Rear wheel drive tyre wear - Marc
Need to get a new pair of rear tyres for my Mercedes 190E. Thing is the shoulders have got tread left but the centres are worn (Pirelli P2000). I check the pressures weekly and they are always OK. The tyres were on the vehicle when I bought it and I have covered 25k on them.

Is this kind of wear pattern normal on a rear wheel drive car?

Re: Rear wheel drive tyre wear - honest john
Rear suspension bushes wear om 190Es.

Re: Rear wheel drive tyre wear - Marc
Would this cause the rear do sit lower than it should? I've often thought mine looks slightly lower than others I've seen. It's not modified however. The car has had two major 12k services in the last year (the first by an MB franchise) - neither of them commented on this.
Re: Rear wheel drive tyre wear - honest john
In that case the coil springs have lost their tension.

Re: Rear wheel drive tyre wear - David Woollard

As HJ says these cars have a multitude of bushes at the rear that can go soft.

But if you are describing a tyre that is worn in the middle to an even shape, ie mirrored on both sides, then I doubt you have a problem with the suspension.

You are describing the classic pattern of over inflation. Now I don't mean that you are over inflating it but think about these points.

If the tyres were on when you bought the car the previous owner could have run them too hard and started a wear pattern that is showing up now they are older. I think this happens and will continue to do so unless a tyre bod tells me that latter running at correct pressures will even this out.

As an aside I had great sport with a "Kwite Fast" tyre fitter a few years ago when taking in a Cavalier for new rear tyres where the old ones showed serious outer shoulder wear. He was advising all sorts of repairs to the rear suspension (set of shocks at least mate!) until I mentioned I had swapped the tyres front to rear that morning. Suppose he was just doing his job but he never thought to ask how long the tyres had been on the back!

The second point is that the advised pressure for your car (31psi??) may be a compromise and, if you run will a light load, effectively the tyres are over inflated most of the time.

Lastly are you sure your gauge is accurate, I think we did this to death about three months ago but it is a factor!

Anyway they seem to be lasting quite well but you could try reducing the pressure a couple of pounds.

Re: Rear wheel drive tyre wear - Marc
David. MB recommends 32psi for the back (but that is for three people and a "suitcase" - little diagram in the petrol flap) Probably is too high considering most of my relatively high mileage is just me commuting to work. Can't say I noticed this wear when I bought the car - just that the tyres had enough tread all over. I got the front two replaced straight away.

I've got one of those brass needle gauges (International Tool Co) purchased via the Telegraph, so I hope it's right!

Buying a new pair of rear tyres at the weekend but this has proved a nightmare in itself. It seems no one stocks Pirelli P2000s in my area - special order item
Re: Rear wheel drive tyre wear - Michael
could faulty shock absorbers cause the same symptoms? I had a mini, many years ago, that sat an inch lower at the front than it should have. New front shocks cured it.
Saggy Mini - Chris
Saggy Mini suspension is different. Closer to a Citroen BX with the engine turned off.

Re: Saggy Mini - Michael
Chris, some mini's had conventional suspension, with springs and shock absorbers, some had fluid suspension as you describe. Mine was the former.
Re: Saggy Mini - Alvin Booth
I don't think any Mini's had springs. There was the hydrolastic ones as you mention and the others had a big rubber cone as the suspension.
Invented by Alex Moulton who designed the Moulton bike.

Re: Saggy Mini - Michael
ok, not a spring in the form of a coil or leaf spring, i guess the cone did the same job, but they did have shock absorbers.
Re: Rear wheel drive tyre wear - John Slaughter

This may not actually be a fault. Many cars with IRS wear the rear tyres in this way. The classic is Mk3 Escort XR3's. The problem seems to be that the relatively short arms make the tyres move through a significant camber change, and the wear for some reason is concentrated in the tyre centres. Although it's often said this is a symptom of overinflation, I really have my doubts that anything but gross overinflation for a very long time would actauly cause this.


Re: Rear wheel drive tyre wear - David Woollard

Just one last post before I nip off again.

Hadn't thought about this aspect because I think the 190E rear suspension has good control of the rear wheel. Unlike the simple Ford swinging arm it has a top link arrangement to give extra control of tyre angle. But I've never followed one looking out for the rear tyres so could be wrong.

Reminds me of the odd tyre wear on my first Triumph Herald. The lettering on the sidewall wore out before the tread! Snap oversteer, these youngsters are so lucky with the "self-correction" of most FWD machines these days.

Re: Rear wheel drive tyre wear - John Slaughter

Reminds me of several trips to work in a colleagues elderly Humber Sceptre. Incredible angles of lean. We commented that replacement tyres should be chosen on the length of the manufacturers name rather than tread pattern, as this would improve grip on corners!



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