I had 4 new tyres(195/50) and 15" alloys fitted about 6 months ago...what tyre pressure should I now be using...As I presume it will be different from my old 14" ones!!! (12/99)
As I understand it - it's 28psi all round. (12/99)

It all depends........
My owners manual just says 26psi all round, making no allowance for tyre sizes. IIRC
Miata.net says 26-32 psi depending if you want comfort or handling.
My own experience with 195/50/R15 tyres is
26psi - a bit soft
27psi - about right for me
28 psi - a bit hard (guess who's got a digital pressure gauge)

Of course the tyre is part of the suspension system, and so it all depends..... (12/99)
cold 28 psi .. and tyres warm up significantly... helps to have a home compressor! (12/99)

Always use the same gauge when setting you pressures (If you don't own your own then buy one, never trust a the gauge at garage). Also note that digital ones may be easier to read but they are not necessarily more accurate. Set them all to the same value.

Check for even tyre wear. If they wear on the edges of the tread raise the pressure a couple of psi. If they wear on the middle of the tread lower the pressure a couple of psi. (or is it the other way round?)

Set them to 26-30 psi (choose the exact value by how they feel when driving and tyre wear).

CHECK THEM REGULARLY. Tyre pressures are the first thing t check when the handling is a bit 'funny' (1/00)

A word of warning:

After an *interesting* day at Brands Hatch I dropped my tyre pressures back to 28psi and set off home. Nearing home it felt a bit loose, and the brakes were pulling so I stopped and found the NSF almost flat. The skinny spare got me home where I examined the tyre for damage, or leakage from the valve ... nothing to see. As a matter of interest I checked it for pressure and it was down to 10psi, and then I spotted a tiny O ring on the floor. It was the one from inside the metal dust cap, and I can only assume that when it was last screwed back on in the paddock it must have been loose inside, got dislodged and partly depressed the valve pin. I've blown the tyre up and it's held it's pressure for an hour so it seems there's no damage. Obviously the plastic valve caps don't have this problem, but if you've got metal ones make sure the O ring is secure. (5/01)
I'm taking my 5 for the first time to a track day this weekend and was wondering what tyre pressures to use. Wheels are 185/60/14. I'm not planning to do anything completely loony.
About 33psi cold - in my Toyo 195/55/14's Should go up to upper 30's after your 1st session and then stabilise. (6/01)
General rule of thumb. Increase your pressures all round by about 5 psi, possibly slightly higher. If the car feels too skittish later on or too bouncy, then reduce by a constant amount all round. Don't be afraid to change the levels of pressure between sessions to give you a better ride. In theory, if the car understeers too much, reduce sligtly the pressure on the front two tyres, and if the rear end feels too light, then add some pressure there. I find the type of circuit can make a difference on pressure balalnce as well. On most tracks I actually run with the rear tyres 2 psi higher than the front. However on Brands I had the difference as only 1, and if there's been a further session I could have seen me doing equal pressure all round. Next year at Curborough I'll have equal all round as well (try to reduce the understeer on the first and final bends). (6/01)
I'm about to go to the Nurburgring for my first track session... My tyres are all speed rated "R" which is 106mph as I understand it... My question is will this be safe? Obviously I intend to do it anyway, but I'd like to know quite how stupid I am being. From my experience i'd say it seems unlikely I'll be going above 106mph for very long (driving round Europe on empty motorways I managed a top speed of 120mph but felt a bit sorry for the car as I was nearly hitting the red line) but obviously some of you guys might know better... (6/01)

You're soooooo lucky :o)

But the Nurburgring for your first track day!!! (Presume you're meaning Nordschlief (sp?) not the European GP track?? Wouldn't advise it myself - cannot remember the rating for 'R' but you sound about right. The tyres are speed rated for a reason and I would've thought you should be easily be able to hit that at the Nurburgring.

Think you have to ask yourself
a: Are you willing to limit yourself to <106mph
b: If not, are you willing to risk a blowout at over a ton??

Personally I would change my tyres...think of it as a positive though, becuase now you can go out and buy the best there is: Bridgestone SO-2 (although these have been replaced by the SO-3, so maybe hard to find) The SO-3 maybe even better, but is unproven at the moment (although I have seen good reviews in USA)

Have fun! :) (6/01)