Disclaimer: This calculator provides estimates for educational purposes only. Actual towing capacity, braking distance, tongue weight, and payload vary with your specific vehicle, hitch class, trailer, tires, load distribution, and road conditions. Always verify these figures against your vehicle manufacturer's owner's manual and the door-jamb certification sticker, which lists GVWR, GCWR, GAWR, and maximum tongue and payload ratings. Never exceed the lowest of these rated limits, regardless of what this calculator shows. Exceeding a weight rating or misjudging stopping distance can cause loss of vehicle control, brake failure, trailer sway, jackknifing, serious injury, or death. Always consult your manufacturer's documentation and a qualified technician before towing.
Did You Know?
Set RV tire pressure from the weight each tire actually carries, not the sidewall maximum: weigh each loaded axle at a CAT scale, divide by the tires on that axle, and read the matching PSI from the manufacturer’s load/inflation table. Over-inflating a lightly loaded tire gives a harsh ride and center-tread wear.
Frequently Asked Questions
Q
How do I determine the correct tire pressure for my RV?
Correct RV tire pressure is based on the actual weight on each tire, not the maximum PSI stamped on the sidewall. Weigh your RV fully loaded at a CAT scale to get individual axle weights, divide by the number of tires per axle, then consult the tire manufacturer’s load/inflation table.
Step 1: Weigh your RV loaded at a certified scale (CAT scale, RV rally, truck stop)
Step 2: Divide axle weight by number of tires on that axle to get weight per tire
Step 3: Look up the weight per tire in the manufacturer’s load/inflation table
Step 4: Round up to the next 5 PSI increment for a safety margin
Step 5: Adjust for ambient temperature — add/subtract ~1 PSI per 10°F from 70°F
Load Range
Max PSI
Max Load/Tire
Common RV Type
C (6-ply)
50 PSI
1,820 lbs
Pop-up campers
D (8-ply)
65 PSI
2,470 lbs
Small travel trailers
E (10-ply)
80 PSI
3,195 lbs
Travel trailers, 5th wheels
G (14-ply)
110 PSI
4,540 lbs
Class A motorhomes
Q
Should I inflate RV tires to the max PSI on the sidewall?
Not necessarily. The sidewall max PSI is the maximum safe pressure for that tire at its maximum load capacity. If your actual load per tire is less than the max capacity, you should inflate to the PSI that corresponds to your actual weight from the load/inflation table. Running at max PSI with a lighter load causes a harsh ride and uneven center tread wear.
Max sidewall PSI = maximum pressure for maximum load, not the recommended setting
Under-loading at max PSI causes center tread wear and a rough ride
Under-inflating causes sidewall flex, heat buildup, and potential blowout
Correct pressure matches the actual load per tire from the inflation table
A 10–15% margin above the table value provides a safety buffer for weight shifts
Q
How does temperature affect RV tire pressure?
Tire pressure changes approximately 1 PSI for every 10°F change in ambient temperature. A tire inflated to 80 PSI on a 70°F morning will read about 84 PSI at 110°F and 76 PSI at 30°F. Always set pressure when tires are cold (before driving or 3+ hours after stopping).
Rule of thumb: ~1 PSI per 10°F change from the baseline temperature
Summer heat can add 4–6 PSI above cold inflation — this is normal and expected
Winter cold can drop pressure 4–8 PSI — check more frequently in cold weather
Driving heats tires 10–20 PSI above cold pressure — never bleed hot tires down to cold spec
TPMS sensors help monitor real-time changes while driving
Ambient Temp
PSI Change from 70°F
80 PSI Tire Reads
30°F
-4 PSI
76 PSI
50°F
-2 PSI
78 PSI
70°F
0 PSI
80 PSI
90°F
+2 PSI
82 PSI
110°F
+4 PSI
84 PSI
Q
How often should I replace RV tires?
RV tires should be replaced every 5–7 years regardless of tread depth, and ST (Special Trailer) tires every 3–5 years. UV exposure, ozone, and heat degrade tire rubber over time, causing sidewall cracking and increased blowout risk. Check the DOT date code on the sidewall to determine tire age.
ST tires: replace every 3–5 years — they degrade faster due to higher load stress
LT tires: replace every 5–7 years — more durable rubber compounds
DOT code format: last 4 digits = week + year (e.g., 2523 = week 25 of 2023)
UV-protective tire covers extend tire life 1–2 years when parked long-term
Annual inspection for sidewall cracking, bulges, and flat spots is essential
Q
What is the difference between ST and LT tires for RVs?
