So let's assume that I've figured out on a given day at a given track what tire pressure to use in my dry weather tires (shaved Toyo RA1s). And it begins to rain so I switch to rains just before the start.
Is there a rule of thumb re tire pressure to use in the rains (full tread Toyos) in this situation? My gut tells me that I need to put in more air as the tire will be running slower - and also cooled by the rain.
Car #: 80
Year : 93 Posts: 602
Be careful about putting in more pressure than you would in the dry. If the rain stops and you start to get drying on the racing line your tires will heat and pressure will go through the roof quickly. Over about 42 hot is getting too high. When it dries the pressures can go up 8 or 10 psi. So if you start with 38 and it goes to 48 that sounds dangerous to me.
Region: Northwest, Oregon
Car #: 79
Year : 90 Posts: 3336
I'm another "lower pressure works better for me" person. In downpour conditions at Portland last month, I ran 29.5f/27.5r cold, and it worked great. The car was very neutral. Grip was good enough that I was able to stay on the track during the race while many others spun off- that alone was enough to return one of my best finishes ever.
I've tried higher pressures in the rain, and the car never felt as good.
-------------------- Crew Chief, 3D Racing #64, aka Team Scrappy 2.0 3rd place E2, 2009 25 Hours of Thunderhill
Crew Chief, EGR/Miller Motorsports #64, aka Team Scrappy E2 Champions, 2008 25 Hours of Thunderhill
Loose Member '09 & '10 Great Lakes Regional Points Champion
Region: Cincinnati Great Lakes
Car #: 60
Year : 1990 Posts: 1487
This thread is obstensibly about full tread Toyo's but the pressure discussions seem to bear on running shaved RA1's in the rain. My question is at what pressures are folks running full tread Toyo's? Rick
-------------------- Fortune Cookie Racing SM 60 Directions for use: Race, Rumple, Repair ... Repeat!