TrailManor Owner's Forum - View Single Post

**rickst29** · 05-02-2006, 07:28 PM

or driving at over 65MPH.

First issue: REDUCE the pressure if the TM isn't loaded to the max. Goodyear provides a table saying how much to reduce your cold PSI when the load per tire is below the maximum. If you always put the tires at the cold maximum (as most TM owners probably do) the tire doesn't contact the ground very well, and it doesn't have the suspension "give" characteristics which it was designed for... your trailer is getting shaken a lot harder than it needs to be.

Here's the "drop the cold PSI according to tire load" table for your 15" tire (Marathon ST225/R15), from the first PDF:

max load <> recommended
per tire: <> cold PSI:

1060 lbs <> 15 PSI
1260 lbs <> 20 PSI
1430 lbs <> 25 PSI
1600 lbs <> 30 PSI
1760 lbs <> 35 PSI
1880 lbs <> 40 PSI
2020 lbs <> 45 PSI
2150 lbs <> 50 PSI (max load and PSI for class 'C' load rated)
2270 lbs <> 55 PSI
2380 lbs <> 60 PSI
2540 lbs <> 65 PSI (max load and PSI for class 'D' load rated)

See the full discussion in this thread: showthread=3357 Lucky for you, I used the 3023 as my example.

Second issue: If you'll be driving fast, you can then ADD some pressure to the result from the table above. This is brand new advice (03/2006) from Goodyear, see showthread=4096

More pressure reduces tire squirm at high speeds. The tread, as it rotates from unloaded to loaded at the front of the contact with the ground, actually bends a lot... too much if you travel at high speed without putting those "extra" PSI back in.

- - - -
WDHSo first, estimate or measure your load per tire (TM dry weight plus weight of heavy options A/C and awning), minus tongue weight, plus load (don't forget the water tanks). Your 3023 has more load capacity than any other TM (special builds like mine excluded), and will often be loaded less than it's tire/axle capacity. If you want to be REALLY finicky, also remember that the WDH puts some weight back on the trailer axle. Then use the Goodyear table (above), add 5 PSI or so as a safety factor in your load estimate (you NEVER, EVER want to be running under-inflated!!!) And then, if you'll drive really fast, add up to 10 PSI more... but don't go past 65 PSI cold, because I don't know if the wheel is designed to handle any more than that.

And remember, "cold PSI" needs to be measured COLD. Don't let air out after you've been going for a while.

05-02-2006, 07:28 PM	#5
rickst29 yes, they hunt lions. Join Date: Aug 2005 Location: Reno, NV Posts: 1,318	TM "65 PSI" is only correct if FULLY LOADED, or driving at over 65MPH. First issue: REDUCE the pressure if the TM isn't loaded to the max. Goodyear provides a table saying how much to reduce your cold PSI when the load per tire is below the maximum. If you always put the tires at the cold maximum (as most TM owners probably do) the tire doesn't contact the ground very well, and it doesn't have the suspension "give" characteristics which it was designed for... your trailer is getting shaken a lot harder than it needs to be. Here's the "drop the cold PSI according to tire load" table for your 15" tire (Marathon ST225/R15), from the first PDF: max load <> recommended per tire: <> cold PSI: 1060 lbs <> 15 PSI 1260 lbs <> 20 PSI 1430 lbs <> 25 PSI 1600 lbs <> 30 PSI 1760 lbs <> 35 PSI 1880 lbs <> 40 PSI 2020 lbs <> 45 PSI 2150 lbs <> 50 PSI (max load and PSI for class 'C' load rated) 2270 lbs <> 55 PSI 2380 lbs <> 60 PSI 2540 lbs <> 65 PSI (max load and PSI for class 'D' load rated) See the full discussion in this thread: showthread=3357 Lucky for you, I used the 3023 as my example. Second issue: If you'll be driving fast, you can then ADD some pressure to the result from the table above. This is brand new advice (03/2006) from Goodyear, see showthread=4096 More pressure reduces tire squirm at high speeds. The tread, as it rotates from unloaded to loaded at the front of the contact with the ground, actually bends a lot... too much if you travel at high speed without putting those "extra" PSI back in. - - - - WDHSo first, estimate or measure your load per tire (TM dry weight plus weight of heavy options A/C and awning), minus tongue weight, plus load (don't forget the water tanks). Your 3023 has more load capacity than any other TM (special builds like mine excluded), and will often be loaded less than it's tire/axle capacity. If you want to be REALLY finicky, also remember that the WDH puts some weight back on the trailer axle. Then use the Goodyear table (above), add 5 PSI or so as a safety factor in your load estimate (you NEVER, EVER want to be running under-inflated!!!) And then, if you'll drive really fast, add up to 10 PSI more... but don't go past 65 PSI cold, because I don't know if the wheel is designed to handle any more than that. And remember, "cold PSI" needs to be measured COLD. Don't let air out after you've been going for a while. __________________ TM='06 2619 w/5K axle, 15" Maxxis "E" tires. Plumbing protector. 630 watts solar. 450AH LiFePO4 batteries, 3500 watt inverter. CR-1110 E-F/S fridge (compressor). TV = 2007 4runner sport, with a 36 volt "power boost".