Semi Truck Tire Sizes
11R24.5 vs 285/75R24.5
A 24.5-inch wheel does not make every 24.5 tire interchangeable. In vocational or regional work, a small size difference can show up as clearance, gearing, or uneven dual wear.
Use the comparison below to ask better questions before ordering replacements.
Where the comparison comes up
Drivers usually compare these sizes when replacing older standard-profile tires, buying used equipment, or trying to align a mixed trailer pool. The safer move is to identify the tire currently approved for the vehicle, then compare candidate tires through current manufacturer data.
Typical dimension comparison
Typical ranges from published manufacturer data. Confirm exact values from the data sheet for the specific tire model being evaluated.
| Dimension | 11R24.5 (typical) | 285/75R24.5 (typical) | Why it matters |
|---|---|---|---|
| Overall diameter | 43.3 – 43.7 in | 41.4 – 42.0 in | Affects clearance, gearing, and dual matching |
| Section width | 11.0 – 11.2 in | 11.0 – 11.2 in | Similar width — but verify approved rim width |
| Revolutions / mile | 471 – 477 | 488 – 495 | Speedometer and gearing impact from diameter difference |
| Loaded radius | 20.8 – 21.0 in | 19.9 – 20.2 in | Affects fifth-wheel height and dock leveling |
Checks before substitution
- Wheel width approval
- Minimum dual spacing
- Overall diameter and loaded radius
- Load range or load index
- Clearance around suspension and bodywork
Mixed fleet caution
The biggest risk is not mounting one tire for a controlled test; it is letting two close-looking sizes spread across a fleet without a written rule. A 24.5-inch trailer pool can quietly end up with mixed overall diameters, different spare inventory, and dual sets that are hard to match in the yard.
Before approving a substitution, decide whether it applies to one unit, one axle, or the whole group. Label the unit record so the next tire call does not undo the decision.
When staying with the original size is cleaner
- The truck runs matched duals and only one tire needs replacement.
- Clearance is already tight around suspension, fenders, or bodywork.
- The fleet stocks only one 24.5-inch spare size.
- Speedometer, gearing, or fifth-wheel height changes would create extra work.
Size Verification Checklist
- Check all tires on the axle, not one side.
- Record current size and tread depth before changing.
- Use the same size and similar wear depth across dual positions.
- Ask the tire supplier for the current data sheet.
FAQ
What is the difference between 11R24.5 and 285/75R24.5?
Both fit a 24.5-inch rim, but the 11R24.5 uses the older radial inch designation while the 285/75R24.5 uses a metric aspect ratio format. The 11R24.5 is typically about 1.5 to 2 inches taller in overall diameter. In vocational or regional service this difference can affect fender clearance, fifth-wheel height, gearing, and dual matching.
Can I replace 11R24.5 with 285/75R24.5?
Not without first comparing the specific size data for the tire models under consideration. The dimensional difference is significant enough to affect clearance and dual matching. Check overall diameter, approved rim width, load range, and dual spacing requirements using current manufacturer data. A qualified tire supplier can pull data for both tires before a fleet commits to a substitution.
Are 24.5-inch tires less common than 22.5-inch?
Yes, 22.5-inch rim diameter is more common in most highway fleets today. The 24.5-inch diameter is found on some regional, vocational, and older equipment. Parts availability and tire model selection may be narrower, which is one factor to weigh when maintaining or purchasing equipment with 24.5-inch wheels.
Do 11R24.5 and 285/75R24.5 fit the same wheels?
Both the 11R24.5 and 285/75R24.5 are 24.5-inch rim diameter tires, so they can mount on the same 24.5-inch diameter wheels — provided the rim width falls within the approved range for each tire. The 285/75R24.5 is typically slightly wider in section width than the 11R24.5, so rim width approvals may differ slightly. Check the tire manufacturer's approved rim width range before mixing or substituting. The overall diameter difference between the two sizes also needs to be confirmed before mixing in a dual set.
Why are 24.5-inch tires harder to source than 22.5-inch?
The 24.5-inch rim diameter is used on some regional, vocational, and older equipment — it is not the dominant size for new highway tractors, which standardized on 22.5-inch rims for most applications. The smaller installed base means fewer 24.5-inch tires are sold, fewer are stocked at most truck stops and tire distributors, and the selection of available models is narrower than for 22.5-inch. Fleets maintaining 24.5-inch equipment should plan for longer sourcing lead times and may need to pre-position spare tire inventory more carefully than for 22.5-inch equipment.
Source Notes
- Manufacturer Bridgestone Commercial Truck Tire Resources
- Manufacturer Continental Commercial Vehicle Tire Care Resources
- Site note TruckTireGuide.com editorial notes
Editorial Review
TruckTireGuide.com editorial team
Maintained by an independent editor with fleet tire-program experience in regional Class 8 operations, supported by transportation regulatory research and commercial vehicle technical writing.
Pages are checked against public regulations, manufacturer resources, industry references, and conservative field practice. The site does not approve tires for service or replace qualified inspection.