Tire size comparison

175/70R14 vs 175/65R14

175/65R14 is −2.9% shorter than 175/70R14: 23.0 in vs 23.6 in (−0.69 in), and the same width. With 175/65R14 on a vehicle set up for 175/70R14, the speedometer shows 60 mph at an actual 58.3 mph. That is within the ±3% difference many shops use as a rule of thumb (not a manufacturer or legal limit).

Set up for: checking a replacement size (175/65R14 instead of 175/70R14) · Different situation?

1

Your current size

e.g. 265/70R17, 2657017 or 33x12.50R20

Where do I find my size?

It's on the tire sidewall, e.g. P265/70R17 115T, and on the tire placard sticker on the driver's door jamb (also in the owner's manual). The placard shows the size the vehicle came with; the sidewall shows what is fitted now. If they differ, use the placard as your starting point. Digits are enough here: 2657017 or 33125020.

2

Size you're considering

 

175/70R14 vs 175/65R14: full comparison

175/70R14175/65R14Difference
Overall diameter23.65 in22.96 in−0.69 in (−2.9%)
Width6.89 in6.89 in±0.00 in (±0.0%)
Sidewall height4.82 in4.48 in−0.34 in
Circumference74.3 in72.1 in−2.2 in
Revs per mile (nominal)853879+26
Wheel diameter14 in14 in±0 in
Diameter in mm601583−18 mm

Speedometer difference

Your speedometer is calibrated for 175/70R14. Fitted with 175/65R14, the actual speed is the reading × 22.96 ÷ 23.65.

Speedometer showsActual speedDifference
20 mph19.4 mph−0.6 mph
30 mph29.1 mph−0.9 mph
45 mph43.7 mph−1.3 mph
55 mph53.4 mph−1.6 mph
60 mph58.3 mph−1.7 mph
70 mph68.0 mph−2.0 mph
80 mph77.7 mph−2.3 mph

Estimate from the size change only. Factory speedometers have their own tolerance, real tires differ from nominal, and recalibration options differ by vehicle.

Real tires: published diameters

175/70R14: 23.6–23.7 in published by 2 makers; 175/65R14: 22.9–23.1 in published by 3 makers. Calculated figures assume a nominal tire; the exact difference between two specific tires depends on their models.

More about each size: 175/70R14 · 175/65R14

Related comparisons

175/70R14 vs 185/65R14−0.7% diameter175/70R14 vs 185/70R14+2.3% diameter185/60R14 vs 175/65R14+1.0% diameter185/65R14 vs 175/65R14−2.2% diameter

FAQ

Which is bigger, 175/70R14 or 175/65R14?

175/65R14 is −2.9% shorter than 175/70R14: 23.0 in vs 23.6 in (−0.69 in).

How much will my speedometer be off with 175/65R14 instead of 175/70R14?

The speedometer is calibrated for 175/70R14. With 175/65R14 it shows 60 mph when you are doing 58.3 mph, and 70 mph at 68.0 mph (−2.9%). Your speedometer also has its own factory tolerance.

Can I replace 175/70R14 with 175/65R14?

The diameter difference is −2.9%. Whether it fits depends on things this calculation can't see: wheel width and offset, clearance at full lock and over bumps, load index and speed rating, and your vehicle maker's approval. Check your door-jamb placard and owner's manual and ask a tire professional.

Important: These are calculated (nominal) dimensions, not a fitment recommendation. Real tires of the same size differ by brand and model (makers allow about ±3% of section height), and width changes with the rim it is mounted on. The math can't see wheel width and offset, clearance at full steering lock and suspension travel, load index, speed rating, or what your vehicle maker approves. Before changing size, check your door-jamb placard and owner's manual and ask a tire professional. A replacement tire must meet or exceed the load index and speed rating on the placard.