Staggered Fitment Checker

Bigger in the rear is a look. The number that matters is how different the two diameters are.

A common square-to-stagger: 245/40R18 front vs 275/40R18 rear — wider in back, almost the same height.

A diameter change moves ride height by half
+1"+0.5"originaltaller
  • The tire rests on the ground, so half of any diameter change goes downward and only the other half lifts the vehicle.
  • A diameter one inch larger raises the vehicle half an inch, and takes half an inch of fender clearance away.
  • That same change shifts the speedometer and revolutions per mile, because the tire covers more ground per turn.
  • Width is a separate problem: a wider tire can rub even when the diameter is perfect.

What it does

Compares one front size to one rear size on diameter, width, sidewall and circumference using the same ISO geometry as Tire size comparison.

How to use it

Enter the front size and the rear size as they are printed. If left and right on an axle differ, this tool is the wrong place — that is not a stagger, that is a mismatch.

How to read the result

Shops often like overall diameter within 2–3% even on RWD stagger. AWD and some 4WD systems are much stricter; the OEM number is in the service manual, not a universal 3% rule. We report the percent. We do not stamp “AWD safe.”

What this does not calculate

Unloaded diameters. Does not know your transfer case, ABS calibration or whether the car is square vs staggered from the factory.

Does not approve a Subaru, Audi quattro or 4WD truck setup. Check the manufacturer’s tire-size tolerance.

Questions

Why won’t you give an AWD cutoff?
Because manufacturers do not agree. Some want well under 1%. Publishing 3% as “AWD OK” would be a made-up safety line.
Does stagger change the speedometer?
The cluster usually listens to one axle. If that axle’s diameter changed, use Speedometer error with that axle’s size.

Related tools

Estimate — not a fitment approval.

Staggered Fitment Checker