what tires...we start the toyo ra1s at 25/26 lf,rf and 29/30 lr/rrend up at about 32 all around
Track day tire pressure methods.
What method works best for setting your on-track tire pressures?
Do you run 3-4 laps and bring it in?
What I have been doing is starting them out really low (25/24ish), and letting then warm up for the first couple laps, where they rise to 36-40ish. My target pressures are around 36/30, but I'm always off the mark at a track day because I typically wait until the END of the session to check them... and consequently haven't developed a good starting number for cold morning tires.
I was rethinking my minor issues with handling balance, and I bet it could all be traced back to inadequate control of hot vs. cold tire pressures.
What is your methed?
I intend to document this time so I know where to start from next time.
Do you run 3-4 laps and bring it in?
What I have been doing is starting them out really low (25/24ish), and letting then warm up for the first couple laps, where they rise to 36-40ish. My target pressures are around 36/30, but I'm always off the mark at a track day because I typically wait until the END of the session to check them... and consequently haven't developed a good starting number for cold morning tires.
I was rethinking my minor issues with handling balance, and I bet it could all be traced back to inadequate control of hot vs. cold tire pressures.
What is your methed?
I intend to document this time so I know where to start from next time.
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I apologize, I thought I had listed.
A032Rs.... My typical favorite autocross pressures are around 36/30.
I also have a set of RA-1s, but I won't use those until the A032Rs are dead.
A032Rs.... My typical favorite autocross pressures are around 36/30.
I also have a set of RA-1s, but I won't use those until the A032Rs are dead.
If you have a pyrometer (sp?) use it to determine the proper temps across the tire. When the temps are close to equal you will have adjusted the tire pressure correctly. Then when the tires cool off at the end of the day you will have your starting pressure. Note due to environmental factors this will still not bring you to the same hot pressure the next time you run, but you will be very close. (Humidity, Barometric pressure, etc.) If you are going to do the pyrometer method let me know and I'll try to pass on what I learned at the SVTOA day.
If your car is still camber challenged use the air pressure that keeps you off the sidewalls. Then at the end of the day when the tires cool off you will have your starting pressure. Same disclaimer as above though.
If your car is still camber challenged use the air pressure that keeps you off the sidewalls. Then at the end of the day when the tires cool off you will have your starting pressure. Same disclaimer as above though.
On my first session on the day I will normally do 4 or 5 laps and then take temps and PSI readings, and I’ll take at the end of the session. I normally find that the PSI should be the same after 4 or 5 laps then it would be after 8-10.
After that I’ll take pressure and tire temps at the end of each session for the rest of the day. Now, on Toyo RA-1 205/40.17 I will start out with 25 psi in the fronts and 30 in the rears if the track temp is around 95 F (will plus or minus 1 psi per 10 degrees of track temp). My target hot PSI is 30-31 in the fronts and 33-34. The only problem I have seen with the ZX3 is no matter what we do, we can not get enough tire temp in the left rear and it doesn’t matter what track or direction we are going. Because of this I might add a pound or two in the right rear.
After that I’ll take pressure and tire temps at the end of each session for the rest of the day. Now, on Toyo RA-1 205/40.17 I will start out with 25 psi in the fronts and 30 in the rears if the track temp is around 95 F (will plus or minus 1 psi per 10 degrees of track temp). My target hot PSI is 30-31 in the fronts and 33-34. The only problem I have seen with the ZX3 is no matter what we do, we can not get enough tire temp in the left rear and it doesn’t matter what track or direction we are going. Because of this I might add a pound or two in the right rear.
and omni...less on left side because on most tracks the majority of the turns are to the right...heck lime rock has only one left turn
I have an IR pyrometer that I am still getting used to using, though I've read recently that a contact pyrometer might be better for tire temps due to surface vs. embedded temps. Not sure what others have experienced with that.
The car isn't camber challenged, thankfully, so I can run fairly low pressures.
The car isn't camber challenged, thankfully, so I can run fairly low pressures.
Omni, I just emailed you the Toyo tire test notes for the Spec Focus.
Great point Gary. We are aligning the Cobras different from left to right for the same reason.
Gary have you ever had any problems get enough Tire temps in the Right Rear?it has worked well for us
not that i recall..well last week at the glen, because of the rain we just went with 30 all around..worked very well..qualified 3rd overall
Yeah, It always happens to me, It also happen to the Spec car, and Andrew said it happens to his USTCC car as well. Because of this we have thought about adding weight to the right rear for all ZX3 spec cars, I don't know if they have a problem with sedans.not that i recall..well last week at the glen, because of the rain we just went with 30 all around..worked very well..qualified 3rd overall
ah wait a moment..that is where our big old battery is mounted...
Loren
Most companies will list an optimal temp range (Kumho is 35-40 (hot), about the same for Goodyear.
I will start 36-38 and then check again when I come in. If they are in the 40-42 psi range I leave them alone. Trick is where they are hot and cold. If I get ready to go out and they are still warm, no problem. If they are cool and still in the 40's, I bleed.
Most companies will list an optimal temp range (Kumho is 35-40 (hot), about the same for Goodyear.
I will start 36-38 and then check again when I come in. If they are in the 40-42 psi range I leave them alone. Trick is where they are hot and cold. If I get ready to go out and they are still warm, no problem. If they are cool and still in the 40's, I bleed.
The ECSTA V700 will work well on most cars with inflation pressures between 35 and 40 psi ("cold" inflation pressures for autocross use and "hot" inflation pressures for racing use). Cars that are light, well-balanced and relatively easy on tires will find slightly lower pressures may work for them, while heavy, high horsepower cars that are generally harder on tires may find that they need slightly higher inflation pressures.
Recently attended a seminar by Kenny Brown about tire temps and have to say it was one of the best things I've learned this fall. I won't try to hack up the seminar but, instead would say that a tire pyrometer (probe kind) is the single best non-car part investment. I found I was over-inflating even at just 36lbs (cold start) on my kuhmo MX. At VIR, I was running dramatically different pressures on each corner. After using his guidance, my tires look like I hadn't even been out on track (other suspension changes helped too). Wear looked perfectly even and his guidance has you taking out as little as a "pssst" after taking readings. Not sure if his site has anything about it.
There are probably better experts here, but if you'd like me to share the info to the best of my ability - pm me.
There are probably better experts here, but if you'd like me to share the info to the best of my ability - pm me.
Have you tried running your Toyos at higher pressures ?
The spec sheet I had found for RA-1s recommended running them at 40 hot. I have been running them in the low 30s cold and end up at 40 hot after a few laps.
Albert
The spec sheet I had found for RA-1s recommended running them at 40 hot. I have been running them in the low 30s cold and end up at 40 hot after a few laps.
Albert
they are greasy enough after an hour or two of racing...that would be murder..i went with advice from world challenge team and have been very satisfied
I find if you go into the 40s they are just too hot. The tire temps are not even across the tire (much higher in the middle), and they'll start to loose some grip.Have you tried running your Toyos at higher pressures ?
The spec sheet I had found for RA-1s recommended running them at 40 hot. I have been running them in the low 30s cold and end up at 40 hot after a few laps.
Albert
I know on the Toyo Spec sheet is says the High 30s to low 40s... The funny thing during our Toyo test with the spec car the Toyo race engineer said to run the tire between 32-35 hot.
1 - 20 of 34 Posts
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