Tyre pressures

[davekmoore]

Correct tyre pressures for 185/60 14s on a road car?

[StanTheMan]

is it 28 psi on the door pace card? But I'd go to about 34psi.

thats assuming its an NA with those tyre sizes

[NMX516]

Everyone around here has a different opinion on this one. My advice, start at 36psi, go up from there if not getting the performance you want. The higher the pressure, the better and more consistent the contact patch that the tyre has with the road. Higher pressures will give less flex in the tread and sidewall, giving more consistent performance and better grip as well as a more responsive drive. Higher pressures also help to open the tread blocks apart to allow for better water clearing in the wet.

[davekmoore]

Thanks. Starting at 34 and will work upwards if necessary. Were at 40 front and 34 rear previously.

[Charlie Brown]

Everyone around here has a different opinion on this one. My advice, start at 36psi, go up from there if not getting the performance you want.

Yep you're correct with that comment. For me 36psi is the pressure you use when you put the car onto the track or if you are running a heavy car similar to a Commodore / Falcon, not an MX-5, especially with aging shock absorbers. Remember the tyre is the first part of the cars shock absorbing system.

The higher the pressure, the better and more consistent the contact patch that the tyre has with the road. Higher pressures will give less flex in the tread and sidewall, giving more consistent performance and better grip as well as a more responsive drive.

Also better fuel consumption but all this is at the expense of the ride quality and the ability to keep the tyres in contact with the road through bumps, rough corners that abound on Australian roads.

Higher pressures also help to open the tread blocks apart to allow for better water clearing in the wet.

Good advice but there needs to be a compromise as you don’t want to be racing to the servo to pump up your tyres every time it looks like it might rain.

Mazda spends a lot of time and money in conjunction with the OEM tyre manufactures determining what is the best all round pressure to suit the MX-5. Sure the pressures don’t suit some of us who are more, shall we say, sportier drivers or who have tyres with softer side walls like the T1-Rs, but in those instances an increase of only 2 psi will make a huge difference in the overall reaction time of the tyre. Bumping it up by almost 30% for road use is crazy stuff.

The best way to determine what pressures you should be running to suit your driving style is to look at your tyre tread and see where it’s wearing. If it’s worn more in the centre you’re running too much pressure. Worn in the inside and outside then you need more pressure.
Worn on the outside you need more negative camber, on the inside less negative camber, so that's an alignment issue rather than tyre pressure.

[GP]

26 is recomended but I've found 28-30 about the best as it's such a light car

[davekmoore]

34 seems ok. If anything slightly less skittish and a bit more comfy now, but only a minor change.

[93_Clubman]

usually 32psi cold on road, but 30psi cold if car is still a bit skittish

[Col]

After running 32psi cold for the past 5 years, and thinking my car was handling at it's best, I've recently experimented running lower pressures. Firstly down to 30psi and now 28psi. I can honestly say the 10AE has never handled better, with added bonus of a slightly softer ride. I won't reduce below 28psi, but I doubt if I'll ever run as high as 32 again. For me 28psi is a winner!
You never stop learning! Thanks for the advice from a couple of very experienced MX-5'ers.

Col

[Steampunk]

I've recently experimented running lower pressures. Firstly down to 30psi and now 28psi. I can honestly say the 10AE has never handled better...

Do you really mean "handled better"? or do you actually mean "grips better"?

[Col]

Yeah 1red5, the lower pressures really increased the grip and made the car feel more sure footed in all driving conditions. Very pleased with the result.

[Wivvix]

I normally run 32psi, but many people run 28psi with good results.

I was at a track day today and a mate with an NA6 was having traction problems at 36psi. Dropped all four to 32 and made the world of difference.

30-32 is a good starting point, experiment from there.

[93_Clubman]

I was at a track day today and a mate with an NA6 was having traction problems at 36psi. Dropped all four to 32 and made the world of difference.

normally at track days you should gain a handling & safety advantage with higher tyre pressures, which is why it's recommended to run them. perhaps your mate's tyres were significantly worn &/ or compound had hardened from age, in which case dropping pressures would help as you noted. generally track day pressures of high 30s or 40psi don't translate well to the road, which is why you'll see people decreasing tyre pressures before they drive home. but it does vary from car to car (specs/ mods), driver to driver (style), & with prevailing conditions.

[16bit]

i have always run low 30's. i did not check them for about 6 months and they were on 22psi with heaps of grip but possibly why my economy was sooo bad. 32psi for me as a good medium between performance and economy