Dura Tracs - Pressure?
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scanny
Senior Member
According pressure tables Goodyear Canada sent me the pressure should be at 35-37 psi. I.e. maximum allowed load per axle match 36 psi in the table. I also asked Toyota about it, Toyota send me to a dealer, and dealer said (not knowing Goodyear recommendations) that LT tires should be at around 36 psi.
Initially I ran Duratracs on 44 psi for a couple of days unless I noticed that only center of the tires touched the ground. This makes tires quieter but less planted in slippery conditions. And I guess they wear out quicker. 36 psi seems to be right for front wheels, rear wheels could use less pressure with empty trunk, but since I'm not going to change pressure every time I need to haul somethin I keep rear tires 36 psi too. So I would say don't go less than 34psi and over 38 psi. I have C load tires, but as far as I understood the only difference is in maximum tire load.
Initially I ran Duratracs on 44 psi for a couple of days unless I noticed that only center of the tires touched the ground. This makes tires quieter but less planted in slippery conditions. And I guess they wear out quicker. 36 psi seems to be right for front wheels, rear wheels could use less pressure with empty trunk, but since I'm not going to change pressure every time I need to haul somethin I keep rear tires 36 psi too. So I would say don't go less than 34psi and over 38 psi. I have C load tires, but as far as I understood the only difference is in maximum tire load.
fifthcircle
New member
This thread on TTORA has some great info!
Chalk Test Tire PSI for Street - TTORA Forum
Basic : chalk test
More involved : calculate the actual weight
Super anal OCD : use an infrared temp sensor and lots of math to calculate air expansion at on road temps.....yadda yadda....
Or just run at 36. :bash:
Chalk Test Tire PSI for Street - TTORA Forum
Basic : chalk test
More involved : calculate the actual weight
Super anal OCD : use an infrared temp sensor and lots of math to calculate air expansion at on road temps.....yadda yadda....
Or just run at 36. :bash:
GrantK
New member
The ideal pressure is the one that gives equal contact across the surface of the tire. That is also lower than most people think when putting on different size tires.
Here’s the old school method I learned when I was involved with vintage car racing:
You’ll need a pressure gauge, some flour and a stiff bristle brush.
1) Locate a level, smooth concrete (preferred) or paved empty parking lot.
2) Start with a higher pressure than you think you’ll need, Then drive around for awhile to warm up the tires and air inside. Then head to the parking lot.
3) Stop in an open level spot, dust the leading edge of all 4 tires with the flour.
4) Pull forward just one rotation of the tires and check how much flour is left on the outer surface of the tires, not down in the treads. You should see more on the outer edges and less in the middle. If not the pressure is too low already.
5) Use the brush to clean off the flour, reduce the pressure a couple of pounds on each tire.
6) Repeat steps 3..5 until the flour left on the tires looks even and make a note of the pressure. Note that the pressure for the front and rear may be different (usually is).
7) Repeat steps 3..5 until you just start to notice there being more flour on the center of the tire and less on the outer edges. Make a note of this pressure.
The final pressure is the mid point between the first point where the flour looks even and where the center starts picking up more flour when the tire is cool. So find the difference between the two pressure points and check the tire pressure again when cool and add the ½ the difference between the two noted pressures to the cool pressure and that is your cool tire pressure.
The newer way is to use an infrared thermometer and check the temperature across the tires after driving around on nice twisty roads to get them good and warm or even hot. The actual temperature doesn’t matter. What you are looking for is even temperature across the tire (the temp will be a little lower right at the outer edges, so check about 1” or so in from the edge). Higher temperature in the middle and the pressure is too high, Higher temperature to the outside and the pressure is too low.
I like to add 1 lb to the final numbers so they will be closer to ideal when cool others I learned this from don't. As the saying goes, "You call the tune, you pay the piper" or "Your Mileage May Very."
Hope this helps and wasn't too confusing.
Here’s the old school method I learned when I was involved with vintage car racing:
You’ll need a pressure gauge, some flour and a stiff bristle brush.
1) Locate a level, smooth concrete (preferred) or paved empty parking lot.
2) Start with a higher pressure than you think you’ll need, Then drive around for awhile to warm up the tires and air inside. Then head to the parking lot.
3) Stop in an open level spot, dust the leading edge of all 4 tires with the flour.
4) Pull forward just one rotation of the tires and check how much flour is left on the outer surface of the tires, not down in the treads. You should see more on the outer edges and less in the middle. If not the pressure is too low already.
5) Use the brush to clean off the flour, reduce the pressure a couple of pounds on each tire.
6) Repeat steps 3..5 until the flour left on the tires looks even and make a note of the pressure. Note that the pressure for the front and rear may be different (usually is).
7) Repeat steps 3..5 until you just start to notice there being more flour on the center of the tire and less on the outer edges. Make a note of this pressure.
The final pressure is the mid point between the first point where the flour looks even and where the center starts picking up more flour when the tire is cool. So find the difference between the two pressure points and check the tire pressure again when cool and add the ½ the difference between the two noted pressures to the cool pressure and that is your cool tire pressure.
The newer way is to use an infrared thermometer and check the temperature across the tires after driving around on nice twisty roads to get them good and warm or even hot. The actual temperature doesn’t matter. What you are looking for is even temperature across the tire (the temp will be a little lower right at the outer edges, so check about 1” or so in from the edge). Higher temperature in the middle and the pressure is too high, Higher temperature to the outside and the pressure is too low.
I like to add 1 lb to the final numbers so they will be closer to ideal when cool others I learned this from don't. As the saying goes, "You call the tune, you pay the piper" or "Your Mileage May Very."
Hope this helps and wasn't too confusing.
scanny
Senior Member
I wonder if anybody actually did that test on 4Runner with Duratracs.
scanny
Senior Member
Maybe there is more difference between C and E load than I thought, but at 44 psi I was able to put a business card under a tire for about an inch. And if cold tires doesnt' touch the ground at the sides for that much I guess warm tires didn't touch the ground even more.
scanny
Senior Member
Strange, maybe E load a little bit different. I drove over parking lot covered by dust of salt and about 1/4 inch from the sides rear tires were still black. At 36 psi. Front tires were all white.
Ryan_S
New member
I'll try that tomorrow. Mine look like they are flat, even a bit "squished".
Never had any problems with them handling funny either. ~40k on them.
