Tire Size Box

235/65R13 vs 235/70R13

235/70R13 compared with 235/65R13

+3.7% diameter, 0.0" width

235/70R13 is 25.95" tall vs 25.03". More than the 3% rule of thumb, so check carefully before switching.

25.0"13" rim6.0"9.3" wide
235/65R13 (solid) compared with 235/70R13 (dashed outline), drawn to scale

With 235/70R13 tires, when your speedometer says 60 mph you are really going

62.2 mph

235/70R13 is +0.93 inches (+3.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/65R13235/70R13Difference%
Overall diameter25.03"25.95"+0.93"+3.7%
Section width9.25"9.25"0.00"0.0%
Sidewall height6.01"6.48"+0.46"+7.7%
Circumference78.63"81.53"+2.91"+3.7%
Revolutions per mile805.8777.1−28.7−3.6%

Speedometer difference

If your vehicle came with 235/65R13 and you fit 235/70R13, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.5 mph+1.5 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.4 mph+2.4 mph
70 mph72.6 mph+2.6 mph
75 mph77.8 mph+2.8 mph
80 mph83.0 mph+3.0 mph

Each size on its own

Questions

Which is bigger, 235/65R13 or 235/70R13?
235/70R13 is taller by 0.93 inches (25.95" vs 25.03"). 235/65R13 is the same width.
Can I replace 235/65R13 with 235/70R13?
It is not recommended without checking carefully. The diameter difference is +3.7%, more than the 3% most shops and makers allow. It will throw off the speedometer and may affect ABS, stability control and clearance.
How much will 235/70R13 change my speedometer?
When your speedometer reads 60 mph with 235/70R13 fitted (calibrated for 235/65R13), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.7%.
Will 235/70R13 lift my vehicle?
Ride height changes by half the diameter difference: +0.46 inches of ground clearance at the axle.

Other comparisons