FTO AUSTRALIA

just wondering how much everyone pumps their tyres at? in psi?

i got 205/40/17s at the front and 225/50/17 at the rear and i pumped them the other day at 33psi and my car seems to hop everywhere over bumps and likes to follow the road all of a sudden...

is 33 psi 2 much for those kinda tyres? i wouldn't know

or could my erratic handling situation b caused by something else?

i have 225/45/17 rubber on mine and i pumped 35psi front rear but the front still looks like it's flat! arrrgh...!!

...but it's not that bumpy though' - in fact i reckon it's more softer, but only very slightly...

I was always under the impression that alittle less then the recommended was better, especially for low profile tyres.

Also, does anyone have trouble with people stealing the friggen caps off of the inlet valve thingos?

the handling problem your talking about is called "tramlining" and is caused by the tread pattern on your tyres. Not much you can do about it except replace the rubber.

Stephen

Hi, i have my pumped at 36psi, is that way too much? the tyre shop told me to put it to 38psi..... he must be crazy???
i have 215/45/17

40 psi all around on 205/50/16

I run close to 40 in any car I drive, but if the profile is too large I lower to around 37 to allow the flex to occur *shrugs*

I don't know whether that's determental to the tyres but I seem to be doing fine, I've never had a blow out before =)

i have 225/40/17 235/40/17

38psi all round..

jono

The sticker added when my car was made imported says 32 psi on stock 16's. I haven't checked them yet, but 40 sounds huge. But whatever you guys reackon!

my god, i've never taken my tyres more than 35psi!
isn't it really really bumpy? especially when u got stiff springs as well?

i just deflated my tyres 2 30psi this arvo and my handlig is so much better, it actually stays on the road instead of hopping about... is that bad at such low pressure?

does it matter what kind of tyre u have? i got Dunlop Le Mans at the front and Nankang at the rear... wondering if i should jack it up 2 38psi like u guys said...

yes i believe different tyre manufacturers and specifications will have different pressure requirements on different cars etc.

just like playing with your suspension, its just a matter of fine-tuning to suit your own needs - dont be afraid to fiddle with it, coz who knows.. maybe you are not using your car to it's full potentials! just make gradual changes ie. dont go from 32psi to 42psi!

*nodS* most of the tyres I use are Z rated so they should thorectically be able to take 45psi under max load . . . =)

Which basically means around 40 psi including the usuall punishment of bumps and other knocks =)

Lower psi will give you a bigger patch area and is generally better for dragging in straight lines as you'll get more girip.

However tyres will flex more which will absorb more shocks but predicable handling will suffer as the tyre moves across the face of the rim, you could also damage the side walls with low psi.

Generally anything below 30 is bad =) but I keep a minimum of 35 =)

Most family sedans will have their pressure around 32 psi.

Having low psi acts as additional shock absorber and comfort is more important to some people compared to handling performance but as G1 said, it's a matter of what you like, you have to play around but check the max pressure under max load for your tyres =)

Just as a side, I was told all tyres can hold 40 psi in them but I haven't done any research myself, they might of been generalising to a specific class and above =)

The guy at Donellans told me that 50 profiles should be 33psi and 45 profiles should be 38psi.

Omg, mine are on 32PSI b/c that's how they came when I had new tyres fitted on em... Maybe I should bump the PSI up a bit eh?

There isn't a exactly should be PSI that you have to be at.

There's an operating range that tyres can be run at. You must remember that the tyre pressure increases as the tyre warms up.

Peole are probably quoting should be marks as they are safe I guess, but there are tyre ratings you can go by.

But no matter what, if you get a nail in the tyre, it's gonna deflate =)

every different brand of tyre has a different max pressure stamped on the side wall. You should inflate your tyre to a couple of psi below the recommended maximum for your particular brand. If the wheels are sliding or spinning then deflate a bit, if it is sluggish out of corners etc then pump em up.

Tyre wear is also a good indicator of bad inflation. Wear down the centre of the tyre - too high, wear on both edges - too low. You have to expect wear on the outside of the front though, no matter what.

MADFTO wrote:You must remember that the tyre pressure increases as the tyre warms up.

=)

I dont think tyre temp changes the pressure by very much though. I dont think it would be more that 1 psi???
By the time you drive to the servo your tyres will be at operating temp anyway.

Yeah, in normal circumstances for a daily driver I'd say 1psi in winter, around 2-3 in summer.

You shoudl be inflating the tyres when they are cold. I usually do it at night to try to keep the temps down.

However, if you're on a road on a hot summer's day, the bitumen can be around 45-50C.

From night temps, that around 35-40 degrees higher, maybe more.

The more pressure you have in the tyre, the more air you have in there, therefore the more it expands.

I try not to go above 40 if I can help it =)

That's right the recommended tyre pressure is for when the tyres are cold. so normally by the time you drive to a servo it will be definitely hotter, so depending on how hot the day is and how much you've heated up the tyres, i would say to be safe at least 2-3psi higher than the recommended.

on a hot summers day i would go at least 5-6psi above.

i think tyre pressure goes up something like 1psi for every 5-10 degrees, but i would have to look that up to be sure..