This does not sound right with regarding road tyre wear. Mike at Sport & Classic set my car up with a trackday set-up and i,ve done 1900 road miles and 50 Laps of the ring, just changed my rear mpsc`s two weeks ago. They definately did wear their inner edges more during road use but no where near that level!!

I know in my case it doesn't sound right. But until I have eradicated user error (ie wrong pressures etc- I did not know at that stage that I should be running higher rear pressures and if anything the rears were too soft, again my fault. This is also the case for the new rears fitted in my absence at a tyre place that was new to me as I had to abandon the car in Derbyshire to have them sorted before repatriating to london a week later) No panic then, but if it continues this way I will refer back to jzm for checking, or a less aggressive setup.

In the OPs case he does not really know what he has and so the logical step would be to check that somewhere sensible. Umpteen threads on preferred places for that on here.

No one should take a blowout caused by tyres wearing out unbeknownst to the driver lightly!
I cannot post a pic of my rears as am abroad, but as I said to my wife who was a tad concerned that the car which had not returned to the pits was mine"could have been worse".

How does that work? Are the tyres not marked inside/outside?

Doesn't come across as rude at all . . . . . more slightly patronising.

That's a given (for me anyhow) but would entirely depend on how confident you are in your local tyre shops abilities.

We're talking about excessive rear tyre wear, if you were to saunter into your local tyre fitter and say "My rear tyres are wearing excessively, how do you suggest we address this issue ?" I suspect it's unlikely they'd say "No problem sir, we'll just check the front toe for you . . . . ."

Furthermore, unless your tyre supplier/fitter is using very basic equipment, ie Dunlop tracking gauges (nothing wrong with them BTW) the rear toe will automatically be checked as part of the process once the four alignment heads have been attached to the wheels.

Yes you can. Just swap the wheels over. The tyres aren't directional and will adapt within a few miles.

The factory settings that you quote are not a setting but a band of settings within which you can adjust for your given style and preference, actually they are quite wide! You can remove or add toe and camber to an appreciable extent and still stay in the factory setting. Your rear geo looks like it would suit your use better if you removed some rear camber - still negative and in the band just at the other end.

Hi, This will help as the majority of circuits I have been on run in a clockwise rotation and the n/s/r tyre gets more loading than o/s/r so will wear slightly quicker.

The problems with geometry set up are several fold. Firstly it depends on the driver and secondly it depends on what you intend to do with the car.

I used to race with a man who had a very powerful car far in advance of his driving ability. The car had been set up by the people who built it assuming a person who's ability matched the car would drive it. This entailed a fairly hefty dose of negative camber. This ensured that when the car was pushed hard into a corner the tyre didn't roll over on it's self and it presented a full footprint to the road. Unfortunately our man was so slow only the inside inch and a half ever made contact with the Tarmac he used to throw away tyres which were down to the innards over and inch, brand new over the remaining 12 inches

S if you set a car up for aggressive track use it will be wrong for the road, and indeed it may even be wrong for your particular track day driving style. There are no set numbers and the numbers you use (geometry, roll bars, tyre pressures and so on) will vary as your driving develops.

The easiest way to check your tyre geometry is with a tyre pyrometer. It is a little temperature probe which pushes a little way into the rubber. What you are looking for is an even temperature across the tyre. The inside to outside temperatures are generally controlled by camber angle and the middle temperature by tyre pressure (the higher the pressure the more the centre of the tyre pushes into the road).

The problem you face is that on the road your cornering forces won't be anything like those experienced on the track and there woun't be anything like the number of corners. By the nature of transport roads try to be straight !

So before you rush out and have supersonic geometry set ups dialed into your cars just check how you are driving and where you are driving. The best investment you could make is a pyrometer which you can use to provide valuable data to the people who set your car up for you. You will also be able to ensure your tyre pressures are correct and remember they will change considerably from start to middle to end of a track day. Race teams know how driver's cars react because the driver does exactly the same thing all the time allowing them to predict starting temperatures which must be used for the entire race (you can't just pop in for a quick pressure check and and cup of tea) but on a track day you can. Have a friend standing by with a pressure gauge so you can remain in the car and any readings are accurate before tyres start to cool down.

On a final point the new tyres you have fitted may well smell a bit more when hot. Rear tyres on a Porsche 911 do a lot of work and generate fair amounts of heat coupled to the engine and exhaust which are all close by.

Henry

Has sir, sorry, has sir's friend, ever considered driver coaching?




Sorry, couldn't resist.
Lot's of good advice in your post though.

This is what an OPC will do. But what about wear and tear? The workshop manual won't take that into account. Forget "factory settings", get someone who knows race geo (doesn't have to be Chris) to do it properly on your car based on the current state of your springs, shocks, bushes etc. to how you want the car to behave on track (not wear the tyres like that, for a start).