High tyre pressures

[BruceT]

Hi all, I was just reading the handbook for the new ZS, yep the one I won't be getting for about 4 months! Yes, I have NO life. Anyway, I've just noticed the tyre pressures are 41psi F/R, which seems high, for cold TPs. Do you think it's right? any thoughts?

 

[Lovemyev]

The Gen1 ZS EV TPMS pressures read around the 2.4 bar mark from memory, which sounds like about 35 PSI to me and the tyres are a 50 profile of the side wall.
The new Gen2 ZS EV is fitted with a slightly taller 55 side wall profile.
Taller profile tends to mean a more forgiving ride.
Extremely low profile tyres on the other hand have very little “Give” in the side wall when travelling over a rough / choppy road surface.
Great on grip and handling in the dry, but a harsh ride.
Nightmare in the snow !.
Sorry, back to the face lift tyres pressures, if it recommended to have them set at 41 PSI then that is around the 2.8 bar at a rough guess ????.
So, a 6 PSI ( ish ) increase over the original tyre pressures on the Gen1 model then?.
The facelift with the long range pack is also packing a bit more weight than the Gen1 version of the ZS EV.
These points may go someway to explain why the increase in tyre wall profile, plus the increase in the tyre pressures across both Gen1 and a Gen2 models ?????.
Increasing the tyre pressures will slightly help the efficiency returns of the car.
Manufactures who MPG test their ICE cars ( in a controlled environment ) will try every trick in the book to inflate the return figures.
That includes over inflating the tyres, which is only one trick ?.

 

[BruceT]

Sorry, back to the face lift tyres pressures, if it recommended to have them set at 41 PSI then that is around the 2.8 bar at a rough guess ????.
So, a 6 PSI ( ish ) increase over the original tyre pressures on the Gen1 model then?.

Yes 35psi old zs to 41 psi in the new one. but that's an extra 17% ish on top of what was already quite a high TP. a few years ago you were looking at 28-30 psi. I'm pretty sure there are lots of cars still about that. Do you think it's purely an economy/range attempt?

 

[BruceT]

Yes 35psi old zs to 41 psi in the new one. but that's an extra 17% ish on top of what was already quite a high TP. a few years ago you were looking at 28-30 psi. I'm pretty sure there are lots of cars still about that. Do you think it's purely an economy/range attempt?

It might be because of the weight, 'cos she's quite a hefty car

 

[Alb]

I wouldn't get hung up on it.
If it's meant to be 41psi then go with 41psi.

 

[Gomev]

Yes 35psi old zs to 41 psi in the new one. but that's an extra 17% ish on top of what was already quite a high TP. a few years ago you were looking at 28-30 psi. I'm pretty sure there are lots of cars still about that. Do you think it's purely an economy/range attempt?

My 2006 Avensis has recommended tyre pressures of 37psi all round. (No idea what that is in bar malarky)

 

[Lovemyev]

My 2006 Avensis has recommended tyre pressures of 37psi all round. (No idea what that is in bar malarky)

Love it !.
The 37 PSI converts roughly into a tyre pressure of 2.5 bar on the "Bar Malarky" scale .
I am a pre-decimalisation kid that went through school and switching over mid term.
Our heads where a "Mush" between both systems.
It's very strange though, even today I find myself switching backwards and forwards.
When measuring for wood, I measure in M.M. and then say to my son ( who is 36 ) - "We need three 6 foot lengths of 2"x 2" and four 8 foot lengths of 3"x 2".
His reply :- "What the hell is 3" x 2" Dad ?".