AndyC

Despite my best efforts to keep the pressures correct, my tyres are showing signs of more wear in the centre of the tread than the edges, which suggests to me that they're overinflated.

Does anyone know where I can get hold of a reasonably accurate gauge?

How far out do the pressures need to be to give visibly uneven wear? I've done 16000 miles on the original Bridgestones, but there's still plenty of life left in them yet (I guess about 4-5mm).

Andy.

paul w

Andy,

16000 miles on the originals,do you go around corners?????

As for the pressure gauge,try ya local tesco forecourt,there really accurate

These answers are probably no use to you but at least you've had a reply

cheers paul

Gary Foster

Andy

16K !!! My good God ! you obviously haven't tried a track day yet then, you ought to come they are great fun.

I don't know about the accuracy but I have one of the Halfords digital gauges which cost a few quid. It seems to line up pretty much the same as my auto inflater which makes me feel pretty hopeful.

Ps are you checking them when hot or cold ? I've noticed it make about 2psi difference on the road and up to 5-6psi on the track.

Gary

^Gazzer^

I have just bought a nice guage from

AndyC

Sure, the temperature will be different, but the temperature _difference_ between 'cold' and 'warm' will be the same. The temperature difference is due to the heat generated mostly in the sidewalls as they flex under the weight of the car, and that's related to speed and (ironically) tyre pressure.

btw: Gary, are you having a slow day at work too?

rjc

Have a look at:

Gary Foster

Ah right, new I should have listened more in Physics class

Yep bit bored here, was on a joll- uhem course last week so I'm finding it difficult to get back in the swing of it.

Ps My Impreza is well modded now

AndyC

Thanks for the replies How many miles is normal for a set of tyres then? I didn't think I cornered _that_ slowly. I did get them swapped front to back at the 7.5k service, so now they're all about the same.

Gary: no, I haven't taken it on a track, although judging by the crop of stone chips I've picked up over the last year, I might as well have done. Damn that DBM paint! Maybe I'll finish them off on a track when they're due for replacement anyway.

I'm checking them cold (which I presume is the right thing to do) - they certainly read much higher warm.

^Gazzer^: which gauge did you get? They've got loads. I can't find any mention of these supre-accurate ones (not that I've got £300 to spend!) - where are they?

Cheers

Andy.

Gary Foster

Andy

Q: When you're driving your car, are the tyres hot or cold ? A: they are warm Always adjust the tyre pressures when the tyres are warm

However, I'd be surprised if 2psi would make much difference to the wear. What are you using at the mo ? The Garage ones regularly over / under read by up to 10psi (In My Experience) which would cause problems.

Average mileage for a set of S02's = 1 track day

AndyC

True: they're warm. But they're usually cold during a service or when I'm doing the routine wash/fluid checks at the weekend, so I presume that the recommended pressures account for this. The only way to get them right otherwise would be to get them thoroughly warm on the motorway, and quickly pull onto the hard shoulder and let some air out before they have chance to cool down.

At the moment I'm using a Halfords brass barrel foot pump with a built-in gauge which is supposed to be certified to BS<somethingorother> - but I've no idea whether it's really any good or not. A mate's digital gauge reads about 3psi higher.

Andy.

Otis

I thought you should always check tyre pressures when cold .


Otis.

Gary Foster

Eh ?

I must be getting confused then obviously. Must be different setting the temperatures on the road from the track

How could the manufacturer account for that ? the temperature difference between cold + working will be different at different times of the year

Oh well not the first time I've been wrong

Hoppy

Andy, get yourself a decent guage now! The ones on those foot pumps are utterly useless.

I have acquired a small collection of guages for no good reason that I can remember - £10 digital, £12-ish dial jobby from Halfords, and a £100-plus posh one. They all read exactly the same.

Get a digital one. Cheap, accurate and fits easily in the glove box.

Richard Hopkins

AlexM

Hi Andy,

May I draw your attention to this:

AndyC

Sounds like a great system - but for £180 it would have to save me quite a lot of tyres during the time I own the car

I'll bear it in mind - in the meantime, thanks for all your suggestions. Looks like I'm going to spend the weekend gadget shopping!

Andy.