Plus sizing calculator

Go up one (or two) rim inches while keeping overall diameter within ±3%. Enter your base metric size to see safe plus-size candidates.

Clay illustration of three stepped-size tires in a row

Plus-size options

How to read this table: Plus sizing adds one rim inch per step (+1, +2) and drops the aspect ratio to keep overall diameter within ±3%. A delta of 0.00% would be a perfect match; anything within ±3% is generally safe.

Size	Step	Rim	OD (in)	Diameter delta

Important: Plus sizing candidates shown here meet the diameter rule, but you must also verify: (1) the new size fits physically in your wheel well at full suspension travel, (2) the load index is adequate for your vehicle's GVWR, (3) the speed rating meets or exceeds the original. Always consult a qualified tire professional before installing.

What is plus sizing?

Plus sizing is the practice of fitting a tire with a larger rim diameter than the original equipment while keeping the overall tire diameter (and therefore the speedometer calibration) approximately the same.

The classic rule: for every additional inch of rim diameter (+1 step), drop the aspect ratio by approximately 10 points and increase section width by 10-20 mm. This maintains the overall rolling circumference — and keeps your speedometer and odometer accurate.

Read our plus sizing guide for a full explanation of the tradeoffs.