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skiroc
01-09-2012, 04:49 PM
I've got a 2006 Tundra 4x4 and will be installing E rated tires and Firestone airbags to support a FWC camper. I've never had this kind of tire, or airbags, and my first camper. So, I'm pretty clueless about what my tire and airbag pressure should be in these scenarios:

No camper - Highway driving, maximize mpg
No camper - Easy off-road - mainly gravel FS roads

Camper and gear (1000 lbs) - Highway driving, maximize mpg
Camper and gear (1000 lbs) - off-road - mainly gravel FS roads

downhill
01-09-2012, 05:30 PM
I've got a 2006 Tundra 4x4 and will be installing E rated tires and Firestone airbags to support a FWC camper. I've never had this kind of tire, or airbags, and my first camper. So, I'm pretty clueless about what my tire and airbag pressure should be in these scenarios:

No camper - Highway driving, maximize mpg
No camper - Easy off-road - mainly gravel FS roads

Camper and gear (1000 lbs) - Highway driving, maximize mpg
Camper and gear (1000 lbs) - off-road - mainly gravel FS roads

It will take some trial and error. I have RideRite bags on my Tacoma and I just air them to level the truck. The tires will take more homework since manufactures don't seem to offer much in the way of guidance. For an unloaded truck start with the vehicle's recommended pressure for the stock tires. Go to a hardware store and get a couple of sticks of file chalk. It is a fat soft chalk used on files to keep chips from sticking. Find a flat smooth piece of asphalt where you can drive a couple hundred feet in a straight line and mess around without getting run over. Chalk a heavy line across the tread on all 4 tires. I usually use 2 or 3 lines per tire. Drive the truck straight ahead for maybe a 100 feet and get out and check the chalk lines. You may have to drive a bit farther, but at some point the chalk will be removed from some portion of the tread. If the center is worn off, drop the pressure a bit, rechalk, and try again. If the edges are worn off, then raise the pressure (yeah you'll need to bring a compressor). When the pressure is correct for the weight, the chalk will wear off evenly across the tire. If you have a tire pyrometer or an infrared thermometer, you can go a step farther. A tire that is properly inflated with have equal pressure exerted across the tread. This will cause the tire to heat evenly. You can measure the temperature across the tire after a short drive and see if the edges are the same temp as the middle. You need to work quickly once you stop so the tire doesn't have time to equalize. High temp in the center = too much pressure. As with any tire, continous high speed driving requires a little more pressure. I've found that Es require less extra pressure than Cs for highway speed. You'll have to repeat the chalking for the loaded and unloaded truck. Once you get everything set, wait till the tires are cold and record those pressures. Those are your baseline. If you don't have a way to measure tire temp, then just watch your tire wear to fine tune.

As for airing down, I just look at the tire and the contact patch. See how it feels driving. A little more trial and error. Every tire and load condition is different so you just have to do the homework to get it right.

upcountry
01-11-2012, 04:06 AM
Happy to hear you jumped in and pulled the trigger on a Tundra! Congrats. You did a good job asking around and looking at different options and asking the right questions.

NothingClever
01-11-2012, 04:41 AM
No camper - Highway driving, maximize mpg - firm bags; firm tires
No camper - Easy off-road - mainly gravel FS roads - decrease tire pressure; soften up your bags so they allow articulation

Camper and gear (1000 lbs) - Highway driving, maximize mpg - firm up the bags to prevent body roll; firm up tires as desired for fuel efficiency/speed
Camper and gear (1000 lbs) - off-road - mainly gravel FS roads - medium inflation of air bags to prevent excessive jounce, air down tires to increase contact patch and soften the ride

Tires are the easy part in all cases. Getting the airbags tuned right will require more attention. Not to slight downhill (first responder) but alludat sounds way too clinical, IMO. Just get out there and fiddle with it all in the dirt and take an air tank if you let too much out of something.