Donnington booked for the 18th December 2021
I just want for the world not to fall apart for another ten days ( big ask I know )
If I don’t have tyre warmers what tyre pressures to start with? Allow one or two laps to get the tyres warm? NC BBR Super 185 17" wheels Vredestein tyres
Cheers
I was advised to increase recommended tyre pressures by 2 PSI and it worked for me in a NB.
2psi increase? are you sure?
if you are on a track the tyres will get very warm (much warmer if you were driving on public roads) so generally if you want them to operate at designed pressures at track temperature you want either to use tyre warmers and set the pressure at the correct value or what most of us do is to start with a lower pressure and so a few laps slowly increasing the pace until they get up to temperature.
well after a quick search I found a few similar threads on the subject but not one answer - because there isn’t “one size fits all”.
I still believe you will need to reduce tyre pressures, by how much I guess its different for each individual, track temperature, the size of the wheels (16 or 17 rim means there will be two different tyre aspect ratios) and how hard one will push the car around the track. I guess I will get the pressure gauge and measure the tyre pressures 10 laps in the first session and take it from there.
For what it’s worth, on a track day, I start at a cold pressure of the Mazda suggested 29psi in my NC1 which when checked after 6 or 7 laps gradually getting faster, have risen to 33 or 34psi. I then drop the pressures again to 29psi in their warm state after another 10 laps or so.
Upon returning to the paddock, I check again and if there is any rise (usually 1.0 to 2psi) I drop them again back to 29psi.
It seems to work fine in my case, every time. I run MeisterR coilovers which I adjust to help the ride/roadholding rather than rely/allow the tyres to dictate (to some degree)
If as expected say after lunch, I’ll do a build up of 5 or 6 laps then return and check again and 9 times out of 10, they’re within 0.5 of 29psi.
Don’t forget to add a little for driving home afterwards when you, the car and tyres have cooled down.
thanks mate
definately worth dropping a couple of psi for track, I do mainly bikes and go from 36 road to 30 for track and journey to and fro - 29 seems to recommended pressure so probably start about 25 cold and see how it goes - pump and gauge needed and big smile
Ambient temperature will be lower so harder to get heat in your tyres which maybe why it was suggested to increase pressures to warm up quicker - unless you’re a track god 
We did oulton a couple of weeks ago and the tyres were barely warm after a run but it was freezing. Also I’m no track god 
I don’t think that’s possible to be honest, if you set your tyre pressure to lets say 29 psi before you set on the trackway, it will be 29 psi when you start driving. If temperature inside the tyre increases gas expands, if it increases too much then you will have ovalized tyre which means reduced contact patch and uneven wear. The whole point starting with slightly lower pressure is to have the 29 psi while you are driving hard on the track. I wouldn’t be surprised that for trackdays if the front tyres need to be at a different inflation pressure from the rear tyres.
To give you an idea on my sports bike I used to use 36 front /42 on the back tyre for normal road use but on trackdays I used 32 /30 (yup it was lower on the rear tyre). If you don’t have/use tyre warmers you effectively have to do (loose) 2 laps each session in order to get the tyres warm (or you will be picking the bike up from the a ditch somewhere 
)
But, if the standard tyre pressure is 29 cold then it is expected that it will increase in normal use to 31/33.
My theory is that the track and ambient temperature in December is low so it will be harder to get to the optimum/normal temperature in standard tyres. That was my experience a couple of weeks ago anyway but I’m not that hard a driver.
With track based tyres different story, and as you say with bike tyres which are already softer so warm up easier and you would reduce the pressures less in winter.
yes exactly, that’s what I’m saying; it cannot be more than 29 psi, Maybe in the winter/summer one need to use different inflation pressure to start with (lets say 26 winter 24 summer?? - I don’t know whether this is a good starting point). However I don’t really think it would be that critical for amateur track use - my lap times will have differences in seconds not tenths 
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So I have been reading a bit more and I found this interesting article (this is page 4 I think so may be worthwhile to go back and read from the beginning of the article if this subject is of interest)
I think I will start with 29 psi, and come out after 5 laps, measure the pressure and see how the tyres look like
First post so please don’t flame me.
Someone stated above that there is no correct tire pressure, this is almost true.
Every tire made has an optimum tire pressure for the carcass and weight of the car. TOYO used to issue recommended hot tire pressures for a given chassis weight for their 888 tires. I don’t know if they still do. I would suspect that this info is probably only available for list 1b tires. So the only real option is to start with the Mazda recommended cold pressures and use that as the optimum hot pressure all round. On a light car, cold tire pressures don’t really change much for road driving, maybe up by 1-2 psi max.
For track days there is only one way to effectively pick the correct cold tire pressure for the car and that is by optimizing each tire after a few laps. The only effective way to do this is using a Tire Pressure Monitoring System.
From what I can tell, the cheapo ones on ebay that fit onto the valves only send a pulse every 5 mins which is no use for track day stuff. You will need one fitted inside the wheel giving a signal at least once every few seconds.
