Trackday tire PSI checking

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JackAttack

JackAttack

Joined
Jul 21, 2017
Messages
168
Location
Nj
Hi all, this is something that's recently come to my attention. Normally when I do trackways, I ensure the PSI is to my liking before the first session when the tires are cold. And then for the rest of the day, I don't touch it. However, usually by the end of the day, my feel on the tires gets gradually worse even if my tires are still in great shape. I always chalked it up to the heat rising on the track, tire degredation, ect, but is it because I'm not looking after the PSI in my tires? If so, how do you make sure the PSI remains constant when after a session, the tire temp and PSI jumps and fluxuates?
 
It could be a lot of things affecting your feel - those you list and more. How are you defining "worse feel"? What is it that seems different?

PSI will fluctuate with temp. Check your pressure before a session, and then after a session - you should see an increase of 3-4 PSI typically - so your "hot" PSI. It's an easy thing to rule out. Check the pressure after every couple of sessions, make sure it's pretty consistent. I'd expect a little bit of variation. Not every session is the same.

If you want to keep temp (and PSI) more constant, get tire warmers. But make sure you have tires that can handle warmers. Some tires can't. You'll overheat them, and they'll end up worse.
 
i check my tires hot (under warmers) before the first session, then first thing when i come back in after every session, with adjustments accordingly.


for you to start out cold is a good baseline, but the real value to look out for is hot after the session.
like ghostdog said, warmers are a good option. and in the long run, they are a money- and lifesaver. (get more out of sessions, have more confidence right away and more grip - less crash prone)
 
What tires are you running? And what do you mean by the feeling gets worse?

Always set your cold pressure (and write it down) and then check your hot pressures after each session. As the track warms through the day and your pace gets faster you are going to put more heat into the tires. The tires could get too hot and become "greasy," therefore you may need to add psi.
 
It depends how hard you ride but if you start off on street pressure and do a couple of sessions on track going fast then your tyres will be dangerously over pressurised. If you are just doing low novice group then it's probably perfectly fine but anything above that you should definitely be compensating by dropping the pressure and checking it after each of the first few sessions and again after lunch.

What tyres / pressure are you using and what group are you running in?
 
Thanks all. I currently run Pirelli supercorsa but had the same experience on dunlop q3 in the past. I run them at 31/31 cold and also don't have warmers. I always thought they weren't worth it considering I use DOT tires.
Regarding the feel, i would say greasy is a good word for it. Also a little sluggish in the change of direction which could mean i have too big a contact patch and need to go up in psi as the day goes on. Hi-speed suggested that but then Royal, you say to lower the psi. So not sure if the best move but I have tried to lower the psi in the past and that definitely didn't feel better.
I guess i need to invest in warmers but as was mentioned, will they damage a DOT tire like the supercorsas?


-Jack
 
You need to tell us what group you are running in? I'm guessing novice group in which case the front will likely go up to about 32-33 psi which is about right when hot, the rear is too high though and is likely to go up above 32. It should be around 28-29 psi when HOT straight after a session for novice , so you should start off with it at 28 maximum and check it as soon as you get back in. Faster guys usually run them at 26psi.

Again it depends on your group but tyre warmers basically save you tyres and money. A tyre will only deal with so many cycles of getting hot and then cooling again. Supercorsas are basically road legal track tyres so they drop off in grip pretty badly once used a bit. If you do a trackday on a set of supercorsas without warmers then you have pretty much had the best out of them during that day and they are going down hill from then on. A couple of trackdays without warmers and they are pretty awful as they have gone through too many heat cycles. If you are cruising mid novice group then they should last a few track days without any problems but anything faster I would seriously consider warmers if possible.

Note - the front and rear do the opposite things. As you go harder you set the front a little higher and the rear lower. I run 34fr/26r.
 
Last edited:
31/31 cold is kinda high imo. But it's hard to find any consensus when it comes to tire pressures.

I also run supercorsas on my 1199 and I usually run 27R/29F cold in the afternoon. This gives me a pressure increase of about 4-5 psi hot. That has worked really well for me and given me almost no tearing. I've gotten 5 trackdays and 1700 street miles out of my rear tire so far, with plenty left (for reference my pace is at the top of intermediate).
 
