Tire pressures

Started by SwansSaab, 25 November 2011, 07:02:14 PM

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jmblack

I have had camber laser checked and all fine - I'm wondering if low load on car and slightly higher offset are impacting....otherwise the laser check was wrong....


Max Headroom

HOW TO READ TRYE WEAR - Unfortunately in American style yukspeak but the illustrations are good

SwansSaab

Well I pumped my tyres up to 38psi and I cannot believe the difference in how the car feels to drive .. Im sure the Kwikfit did not inflate the tyres to 38psi when they fitted them.

The car felt a little strange in the wet with the increased pressure but I put that down to that fact I was un used to it.

sgould

Tyre places rarely bother with getting the pressure right.  I think there's a rule that they just set the machine to 32psi and do all the tyres to that.

Just lazy.
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TomPaine

Quote from: SwansSaab on 29 November 2011, 12:20:58 PM
Well I pumped my tyres up to 38psi and I cannot believe the difference in how the car feels to drive .. Im sure the Kwikfit did not inflate the tyres to 38psi when they fitted them.

Another convert to the high-pressure club.  :D

twoshots

#20
Yep, another running higher pressures here!

I run 41psi in my Falken 912's on 215/55/R16, but I think they are known for their soft sidewalls. Definately makes the car feel better IMHO, and improves fuel economy too. I managed to get 47mpg (on the SID...) on a slow 150 mile motorway run last month!

At 36psi I was getting more wear on the outer edges of the tyre, we'll see if I've over compensated in time.

The new toy (Aero) is still at 36psi, up from the previous owners aparent <32psi. I may go up to 38psi next time I pass a garage on coldish tyres. (We live in the sticks!)

TomPaine

Quote from: twoshots on 30 November 2011, 11:33:58 AMThe new toy (Aero) is still at 36psi, up from the previous owners aparent <32psi. I may go up to 38psi next time I pass a garage on coldish tyres. (We live in the sticks!)

But have your own gauge and never, ever trust forecourt gauges. They're notoriously inaccurate.

paolo

Quote from: SwansSaab on 29 November 2011, 12:20:58 PM
Well I pumped my tyres up to 38psi and I cannot believe the difference in how the car feels to drive .. Im sure the Kwikfit did not inflate the tyres to 38psi when they fitted them.

The car felt a little strange in the wet with the increased pressure but I put that down to that fact I was un used to it.

Yep used to run it at 37/38psi.   32psi made the handling go a little wobbly - sorry i missed this thread earlier!
P

Nu2sabbie

 :)
having read this thread i have today increased the pressure in my tyres from 32 to 36. what a difference.
is there any point in raising this as some of you appear to be going upto 40.
i have an 02 hot areo 95 estate.

TomPaine

Quote from: Nu2sabbie on 06 December 2011, 06:51:08 PM
:)
having read this thread i have today increased the pressure in my tyres from 32 to 36. what a difference.
is there any point in raising this as some of you appear to be going upto 40.
i have an 02 hot areo 95 estate.

Well as I said earlier I run 39 (Michelin Primacy HP). What does the sticker on your door column say? Mine (also Aero, so 17") says 36 min, 43 max. If yours is the same you're still at the bottom of the spectrum.

nine-fiver

In a 17inch tyre there isn't all that much volume. Which is why extra pressure makes a decent difference. But in a 16in an LPT setup extra pressure just makes the thing feel like it is riding on rocks.
I think you want to push them to the higher end of the rating and then back it off until you can tolerate the 'crashiness'. Last thing you want it to feel like is a V70. 

luckyegg

Interesting thought on rear camber after the 4 wheel alignment,

i have recently had mine done after the engine rebuild and rear suspension parts rebuild,
i had a full alignment on a brand new state of the art alignment machine,
very little wrong apart from tracking and rear camber,

And thats where the interest comes from, i have been told catagoricly that the is no adjustment on the rear camber, also had this confirmed by my indie, who reffered me to them, the service cost me £123 inc vat, and this was a proffesional motor sport company.
so without wanting to put a damper on your statment i think they may of been lying some what,
Unless they fitted shimms on the rear hub.
Maybe worth check to see if they did do it.

for uneven wear maybe think rear bushes shocks, and sub frame bushes

Audax

Quote from: luckyegg on 07 December 2011, 06:04:04 PM
And thats where the interest comes from, i have been told catagoricly that the is no adjustment on the rear camber, also had this confirmed by my indie, who reffered me to them, the service cost me £123 inc vat, and this was a proffesional motor sport company.

Sorry, but both these companies are wrong. The shims to adjust camber are supplied by Saab (part numbers are 4908174 and 4908166) and there is a procedure for doing this in the workshop manual.

luckyegg

your kind of right, as the shims are available from lots of sources, but unless you have them there with you and the garage has time to fit them, the is no adjustment on the rear camber, and for a garage to fit them its going to be 2 hours labour maybe less but not done for £50
so from that neither company was wrong,
If you can guide me otherwise please do.

Quote from: Audax on 07 December 2011, 06:10:51 PM
Quote from: luckyegg on 07 December 2011, 06:04:04 PM
And thats where the interest comes from, i have been told catagoricly that the is no adjustment on the rear camber, also had this confirmed by my indie, who reffered me to them, the service cost me £123 inc vat, and this was a proffesional motor sport company.

Sorry, but both these companies are wrong. The shims to adjust camber are supplied by Saab (part numbers are 4908174 and 4908166) and there is a procedure for doing this in the workshop manual.

Audax

The bit where you stated you had *categorically* been told by both these companies that there was *no* *adjustment* on the rear camber, it's quite blatantly incorrect and why I have an issue with it. Please don't spread incorrect information about as it isn't helpful. Yes you do need shims, yes they are not easy to fit but in no way does this amount to no adjustment on the rear camber...