi who are the grand daddy of 4 wheel drive cars have the same issues, I know lots of people who have/had quattros and don't recall these issues being discussed
As I can see the handbook makes no specific reference to these tyre requirements so I just wonder how 1-- An owner is expected to be aware f them 2-- How would BMW claim damage caused by the incorrect tyres,with it being in the handbook.
No they do not! The way Quattro works is completely different. The car I just sold was a 2017 Q5 2.0 litre TFSI Quattro and when I discussed tyre depth when it when it went in for service in November 2019, they swapped the wheels round to even up wear.
Historically older designs of AWD systems have been very sensitive to tyre tread depth, to the point some have recommended changing all four tyres at one time, or 'shaving' tyres if only replacing one or two tyres. Whether Audi designs are less sensitive to tread variations than other marques, I'm not sure, (I've read there have been some issues). Same for Subaru. BMW use a clutch pack system that has to compensate for RC variation, front to rear. Fundamentally, unless there is an open differential between axles, there is going to be extra stresses and wear if tyres are of different depths. We either scrub the difference off through extra tyre wear, and/or clutch slip, there is no other way to accommodate the variations. BMW's design is to get a BMW RWD bias, with a fast reaction time. The design of transfer case suits that brief and demand, but means the clutch pack is a possible weak link, (heat and extra wear), if we push the working tolerances with less than ideal tyre dimensions. Peter
This is the old chestnut... why no directions for users? BMW pass it off with, "only use Star marked tyres and see the Service Centre for details", type comments. They typically mention incorrect tyre installations can impair various systems, such as ABS, DSC and xDrive. Peter
Just wanted to add a little known fact. BMW sold more awd cars than any other European marque for years and years, we just didn't realise as we didn't have them in the UK due to marketing reasons for a couple of decades. BMW sold more awd cars than Audi for many many years.
