tyre pressures

[powerhouse]

Recently replaced my 2.0 tyres on the rear, car came on the OEM Pirelli which were diabolical, upgraded to four new Continental Sport Contact 6 tyres, went up to 305/30/20 on the rear , the fronts were half worn so took them off to and put on 265/35/20, the grip of these tyres are unreal in any condition, great reviews and seem to be the next choice to the Michelin.
I always run the tyres at 34 psi. Since I got the car tyres on Ive added 15mm spacers all round and lowered on Eibach springs, rear boot lip spoiler fitted and rear diffuser splitters.

[scm]

Recently replaced my 2.0 tyres on the rear, car came on the OEM Pirelli which were diabolical ...

Now you did confess in another post that the rears were worn down to the markers, so you can't expect them to perform all that well, can you?

[simpleR]

Ah tyres..... (One of those topics).
There are two things that bug me.

1) If I'm running a 400ps car, in the cold and wet on a set of anything down to the legal limit and I change to any new tyre of course it's going to be better and be amazing. Last spring I went from a set of old Pirelli on the rear to a new Pirelli and of course it was amazing and better in every way. (Yes I might change brands later, I stayed stock as the fronts were fine. Next year all 4 might need doing).

2) Tyre reviews. Firstly they are always a brand new set and we judge which is best. Unfortunately a new set is just that. What are they like as tread drops to 3mm. Do they all start to feel the same? And secondly they are always either on a track and testing the extremes IE max apex speed, 100mph to 0. I don't doubt they are valid tests but I will run out of skill long before the tyre decides it wants to give up.

Anyway. Back on topix. My 20's are 37 all round at around 7c when cold.
This morning it was -2 and they were at 35 all round when starting.
Friday when it was 9c and after 100 mile motorway run they were 39 all round.

[scm]

My 20's are 37 all round at around 7c when cold.
This morning it was -2 and they were at 35 all round when starting.
Friday when it was 9c and after 100 mile motorway run they were 39 all round.

Yeah, it's tricky these days deciding what the right pressures are!

[simpleR]

LOL. Yes it's a challenge!
The Pirelli are definitely better when over 37psi when it's cold. Anything lower than 35 and they tram line and move around a lot.

[powerhouse]

Recently replaced my 2.0 tyres on the rear, car came on the OEM Pirelli which were diabolical ...

Now you did confess in another post that the rears were worn down to the markers, so you can't expect them to perform all that well, can you?

True, but even when new they were bad, in cold wet conditions grip was bad, would never use Pirellis again

[PhilB]

Yeah, it's tricky these days deciding what the right pressures are!

Some recent My20 JLR models have an updated TPMS system where the car adjusts the recommended pressures you see in brackets to take account of temperatures (external and tyre).
Makes things a bit easier and hopefully on the next F-Type.

[Dan_Veluwe]

I must say that when the tyres were new, it put the tail out on rather unexpected moments. Since the summer trip [ > 10.00km used],
they behaved realy well. Since I raised the pressure they are near perfect.. Maybe I should stay with the Pzero as the rim protection
rubber ring all around protected my rims about 3 times. A valuable details ; rims outweigh the costs of tyres...

[steviegtr]

36 to 38 psi is usually the sweet spot for the F-type. Any lower & they can feel a bit slewey & any higher a bit bouncy & uncomfortable. Remember when you push the car the tyres heat up & the pressure rises quite a bit. It's down to the volume of air in the tyre. A small thin profile tyre with say 30psi would drive completely different to the same car with carlos fandango wheels. I guess when Jaguar developed the car they worked out the ideal tyre pressures. We know better & change them because we know better. ?????????. NOT.

[Tony]

The computer comes on when the tyre pressure is below recommend, how would you solve this?