295/70R17 vs 295/70R18

295/70R18 is 1.0" taller than 295/70R17 (3.0%)

Diameter difference+3.01%diameter 33.26" → 34.26"
295/70R17295/70R18
295/70R17295/70R18Difference
Overall diameter33.26"34.26"+1.00"
Section width11.61"11.61"±0.00"
Sidewall height8.13"8.13"±0.00"
Circumference104.5"107.6"+3.1"
Revolutions per mile606589−18
Wheel diameter17"18"+1"

Speedometer

ShowsActualDiff
30 mph30.9 mph+0.9
45 mph46.4 mph+1.4
60 mph61.8 mph+1.8
70 mph72.1 mph+2.1
80 mph82.4 mph+2.4

Gear ratio to match

CurrentEquivalent
3.423.52
3.553.66
3.733.84
4.104.22

295/70R18 is 1.00" taller than 295/70R17, a +3.01% 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 0.50" (half the diameter change), and the tire needs 0.50" more room above it.

Both tires are the same width, 11.61".

295/70R18 needs a 18" wheel instead of 17", and its sidewall is 0.00" taller.

Details: 295/70R17 in inches · 295/70R18 in inches · change sizes in the calculator

FAQ

What is the difference between 295/70R17 and 295/70R18?

295/70R18 is 1.00" taller (+3.01%) and 0.00" wider than 295/70R17.

Will 295/70R18 change my speedometer?

Yes, by +3.01%. When the speedometer shows 60 mph you would be going 61.8 mph.

Can I replace 295/70R17 with 295/70R18?

It is a +3.0% diameter change, larger than the common 3% guideline, so check clearance and plan to recalibrate.