[satz]

Hi all

I know this should go in the Tyre FAQ, but I don't think many people look at that to find new posts...

Anyway, am taking the big step (for me), of moving from 18in wheels to 19in. I'm going with the 225/35 front and 255/30 rear, non RFT Goodyear Eagle F1 A3.

What is the optimum cold pressure for 19in tyres on an E90 LCI 335i?

Can i just use the pressures I used for the 18 inch non RFT tyres? I think it was 38 fr and 38 rear (cold). or perhaps it was 38 hot. I have it written in the car.

many thanks

S

p.s. I have this love/hate relationship with this board.... Love the advice and help, but 'hate' that I keep being tempted to spend money on my car when i see what other guys do...

[Montye90]

hi mate, shouldn't you run 235/35's on the front and 255/30's on the back? 38-40 PSI I believe should be correct.

[satz]

hi Monty, sorry my typo.. what I'm getting is F: 225/35/19 and R: 255/30/19

Will try to edit my original post.

I stuck with the 225 (rather than 235) at front to maintain same footprint and rolling diameter as my current 18s. Didn't go for wider tyres as I wanted to keep weight down, and not over-tyre the car.

cheers

[Montye90]

Ok, cool. I have 235's on mine, but I can't comment on the different between 225's and 235's. I imagine it would be negligible, maybe 1-2%.

I am running Potenza S001's and so far they have been quite good. Excellent in the wet, but I imagine they don't have the same dry grip as the Mich PSS.

Tyre pressure will come down to the type of driving you are doing. Forgot to mention that in my first post. From memory, 38-40 is default.

[Ken Oath]

You need to provide the ETRTO tyre information from the sidewall to determine the load inflation information.

The load index and speed rating is what is required. eg. 255/30 R19 91 Y XL

[jadatis]

And once you determined the ETRTO tyre information like former poster gave and example of, you also need axle weights in your use, or better axle-ends weighed ( so for your car per wheel).
The car-maker calculates the pressure-advice nowadays for maximum technical car speed and MPAW ( max permissable axle weights ), wich you can find on the VIN-plate , that every European car must have since about 1980.

So look on tires ( or ask when searching ) and on that VIN-plate for the needed information.

If you want to know it for normal use , wich is mostly max 3 persons and a little load and speed up to 160km/99m/h. I can estimate the axleloads when you give me empty weight of car, asuming motor in front so front more heavy.
If you use other maximum speed ( you wont go over for even a minute) give that speed and I can give a more precise advice-pressure.
So for every axle also need the tyres used, in your case different.

Greatings from a "Pigheaded Dutch Selfdeclared Tyrepressure-specialist"
( ja dat is) Peter ( from a Dutch name song means Yeah thats Peter)

[DTM_]

Originally Posted by satz

hi Monty, sorry my typo.. what I'm getting is F: 225/35/19 and R: 255/30/19

Will try to edit my original post.

I stuck with the 225 (rather than 235) at front to maintain same footprint and rolling diameter as my current 18s. Didn't go for wider tyres as I wanted to keep weight down, and not over-tyre the car.

cheers

Hi Satz - for what it's worth, I reckon the advantages of going for the 235/265 combo are worthwhile.
I did with my car a year ago when I changed over from P Zero RFTs to Mich PSS' and found that they are lighter than the RFTs; the wider size fits without rubbing the fenders; the PSS higher profile actually raised the ride height by about 9mm, but it still scrapes a lot; and the +1 size corrected an optimistic speedo error. The ride quality is also much better.

I am still experimenting with tyre pressures - currently using 34psi F&R which is OK around town - I have not been on the highway yet with the PSS' thou.