305/40R22 vs 305/45R22

305/45R22 is 1.2" taller than 305/40R22 (3.8%)

Diameter difference+3.80%diameter 31.61" → 32.81"
305/40R22305/45R22
305/40R22305/45R22Difference
Overall diameter31.61"32.81"+1.20"
Section width12.01"12.01"±0.00"
Sidewall height4.80"5.40"+0.60"
Circumference99.3"103.1"+3.8"
Revolutions per mile638615−23
Wheel diameter22"22"±0"

Speedometer

ShowsActualDiff
30 mph31.1 mph+1.1
45 mph46.7 mph+1.7
60 mph62.3 mph+2.3
70 mph72.7 mph+2.7
80 mph83.0 mph+3.0

Gear ratio to match

CurrentEquivalent
3.423.55
3.553.68
3.733.87
4.104.26

305/45R22 is 1.20" taller than 305/40R22, a +3.80% change in diameter. That is more than the 3% many tire shops use as a limit, so plan on recalibrating the speedometer and checking ABS and stability control.

Ground clearance changes by 0.60" (half the diameter change), and the tire needs 0.60" more room above it.

Both tires are the same width, 12.01".

Both fit a 22" wheel; the sidewall is 0.60" taller on 305/45R22.

Details: 305/40R22 in inches · 305/45R22 in inches · change sizes in the calculator

FAQ

What is the difference between 305/40R22 and 305/45R22?

305/45R22 is 1.20" taller (+3.80%) and 0.00" wider than 305/40R22.

Will 305/45R22 change my speedometer?

Yes, by +3.80%. When the speedometer shows 60 mph you would be going 62.3 mph.

Can I replace 305/40R22 with 305/45R22?

It is a +3.8% diameter change, larger than the common 3% guideline, so check clearance and plan to recalibrate.