Jump to content
SAU Community

Tyre Pressure

ironpaw

By ironpaw,
in Four Door Family & Wagoneers

 Share

Recommended Posts

Global_Warmer Proficient

Global_Warmer

Posted
Posted

I also run 40 psi all round in 255/35/17s.

If I know I'm going to be smashing it, 50 will be what I run.

Will say though, that my car isn't a daily, already has rock hard suspension and no rear seats :P

Must handle like a dog on tiles.

  • Replies 44
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

WGNPWR
WGNPWR

pV = nRT

PN-Mad Grand Master

PN-Mad

Posted
Posted

OK, its basics but in case anyone has overlooked it -

You set your pressures when the tyre is cold. when you drive the tyre gets hot and pressure increases.

Read it like this - your a dead set idiot if your tyre says max 50psi on the sidewall, and you go pump it up to 50psi when its stone cold. When it gets hot- it'll add much more pressure leading to potentially unsafe situations.

Thats why "Global Warmer" had a better experience on putty rd, when he lowered his pressures, because it wasn't causing his tyres to over pressurise when hot.

Sorry if you know all this and I have wasted your life.

Old Gregg Enthusiast

Old Gregg

Posted
Posted

OK, its basics but in case anyone has overlooked it -

You set your pressures when the tyre is cold. when you drive the tyre gets hot and pressure increases.

Read it like this - your a dead set idiot if your tyre says max 50psi on the sidewall, and you go pump it up to 50psi when its stone cold. When it gets hot- it'll add much more pressure leading to potentially unsafe situations.

Thats why "Global Warmer" had a better experience on putty rd, when he lowered his pressures, because it wasn't causing his tyres to over pressurise when hot.

Sorry if you know all this and I have wasted your life.

Wouldn't the pressure ratings on the tyres be cold values taking into account any increase due to heat build up? ie 50psi max means 50psi max when cold.

WGNPWR - Wouldn' Charles' law be a better one to throw in there? :nyaanyaa:

Brandon Veteran

Brandon

Posted
Posted

OK, its basics but in case anyone has overlooked it -

You set your pressures when the tyre is cold. when you drive the tyre gets hot and pressure increases.

Read it like this - your a dead set idiot if your tyre says max 50psi on the sidewall, and you go pump it up to 50psi when its stone cold. When it gets hot- it'll add much more pressure leading to potentially unsafe situations.

Thats why "Global Warmer" had a better experience on putty rd, when he lowered his pressures, because it wasn't causing his tyres to over pressurise when hot.

Sorry if you know all this and I have wasted your life.

Very true. Once I check the pressure after driving from Brisbane to Gold Coast on a hot day and its showing 58 (was 40 at cold)! I got a shock of my life and immediately reduce it. I normally set mine to 38 (cold) these days and around 34 (cold) for some spirited driving.

zei20l Grand Master

zei20l

Posted
Posted

how about measure the pressure before you leave home. if they are down 4psi each, then go put 6 or 8psi in at the servo.

drive around normally. check them again the next morning when cold, then release any excess pressure.

easy!

bubba Grand Master

bubba

Posted
Posted (edited)

You must have good suspension to compensate your tyres which are as hard as concrete!!

Must be bloody slippery in the wet/rain with those pressures.

Tein super wagons, 33gtr front swaybar.

And no, it's actually got a fair bit of grip in the wet even in 2WD.

Edited by bubba
910trx Proficient

910trx

Posted
Posted

36 psi cold for 17 inch wheels, but every tyre is different

higher pressures, better response

lower pressures better grio

but this does not mean that 22 psi handles better than 36psi thats just stoopid - thought i'd throw that in just incase someone tries it...

also i have about 75% of my tyre filled with nitrogen from the servo :nyaanyaa:

RS4-S Proficient

RS4-S

Posted
Posted

41 psi on 235/40R18. was running 36psi and it cornered like shit with abit of understeer. much less understeer and 'IM ON A BOAT' feel.

as for nitrogen.

1- much less moisture in your rims/tyres.

2 - psi doesnt get higher with tyre temp (more stable pressure).

3 - pure nitrogen is more dense than compressed air, so less frequent pressure top ups at the servo. (perfect for trailer tyres)

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Komdotkom
      High temp brake fluid?

      By Komdotkom · Posted

      Reasonably hard, although I haven't run it with the new Endless setup yet. The old brakes were F50's on 335mm rotors and the car did a 1:40.6 at Phillip Island which is a reasonable time, I'm seeing high 600s on the temperature paint. A guy I know ran the Endless fluid at WTAC without issues and he was doing 1:33's I think (Evo) with a 355/332 setup. I don't get out to the track as much as I'd like but we put the car on the hoist and spanner check every bolt and re-paint mark everything, bleed the brakes, change the fuel, check the coolant system and re-bleed blah blah blah before every event. Motorsport is expensive, RB's are expensive so a couple of hours before an event is time well spent. It's also a net time saving because if you can keep your RB from self destructing it saves you time in the long term!
    • Duncan
      First/Second Post

      By Duncan · Posted

      Welcome Alice......hope you have a bit more luck from here on! What was done in the build?  
    • svenskalice
      First/Second Post

      By svenskalice · Posted

      Hello! I'm new here, I have an R33 GTST that is currently being finished up! Last year was pretty rough, blew two stock turbos so I decided to build the car. Has been down since November, but I get it back next weekend!
    • svenskalice
      Kaizo Industries

      By svenskalice · Posted

      Hello, I believe my car was imported to America in the 2000s by Kaizo Industries. Would anyone be able to help me find more info on them? I've only found all the basic stuff like that paul walker bnr34, them being shutdown by feds, just stuff like that. Any help would be much appreciated, thanks!
    • believer
      HKS Vcam Step Pro Issues

      By believer · Posted

      I am using Motec M150.  I am not working on the car myself actually.  My workshop is giving all these info, they are quite reputable in the industry and are very familiar with Motec and RBs and have done a few big setups with VCam and single turbo on RBs.  In fact, they built and tuned my engine from day one.  But they are stumped with my engine at the moment and cannot work out how come the compression is so low with the VCam. They told me that they have now swapped in some Kelford cams (without the VCam) and can achieve around 130psi compression and the low end torque is better, but now the engine is doughy as.  It boosts and peaks at more than 1000rpm slower, with twin HKS GTIII RS, it doesn't get full boost until over 5000rpm. I have always thought the VCam was a bit disappointing at the low rpm. To a point I had to ride the clutch a fair bit to get up a small hill from stand still.  That was when I had a clutch.  Now changing to a 8HP, I don't have that luxury and this problem has become a major issue. I am beginning to think the VCam never work since the day it was installed.  Maybe it was just sitting at the most advanced point, that is why it went good at top end but very ordinary at the bottom.  Therefore, with the help of the Holinger 6 speed and paddle shift, as long as it was moving, it drove pretty good.
×
×
  • Create New...