Advice on tyre pressures!
Discussion
After buying my Mazda MX-5 MK2 two weeks ago, I checked the tyre pressures and was surprised they were 31 at the back and 33 at the front. The book suggests 26 front and back for the tyre size of 195/50/50 82. I lowered them a little to 29, after reading some comments on owners forums where a lot of owners run the tyres over the recommended pressures and the back feels much more lively now! That's the opposite to what I expected, as I assumed a higher pressure would give less rolling resistance and hence less grip.
Back tyres are Firestone 300a and fronts, Toyo T1-r. I am thinking that the Firestones have harder sidewalls than the Toyos and wonder if that's why the previous owner ran the fronts at higher pressure.
Anyway, any thoughts on tyre pressures? Is 31 too high on a recommended pressure of 26?
Perhaps I should have left the pressures alone, it drove ok as it was. Now I have tampered with them, I am struggling to find the ideal pressure!!
Back tyres are Firestone 300a and fronts, Toyo T1-r. I am thinking that the Firestones have harder sidewalls than the Toyos and wonder if that's why the previous owner ran the fronts at higher pressure.
Anyway, any thoughts on tyre pressures? Is 31 too high on a recommended pressure of 26?
Perhaps I should have left the pressures alone, it drove ok as it was. Now I have tampered with them, I am struggling to find the ideal pressure!!
As you say, 26psi all round is the recommended pressure. T1R do have soft sidewalls so I tend to run a couple of psi higher on mine (30psi summer and 28psi winter i.e. from now to about April). The Firestones will likely have stiffer sidewalls but also they are likely to be a bit crap (all relative - MX5s are quite sensitive to tyres) so will likely need a bit less pressure.
If it was mine I'd dump the Firestones and fit matching tyres all round. Failing that, I would at the very least swap them around so the Toyos are at the rear. You should always have the best tyres at the rear.
Additionally - get the alignment (full 4-wheel laser alignment, not "tracking") sorted. I'll bet it's a fair way out if you don't know that it's been done in the last couple of weeks and it can completely transform these cars.
If it was mine I'd dump the Firestones and fit matching tyres all round. Failing that, I would at the very least swap them around so the Toyos are at the rear. You should always have the best tyres at the rear.
Additionally - get the alignment (full 4-wheel laser alignment, not "tracking") sorted. I'll bet it's a fair way out if you don't know that it's been done in the last couple of weeks and it can completely transform these cars.
MX-5 Lazza said:
As you say, 26psi all round is the recommended pressure. T1R do have soft sidewalls so I tend to run a couple of psi higher on mine (30psi summer and 28psi winter i.e. from now to about April). The Firestones will likely have stiffer sidewalls but also they are likely to be a bit crap (all relative - MX5s are quite sensitive to tyres) so will likely need a bit less pressure.
If it was mine I'd dump the Firestones and fit matching tyres all round. Failing that, I would at the very least swap them around so the Toyos are at the rear. You should always have the best tyres at the rear.
Additionally - get the alignment (full 4-wheel laser alignment, not "tracking") sorted. I'll bet it's a fair way out if you don't know that it's been done in the last couple of weeks and it can completely transform these cars.
Thanks for that, I completely agree about the Firestones! They actually squeal since I reduced the pressures down to 28 near the limit and really don't have a great deal of grip! The back comes out at fairly low speed tbh. I haven't owned a car that squealed on the limit for years!If it was mine I'd dump the Firestones and fit matching tyres all round. Failing that, I would at the very least swap them around so the Toyos are at the rear. You should always have the best tyres at the rear.
Additionally - get the alignment (full 4-wheel laser alignment, not "tracking") sorted. I'll bet it's a fair way out if you don't know that it's been done in the last couple of weeks and it can completely transform these cars.
However, flicking through the Mazda MX-5 owners Club forum which I joined yesterday, there was a fair bit of negativity on there towards the Toyos. Therefore given my general dislike of squishy tyres, I might ditch all four...
But I am open to suggestions and it would be cheaper just to buy 2 Toyos as they are only £45 each at Blackcircles!!
Tyre alignment seems a good idea! Previous owner spent tons on the car and all four tyres are fairly new. He may have had a tyre alignment done. Actually seems a pity to ditch almost new tyres!
