too much pressure

[waynester]

Tyres that is.

I've had new 235/40 Toyo Proxes fitted on my 17" rims, also new shocks and new steering bushes etc...and the steering still felt awful!!
It was kicking really bad, pulling up unevenly..horrible. It then occurred to me to check the pressures.
What a revelation....They were: FL had 39psi, FR had 32psi, rears had 33psi. All now at 32psi, and the car feels much better when..

I love simple solutions, and just wanted to share

[redcar]

waynester said:

Tyres that is. I've had new 235/40 Toyo Proxes fitted on my 17" rims, also new shocks and new steering bushes etc...and the steering still felt awful!! It was kicking really bad, pulling up unevenly..horrible. It then occurred to me to check the pressures. What a revelation....They were: FL had 39psi, FR had 32psi, rears had 33psi. All now at 32psi, and the car feels much better when.. I love simple solutions, and just wanted to share

[redcar]

waynester said:

Tyres that is. I've had new 235/40 Toyo Proxes fitted on my 17" rims, also new shocks and new steering bushes etc...and the steering still felt awful!! It was kicking really bad, pulling up unevenly..horrible. It then occurred to me to check the pressures. What a revelation....They were: FL had 39psi, FR had 32psi, rears had 33psi. All now at 32psi, and the car feels much better when.. I love simple solutions, and just wanted to share

Hi Wayne

Why so high, in my handbook it says 22psi front 24psi rear, any more or less than that and the handling is very twitchy, interesting, anyone throw any light on this.
Martin

[waynester]

Hi Martin
I'm assuming it's because of the low profile of the tyres? If i used 22 psi the 1st pothole i hit the rims may well get damaged...?

Is 32 psi to high on 235/40/17 tyres..?

[19560]

It's normal to run lower pressure on lower profile tyres, say 20f & 22r. Thats a very wide tyre esp for the front (215/45/17 is dimensionally correct) and probably helps to explain your steering problems as they will tend to tramline.

Edited to say did not realise that you now have a 400 instead of a 350 so dims are OK but pressure comment and low profile tramlining/steering problems are still the same. If it is a long term problem you could try 245/40 at the rear and 215/40(or 45) at the front.

>> Edited by 19560 on Saturday 14th May 19:33

[gsx600]

I tend to imflate to about 30 - 32 on the 17's - 215 on the 350.
About 26 - 30 on the 15 - 225 on the 400
and about 26 - 29 on the other 15's - 265 on the Vitara

Not sure about the Co Vecci as never bother checking them unless they are flat

[shpub]

waynester said:

Hi Martin I'm assuming it's because of the low profile of the tyres? If i used 22 psi the 1st pothole i hit the rims may well get damaged...? Is 32 psi to high on 235/40/17 tyres..?

Yep.Probably. As for damaging rims on the first pothole, the tyre flex is part of the suspension design and is designed to give. Make it too hard and instead of absorbing it transmits the shock through to the other components, including the rim. The problem is that some of the tyre manufacturers recommend a high minimum pressure to ensure the tyre beading stays in place for low profile designs. Without this pressure, there is a risk of the tyre deflating on a bump. Trouble is that this pressure takes all the tyre flex out and the end result is a suspension setup that is very harsh and unforgiving. Dropping the tyre pressures restores the flex and removes the harshness but then the risk of beading problems and leaks raises its ugly head.

Best suggestion I can make is to talk to Toyo and see what they recommend. If it is a high pressure then the suspension may need to be softened to compensate.

Steve
www.shpub.co.uk