I have to make an admission. I can’t figure out what tire pressure is required for safe travel. I am “Inflation Table” challenged. I’ve looked at various Inflation Tables online but, as soon as I do, my brain gets a cramp. I’ve been running the max 110 psi molded into the sidewall but, now I want to do this right. I just weighed my,
‘ready to go someplace’, 1988 HR Alumalite. I was only able to get the axle weights because space restrictions didn‘t allow individual wheel weights. I kinda feel like I’m asking someone to do my homework and I guess I am. I would appreciate an experienced RV’er to give me a bit of assistance or lead me to a web site that would fully explain what I need to do. Thanks in advance for any help. You guys are the greatest…carl
The info I have:
Tires - 8R19.5, Road King Radial Highway LT/RV, Load Rate F.
Total Weight - 14810 lb.
Front Axle - 4530 lb.
Rear Axle - 6580 lb.
Tag axle - 3700 lb.
txmedic471 wrote: I have to make an admission. I can’t figure out what tire pressure is required for safe travel. I am “Inflation Table” challenged. I’ve looked at various Inflation Tables online but, as soon as I do, my brain gets a cramp. I’ve been running the max 110 psi molded into the sidewall but, now I want to do this right. I just weighed my,
‘ready to go someplace’, 1988 HR Alumalite. I was only able to get the axle weights because space restrictions didn‘t allow individual wheel weights. I kinda feel like I’m asking someone to do my homework and I guess I am. I would appreciate an experienced RV’er to give me a bit of assistance or lead me to a web site that would fully explain what I need to do. Thanks in advance for any help. You guys are the greatest…carl
The info I have:
Tires - 8R19.5, Road King Radial Highway LT/RV, Load Rate F.
Total Weight - 14810 lb.
Front Axle - 4530 lb.
Rear Axle - 6580 lb.
Tag axle - 3700 lb.
TX that is the same size, brand and weight of our set up. The placard calls for 65 but we run more like 85. It is not much more harsh and it just feels more stable than the softer 65 PSI ride.
From the chart I think anything 70 and above should be OK. Our rims are rated at 95 and we seldom see triple digit reouts from the TST TPMS underway.
Charts do not tell you what PSI to use but state the MIN for your load. I would used weights that are 30% over the scale figures for a safety factor because the scale and road weigh are not the same due to load shifting and road tilt and crown.
The Michelin web site has a download-able booklet that includes the procedure for weighing and adjusting the pressure. Use the pressures from the chart, not 30% over. Over inflation is almost as bad as under but some including myself add 5 psi to allow for minor leakage, etc. You should check them regularly but if they are in good condition you should rarely need to add air.
hwybnb wrote: The Michelin web site has a download-able booklet that includes the procedure for weighing and adjusting the pressure. Use the pressures from the chart, not 30% over. Over inflation is almost as bad as under but some including myself add 5 psi to allow for minor leakage, etc. You should check them regularly but if they are in good condition you should rarely need to add air.
I appreciate ya'lls help. I couldn't find an inflation table for the Road King tires. The placard behind my driver seat says 70 psi but I thought it might be too low - especially since I didn't know my weight. I'll adjust from about 75 psi upwards in + 10 psi increments while checking how it handles. If someone knows where I could find a Road King inflation table, I'd appreciate that, too. Thanks to all. I wish you fair roads and weather. Be safe....carl
It seems the rear axles are only putting about 1,700 pounds on each tire, so you are well within the weight rating on each tire. The front axle is probably 2,500 on the heavy side and a maximum of 2,400 on the lighter side.
I would say it is possible to safely run 75 PSI in the rear tires and I would run 85 in the front tires, so they will stay nice and stiff, without being harshly stiff.
You really need a load and inflation table to figure out your exact pressure minimum for your tires, I suspect it might be 50 or 60 PSI. Then add 10 PSI to that amount in the even that you might reach 75 MPH or some air is lost at some point. But the front tires should be a little higher than their minimum pressure rating, just so they will have extra sidewall stiffness.
Fred. Thanks for the advice on the front tires. I forgot something else. My placard also say GAWR = 18,000. Does that mean I can carry another 3,000 lb inside the RV? Or maybe pull a very light toad? Don't have a toad but would like to. thx....carl
I tried taking the actual weights for my MH and adding 30%. The result was outside the load range of my factory-installed tires, even inflated to their maximum pressure.
I think I will stick with the chart pressures using actual weights.
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