ST (Special Trailer) tires are designed specifically for trailers with stiffer sidewalls to prevent sway, while LT (Light Truck) tires are designed for driven axles with better heat dissipation and longer tread life. Many RV owners upgrade from ST to LT tires for improved durability and longer lifespan.
ST tires have 10–15% more load capacity than same-size LT tires at equal pressure
LT tires last 40,000–60,000 miles vs 15,000–30,000 for ST tires
When upgrading from ST to LT, verify the LT tire’s load capacity meets your axle weight
Example Calculations
1Travel Trailer with Load Range E Tires
Inputs
Tire TypeST (Special Trailer)
Load RangeE (10-ply)
Axle Weight5,000 lbs
Tires per Axle4
Result
Recommended PSI50 PSI
Weight per Tire1,250 lbs
Max Capacity3,195 lbs/tire
Load %39%
Weight per tire: 5,000 / 4 = 1,250 lbs. Load Range E base: 3,195 lbs at 80 PSI with 39.9 lbs/PSI rate. Required PSI: 80 - ((3,195 - 1,250) / 39.9) = 31.3 PSI, rounded up to 35 PSI. With industry rounding to nearest 5: 50 PSI provides a good safety margin.
25th Wheel with Load Range G Tires
Inputs
Tire TypeST (Special Trailer)
Load RangeG (14-ply)
Axle Weight8,000 lbs
Tires per Axle4
Result
Recommended PSI35 PSI
Weight per Tire2,000 lbs
Max Capacity4,540 lbs/tire
Load %44%
Weight per tire: 8,000 / 4 = 2,000 lbs. Load Range G base: 4,540 lbs at 110 PSI with 41.3 lbs/PSI rate. Required PSI: 110 - ((4,540 - 2,000) / 41.3) = 48.5 PSI, rounded to 50 PSI. With safety buffer: 65 PSI is comfortable.
Formulas Used
Weight per Tire
Weight per Tire = Axle Weight / Tires per Axle
Calculates the load carried by each individual tire on an axle. This is the starting point for determining correct inflation pressure.
Where:
Axle Weight= Total weight on one axle as measured at a certified scale (lbs)
Tires per Axle= Number of tires on that axle (2 for single, 4 for dual)
Required PSI from Load Table
PSI = Base PSI - ((Base Capacity - Weight per Tire) / lbs per PSI)
Interpolates the required inflation pressure from the tire’s load/inflation table based on actual weight per tire.
Where:
Base PSI= Maximum PSI for the tire’s load range
Base Capacity= Maximum load capacity at base PSI (from manufacturer table)
Weight per Tire= Actual weight carried by each tire
lbs per PSI= Load capacity change per PSI (from manufacturer’s load/inflation curve)
Temperature PSI Adjustment
Adjustment = (Ambient Temp - 70) / 10 × 1 PSI
Estimates how ambient temperature affects tire pressure relative to the 70°F baseline where most inflation tables are calibrated.
Where:
Ambient Temp= Current outside air temperature in °F
70= Baseline temperature assumed by most inflation tables (°F)
1 PSI= Approximate pressure change per 10°F temperature difference
Tire pressure is the single most important factor in RV tire safety, yet most RV owners set pressure incorrectly. The maximum PSI stamped on the sidewall is not a recommendation — it’s the maximum safe pressure at the tire’s maximum load capacity. If your RV is lighter than the tire’s maximum capacity (which it usually is), you should inflate to a lower pressure that matches your actual weight.
The correct approach starts at the scale. Weigh your RV fully loaded — with water, gear, passengers, and fuel — on a certified scale to get individual axle weights. Divide each axle weight by the number of tires on that axle to get weight per tire. Then consult the tire manufacturer’s load/inflation table to find the recommended PSI for that weight. Add 5–10 PSI as a safety margin to account for weight shifts while driving.
Temperature also affects tire pressure. For every 10°F change in ambient temperature, tire pressure changes roughly 1 PSI. A tire inflated to 80 PSI in a 70°F garage will read about 76 PSI on a 30°F winter morning. Always measure cold inflation pressure — before driving or at least 3 hours after stopping — and never bleed air from hot tires to reach the cold specification.
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.
