Keep overall diameter when moving to a larger rim. Get metric size suggestions within ±3% of your current tire, with Preferred ±2% rows — free, private.
New wheel diameter in inches (10–30).
24.97"
Current diameter
18"
Target rim
10
Suggestions
| Size | Diameter | Δ vs current | Band |
|---|---|---|---|
| 295/30R18 | 24.97" | -0.02% | Preferred (±2%) |
| 355/25R18 | 24.99" | +0.06% | Preferred (±2%) |
| 255/35R18 | 25.03" | +0.22% | Preferred (±2%) |
| 135/65R18 | 24.91" | -0.25% | Preferred (±2%) |
| 195/45R18 | 24.91" | -0.25% | Preferred (±2%) |
| 175/50R18 | 24.89" | -0.33% | Preferred (±2%) |
| 225/40R18 | 25.09" | +0.46% | Preferred (±2%) |
| 145/60R18 | 24.85" | -0.49% | Preferred (±2%) |
| 165/55R18 | 25.15" | +0.69% | Preferred (±2%) |
| 345/25R18 | 24.79" | -0.73% | Preferred (±2%) |
100% browser-based
Runs locally in this tab
No upload required
Your files never leave this device
Nothing is stored
Close the tab and the input is gone
Instant results
No queue and no server wait
Enter your current metric size (for example 225/45R17) and the rim diameter you want (18, 19, 20). The calculator searches standard widths and aspects on that rim and keeps overall diameter within ±3% of stock — the usual plus-one / plus-two idea without guessing aspect ratio by hand.
Each row is a shoppable size, its overall diameter, percent change, and Preferred (±2%) or Acceptable (±3%). That is how you see whether 225/40R18 is a plus-one or a speedometer surprise. Suggestions prefer the same construction language as the size you typed.
Plus-one usually means one inch more rim. Here you type the target rim yourself (10–30"). There is no automatic +1/+2/+3 button — that keeps a 20-inch winter downsize and a 22-inch plus-size on the same math. Load index and speed symbol still have to meet or exceed OE.
No account and no upload. The search runs on the encoded width/aspect tables, not a live tire inventory. Close the tab and the current size is gone. Check rim width and load index before you buy a suggested size. Nothing is stored on a server.
Use the metric code on the sidewall or the door placard, such as 225/45R17. That diameter is the reference the suggestions must stay near.
Plus-one is typically current rim + 1. Type 18 if you are leaving a 17, 19 if you want plus-two, and so on.
Up to ten metric sizes within ±3% overall diameter. Prefer the ±2% band if you want speedometer and clearance close to stock.
A matching diameter can still be too wide. Use Rim Width Compatibility, Load Index Lookup, and a tape on the car before you order.
Straight answers on privacy, limits, and how the workspace behaves.
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