Tyre Pressure?

mmm

Like I said, higher pressures are desirable, even necessary, on the low profile tyres mentioned by many people here, but I have pretty serious reservations about them on standard wheels and tyres on a 504, especially as the Michelin XZX tyres on the particular car in question are pretty old too.

I've used 504's with up to 34 psi all round on long fast trips with heavy loads, but even this is pretty close to the useable limit in them I reckon. For the sort of driving that James is suggesting (suburban / round town.etc) I think 30 psi remains the best bet. Apart from potential tyre wear issues the extra hardness will putting more stress on just about everything else, from suspension components to exhaust and engine mounts, none of which will be exactly "new" anyway given the age of the car.

Cheers

Rod
 
Well all the rubbers are new. Crossmembers were not fun to do. Are there any other rubbers at the back apart from the ones at the top of the shocks?

If driving at 30psi means I don't have to all that again. 30 Psi it is:). Maybe even 32 at the front, 30 is a little sloppy for me

Its mainly the rear that is the issue. It just jumps up on any bump. That was the initial reason for the lower pressures.

Does the lower pressure lessen the tire life span? I guess if it saves the suspension then its a good thing.

thanks

James
 
Shobbz:


Does the lower pressure lessen the tire life span? I guess if it saves the suspension then its a good thing.

thanks

James
Click to expand...
Low tyre pressures can reduce tyre life, James, but 30 psi isn't "low" in the present context. I suspect they will last longer (in terms of tread wear) at 30 psi than they would at 36. You risk wearing out the centre tread line with these sorts of tyres at that sort of pressure in a reasonably light vehicle.

Cheers

Rod
 
Alan S:
As a rule of thumb, scrubbing the outer edges is usually a sign of too low a pressure and scrubbing out the centre of the tread indicates too high.
Alan S
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I understand that too-low pressure causes the tyre to sit curved with the centre not touching the road (exegerating a bit), thus wearing out the outer edges only. While too-high pressure causes the tire to expand and thus sits with only centre touching the road, so wears out the centre only.

But does frequent fast/hard cornering causes the tyre to wear out the outer edges faster as well? (assuming the tyre is always at right pressure)
 
Has to have some effect but with mine recently it turned out to be a worn tie rod end allowing a wheel to toe in excessively on corners so it pays to check the front end including the alignment before jumping to that as a conclusion.

Alan S
 
Remember reading somewhere that faulty wheel alignment was responsible for something like 60 per ecent of all front tyres being replaced before they were had reached the end of their overall tread life!

Cheers

Rod
 
What I mentioned about fast corner wearing out edges was on fairly new cars (under 5 years old), and regulary wheel-aligned. So assuming the alignment was correct, then can assume fast cornering does wear out edges faster?

Come to think of it, the last 4 wheel alignment I had done (on mine and friend's car) by 3 different tyre fitters were all somewhat bad workmanship.

I bought a second hand car and car was vibratig t 80km/h+ speeds, so I had wheels balanced and aligned. First 2 was done and car had not much improvement, so I had accept that as the way it is due to old components. Then after the 3rd one the vibration disappears, only minor vibes above 140km/h, which means the first 2 weren't done properly. BUT the steering wheel were off center say 5-10 degrees. The 4th one was on my firend's car after new tyres, the steering wheel were off by about 30 degrees, went back to get it re-done, and still off by 10-15 degrees.
Really makes you wonder on how the rest of adjustments go...
 
rc968:
What I mentioned about fast corner wearing out edges was on fairly new cars (under 5 years old), and regulary wheel-aligned. So assuming the alignment was correct, then can assume fast cornering does wear out edges faster?

Come to think of it, the last 4 wheel alignment I had done (on mine and friend's car) by 3 different tyre fitters were all somewhat bad workmanship..
Click to expand...
I've found that at the very least its necessary to go along with the correct specs in your hand, and demand to see the printout etc at the end of the process, rc. Some (many?) aligners simply work off a set of "generic" figures of the" If its FWD it must xx toe in" variety.

Even then, of course you have the possibility of shoddy set-up etc, not to mention the problems that your own vehicle might impose because of tyres that are already worn etc.

Its no wonder, really, that we run into so many problems with wheel alignment. When you find someone who does it well and knows what you want hang on to them!

Cheers

Rod

<small>[ 09 September 2003, 01:45 PM: Message edited by: Rod Hagen ]</small>
 
I did a bit of general driving around today at 30psi all round. Steering is a bit heavier. I will stick with 30 for the moment , maybe go a little higher later on:).

James
 
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