Travelin2 wrote:
I would like to hear what you guys think would be a good pressure to run in these new tires. Running at max pressure would, in my mind, make for a harsher ride for the rig and it's contents.
Answer: run them at sidewall max of 65 psi (assuming the rims are good for 65 psi and are required width). Harsher ride or uneven tire wear not an issue.
Some great info. on RV tires can be found on the RVtiresafety.net blog as mentioned by JIMLIN above, which is run by a retired tire engineer. You can find a post he made on psi, load capacity, etc. if upgrading to the Endurance tires
here on his blog here.Your TT has a GVWR of 6500 lbs and CCC of 2287 lbs. Loading that TT up to around 6K lbs seems somewhat high for it's length. For ex., our TT is 29' and from the dealer to fully loaded for camping for two, plus Reese DC WDH, plus a bunch of mods & upgrades added only 666 lbs total (empty tanks & 1 battery).
If you were to load it up to the max GVWR, the tongue weight could be up around 800 lbs making the total weight on the tires 5700 lbs (approx.), or 1425 per tire. If using the GVWR and an avg. 12-13% TW, the old tires had 19% reserve load capacity (at 50 psi) which is good. The Endurance tires will give a reserve capacity of 30% which is very good. You want an adequate spare capacity of 10-15% and more is better to reduce stresses on the tires.
Won't really be a factor in the tire question, but it's always a good idea to a scale and weigh a TT (fully loaded) and get it's GVW and GTW (and TV's actual payload capacity).
Nothing negative from running 65 vs 50 psi. If you reduce the pressure based on a chart, you will be reducing the reserve capacity. Have never heard of needing to reduce pressure to reduce ride harshness of a TT and doubt you'll ever see an uneven wear pattern caused by running at max psi. It appears that GY has designed the Endurance tires so you *can* run them if needed/wanted at the same max psi as your old tires (in same width) despite going to one higher LR rating which will result in the same rating as the old ones.
Our TT is way over-tired based on the Marathon LRD with over 10K total load capacity with under about 6000 lbs actual weight on the tires. While I *could* reduce psi, I've always run them at 65 psi for 4 years and about 20K miles and zero signs of uneven tire wear and they actually look almost new.
The thing about the Endurance tires is that they aren't a direct on to one replacement in the same width. Not an issue for the OP tho. I want to install a set of them at the end of next season and if I want to stay with 225/75R/15, the same width in Endurance are rated LRE at 80 psi max and have a higher max load rating (2830 vs 2540). I do not know yet if our rims are rated for 80 psi but if they're not, I may reduce the psi based on a load inflation table and would still have a high reserve load capacity. Or I could reduce tire width to 205 wide but don't want to.
One thing I've never seen discussed in RV forums is handling. For better handling of any vehicle, wider tires and/or running higher psi improves handling esp. if you like towing on mountain roads with lots of twists and turns. Reducing psi from the max rating will only worsen handling. Another reason to run those tires at 65 psi.
