non run flats tyre pressures

[Cobers Vxr]

Hello

i have just got 4 new non runflats 17s "Kumho" on my car and i was wondering what PSI you would recommend?

I cant believe how much better they are not being run-flat aswell.

Thank you

[PK5]

are they not supose to be 28psi at the front and 32 at the rear

[The Eggman]

MCS, 32 front 28 rear I run on 215x40 17's. The weights on the front remember and yes non R/F's are far better.

[mooneymini]

Looking at the info on the sticker on the inside of my door, the bar pressures convert to 33psi on both front and back .

Strange how the info varies.

[frashed]

I'm running 40psi on my Kumho KU31 and would not go lower.. 28 and even 32psi sounds wrong?

Edit: I'd think that going to a conventional tyre would require a higher psi than the run flats seeing as they aren't nearly as stiff...

[Cobers Vxr]

Yesterday i put 35psi in all 4 Kumho tyres and it seams very good, i will see if they need to be upped after a few hundred miles,

Thank you for all the comments.

[DaFlake]

OK guys, these are not run flats. The information on the inside of the door is for a run flat tire and is lower than it should be. I generally run mine at 6 psi below the max listed on the tire and seems to be good for me. You might have to play with it a little but on my Kumhos, this is what I use.

[frashed]

I would have to agree with DaFlake.

32/28 seems way too low for my Kumho's. Even 35 on front looks and feels too low. 40/38 seemed just about right for me but was worried about everyone's comments. I'm now on 37/35 and it feels fine.

Can anyone offer an explanation in the variation in tyre pressures?

[DaFlake]

The RF tire is made differently. It has a thicker sidewall thus requiring lower psi as the side helps to support the tire.

[frashed]

I understand that... what I'm referring to is the difference in tyre pressures for conventional tyres.

[DaFlake]

That was the point... Conventional tires have a less rigid sidewall which requires more pressure to keep them from collapsing. The RFs don't needs as much air as they have a stiffer sidewall which provides the support.

[frashed]

I should be clearer.. what I mean to say is why is there such a difference in pressure throughout conventional tyres. For example; I thought 40psi felt fine for conventional tyres, others say 32, other say 35.

The logic behind needing higher pressure in conventional tyres I understand, but it seems as though people are sticking with what it says on their door - even after switching to conventional tyres. So what is the correct pressure? Based on what you're saying I'd go around 3-5 psi over what it says on my door (which assumes you are using RF's). But people are telling me this is too high?

We need to find something everyone can agree on..

Sorry if I'm not making any sense

[iain cooper]

in my opinion 40/38 psi is far too high...........this is what I used to put in my discovery !!

your mini would be bouncing all over the road, and I'm sure the tread would wear around the middle of the tyre.

I would advise 32 psi all round.............but only my opinion.

[fakesnake]

I put 35 all round in my non run flat 215/40/17 falkens or at least I thought I did. Infact the tyre gauge was faulty & I ended up with 35 front & 40-42 rear. It took me a while to cotton on why I suddenly had oversteer when pushing it hard. Dropped the pressures & it's fine.
I'm now certain the pressures should be equal front/rear. They were for the old runflats afterall

[DaFlake]

The card in the door is based on RF's if that is what your car came with so those numbers will be too low. Most automakers put the recommendation on what the pressure should be based on weight and handling. However, we don't have those numbers so we have to guess. Max pressure on tires will vary so you have to look on the side. Most companies knock off 5 psi and start from there. So, if your max is 40, start at 35 and see how it feels. Then you can back off a little at a time until you find the sweet spot.