Tyre pressures

[wasted years]

What should they be for a '93 400?

Thanks guys.

[aerospoke]

Hi there

Depending on what size io tyre and what brand something between 20 and 28 psi. Normally 24 front 26 rear.

Cheers Jens

[wasted years]

Thanks Jens

[miketvr]

I have a '94 Chimaera and I have monitored the eveness of tread wear versus tyre pressure over the last 5 years. The front need to be higher presuure than the back because they are under greater weight from the engine. I would recommend 23 rear and 28 front.

Mike

[wasted years]

Thanks Mike

[targarama]

22 front 24 rear for 6 years of Chimaera ownership for me. 3 sets of tyres. Always wore evenly across the tread.

[tvrbob]

miketvr said:

I would recommend 23 rear and 28 front.

Mike

This goes completely against convention and you are the only owner I have ever read suggesting such high pressure in the fronts. I'm not suggesting that you are wrong; I'm just shocked by it.


Gary, The pressures you need to set your tyres at depend greatly on the tyres you are using. Tyre pressure is used to do several things. Pressure holds the tyre on the rim and prevents the tyre from rotating around the rim. Pressure balloons the tyre so that in normal operation and in flat road use the maximum cross tread contact can be maintained. Pressure controls the contact patch length and the consistency of the length across the tyre.

The pressure also contributes to the cars overall suspension. There are many elements to the suspension and the duty of all these elements combine to give you the handling characteristics you feel when driving.

The main suspension contributions from tyre pressure are to provide a soft initial bump that effectively allows the tyre contact patch to remain in contact with the road over small irregularities in the road. This prevents bump steer and tramlining and alters the level of progressiveness in oversteer.

The tyre pressure works in tandem with the tyre wall rigidity. This has resulted in many owners having to deal with the change from the factory fit Bridgstone SO2pp's to other makes of tyre. The often favoured Toyo T1-R and S have less rigid walls than the old Bridgestone's and so owners have found that they need to increase the pressures a few psi to compensate.

Different pressures can be used for different road conditions. As roads get smoother the amount of flexibility required to maintain the contact patch reduces so tyre pressures can be increased. This will stiffen the ride, reduce heat generation and rolling resistance.

What tyres are you using Gary?

[targarama]

tvrbob's right - the S03s are tough buggers and need a few PSI less (found this out on other cars, didn't fit them to the TVR luckily).

[wasted years]

I'm on Bridgstone

[tvrbob]

wasted years said:

I'm on Bridgstone

Not quite enough info. SO2pp sidwalls are less rigid than standard SO2's. SO3pp's are harder than both.

[wasted years]

I'll pop out later and have a look.

[wasted years]

Standard SO2s

[tvrbob]

wasted years said:

Standard SO2s

So just to confirm, they are not SO2 Pole Position. If they aren't 'Pole Position' I would suggest changing them. I once made the mistake of buying standard SO2's and had to replace them after only a couple of thousand miles because they had bu99er all adhesion on green or wet roads.

That said, and to answer the initial question. 22 front 24 rear for general use, 24/26 for motorways. It would be a mistake to have more than 22 in the fronts if you're driving country roads. These are cold settings; tyres increase in pressure as they heat up, a result of moisture volatilising and the natural heat expansion of air. This pressure increase is taken into account when 'cold' pressures are stated.

[wasted years]

Thanks Bob.

[Gavstar]

Excuse the hijack, but can anyone tell me what the pressures should be for Dunlop SP9000s on the front and SO3PPs on the back?
Cheers!

[FlipFlopGriff]

Gavstar said:

Excuse the hijack, but can anyone tell me what the pressures should be for Dunlop SP9000s on the front and SO3PPs on the back?
Cheers!

24 on both Griffs for the front for SP9000 (assume 15&quot, general consensus on Bridgestone is as per TVR - ie 24.
FFG

[_Neal_]

In case anyone's interested, I used 24 front, 26 rear on Toyo Proxes T1-R (99 Chim 400) - worked well

[FunkyGibbon]

24 front, 26 rear - SP9000s all round

[spend]

If you dawdle around and rarely get your tyres warm, there is an argument to run a few psi higher. I tend to blast around when its quiet, its quite reassuring to feel the car slightly squirmy when the tyres are cold - you know when they are warmed up then. Much of all this is down to personal preferences, like a service schedule- rec tyre pressures are just a general guide which you may deviate from.

Dave

[JR]

FlipFlopGriff said:

Gavstar said:

Excuse the hijack, but can anyone tell me what the pressures should be for Dunlop SP9000s on the front and SO3PPs on the back?
Cheers!

24 on both Griffs for the front for SP9000 (assume 15&quot, general consensus on Bridgestone is as per TVR - ie 24.
FFG

Best to read bob's prose. Standard TVR is for S01/S02PP, both of which are a fair bit softer than S03PPs so try 22 for S03PPs to try an adjustment and compensate, e.g.

_Neal_ said:

In case anyone's interested, I used 24 front, 26 rear on Toyo Proxes T1-R (99 Chim 400) - worked well

the Toyos are softer than the S01/S02PP so he's added 2 psi to try to adjust.