Woah, sorry forgot to tell you my group, I'm slow for group 3 but fast for 2. And yes I go to NJMP, I'll have to speak with Markbuilt, he just helped me with my suspension! Totally didn't realize the heat cycles were an issue with non slicks, def going to look into warmers. So far on these supercorsas I've done 3 trackdays and a day of canyon riding. I guess they're pretty much shot then considering the heat cycles but there's still a little bit of rubber left.

So just to be clear on the heat cycles, If I do 6 sessions per 3 track days, without tire warmers, that's like 18 heat cycles but if I had used them, I would only have gone through 3? Also, does queuing up for the track cool down the tires too much while waiting or is it negligible if you just had them on warmers?
 
Assuming your still running Pirelli SC's I run front 31 and rear 28 and both of those are HOT. If you have swapped out to a different tire manufacture the numbers are not valid and you need to find someone running that brand/model for numbers.
 
JackAttack said:
So just to be clear on the heat cycles, If I do 6 sessions per 3 track days, without tire warmers, that's like 18 heat cycles but if I had used them, I would only have gone through 3? Also, does queuing up for the track cool down the tires too much while waiting or is it negligible if you just had them on warmers?
Click to expand...

Yes like that. It's not an exact science as it depends on so many factors such as your riding style and the track surface, ambient temps etc. Queuing for a long time will cool them down a bit but it's not really a heat cycle as they'll still be hot inside. If I'm hanging around off the warmers I just try to go easy for the first few corners and warm them up a bit again by accelerating and braking in a straight line.
 
So what kind/type of warmers do you guys recommend. There's a lot out there when I look and I dont know if dual temp are needed? Pretty sure digital is needed to set the exact temps right?


-Jack
 
JackAttack said:
So what kind/type of warmers do you guys recommend. There's a lot out there when I look and I dont know if dual temp are needed? Pretty sure digital is needed to set the exact temps right?


-Jack
Click to expand...

Having a low setting is nice during long breaks like through lunch. I usually just use the high and low settings on my chicken hawk pole positions.
 
Gotcha. I think someone here mentioned that they do their first run, measure the temp of the tires, and then set their warmers to that setting.


-Jack
 
I'll echo some of the posts... Check first thing when they're up to temp on the warmers, and then it's the first thing I check when I pull in. I try to ride reasonably hard after the checker to keep the heat in the tires. Also at the end of last session, put on the warmers on right away, even if they're off to prevent them from going cold too fast.
 
maslov said:
I'll echo some of the posts... Check first thing when they're up to temp on the warmers, and then it's the first thing I check when I pull in. I try to ride reasonably hard after the checker to keep the heat in the tires. Also at the end of last session, put on the warmers on right away, even if they're off to prevent them from going cold too fast.
Click to expand...



Damn this is some good info


-Jack
 
Maslov seems to have it right.

Setting cold temps is really only going to give you a rough idea, and not something I would rely on. Pressures go up a lot or a little depending on many variables: ambient temp, track temp, circuit characteristics, riding style/pace, weight of bike, duration of session, etc. The most reliable way to account for all of that is not to conclude that "pressures go up 4 psi," but rather to check your temps when you come in -- as Maslov suggests. Second best is to check them when they have been in the warmers for about 45 minutes.

I second Maslov's suggestion to wrap up the tires in warmers as soon as you come in. This makes the range of the heat cycle smaller and also makes the cycle less abrupt. All good for tire life and consistency. For the truly concerned, it's a good idea to throw the warmers on unplugged after the last session/race of the day -- that will give the heat cycle a much slower and gentler transition to amibent temperature.

One final note: if your tires are greasy, I would NOT add pressure without verifying that the pressure is too high. Your tires may feel "greasy" because they are actually over-inflated. Adding more pressure will give you even less grip. In my experience, the answer is usually to go down in pressure, or try a harder compound, or be happy you've reached the limits of your setup/tires/conditions and enjoy.
 
Back in the day I would always go of off the Goodyear reps cold pressure recommendation. And then check my pressure gain coming off the track. If I was getting too much gain I would go up a pound or two on pressure to cut down on carcass flex and reduce heat.
No one used nitrogen back then, now I use nitrogen on my street bikes, race cars, even go karts. It stays much more constant and predictable on gain, due to low moisture content.
 

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