My suspension guru, who has loads of MX5 experience, recommends 1.8 bar (26psi) all round regardless. Seems to work for mine.
Regarding tyres I've just been looking at new fronts and F1 Autocentres on-line will do Michelin Pilot Sport 3's for £57.40 fitted. I can vouch for their all-round performance, especially in the wet.
We were at a Combe track-day in July when it tipped it down all day.
The track was saturated and the Michelins had more grip than I was able (or willing ) to explore!!
Second Lassa saying you need the same tyres all round and proper alignment.
WIM Chesham have a Hunter and know how to use it.
Both the above companies are of course South East but there are others who know what they are doing....
HTH.
Cheers, Pewe.
Regarding tyres I've just been looking at new fronts and F1 Autocentres on-line will do Michelin Pilot Sport 3's for £57.40 fitted. I can vouch for their all-round performance, especially in the wet.
We were at a Combe track-day in July when it tipped it down all day.
The track was saturated and the Michelins had more grip than I was able (or willing ) to explore!!
Second Lassa saying you need the same tyres all round and proper alignment.
WIM Chesham have a Hunter and know how to use it.
Both the above companies are of course South East but there are others who know what they are doing....
HTH.
Cheers, Pewe.
MX-5 Lazza said:
As you say, 26psi all round is the recommended pressure. T1R do have soft sidewalls so I tend to run a couple of psi higher on mine (30psi summer and 28psi winter i.e. from now to about April). The Firestones will likely have stiffer sidewalls but also they are likely to be a bit crap (all relative - MX5s are quite sensitive to tyres) so will likely need a bit less pressure.
If it was mine I'd dump the Firestones and fit matching tyres all round. Failing that, I would at the very least swap them around so the Toyos are at the rear. You should always have the best tyres at the rear.
Additionally - get the alignment (full 4-wheel laser alignment, not "tracking") sorted. I'll bet it's a fair way out if you don't know that it's been done in the last couple of weeks and it can completely transform these cars.
The handbook for my wife's 06 plate car quotes 29psi all round,it also states these pressures on the door shut plate.(fitted with Toyo all round)If it was mine I'd dump the Firestones and fit matching tyres all round. Failing that, I would at the very least swap them around so the Toyos are at the rear. You should always have the best tyres at the rear.
Additionally - get the alignment (full 4-wheel laser alignment, not "tracking") sorted. I'll bet it's a fair way out if you don't know that it's been done in the last couple of weeks and it can completely transform these cars.
Edited by cjb44 on Tuesday 27th October 18:45
MX-5 Lazza said:
You are wrong.
In what way? I have thrown things around from tiny vans to larger 300+ bhp RWD / FWD motors and just always stuck 30 psi in. Never had a problem. My Jag wheels were running 20, 24, 26 and 34 psi when I collected it and you would struggle to notice.It now has 30 psi all round but doesn't drive significantly better or worse. All seven of my old MX5's including the turbo had 30 psi in them and some of them took a serious pounding. Same with my Westfield, T5's etc etc..
I would probably look in to it if I were on a track or something very specifically needed a much higher or lower figure, but average types of tyres on average cars, I just stick to what I have done for 28 years.
MX-5 Lazza said:
I'm not going to bother with a long post on this one but do you seriously think an 800Kg Westfield, 1100Kg MX5, 2000Kg Jag and 3000Kg van all just need 30psi?
Van would be more, as for the rest, they all have / did.If you look up Jag tyre pressures, you are presented with a table listing dozens upon dozens of psi figures ranging from 26 to 33.If you ask on the forums, they will say the same.
If you ask on the Westfield forum what pressures most run, they will suggest figures from 18 to 30 depending on which car you have, which wheels you use etc etc (lots of variables)
If you ask on various MX5 forums, the suggestions will be much the same again.
I always went with a middle figure on almost everything and have never had a single issue. I would be highly suprised if someone could go out for a blat and leave behind a car running a few psi less or a few psi more. If it mattered that much, we would be seeing cars with slightly leaking valves etc upside down in fields all the time.
Hill climbs and races may produce different results with different psi figures, but would probably still only matter to those who need to shave a few seconds off a time.For most of us, it won't really matter; not to mention many will be chucking air in at a petrol station or with some Halfords foot pump - hardly the last word in accuracy.
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