Tire Service Description Comparator
Compare full tire service descriptions such as 94W vs 91V. Check load index and speed rating together against the original spec.
Compare load index and speed rating.
Tire Service Description Comparator: Tire Size Inputs
Compare two tire sizes here. Use the formulas and reference tables below for this tool's specific calculation.
How Tire Service Description Comparator Works?
The Tire Service Description Comparator works by splitting each service description into its load index and speed rating and checking both against the original. The tool uses 3 steps.
Enter the original
Type the original service description, for example 94W.
Enter the replacement
Type the replacement, for example 94V.
Read 2 results
The comparator returns Load: pass (670 kg each) and Speed: fail (240 km/h vs 270 km/h).
Tire Service Description Comparator Formula
The Tire Service Description Comparator passes a tire when LI_rep ≥ LI_orig AND V(SR_rep) ≥ V(SR_orig).
SD = LI + SR (for example 94W)L(LI_rep) ≥ L(LI_orig)V(SR_rep) ≥ V(SR_orig)- SD
- Service description
- LI
- Load index
- SR
- Speed rating
Worked example
Replacing 113T with 116H raises capacity from 1,150 kg to 1,250 kg (2,535 lb to 2,756 lb) and speed from 190 km/h to 210 km/h (118 to 130 mph). Both tests pass.
Tire Service Description Comparator Conversion Table
The Tire Service Description Comparator conversion table checks load and speed together for 6 service description changes.
| Change | Load | Speed | Load test | Speed test |
|---|---|---|---|---|
| 91V → 94W | 615 → 670 kg | 240 → 270 km/h | Pass | Pass |
| 94W → 94V | 670 → 670 kg | 270 → 240 km/h | Pass | Fail |
| 98Y → 95Y | 750 → 690 kg | 300 → 300 km/h | Fail | Pass |
| 113T → 116H | 1150 → 1250 kg | 190 → 210 km/h | Pass | Pass |
| 102V → 104H | 850 → 900 kg | 240 → 210 km/h | Pass | Fail |
| 88H → 91V | 560 → 615 kg | 210 → 240 km/h | Pass | Pass |
What is Tire Service Description Comparator?
A Tire Service Description Comparator is a tool that compares the complete load and speed marking of 2 tires in one step. The service description is the 2-part code after the size, such as 94W.
A tire passes only when both parts pass. A higher load index does not make up for a lower speed rating, and a higher speed rating does not make up for a lower load index.
LT tires carry 2 load indexes, such as 121/118S. The comparator uses the first (single) index for the main test.
What are the uses of Tire Service Description Comparator?
There are 4 main uses of the Tire Service Description Comparator, including one-step replacement checks and catalog filtering.
One-step replacement checks
Check load and speed together.
Catalog filtering
Filter tires by a minimum service description.
Inspection prep
Confirm compliance before a roadworthiness test.
Fleet purchasing
Set a minimum service description in a tender.
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