When to change tyres?

[kotafey]

Rears have about 4-5mm in the middle, a bit less on the edges. Fronts are OK. I know the legal limit is considerably lower, but when do people start thinking about changing them?

Arse end just came out at around 30mph which surprised me a bit as it's +11 here and only just started to drizzle slightly. Caught it with the help of traction control, but would rather not have to do that again!

Thanks for your input

K

[blackburn]

I've just changed a pair of rr Pilot Sports on the Boxster. They were down to 3.5/4.00mm in the middle, bit less on the edges. Drove the car over a moorland road in November, slightly damp conditions and not particulary warm and had two big, unplanned sideways moments.

I think the problem was mostly the colder weather/greasy conditions, but new tyres have improved things considerably.

[gsewell]

If it was only just starting to drizzle, then the 3-4mm of tread will not have been the problem. However, the roads feel as if the councils are already dosing with salt and becoming greasy. So any degree of over-zealous right foot will result in loss of traction.

Be very careful on brand new tyres until the releasing agent has scrubbed off as that can be a treacherous scenario.

Edited by gsewell on Friday 23 December 16:17

[cslwannabe]

I nearly spun my boxster at similar speed recently (6.5 degrees) and very light but constant throttle - rears are down to 3mm and I have a full set of PS2s ready to be fitted. Took it out yesterday for the first time since my near spin - was 10 degrees plus and very slightly damp roads but didn't push it as hard as usual as still mindful of my near spin. Even a few weeks before that I noticed that when accelerating hard in 2nd gear even when the car was in a straightline it was struggling for grip (I'm talking about on warm days), whereas a few months earlier it wasn't. I'm not planning on using mine much over the winter (but will take it out when I can) so will still wait until spring before fitting my PS2s but if I was using it everyday I'd definitely replace at 3mm or sooner.

[343bhp]

what tread do the michelins pilot sport cups+ have when new ?

[daveyb662]

I have had these sideways movement on new-ish tyres, I think its normal if you give it a little on slightly damp roads

[chris7676]

As mentioned - nothing to do with the tread.
I have 7 mm tyres that are st in the wet and also have ones worn to hardly 2mm that are great in the same conditions in spite (or thanks to) being thinner and on smaller rims.

[cslwannabe]

Not sure if it's true or not but I've heard that when a tyre gets down to say 3mm the rubber construction is harder and doesn't wear as quickly as say when it has more tread present.

[6C4GTS]

343bhp said:

what tread do the michelins pilot sport cups+ have when new ?

5mm

[Xstyle]

Would a C4S or Turbo be better equipped, as a 4WD car than the 2w cousins?

Edited by Xstyle on Friday 23 December 19:36

[Trev450]

cslwannabe said:

Not sure if it's true or not but I've heard that when a tyre gets down to say 3mm the rubber construction is harder and doesn't wear as quickly as say when it has more tread present.

I've known of tyre be dual compound. On bikes for example the rear tyre can have a harder compound in the centre so as to prevent it wearing out quicker than the edges, but have not heard of mixed compounds within the treadblocks.

[kotafey]

Thanks for the feedback. It sounds like my slip probably wasn't entirely due to the tyres. I'll wait until they're a bit closer to 3mm before changing them.