Tire Pressure

[Hjalle]

I recently had my Fiesta in for a service at an independent garage where I got them to do a tire check and rotate for me as well, the garage I used put a sticker on the windscreen recommending 34PSI all around.

When I checked the pressure on Saturday night I saw I was running 35PSI. I thought all of this sounded very high and upon checking Ford suggest 31PSI front 29PSI back on 195-45-16 84W tires.

I let the pressure down to the Ford recommended pressure and have found my ride to be less crashy - does anyone have any idea why they would have me running such a high PSI and what do you run? Higher, lower or recommended pressure?

[D13 HPD 95]

i run 31-34 psi but if i have a heavy boot which i do some weeks ill put 38 in the rears i was told 32psi from a ford garage but the manual and the haynes manual says different

[Stoney871]

All our work cars (Focus) have a 31psi label on the wheel arches.

[FOCA]

I run 39psi in the front and 41 on the back, the higher pressures reduce friction/ drag so you should get a (slightly) higher MPG,

the higher pressures protect your wheel rims/ alloys

I like the direct feel with these pressures, the steering response is quicker i get more grip in wet/ cold conditions (because i get more heat into the tyres) and get quicker feedback when the car is about to "let go" - if i have a slow puncture and one of my tyres is down just a few PSI -i can feel it immedeately

With the (realatively) high front tyre pressures, the steering is lighter at parking speeds, so it gives the power steering an easier time, in snow/ ice, i can feel when the car is about to slide, sooner than with lower pressures

if you corner very hard, the higher pressures stop your tyre sidewalls from deflecting, if you drive mostly on twisty roads and corner hard(ish) even if you use very high pressures you will not wear the middlmiddle of your tyres out, you will wear the "shoulders" out 1st , if you do a lot of motorway / straight line driving, you will wear the middle of the tread out faster (with "too high" a pressure) - so the wear on the tyre is a good indication of the pressures you should run - if you are running very high pressures and you are still wearing your front shoulder/s tread out (FWD car) you probably need to slow down a little on the bends

"back in the day" a car would have 2 sets of pressures, higher ones fior "high speed/ heavily laden" and lower ones for "normal" driving (read- your gran going down to the shops- if that is "normal" for you)

Tyre pressures are only "recommendations" you should try different pressures (within the tyres maximum limit) to see what is right for you - it took me a long time to find the ideal 39-41PSI for me/ on my car - yes the ride is harsher - we ex race drivers have had heated discussions about the best pressures to run - but 29psi is for comfort (gran going down to the shops) - not grip/ handling or getting that extra MPG

PS - that (OPs) Fiesta desperately needs de-tangoed

　jUST to add, diesel engined cars engines can be very heavy, so a high front PSI is often required, (Mondeo MK3 2.0L diesel 41pst recommended in the front wheels ) even with this high pressure, the tyres can look underinflated - if it looks underinflated, it probably IS underinflated - if you increase the PSI in the front, you should do the backs too, as you may get lift-off oversteer if your rears are softer than your fronts

[Hjalle]

Ah ha I see, after having had the lower pressure for the past couple of days and felt it nice to be comfortably wallowed around the pothole ridden roads by me, I am starting to get over it and notice that it doesn't suit my teenage male driving style and as you said FOCA the steering is heaver when in city driving which is kind of annoying.

I also phoned the garage up today and asked and the gentleman on the phone said that Ford recommend the lower pressure for the comfort of grandma's but with my tires they run squarer, give better performance and wear more evenly when run at 34PSI

So Ive put the pressure back in and am much happier, as driving pleasure comes before comfort

[LightningMat]

Tyre pressures are a bit of a personal thing, but the key aspect for a normal road car is even tyre wear. Too low and both edges will wear out, too high and the middle will wear.

If just one of the edges is wearing out, then this is most likely a sign that the geometry is incorrect for the type of driving you are doing, and you should get this checked.

In an ideal world, you would adjust your tyre pressures to suit the roads and type of driving you are doing, but in reality, nobody is going to do that on a road car! So, as a compromise, the best advise is to find a happy medium (using even tyre wear as an indicator) and stick to that (although perhaps adjusting for winter / summer if you really want to).

1.0 125 Zetec S on order!

[mite_jan]

hi
i am using 36 front and 41 psi back following the sticker in my car

tyres are 195/50/r15
is it ok or it is a bit too much ?
couple of people noted to me that it was too much

usually 4 to 5 people are in the car
car is 1.6 tdci Fiesta Ghia facelift mk6

[bwoody]

That reminds me I need to give my tyre pressures a check, was running 205/40/17's on the unladen pressures, but might stick a bit more in them, go half way between lower and upper limits I think would make sense for most eventualities.