tyre pressures

[vinderliker]

Hi all,
Can't sleep, the question of tyre pressures popped into my head. Should the pressures for a Front wheel drive be higher in the front than the rear. Had some advice years ago in a rear wheel drive that in Canberra beacause of the nature of the roads (all the round abouts) they suggested that I put higher pressure in the front than the rears. can anyone shed some light on the subject?

James

[vee_dub]

From what I know and what i do.
MY front tyres and rear tyres have 1psi difference. Cause knowingly is Frontwheel drive.

If the rear end grip is higher than the front end grip, will induce understeer. In order to counter act, front tyres pressure is higher but not too high. Where front tyres have more grip than the back.

But I really dont notice the difference at all hehe. Cause going to petrol station pumping it up is not accurate at all.

[Golfwise]

Changing tyre pressures front to rear is a sign of a poor handling car having to make up by changing pressures. ala VW Beetle.
Lower pressure induces more slip angle.
Not my idea of making a car handle.
Stick to tyre manufactures recommendations only.
Remember modern tyres were designed yesterday but your Passat over 30 years ago. :D

[kai_h]

Tyre pressures are a complex problem.
On some tyres, lowering the pressure will decrease grip. On others, having too high a pressure will reduce grip.

FWIW, I always run my tyres at somewhere within 1-2 PSI of their rated maximum, I like the firm, direct feel it gives me, and it generally gives me better fuel economy.

If you really want to play around, you will need a portable compressor and tyre pressure gauge and an empty carpark. Vary the pressures front/rear until you come up with something you are happy with =)

[gldgti]

ok, from an engineering perspective:

the golf is far heavier over the fron than the rear. your specific tyre pressures will depend largly on the size of tyres you are running - 70 profile tyres need to be very hard to stop them from rolling under the rims etc.

its always beneficial in a golf to run significantly higher pressure on the front than in the rear. for 13in wheels, you may find 34-39psi is good in the front, where 25-32 is fine for the rear.

the high pressure gives the tyre more strength to keep its form, and hence stay neatly below the rim.

more grip may be gained from lowering tyre pressures but you might find you lose some feel and responsivness, which is going to offset any gain from the lower pressures.

tyres inflated to a good running pressure last far longer than ones underinflated too.

[deemoE36]

on my tank cap says 230 psi at the front and 220 at the back

now when i got diff. size tires, 205/40 17x7 40 kpa all around is used

[aprr32]

You may wish to check your tyre placard again.If you can find a compressor that will put 200+psi in your tyre and when you do I don't think I'd like to be in the same suburb as you, because the tyre and car will go in 2 million different directions.

[mikinoz]

tough rap - clearly the dude is confused! :D

Agree with the comment regarding trying your own car in a controlled environment with a compressor to feel varied pressures.

No one supension/pressure set up can suit all tyre types. Different tyres need different pressures. This can even vary on the same tyre as the tyre ages and the differing wear on the tread.

Have just gone from Avon's with 36 front 34 rear to Yokohama A-Drive running 32 front 30 rear. I have tried the yokis with more pressure and there is a big difference in handling, even if you go to 34/32. Road condition and weather are all factors to be aware of (read be careful for the first few times) if you have higher pressures set for dry conditions.

Go and buy yourself a tyre pressure guage so that you can use a service station compressor but do not have to rely on their guage.

Finally, check the pressure after you get new tyres from your tyre merchant. I have had big variances on a new set straight out of the shop!!

[ibeezer]

This is just my experience with front wheel drive cars, i put a little less than recommended at the front. Might be my imagination but it feels a little grippier, but too soft i get more understeer.

[dswiders]

What sort of tyre pressure should I be running when I've got 18x7.5 wheels ?
Currently it's got 36 all round.

Daniel

[gtimk5]

Hi dswiders and another big welcome to thr forum if you didn't get it the other day before the server "crash"! Gtigrl and myself did a GTI drive day last month at Sandown with VW and Murcotts driver training. They insisted that we ran a minimum of 38 psi all round in our tyres. They mentioned that manufacturers reccomend lower pressures for a smoother ride only. There is no proof that higher inflated tyres will lose grip quicker. I run 38 all round in the GTI, customers Mk5s I set at 38F, 36R if they are normal type drivers.
With 18s I would set to 38 all round. Cheers, Andrew :) :)

[gtigrl]

LOL go back to sleep and worry about in the morning ;)

[brackie]

I run 35psi on all of my Golfs and have done for years. No performance penalty, tyres wear evenly and it reduces rolling resistance.

[gtimk5]

LOL go back to sleep and worry about in the morning ;)
:? Did I miss something there?;)

[WEDEL.1]

Don't forget that the front tyres do all the work. They brake, accelerate, steer and carry the wieght of the front end. The rears only hold up the back of the car, so you need much less pressure in the rear. Check the differance on you tyre placard.

Maris

[gtimk5]

In my competition Golf I ran 34 in the front and 24 in the rear on a nice day. The worst thing that can happen in a Golf is to have the rear end snap out on you at speed. They go very quickly and its very hard to grab em! I had a fair few scary moments, and so did 4 photographers on the Highclere stage in Rally Tas back in 03. Still got 5th fastest time overall. Had the mother of all loses to. Didn't believe the time but we weren't arguing! :?