Tyre PSI ?

pudzey101

Hi what pressure roughly should tyres that say " MAX 51 PSI " on the wheel theres no guidelines on the panel of my door , or inside my petrol cap is why i ask ?:)

cheers

Supergurrier

Car/engine/tyre size ?

pudzey101

Supergurrier wrote: »

Car/engine/tyre size ?

Honda integra , 1.8 , i think there 15's / 16's i currently have them at 40 think its too high though coming into this cold weather , just wanted your guys opinions

BMJD

30-33 is the normal. I had my itr on toyo t1rs at 33psi. Just make sure they are all the same pressure.

pudzey101

BMJD wrote: »

30-33 is the normal. I had my itr on toyo t1rs at 33psi. Just make sure they are all the same pressure.

thanks bud , il lower them down today ,

No Pants

Might have a table in the manual also. 32 PSI is the average in my experience for driver only/driver and one passenger. Maybe add a couple of pounds if the car is full.

Chimaera

Tyre pressures are generally specific to the model and tyre size. Correct pressures should be specified in the manual.

Wossack

BMJD wrote: »

30-33 is the normal. I had my itr on toyo t1rs at 33psi. Just make sure they are all the same pressure.

do you not typically run the fronts at a slightly higher psi?

corkgsxr

33-37 is a good guideline imo. You wont go far wrong with that

mcer

pudzey101 wrote: »

Hi what pressure roughly should tyres that say " MAX 51 PSI " on the wheel theres no guidelines on the panel of my door , or inside my petrol cap is why i ask ?:)

cheers

Bring it to 35 psi by the time you take the Air line off it drops to 32 psi give all wheels the Same never go to the Limit. Tyre wears quicker

biko

I run 32 all round but recommended for my car is actually 29.
Sticking with manufacturer's recommendations is best when uncertain, they usually know what they're talking about - they built the car after all..
I think anyone can run 30 and don't go wrong.

Oh and with winter coming and slippery street with leafs and rain you may want to keep tyres lower than in the summer, you'll need all the grip you can get.

mcer

mcer wrote: »

Bring it to 35 psi by the time you take the Air line off it drops to 32 psi.

In my experience it never drops more than .5-1 PSI when removing the airline. Different methods I suppose

corkgsxr

biko wrote: »

I run 32 all round but recommended for my car is actually 29.
Sticking with manufacturer's recommendations is best when uncertain, they usually know what they're talking about - they built the car after all..
I think anyone can run 30 and don't go wrong.

Oh and with winter coming and slippery street with leafs and rain you may want to keep tyres lower than in the summer, you'll need all the grip you can get.

Manufacturers have a habit of putting the psi a touch low as they can get away with cheaper suspension. Id always go a few psi up.

HandsomeDan

corkgsxr wrote: »

Manufacturers have a habit of putting the psi a touch low as they can get away with cheaper suspension. Id always go a few psi up.

It wouldn't cost a manufacturer any more to fit softer springs/lower rate dampers.

It would effect the handling, but then so would under-inflating tyres

corkgsxr

Wossack wrote: »

do you not typically run the fronts at a slightly higher psi?

HandsomeDan wrote: »

It wouldn't cost a manufacturer any more to fit softer springs/lower rate dampers.

It would effect the handling, but then so would under-inflating tyres

Its quality of the units rater than spring weights.

GTE

Wossack wrote: »

do you not typically run the fronts at a slightly higher psi?

My Golf states 1.9 bar (27-28PSI) of pressure on the front and back for cold tyres with a raise when the car is fully loaded with a higher rating on the rear. 2.3 front (33PSI) to 3 rear (43PSI) if I remember correctly, or at least remember roughly.

I think cold tyres is there because the hotter the tyre is from motorway use, the higher the PSI - or so Google says.

corkgsxr wrote: »

Manufacturers have a habit of putting the psi a touch low as they can get away with cheaper suspension. Id always go a few psi up.

Could that observation just be down to the cold tyre thing?

SleeperService

Just to throw another conflicting opinion into the mix, I'm of the opinion that manufacturers spec a psi based on economy, along with lighter oils etc to reduce emissions. I've felt a car handle much better and be nicer to drive on irish roads with 2-3 psi less. (no noticeable effect on tyre wear in that particular case).

Chimaera

Tyres should always be checked cold as temperature will have an effect on pressure (the whole equation of state thing: pV=mRT). Temperature increases uniformly with temperature if the volume is constant (as it will be more or less inside a tyre).

The friction of driving will heat up the tyre and affect the pressure inside it.

There are many arguments for varying tyre pressure but it's always good to start from the manufacturer's recommendation if you're going to vary things.

Lower pressure leads to:
Softer ride
More traction
Poorer handling
Higher fuel consumption
Higher and/or uneven wear

So it's obvious what higher pressures can achieve. The uneven wear can occur at either high or low pressure though.

Tyre pressures need to be adjusted depending on unladen vehicle weight plus loading. Manufacturers will quote varying pressures depending on how loaded the car is (usually limited to full passenger and boot vs driver only). The rear pressures will usually increase much more than the fronts when the vehicle is loaded up. Unless fully laden, most modern cars will need higher pressures at the front than the rear to counter the heavier loading of the engine and transmission, especially front wheel drive cars.