carlisle tires

[wildwood]

If i was going to replace my tires on my TT with a new safe tire what would you recommend. My gross weight is 11035 pounds, dry is 7700 lb. My current tires are carlisle ST 225 75 D15/ D Sport Trails? My current tires have a load rating of 2540 pounds each, tongue weight is 875 lb.

Thanks for your input and experience

[rockwood06]

It looks like you can go to a ST225/R15 load range " E " max load capacity 2830. the tire is the same height as the ones you have on, but they are a little wider. You might want to check the clearance from a normal resting position from the top of the tire to the bottom of the wheel well and then use an E-Z jack to bring one tire up of the ground to see what the clearance is at that point from the top of the tire to the bottom of the wheel well. the E-Z jack will bring the tire up 6" off the ground. In this position if there is enough clearance you might be able to go to a 16" tire that has a higher load capacity.

[wildwood]

thanks

any preference for make, or no plys, radial vs bias

[rockwood06]

Cooper tires comes to mine, "C" rated are 6 ply, "D" rated are 8 ply and "E" rated are 10 ply. There is a tire with an "F" rating on the list, it is a ST235/85R16, I am not sure but it may be a 12 ply. This tire is 31.9" in dia, and a width of 9.0", max air pressure of 95 psi, and a max load capacity of 3960 lbs. This tire might be too large, just depends on clearances. By the way this tire has a weight of 41.2 lbs and the tread depth is 16/32 nds and you need a rim that is 6" wide..... I hope this helps you, I am still trying to post the tire list.

[wildwood]

Thanks

[gillguy]

New to the FRF but have been over on RVNet for several years.
Any way I noticed that no one has mention Denman or Maxxis tires. Why?
On my 8317SS it came with the Carlisle Ultra CRT 205/75/15 load range C tires.
I replaced them with the Denman Radial ST in a load range "D". Why? Price, availability, and the same size as I took off. I like the Maxxis also but the ones I found, the date on the tires were a year old, the Denman's that I bought the date code was a month old.
Another tire not mentioned is the Michelin XPS Rib. I can understand on this one though because you have to go to a 16" wheel and most people don't want to do that, plus on some you will need to flip or lower the axles to get the height clearance you'll need. Good tire though, as is the Cooper.
A few others are the Tow Master, Titan, and Load King.
Also this is a great time to switch to metal valve stems.
And remember to get the new tires balanced. You wouldn't want unbalanced tires on your car/truck would you? No you wouldn't.
Some other questions.
You rotate the tires on your car or truck, right?
What about on your trailer? Why not? perfectly balanced?
Good luck in your quest for the perfect tire.

[chambersb43]

I just replaced all 4 tires on my GS290. It had 205R75 14 load range B (1430 lbs ea.) The trailer gross is 6500, so even with 650 lbs tongue weight the peanut butter and the bread does not come out even.
I put 4 Goodyear Marathon 215 R75 14 Load range C (1870lbs) on and run with 40lbs pressure vs the 50lbs max. I now have approx. 1000 lbs excess tire capacity and get a better ride at the lower pressure. Now I have to get a wheel aligment done to correct some wear problems. Bob

[jmyers]

Originally Posted by chambersb43

I just replaced all 4 tires on my GS290. It had 205R75 14 load range B (1430 lbs ea.) The trailer gross is 6500, so even with 650 lbs tongue weight the peanut butter and the bread does not come out even.
I put 4 Goodyear Marathon 215 R75 14 Load range C (1870lbs) on and run with 40lbs pressure vs the 50lbs max. I now have approx. 1000 lbs excess tire capacity and get a better ride at the lower pressure. Now I have to get a wheel aligment done to correct some wear problems. Bob

You may want to talk to a knowledgeable tire guy, but I believe the 1870 lb rating is at 50 lbs max air pressure. Running lower air pressure, especially on trailer tires, adds unnecessary stress on the tire sidewalls. It will also cause inside and outside wear at the same time, regardless of the alignment. You may be OK but for your safety and peace of mind please get an expert opinion. I'm running 225 75R 15 Load Range D Marathons (made in Canada) on my 30' Sandpiper (7,000 lbs dry) and I keep them aired up to the 65 lb max, and I never go faster than 60 mph, no matter what the speed limit. Maybe I'm overcautious but life's too short to spend my camping time on the side of the highway changing flats... or worse!

