Hi
Before any one say i have tried searching and have been looking that last 30 minutes but could only find info on Track day pressure.
So does any one know what pressure my tyres should be at. It only gives me 39’s pressures in my manual
Thanks Guys
Nath
Whilst it’s still cold weather, I’d try 20psi front 23psi rear.
In summer try 23:26.
A lot will depend upon how the car feels to you, & also if over inflated (esp the rears) uneven wear. Car’s geo will also be a factor. It’s surprising how sensitive the exige’s handling is to the difference in a couple of psi.
HTH
Thanks for the sharp response peskey! Main problem if that i have done about 100 miles since i Bought my exige in december and wondered if it has lost any pressure in the tyeres. i am going out in it on sunday so wanted to check this and get them back up to the correct pressure.
Cheers
It would be the contrary Pesky, lower pressures on hot weather and higher pressures on cold.
Because the air inside the tyre will expand more on higher temps.
Look at it this way: you should run the pressures about 24-25 psi front and rear when the tyres are at operating temprature, i.e. warm.
And they don’t get very warm on winter, do they?
for reference, I ran mine at 20F, 18R psi in summer , anything up to 23F, 26R in winter.
And yes, I know the fronts are higher in summer, but that’s the way they ended up after the track session’s adjustments with pyrometers.
Ah, and that’s for 1 hr long sessions, if you do 15 min sessions you’ll have to run them higher because they won’t get as hot then.
Uldis
Interesting one this! There’s no real difference in our opinions of the optimum temp & pressure, it’s just the way of getting there! I do however, appreciate your comments
My take on it is that with a lower starting pressure when cold, the tyre flexes more, thus generating heat, which then in turn creates more pressure.
Fortunately, I don’t now need to use my car much in winter. When I did, & using cold starting pressures of 23:26 (per handbook & Lotus suggestion), I found the centre sections of the rears wore a lot quicker than the sides.
Anyway, I too will have a “play”, as I’m off to Anglesey on Saturday.
I agree with your point of view, for track that is.
In the road (city driving for ex.) tyres don’t really have time to warm up.
But the same applies to warm weather, and the temperature outside is already higher, the rubber is more flexible, pressures will rise quicker, hence lower in summer (as a rule of thumb)
See? we agree!
Ok I disagree with both!
23psi is 23psi whether its summer or winter.
Boyle’s Law applies. When the ambient temperature is low more air in the same volume is required to maintain the pressure. As summer approaches and the ambient temperature increases you will probably need to let some air out to get the right pressures. If you always check the pressures hot then this may negate the problem but be wary of the fact that hot tyres may not have warmed consistently - this is why race teams are so careful to measure tyre temps HOT and to make adjustments when HOT. For road use cold is more consistent but even here be careful - in summer the side with the sun on when parked will have higher pressures than the side in the shade so do it in the garage or just after you take it out. Our cars are very susceptible to tyre pressure changes…
Whether 23/26 is right is another matter altogether and, as suggested, experiment until you find what works for you. Having a little less in the rear (e.g. 23F/24R) will help decrease understeer in my experience.
Whatever pressures you decide work for you stick with them all year round.
And I thought this issue was sorted!
The pressures I mentioned were cold after the correct pressure has been acheieved on track and measured next morning.
Hot look for 24 psi F/R.
And I see where you’re coming from, but you’re not taking into consideration the added heat put into the system by sidewall flex.
In summer heat will build in faster, even in road use.
But hey, if it’s city driving use whatever you like, it won’t make a real difference.
When yu’re looking for traction like in a trackday then go out with a pyrometer until the temps you read are even across the carcass, letting air out if the middle is warmer and putting air in if the outsides are warmer.
After the trackday measure next day the temp.
You will see the cold temps in winter are higher than in summer. And this is not theory, many have proved it countless times (I surely have).
Just try it if you want to convince yourself.
Oh bugger!
Even I find hard not to accept that 23psi is the same in summer or winter!
But a tyre, whose rubber compound/carcass is warm, will behave differently to a cold tyre, at the same pressure for both - won’t it?
My brain hurts!
Mr Pesky I think i’m with you, mine were 23F 26R but the middle of the rears was wearing at a greater rate than the sides. I’m now running 20F 23R because I was also getting understeer in fast bends. Love to tell you if this is sorted out but the cars off the road for a bit. I’ll get back to you when i’m back on the road.
Uldis
I found the centre sections of the rears wore a lot quicker than the sides.
I agree. 26 psi on the rear leads to higher wear in the centre. 24psi gives a flatter contact patch, better control, tendency to drive harder and on the power, less understeer… 26 psi is the factory ‘safe’ setting
amyway, i’m at the edge of my knowledge envelope now so I’m bowing out…
That for all this infor lads, will try out a few of these and let you know how it feels! Now is only it would stop snowing i would go out in the car! YES SNOWING IN APRIL
That for all this infor lads, will try out a few of these and let you know how it feels! Now is only it would stop snowing i would go out in the car! YES SNOWING IN APRIL
Global warming leads to snow in April… ??
Global warming leads to snow in April… ?? [/quote]
True mate, Bet my Exige isn’t helping I blame it on the Yanks though
Nath if your happy now… I should probably stay out of the discussion, but… mmmm… call me mischievous
Anyway, my experience is the same as mentioned above in that when running A048’s on an S1 the book recommended 23/26 (which are cold recommendations) are too high… evidenced by my tyres wearing too much in the centre tread section. I think the front 23psi is a bit closer but the rear 26psi is deffo too high.
For this reason I now try to have them around 20-23 front and more like 23-26 rear WHEN at operating temperatures. The exact temp will depend on where i’m driving and how it feels but anyway they feel better to me in terms of grip when i do this.
As Uldis says… in summer and after a track day this has meant that when I check temps the following morning I have seen pressures as low as 16-17psi COLD. However, doing this has meant my last sets of A048’s have worn quite evenly and I grip has been excellent (at the track i usually allow a couple of ‘easy’ laps tho’ to get them up-to-temp).
Get a tyre temperature tester, anything else is just guessing. The track and air temp on the day can make your ideal preasure vary by so much it makes a finger in the air ballpark figure meaningless.
50-100quid.
Get a tyre temperature tester, anything else is just guessing. The track and air temp on the day can make your ideal preasure vary by so much it makes a finger in the air ballpark figure meaningless.
50-100quid.
Would something like this suffice? It’s a catering thermometer but only �23.50. Eco Temp Thermometer. or this Infrared Thermometer for �35.24. Cheap as chips .
John
I’d go for the infrared one (well, already have, that’s the type I use )
check out this thread
Get a tyre temperature tester, anything else is just guessing. The track and air temp on the day can make your ideal preasure vary by so much it makes a finger in the air ballpark figure meaningless.50-100quid.
But the question is about ROAD pressures… not track pressures which is where such kit can best be used. No-one is going to use a pyrometer whilst out road driving (unless they’re really keen… )