Watch your pressures!

[pepejesus]

I've got Toyo T1Rs in 205/50/15. I can't stand them at anything less than 35psi. I usually run them around 36psi.

I have no idea whether the higher pressures are empirically faster but they sure do feel nicer. The tyre is very soft and unresponsive at lower pressures.

I'm starting to think I should have got the RT-615s instead; I was worried they would be too aggressive for the street but I'm not a huge fan of the unresponsiveness of the Toyos. Great all-around tyre, though.

[wun911]

When I did the driving course that came with buying the MX5, the instructor advise to pump the tyres at 35psi @ city driving and about 38psi highway driving. I've been doing it since.

Why more pressure when doing freeway driving???

My theory is driving faster heats up the tires and thus gives even more pressure???

[Nark]

What you guys are saying with the T1Rs is absolutely right.

When I got my MX-5 a month ago it was running 28psi and I couldn't stand it!

I'm slowly building up the pressures to find the sweet spot for these crap tyres. Currently at 34psi and still going up.

I've got 225/45R18 RT615s on my spec.B Liberty and they're absolutely fantastic! Sidewalls are stiff but not class-leading.

If you want stiff sidewalls then have a look at the RE050As. They were OEM on the Liberty and are as firm as you can get. They're also hideously expensive and don't grip anything like the RT615s though...

BTW I rum 42psi on the RT615s. 40psi on the RE050As. I find I need to run the higher pressures 'coz the RT615s can squirm a bit.

Why more pressure when doing freeway driving???

My theory is driving faster heats up the tires and thus gives even more pressure???

I wondered about this as well. I think it might be wise to ignore everything that that person told you...

[Biggles]

Geeze, Benny! I hope you held onto them for the next 'burn-out' day!

With your LSD and that sticky rubber, we could coat the pan in tyre goo (that's all that would be left of them with your HP) and you could take the canvas hoops off and throw them away, deeply satisfied that you have wrung every cents worth out of them!

[marvis]

I check mine way to much, like every 3-5 days, or if I'm going for a thrash I'll check before hand.

[Quicksilver]

I read on another forum that to check if you hve the right tyre pressures:

1. Inflate tyres to pressure you believe correct.
2. Drive about one hour at 100kph to get full operating temperature.
3. check tyre pressures as soon as you stop.
4. Pressures should now be 4 psi higher than when you started.
5. If higher, tyres are too hot and need less pressure.
6. If lower, tyres are too cold and need more pressure.

I haven't tried this yet on the MX-5 but seems about right on the Commodore and caravan.
Anyone else tried this?

[AJ]

too many variables in the scenario quicksilver, that is why the tyre industry adopted the "check pressure at cold" format, the wide variety of profiles in tyres these days preclude your suggested method from being accurate, as well as actually finding an area where you can maintain a constant speed for an hour, one good hard jump on the brakes skews the results completely, as the heat that is radiated out through the rims to the tyre affects the results. The low profile performance tyres we run on our lightweight sports cars react in a different way to heat build up to say a standard 65/75 profile tyre on a family sedan (not that many of them run those profiles these days) I wouldn't take that method as gospel mate, but hey, it's worth a try if you can be bothered.

[GP]

5. If higher, tyres are too hot and need less pressure.
6. If lower, tyres are too cold and need more pressure.

These 2 are the wrong way around

[Caffeine]

I only check it because I want better milage.

I have same size wheel and usually aroud 32 psi for me.

wow... I cant handle mine with more than 28.

I guess you don't have super hard bushes . But my size RT 615's are 50 profile

I run 36 in mine, with the same bushes as you STM!

Not as stiff suspension though I think...

[matt9111]

Wow, my tyre pressures are WAY out, the fronts are 28, and the rears are 32, maybe ill, try 36 on the front and 38 on the rear, sound high though?

I used to drive a 4WD in the bush alot, so I never had my tyres above 30, because it took to long to deflate them...lol so lazy.

The reason I run different pressures on the front to the back is I found my car was under-steering a lot more than it should be, it seems to behave a little differently now, but certainly isn't as responsive

Im just on standard rims, and using (please don't laugh, haha but I know you will) Savis somethings on the front 205/45 R16, and Champiro GT's on the rear 205/45 R16's

[bensale]

I've found that around 38-40psi feels a lot better to me than the lower pressures. This is a na6 running the 16' 205/45 nb8b wheels running bridgestone turanzas.

Matt you'll be amazed the difference high pressures will make, pressure seems to make a huge difference with these.

I run slightly higher pressure on the fronts as it seems to improve turn in slightly. Although I am far from an expert though, this is just what feels right to me...

[matt9111]

I agree with you on the turn in, but I felt mid corner they'd just overheat and then I'd understeer, but I'm definitely going to try higher pressures anyway, maybe I'll just buy some good tires, haha