[rockwood06]

Originally Posted by jmyers

You may want to talk to a knowledgeable tire guy, but I believe the 1870 lb rating is at 50 lbs max air pressure. Running lower air pressure, especially on trailer tires, adds unnecessary stress on the tire sidewalls. It will also cause inside and outside wear at the same time, regardless of the alignment. You may be OK but for your safety and peace of mind please get an expert opinion. I'm running 225 75R 15 Load Range D Marathons (made in Canada) on my 30' Sandpiper (7,000 lbs dry) and I keep them aired up to the 65 lb max, and I never go faster than 60 mph, no matter what the speed limit. Maybe I'm overcautious but life's too short to spend my camping time on the side of the highway changing flats... or worse!

I agree with Jmyers, it is unsafe to run under pressure, there is more stress on the side wall. The belts in the side wall can damage the tire causing a blow out, the bead could break loose from the rim, and sense all 4 of your tires are under pressure if 2 tires on one side develop a problem and they blow out you would have some serious handling problems. Please check into this before you go any farther for your own safety.

[gillguy]

Here is a chart you can use.
Sorry I can't get the alignment on the rows right, but you can figure it out.

LOAD/INFLATION INFORMATION FOR RV ST METRIC TIRES
MaxSpeed
Tire Rating Inflation Pressure - PSI
Size (MPH) 15 20 25 30 35 40 45 50 55 60 65
ST175/80R13 65 670 795 905 1000 1100(B) 1190 1270 1360(C)
ST185/80R13 65 740 870 990 1100 1200(B) 1300 1400 1480(C)
ST205/75R14 65 860 1030 1170 1300 1430(B) 1530 1640 1760(C)
ST215/75R14 65 953 1110 1270 1410 1520(B) 1660 1790 1870(C)
ST205/75R15 65 905 1070 1220 1360 1480(B) 1610 1720 1820(C)
ST225/75R15 65 1060 1260 1430 1600 1760 1880 2020 2150(C) 2270 2380 2540(D)
ST235/80R16 65 1720 1920 2090 2270 2430 2600 2730 2870 3000(D)

[chambersb43]

Originally Posted by jmyers

You may want to talk to a knowledgeable tire guy, but I believe the 1870 lb rating is at 50 lbs max air pressure. Running lower air pressure, especially on trailer tires, adds unnecessary stress on the tire sidewalls. It will also cause inside and outside wear at the same time, regardless of the alignment. You may be OK but for your safety and peace of mind please get an expert opinion. I'm running 225 75R 15 Load Range D Marathons (made in Canada) on my 30' Sandpiper (7,000 lbs dry) and I keep them aired up to the 65 lb max, and I never go faster than 60 mph, no matter what the speed limit. Maybe I'm overcautious but life's too short to spend my camping time on the side of the highway changing flats... or worse!

You are quite correct, the max load rating of this tire is 1870 lbs. Times 4 gives a total capacity of 7480 lbs. My TT weighs a maximum of 6500 lbs, with a tongue weight of 650 lbs leaving 5850 lbs on the trailer axles ,1990 lbs less than the tire capacity. If I reduce the tire pressure by 20% (10lbs), i will get a corresponding 20% (approx) reduction in carrying capacity to approx 6000lbs. This means the tires are well matched to the load, and therefore tire life,tread wear and safety are not jeopardized. Running these tires at 50 lbs would result in abnormal wear pattern and a very harsh ride. Unnecessary shock loads would be transmitted to the wheel bearings and trailer suspension.

Another example would be my TV ( 2008 F250) Tires are LT275R70/18 Load range E 3640 lbs.......times 4 = 14560 total tire capacity @ 80 lbs inflation.
GVWR on this truck is 10,000 lbs,or approx 70% of the tire capacity. Ford recommends no more than 65 lbs tire pressure, front and rear.Tire wear is normal at this pressure, although I don't usually run quite that heavy.

Many thanks to Jmyers@ rockwood06 for their replies/concerns. Bob