Tire pressure

[sdio]

Hi all

I am new to pistonheads and caterham ownership and have plenty of questions to ask until i understand how both of them function.

My question is what is the preferred tire pressure for the 048 when 13inches 185 x 60 all round.

Thank you

[downsman]

You won't go far wrong if you start at 18psi cold and adjust to your preference from there.

[sdio]

Thanks i will try,different pressure around the 18psi range
Now at 20/20 there is plenty of understeer with an LSD if the throttle opening is not enough to break rear traction.
How much difference front to rear do you have to reduce the understeer on these conditions?
Can i try as much as 16/20 (cold) for fast street driving
Front camber is about -1.3

Thanks

[shrink1061]

tyre pressures isn't a good way to fix understeer / oversteer generally.

Set all your tyres to 18psi cold and see how you get on.

if you have understeer, then you need to look at things like geometry, roll bars, track width etc.

For more oversteer, you could either adjust your roll bar at rear to be stiffer (or fit a roll bar if you don't have one), or fit a softer front roll bar.

You could also look at adjusting camber and toe for better turn in and cornering grip, or look at doing a wide track modification to the front of the car.

[sdio]

The car is on wide track watts rear link and lsd. No rear anti roll bar.
Should there be this sort of understeer with this set up ?

[Red Seven]

What front ARB? (look at the colour of the rubber bushes - orange = 1/2, blue = 9/16", red = 5/8", green = 18mm, yellow = 3/4")
A little more negative camber may help, as may lifting the rear or lowering the front ride heights.

[sdio]

Thank you 😊 10 years a fanatic supporter of SELOC I didn't know pistonheads was so great...

[sdio]

Red Seven said:

What front ARB? (look at the colour of the rubber bushes - orange = 1/2, blue = 9/16", red = 5/8", green = 18mm, yellow = 3/4")
A little more negative camber may help, as may lifting the rear or lowering the front ride heights.

Bushes are green

[shrink1061]

that's pretty stiff! and against a rear with no roll bar you could get a fair bit of understeer. Also depends on what kind of camber / caster you're running.

I'd suggest even at its softest, a rear roll bar should be beneficial to balancing out the car.

[framerateuk]

sdio said:

Thanks i will try,different pressure around the 18psi range
Now at 20/20 there is plenty of understeer with an LSD if the throttle opening is not enough to break rear traction.
How much difference front to rear do you have to reduce the understeer on these conditions?
Can i try as much as 16/20 (cold) for fast street driving
Front camber is about -1.3

Thanks

I've never felt much difference between tyre pressures on the road, but the difference between 18psi and 22psi on track was huge (ie, the car was a massive uncontrollable, unpredictable mess at 22psi! Understeer into corners and snap oversteer coming out!).

[GreigM]

shrink1061 said:

I'd suggest even at its softest, a rear roll bar should be beneficial to balancing out the car.

A quicker and easier way would be to remove the front ARB completely, especially at this time of year when you want the front to be a bit more compliant.

[sdio]

If i add one on the rear wont be a preferable option and if so which one ?

[sjmmarsh]

Don't forget that driving style can also induce understeer. Entering a corner too fast / getting on the power too early may well give you understeer, particularly the latter as you have an LSD. Are you trail braking into corners, or doing straight line braking/ turn /straighten / power?

Geometry might be the problem, but understanding what you need to do to drive around it can help diagnose where the improvements can be made.

Steve

[sdio]

sjmmarsh said:

Don't forget that driving style can also induce understeer. Entering a corner too fast / getting on the power too early may well give you understeer, particularly the latter as you have an LSD. Are you trail braking into corners, or doing straight line braking/ turn /straighten / power?

Geometry might be the problem, but understanding what you need to do to drive around it can help diagnose where the improvements can be made.

Steve

I am coming from a superbly setup nitronned elise with which i could approach any corner tight or open any way i wanted and still have a very neutral handling or 4 wheel drift and no understear. The caterham needs a different style i know and demands to be provoked. I can adjust no problem but my car has certainly not a neutral handling