Tire pressure can drop maybe 2-3 psi on the cool down lap coming back into the pits so measuring with a gauge after you have stopped is not as effective. Normally the outside front tire will increase 3-5 psi where the inside will go up by 1-2 psi. The aim is to get all four tires at the same pressure after maybe four laps hard running. The difference in car feel and confidence is significant.
Buy a good TPMS system. It has the potential to improve your lap times much more than a set of fancy dampers.
And if you notice the fronts are different to the rear in this picture, that is because they are different size tires on the Elise with different recommended hot pressures from TOYO…
Tbh I’m not sure a tpms sensor is as good indication or at least it would be just part of a series of sensors used. I think most teams use heat cameras on the whole tyre width to check for wear and indication whether wheel geometry needs adjusting (or the effect of)
For the occasional trackday user… A gauge meter once you have done a few laps is all thats needed. If stuff come off your road tyres you essentially are asking too much from them. Reduce tyre pressures and if that doesn’t work then you need track tyres.
Sorting out tyre pressures for track use really isn’t difficult, but is often neglected and/or got completely wrong!
The tendency is to run pressures that are far too high. Many believe that you should start out with pressure set as per cold recommendations in the Owner’s Manual. But then never check them and assume all will be well.
I reality, unless you drive mega slowly you will find that pressure come up way beyond normal recommended hot pressures. 35ps hot from a starting 29psi would be normal, and they might even reach nearer 40psi. At those kinds of pressures you really won’t be getting the best out of your tyres so you have two choices - either start off with lower pressures or check pressures when you come in off circuit and adjust down from there.
Normally I’d do both. So maybe start with 26 psi all round cold and then check after a ten to 15 minute track session. The longer the interval between coming off track and checking the pressures then clearly the more they will have dropped, but don’t worry too much about that because you the odd psi difference here or there won’t really make much difference to how things feel actually on track. And as already mentioned, on right hand circuits it’s normal for a left front to reach a higher pressure than a right front. So bear that in mind. In my experience it’s not normally more than 1-2 psi.
The “clever” bit is deciding on the optimal hot pressure for your car given the particular tyres you are using and your personal driving style. And there are no hard and fast rules about getting this right. Some really good drivers can help with feedback of what going on eg “I’m feeling that the front end isn’t quite connecting” and you might then try to drop the front pressures a bit, but you then need to get the car back and see if that’s made any difference, whether for better or for worse. And never make multiple changes at one go eg a tyre pressure and damper setting change.
At the end of a track day, if at all possible, let your tyres cool down completely - easy if trailering, less so if you need to drive the car home. And you’ll be amazed at just how much the pressures will have dropped. On one fwd race car I do quite a lot of stuff with we target 30psi hot all round, but that will produce stone cold pressures of as low as 16psi front and around 21/22ps on the rearsi!! And that’s the other thing to watch - if you do need to drive the car home you most likely will need to put pressure back in before you set off.
Another thing to be wary off on a road car is that whilst dropping pressures may be the best way to improve grip, but you may find that under hard cornering you start to wear the shoulders of the tyre. To get round this we would normally add static negative camber, but that might not be best for a road car so then you may have to compromise by running higher tyre pressures. Better that than risking severe tyre damage.
I’ve done a few trackdays with the five since I asked the question. what has worked for me is to start around 26 psi cold and check pressure after 5 laps. adjust pressure and check tyre condition. I fully agree you cant have one recipe that works for everyone. The conditions on the day (air and track temperature) as well as the effort you put in and what you ask form the tyres are too many variables to recommend a tyres pressure to someone. I wholeheartedly agree with this…
I would also say look for weird wear marks on the tyres. if you see bits peeling off then you are cooking your tyres and you have successfully migrated from a novice to having to buy track tyres… if you are in between sessions either stop a couple of laps earlier or ease off a bit.
Mind you, track tyres can withstand more abuse because they are built different to road tyres but for the same reason do not work at low temperatures. If you can’t keep the heat into track tyres then you will be worse off using them.
Just my experience to date.
This is the way to do it. Start at manufacturers standard pressure from cold and do few laps, maybe 3-5 depending on the size of the track then come back in. Don’t be tempted to stay out longer.
Check pressures and drop them back to the original pressure. Go out and do a few more laps and repeat.
It will eventually stabilise and you’ll be able to stay out for longer sessions.
Just don’t forget to let them cool at the end of the day so that you can put air back in them from cold.
30 hot all round, is my go to
I stick to 28 hot on road tyres and there’s good even wear with loads of grip. Ps5 are very predictable and extremely happy how they perform.
For me generally this translates to 24-25psi cold
Don’t reduce tyre pressure below what you would be normally running with immediately before going to the track. Go with standard pressure, do a couple of laps and come back to the pits. Temperature will drive pressure higher obv, then you can measure and release until you get the sweet spot. It seems there is no difference, but if you go to the track with low cold pressure, until you heat them you may damage tyre wall pinching against the wheel. So the “two laps warm up and check again” practice can save you tyres and a whole session trying to find a mobile tyre seller/fitter while on track 
