RV Tire Size Comparator
Compare tire and wheel needs for an RV. Use the calculator below. Results update as you type.
How the RV Tire Size Comparator Works
This comparator works by comparing RV tire sizes by motorhome class, diameter, width and revs per mile. It covers Class A, Class B and Class C motorhomes.
- Enter the current size, for example 245/70R19.5 on a Class A gas coach.
- Enter the proposed size, for example 255/70R22.5.
- Read the diameters: 33.0 in vs 36.6 in.
- Note that a rim diameter change requires new wheels and a speedometer update.
The Formula
The formula is the standard diameter formula with a percentage comparison.
D (mm) = (Rim × 25.4) + 2 × (Width × Aspect Ratio ÷ 100) Change (%) = (D_new − D_old) ÷ D_old × 100Worked example: LT225/75R16 (29.3 in) to LT245/75R16 (30.5 in) is +4.0%. That is above ±3% and needs a load and clearance check.
Conversion Table
The conversion table lists 8 RV tire sizes by common motorhome class. Sizes run from LT225/75R16 on Class C coaches to 315/80R22.5 on large Class A coaches.
Class A diesel pushers use 22.5 in commercial sizes. Class C coaches use LT sizes on 16 in wheels or 19.5 in commercial sizes.
| Size | Common Class | Diameter (in) | Width (in) | Revs / Mile |
|---|---|---|---|---|
| LT225/75R16 | Class C | 29.3 | 8.86 | 689 |
| LT245/75R16 | Class C / B | 30.5 | 9.65 | 662 |
| 225/70R19.5 | Class C (Super C) | 31.9 | 8.86 | 632 |
| 245/70R19.5 | Class A (gas) | 33.0 | 9.65 | 611 |
| 255/70R22.5 | Class A (gas) | 36.6 | 10.04 | 552 |
| 275/70R22.5 | Class A (diesel) | 37.7 | 10.83 | 536 |
| 295/80R22.5 | Class A (diesel) | 41.1 | 11.61 | 491 |
| 315/80R22.5 | Class A (large) | 42.3 | 12.40 | 476 |
What Is the RV Tire Size Comparator?
The RV Tire Size Comparator is a tool that compares documented tire and wheel requirements for recreational vehicles. RVs often run close to their tire load limits, so size and load index matter more than on a car.
RV makers list the tire size and minimum load range on the coach's weight label. Weighing each corner and matching tire capacity to that weight is standard practice.
Common Uses
This comparator has 4 uses: coach replacements, weight checks, class comparisons and towed-vehicle planning.
- Replace coach tires: Confirm the documented size.
- Check weights: Match capacity to corner weights.
- Compare classes: See how sizes differ by class.
- Plan towed vehicles: Check RV speedometer accuracy for towing.