Hi all,
Got a quick simple question for those running 19s on their 380 or Magna, or whatever.
What tyre pressure do you use and prefer? With my recently fitted 19s, I was told to use 38psi (but I had previously heard people say 40).
I checked the pressures today with the new setting of 38 and they all came down from 39 & 40 (that's driving the car straight into a servo minutes after work).
Driving home I could easily feel the difference (possibly due to the slimmer 35 profile tyres?). When they were around 40 (as done by tyre place) the ride was quite firm. But now with 38 today, the ride is a lot softer. Obviously there are different arguements for and against a higher and lower pressurised tyre, for ride, handling, wear, etc etc.
I think I prefer the higher pressure, but I was wondering what other peoples opinions and findings are/have been, on this matter.

I'm running 19's on mine with the pressure set 38 for round town for comfort plus I'm on lower/stiffer suspension.
But for highway driving I tend to increase to between 40 and 42 for better fuel consumption.

i've got 36 in my 19's on my TJ, thats what bob jane said when i got the rims

40psi - I don't believe in compromising comfort for handling and safety.

If I wanted comfortable I would've stuck with the 15s lol

In my 20s I used to run somewhere between 38-42.

Found the best combo to be 41 fronts, 39rears, cold.

Bob Jane put mine on & recommended 36PSI.

i always run 40 in my 19s

every tyre/rim combo ive had was ran on 40psi.

40psi - I don't believe in compromising comfort for handling and safety.

If I wanted comfortable I would've stuck with the 15s lol
How do you know how much pressure is "safer"? If you set it too high then you have less surface area therefore less grip for manoeuvring (less safe). Set it too low and you overwork the tyres wearing and heating up faster, using more fuel too.

Finding the right balance is they key - IMHO as someone said, higher setting for highways (better fuel economy) and lower setting for city drivers (better grip for more turns)

I woulnt go lower than 38 in that profile.... i run that in my 17's and find its a good all round.

In my 20s I used to run somewhere between 38-42.

Found the best combo to be 41 fronts, 39rears, cold.
Yeah I'll try this combo next time (maybe tomorrow).

How do you know how much pressure is "safer"? If you set it too high then you have less surface area therefore less grip for manoeuvring (less safe).

Seriously, I don't think this is the case. The Wheels Handling test and other handling/tyre comparison tests they use 50psi. It reduces tyre squirm at high cornering loads and ensures as much as the contact patch stays on the road surface as possible.

I run 40psi and have no issues with ride. And I don't like hard riding cars.

Seriously, I don't think this is the case. The Wheels Handling test and other handling/tyre comparison tests they use 50psi. It reduces tyre squirm at high cornering loads and ensures as much as the contact patch stays on the road surface as possible.

I run 40psi and have no issues with ride. And I don't like hard riding cars.

Are you sure??? Might check myself, because that doesnt sound right. I know that on the sidewall of my 18's it says maximum pressure 44psi. I think most of the tyres are the same. And 50psi is WAY higher than ive heard anyone use. Would also be a bit dumb to test tyres at a pressure that no one else would use....

Ollie

50 psi sounds very high for any normal road car,and with higher pressures,this can reduce tyre contact patch as the middle bulges out which leads to the outside of the tyres loosing contact with the road,not ideal really,38-42 psi would be the optimum for most low profile stuff today id say

Steve

I run 40 in the front and 38 in the back, on 16inch stockos.

I used to run 42psi in my 20's on my 380, gave that bit of extra "insurance" over potholes and ride was still very compliant.

For whats its worth I have 19s standard on my current VE HSV and the tyre placard recommends a pressures of 36 front and rear for normal loads and 39 for fully laden load driving. I normally run them at 40 though for everyday driving as I find this to be the best for both ride comfort and handling.

Cheers.

50 psi sounds very high for any normal road car,and with higher pressures,this can reduce tyre contact patch as the middle bulges out which leads to the outside of the tyres loosing contact with the road,not ideal really,38-42 psi would be the optimum for most low profile stuff today id say

Steve

For the middle of the tyre to be bulging enough to lift the contact patch you'd probably need 100psi (jk). I don't know without doing the math.

We're talking a handling test ppl, not normal running and they pump up the tyres as hard as they can.

I'm sticking with my recollection (I can't check the Wheels issues because I threw them out when I moved in December)

:gtfo:
For the middle of the tyre to be bulging enough to lift the contact patch you'd probably need 100psi (jk). I don't know without doing the math.

We're talking a handling test ppl, not normal running and they pump up the tyres as hard as they can.

I'm sticking with my recollection (I can't check the Wheels issues because I threw them out when I moved in December)

... they use 50psi. It reduces tyre squirm at high cornering loads and ensures as much as the contact patch stays on the road surface as possible ...
Ok, point taken - agree with the tyre squirm. The front tyres look deflated (should I say flaccid?) on normal setting. But that leads me to question why the manufacturer decided 32psi was a good setting.

The manufacturer will undestate tyre pressure for ride comfort, as tyre people sometimes do the same so the edges wear quicker and they see you again sooner, I'd say Knotch'd is pretty close to the money. Zero input Zero?????

The manufacturer will undestate tyre pressure for ride comfort, as tyre people sometimes do the same so the edges wear quicker and they see you again sooner, I'd say Knotch'd is pretty close to the money. Zero input Zero?????
I think 50 will wear out the centre patch of tread prematurely.:confused:

Agreed, just because you can't tell its bulging, doesnt mean it wont affect tyre wear. Its not like you can see a gap in the middle of the tyre when its under inflated, and that WILL cause the edges to wear fast.

Im pretty sure wheels would have used a recommended street pressure, I bet its 40 or under. I will get around to checking one day

Ollie

Hang on. I said 50psi was for testing, and only testing for handling.

I wouldn't run any tyre at that pressure except on a track.

This is the third time I've said this :roll:

Hang on. I said 50psi was for testing, and only testing for handling.

I wouldn't run any tyre at that pressure except on a track.

This is the third time I've said this :roll:

Yes, I think you misunderstood, im saying im sure wheels used 40 psi or less 'for testing' as it would make sense to test at the pressure that would be used on the street.

Ollie

Like they do a Dyno:doubt:

Yes, I think you misunderstood, im saying im sure wheels used 40 psi or less 'for testing' as it would make sense to test at the pressure that would be used on the street.

Ollie

OK. I'll see if I can find the reference.

Like they do a Dyno:doubt:

?????

I guess he means "Like they do ON a dyno."
My mechanic told me (when I did my dyno run) that even tyre pressure can make a difference to the final figure.

I guess he means "Like they do ON a dyno."
My mechanic told me (when I did my dyno run) that even tyre pressure can make a difference to the final figure.

Funny you should mention that.

Every time my car has been on a dyno the operator inputs 50psi onto the dyno sheet but I have never seen them check my pressures beforehand...and I can tell you that I never run my pressures at 50psi.

Funny you should mention that.

Every time my car has been on a dyno the operator inputs 50psi onto the dyno sheet but I have never seen them check my pressures beforehand...and I can tell you that I never run my pressures at 50psi.
Shoot mate,you're paying,ask him WTF.:)

Thread's getting a bit old, but just thought I'd make a final update...
I put 40 in the fronts and 39 in the rears, feels a lot better. (Previously had 38 all around, which showed as 36-37 when I did this)