14 replies to this topic

[cal844]

Hiya folks

I have a question about 10 inch tyres, I've had to replace the front tyres on my Clubman Estate as they were generally worn but more so in the centre (run too hard) I usually set them to 30psi all round, the rear tyres sit nice and uniform with regards to sidewall deflection the fronts are squatted somewhat(like a slightly under inflated tyre would)
I need to go to 35 psi to make the sidewall sit naturally.

I know the tyre will squash slightly with the weight of the engine.


I have the Falken Sincera SN807 fitted.

I dont have any heavy loads in the car.

Any advice on what pressure to use so I dont ruin the centre of the tyres.

Thanks Cal

[imack]

Saloons with 145/10's used to be 28 front, 26 rear - don't remember estates being anything different.

[GraemeC]

I’d take the wear as a far better indicator than the appearance of the sidewall and be trying them at 28psi

[cal844]

Thanks guys, I will experiment, I currently have them at 32 front 30 rear but will try them at 28, I just dislike the look of the contact patch sidewalls.

[MiniMadRacer]

On my Pickup I run 28 all round seems to be a reasonable compromise.. by in large a wear pattern in the middle of the tyre points to over inflation of the tyre..

[cal844]

On my Pickup I run 28 all round seems to be a reasonable compromise.. by in large a wear pattern in the middle of the tyre points to over inflation of the tyre..

I will try 28 all round, I usually run 30 all round but the front tyres wore out even though the sidewalls are slightly squashed, I've only done about 3500 miles to a pair of tyres set at 30 psi, the rears still look brand new!

[cal844]

Reduced the front tyres from 30 to 28. Car drives great but when I go over a speed cushion I get the front end bouncing vertically. I will just put up with it as it is driving ok ? now just to fix the fuelling again

[Mini Manannán]

I used to run at 30psi all round, now I prefer the slightly more plush 28.

[cal844]

I used to run at 30psi all round, now I prefer the slightly more plush 28.

I do prefer 28 on the front for road holding and handling but 30 psi has less bounce when I come to a speed cushion. I'll try 29 as a compromise and report back, I'm also making fuelling changes too so keeping busy

[Cooperman]

The pressures will vary by a few psi depending on the tyre temperature.

You really are unlikely to notice the difference between 28 psi and 30 psi.

I always just put 30 psi all-round on both 145 & 165 section tyres and 10" and 12" wheels.

[cal844]

The pressures will vary by a few psi depending on the tyre temperature.
You really are unlikely to notice the difference between 28 psi and 30 psi.
I always just put 30 psi all-round on both 145 & 165 section tyres and 10" and 12" wheels.

Thanks Peter, I'll revert back to 30 psi and try that, if it wears the centre I'll drop to 28

[sonscar]

You could get technical and measure the tread temp across the tyre.It used to work with a single seated race car I used to crew for.Steve..

[Cooperman]

You could have put 30 psi into ypour tyres at 15-00 hours today and I would bet that by midnight tonight the reading would be about 27 psi due to drop in temp.

[cal844]

You could have put 30 psi into ypour tyres at 15-00 hours today and I would bet that by midnight tonight the reading would be about 27 psi due to drop in temp.

I always make any changes to pressures before 12 mid day, theoretically the coolest time of day.

When I'd had the new tyres fitted last week the fitter set them to 30psi on his guage, when I got them home (probably about 20 minutes later) I'd checked them on my guage that I'd bought in January, it was at 28psi, I will set the tyres to 30psi all round in the morning and go from there.

Thanks again for the advice

Cal

[malc_west]

Depends what you want from your tires mate it's basically always a compromise between contact patch size and mechical grip. All tires have a temperature that means the compound its self gives off the maximum grip and running high pressures mean the tires heat up faster and hotter. In the karting world maximum contact patch happens at around 16psi (depending on brand) wheres in racing to get the tires to best heat you run 20psi or even as high as 50 in the rain on a smooth track. It is easier to figure out though doing repeat laps with a timer on the steering wheel. All in all with road tires decide what you want whether its fuel consumption (easily tested), feel which is entirely up too you or performance which has too be tested with a stopwatch