percymon

OK first post so be gentle

My father has a 2004 530d with the 5 spoke 17" wheel upgrade - he runs 225/50/17 Bridgestone runflats - the original factory tyres - they have covered about 18000 miles now.

He regularly checks tyre pressures but a recent check of the tyres showed the front pair to be wearing slightly more in the centre (marginal), but the rears to be wearing a lot more in the middle. The fronts are about 5mm on the outside and 4-4.5mm in the centre. The rears are around 2.5mm in the middle and 5mm at the edges. There is no other wear - no feathering of tread blocks - perfectly even wear around the circumference, just extra wear on the centre line. The car normally carries either driver, or driver and front passenger, with no load in the boot (trunk)

Now my first tought is over inflation - BUT he runs the pressures lower than those quoted on the sticker on the drivers door pillar to improve the ride quality (he thinks its crashy at the stock pressures)

My second thought was an inaccurate gauge - he has two gauges which measure within 1 psi of each other, and my more expensive gauge reads the same as his. I don't have any issues with tyre wear on my cars which suggests the gauges are all accurate.

He has now dropped the tyre pressures further (not sure what to but well below the factory settings) on the belief they are still overinflated, but i'm concenred they may be underinflated and underperform in wet weather or emergency manoeuvres.


So...

1. Has the recommended pressures changed during the E60 model life - have they been revised ?
2. Is this just a symptom on run flats ?
3. Anything else ??

Many thanks.

BMDiesel

I believe I have the same wheels and I use the numbers on the sticker +.1 bar (he's not confusing unit scales here?!)

My tyres are deflating .1 per 1000 km or so.

Have not noticed any excessive center or outer wear although my front tires are somewhat 'chipped' (blocks on the sides worn like a saw tooth because of high speeds + sideways pressure = very fast cornering)

I'll ask the dealer to check wear on the front tires as these are about to be changed.

percymon

Not confusing the scales at all i'm afraid - i think he's now running both fronts and rears at around 2.2Bar.

colejl

I was going to blame the RF's but the normal wear is on the inside edge due to the camber and stiff sidewalls. It does sound like over-inflation - what pressures are you running?

my2007

What are the recommended pressures on the sticker? I have the exact size RFT but Dunlops and the recommended pressure for medium load (up to 4) is 2.0 bar for the front and 2.4bar for the rear. I usually keep to these as the car feels bumpy at higher pressures. I have only got about 5000km on the car and so far there isn't any uneven wear.

Ricracing

Go for what the drivers door says as max.

I drive with 18" RF's and the 2,5 F and 3,0 R bars works great.

The RF's are so hard tires anyway, so no more comfort with lower PSi's,
only more tramlinging.


(This I will review this with new tech 17" RF on a new LCI car, but that's next year.)

my2007

Hi! Ricracing, do you have uneven wear on your tyres witb those max tyre pressures? I tried a higher pressure but far from the max and found that the ride was bumpy.

Ricracing

No uneven wear. I must change from summer to winter tires twice a year, always checked.

Always remember to have the better tires rear! Look out also for rolling directions!

My summer tires (and wheels) was from my old '04 E60 and they are now only with 3 - 4 mm of thread left.

Changed to my non RF winters this week and I run them with 2,2 F and 2.7 R (BARS).

Feels like driving over clouds compared with the summer's!


My new car (see sign) is not still under manufacturing, but before Christmas it will be born...
New tires and wheels also.

percymon

Thanks for those settings - he's running 2.1 front and back now, ride seems better, maybe needs a bit more in the rears from your posting.

The door sticker quotes 2.4 front and 2.8 rear no wonder the rears are in the state they are

The heavier diesel engine might need a touch more pressure up front, but no reason why the rears should be so different to the ones on your sticker

Ricracing

Note the differences between BARs and PSIs.

Whatever pressures you have (or unsure) better more than less,
and always about 0.5 more rear

PS. The better tires should also be on the rear axle.