Tire Size Report Generator
Save a report that compares your sizes. Use the calculator below. Results update as you type.
How the Tire Size Report Generator Works
This generator works by collecting the original and proposed sizes, running every comparison and exporting the results with the assumptions stated. It produces a single document for records or customers.
- Enter the size fitted today, for example 265/70R17.
- Enter the proposed size, for example 285/70R17.
- Review the computed differences: diameter, sidewall, circumference, revs, speed and clearance.
- Export the report as a PDF or CSV file.
The Formula
The formula combines the comparison equations into one report: Difference = Proposed − Original for each field.
ΔD (%) = (D_p − D_o) ÷ D_o × 100 ΔSidewall = W_p × AR_p ÷ 100 − W_o × AR_o ÷ 100 True Speed = 60 × D_p ÷ D_o ΔClearance = (D_p − D_o) ÷ 2Worked example: 265/70R17 to 285/70R17 gives +3.49% diameter, +14.0 mm sidewall, a true 62.1 mph at 60 indicated and +0.55 in clearance.
Conversion Table
The conversion table shows a sample report for 265/70R17 to 285/70R17 with 8 fields. Each field lists the original, the proposed value and the difference.
The last row states the assumption: results are nominal, and measured values vary by 1–3%. Every exported report includes that line.
| Report Field | Original | Proposed | Difference |
|---|---|---|---|
| Size | 265/70R17 | 285/70R17 | +20 mm width |
| Diameter | 31.61 in | 32.71 in | +3.49% |
| Sidewall | 185.5 mm | 199.5 mm | +14.0 mm |
| Circumference | 2522 mm | 2610 mm | +88 mm |
| Revs per mile | 638 | 617 | -22 |
| True speed at 60 mph | 60.0 mph | 62.1 mph | +2.1 mph |
| Ground clearance | — | — | +0.55 in |
| Assumption | Nominal size math | Nominal size math | Measured values vary 1–3% |
What Is the Tire Size Report Generator?
The Tire Size Report Generator is a tool that exports assumptions, specifications and calculated differences for a tire size change. A report gives a record that outlives the browser tab.
Shops attach reports to work orders. Owners keep them with modification records for insurance and resale.
Common Uses
This generator has 4 uses: work orders, insurance records, resale files and fleet approvals.
- Attach to work orders: Document the change for the customer.
- Support insurance records: Record modifications.
- Build resale files: Show buyers what changed.
- Get fleet approvals: Submit size changes for sign-off.