My car has now done 34k miles. The fronts are about 1k off the marker and the rears aren't far behind (surprisingly even wear between front and back)

Recently the car has next to no grip or handling at all!!

Why as the tyres wear down does the grip get worse. Surely the surface area in contact with the road is the same. I understand the less tyre, the less ability to channel water away, but what about on dry roads???

JD

German tyre by chance?

Michelin Pilots which came standard when new.

Seem to cover the miles, but the grip really suffers.

JD

Strange one, if bald then = slicks, should give excellent handling in dry, not best in wet tho :lol: Could it be if they are a softer compound the deeper the tread the more sideways/ squashing/lateral movement available in the raised part of the tread so giving an effective larger surface area?? as tyre wears down less 'bend' available in tread?????

I've just changed my Dunlop Sport 01's, they were down to the tread wear indicators. Maybe it's due to the winter weather, but I had no grip during the last 1k miles or so.

I have now got Conti's Sport Contact 2's, due to a very good price, grip now restored.

As a side issue, they have fitted 'W' speed rated tyres. I know these are built to withstand higher speed etc. But here's the thing..... At a higher speed, the tyre would build up to a higher temperature, does this mean that the compound of the tyre is actuall harder than a 'H' or 'V' rated tyre? Does this mean less grip and a longer life?

Side issue No.2, They have also inflated the tyre with 'nitrogen' the leaflet in the tyre place gives all sorts of reasons to do this. Anyone one had any experience of a nitrogen inflated tyre? other than the snazzy green valve covers.

By the way I paid

yaktrebor

I have actually been thinking about getting Dunlop SP Sports as a replacement. I have been given a really good price of

The Dunlop's were excellent, I paid about

Any opinion on the nitrogen inflation?

I got nitrogen in my Toyos when they were fitted. Pressure has hardly changed in 9 months, so it seems to work.

Hi

Dry grip may suffer with reduced tread depth because the tyre runs cooler. The tread moves about under load producing a warming effect on the rubber and increasing grip. Less tread depth = less movement.

Another possibility is the tyres are zone moulded. If I understand it correctly, a softer compound exists at the top of the tread than the base enabling a soft compound, good tread block stability and a high void area. As the tyre wears, you will be getting onto the harder rubber. My Conti Sport Contact II were just starting to loose a bit of wet grip at the front after 10,000 miles, even though they have plenty of tread on them. Stuck them on the rear and the difference is quite maked. It is not standing water dispalcement that is the issue and even on damp roads, the fronts were obviously not as sure footed as at 5,000 miles.

Chris

PS at 34,000 miles the carcass and sidewalls are going to be tired.

Dry grip may suffer with reduced tread depth because the tyre runs cooler

I disagree. On a dry surface a worn tyre will grip more because there is more rubber in contact with the road. Thats why racing cars run on 'slicks'.

I disagree. On a dry surface a worn tyre will grip more because there is more rubber in contact with the road. Thats why racing cars run on 'slicks'.

Er wot?

Racing cars run on slicks to reduce heat build up in the tread. The area of rubber on the road makes little difference to outright grip. The force per unit area rises as the tyre gets less rubber on the road. The limit of grip over time is defined by the tyres capacity to work at maximum temperature for the loads going into it. Slicks suffer less heating, so can be made to survive the stresses for longer for any given compound hardness. You then have a balance against wear rate (the slick will have more rubber to remove for any given width) so you can run longer on softer compound with a slick.

Running a slick enables you to run a softer compound than with tread. This then allows for greater adhesion. If you put tread on the tyre, the blocks shift about under load, increasing heating of the tread and leading to an overheat if under extreme loads.

Conversely, a slick not being worked hard enough will have less grip than a road tyre. So a small engined car fitted with wide slicks may not be able to get them up to temperature and would be quicker on road rubber. Have you driven on cold slicks? It can be a good idea to run lightly cut tyres instead of slicks in winter in the dry to get the heat in.

A worn tyre (of the road variety) will genrally run cooler as the tread blocks dont move about as much. This makes for colder contacting rubber that is in turn harder and thus has less grip. Add in the effect of zoned moulding of the tread and you have a reasonable possible answer to the fall off of grip in some tyres. Also consider the carcass is being worn as well with the miles, so the contact patch may not be as well maintained on the worn tyre. Sidewalls go baggy as well.

Chris

My Pirrelli P6000's seem to be going off now, they are just about 2 3rd's worn.

Sorry .....ZZZzzzzzzzzzzzzzzzzzz.