155/70R13 vs 175/60R13: Tyre Size Comparison, Diameter Difference & Speedometer Effect

If you are choosing between 155/70R13 and 175/60R13, the first question is how far apart they really are. 175/60R13 is the shorter tyre: its diameter is 540.2 mm against 547.2 mm, -7.0 mm (-1.3%) smaller. The sidewall goes from 108.5 mm to 105.0 mm (-3.5 mm), the circumference from 1719.1 mm to 1697.1 mm, and the revs per mile from 936.2 to 948.3. The tables below lay all of that out, then work through the speedometer effect in each direction and the clearance checks that matter before either size goes on the car.

Two things decide whether this swap makes sense: the diameter difference and the physical fit. On diameter, 175/60R13 is -1.3% smaller than 155/70R13, which is inside the plus-or-minus 3% guideline. On physical fit, the width change of +20 mm and the rim change from 13 to 13 inches both need checking against the arches, suspension and steering lock. The sections below take each of those in turn, with the numbers worked out rather than asserted.

This is a calculation, not a safety approval. Always check your vehicle's door-jamb placard, load index and speed rating, and confirm fitment with a tyre professional before fitting a different tyre size.

155/70R13 vs 175/60R13 side by side

Measurement 155/70R13 175/60R13 Difference
Overall diameter 547.2 mm (21.5 in) 540.2 mm (21.3 in) -7.0 mm (-1.3%)
Sidewall height 108.5 mm 105.0 mm -3.5 mm
Circumference 1719.1 mm 1697.1 mm -22.0 mm
Revolutions per mile 936.2 948.3 +12.1
Section width 155 mm 175 mm +20 mm
Rim diameter 13 in 13 in +0 in

Diameter difference between 155/70R13 and 175/60R13: -7.0 mm (-1.3%)

Put the percentage in context. The plus-or-minus 3% guideline exists because small diameter changes produce small speedometer errors, and this change is -1.3%, which is inside that band. In revs per mile the shift is +12.1 (936.2 to 948.3), and in circumference it is -22.0 mm per turn. Those are not abstract figures: every mile you drive, the car covers -22.0 mm more or less per wheel revolution than the instruments expect, and the gap accumulates exactly like interest.

Speedometer error: 155/70R13 to 175/60R13 and back

Here is what the speedometer does in practice. Fit 175/60R13 where 155/70R13 was, and the dial understates or overstates speed by 1.3%: indicated 30 mph is really 29.6 mph, indicated 50 mph is really 49.4 mph, and indicated 70 mph is really 69.1 mph. Swap back from 175/60R13 to 155/70R13 and the error flips sign — 70 mph indicated becomes 70.9 mph. The odometer drifts by the same percentage in each direction, so recorded mileage and any service intervals based on it shift too.

Indicated speed Actual speed fitting 175/60R13 (from 155/70R13) Actual speed fitting 155/70R13 (from 175/60R13)
30 mph 29.6 mph 30.4 mph
50 mph 49.4 mph 50.6 mph
70 mph 69.1 mph 70.9 mph

Sidewall height and ride comfort: 155/70R13 vs 175/60R13

The sidewall is where the ride difference lives. 155/70R13 has 108.5 mm of sidewall and 175/60R13 has 105.0 mm, a change of -3.5 mm. Less sidewall generally means sharper steering response and less cushioning, so more of the road surface reaches the cabin. The aspect ratios tell the same story in percentage terms: 70% for 155/70R13 against 60% for 175/60R13. Sidewall height also affects vulnerability to kerb damage — a shorter sidewall leaves less rubber between the rim and the road.

Width, grip and fuel use: 155/70R13 vs 175/60R13

On width, the two sizes are 20 mm apart. The wider tyre (175/60R13) offers more rubber on the road, which tends to mean more grip in the dry and slightly more resistance to roll. Do not expect a dramatic change in fuel use from a width change of this size; the bigger influences on fuel use are the tyre compound, the pressure and the way the car is driven.

Revolutions per mile and gearing: 155/70R13 vs 175/60R13

Think of the gearing change as the diameter change in disguise. The revs-per-mile gap is +12.1, which is 1.3% of the original figure — the same percentage as the diameter gap. That is because revs per mile is just a mile divided by the circumference, and the circumference is pi times the diameter. So everything the gearing does — engine speed at a given road speed, acceleration in each gear, cruising refinement — shifts by 1.3% and no more. Small percentages mean small effects, which is another reason the plus-or-minus 3% guideline is a useful yardstick.

Will 175/60R13 clear after 155/70R13? What to check before fitting

Clearance is the check the numbers cannot do for you. 175/60R13 is shorter and 20 mm wider than 155/70R13, so check the wheel arches, the suspension components and the steering lock: turn the wheel fully in both directions and check for contact, and check again with the suspension compressed and the car loaded as it will actually be used. A size that clears when the car is stationary and unloaded can still rub over a bump or at full lock. This page does not claim that 175/60R13 clears your car, and no diameter table can — only a physical check on your vehicle can confirm it. Also confirm the load index and speed rating of 175/60R13 meet what your placard asks for, and that the 13-inch rim suits the car.

Which size suits which priority: 155/70R13 or 175/60R13

Weigh the four effects separately. Sidewall (-3.5 mm) for comfort. Width (+20 mm) for grip and rolling resistance. Diameter (-1.3%) for the speedometer, odometer and gearing. And clearance for whether the swap is physically possible at all. If the diameter is inside the plus-or-minus 3% guideline and the clearance check passes, the remaining differences are small enough to be a matter of taste; if either of those fails, the comparison is academic until it is resolved.

Related 155/70R13 vs 175/60R13 comparisons and tools

Frequently asked questions

What is the diameter difference between 155/70R13 and 175/60R13?

175/60R13 is -7.0 mm (-1.3%) smaller in diameter than 155/70R13: 540.2 mm against 547.2 mm. That is inside the commonly used plus-or-minus 3% guideline for keeping speedometer error small.

How much will my speedometer be out if I fit 175/60R13 instead of 155/70R13?

The error follows the diameter ratio, -1.3%. At an indicated 30 mph the true speed would be 29.6 mph, at 50 mph indicated it would be 49.4 mph, and at 70 mph indicated it would be 69.1 mph. The full table in both directions is in the speedometer section above.

Is 175/60R13 wider than 155/70R13, and does that matter?

Yes — 175/60R13 is 175 mm wide against 155 mm for 155/70R13, a difference of +20 mm. A wider tyre generally gives more dry grip and can increase rolling resistance and road noise slightly. Width also affects clearance, so check the arches and suspension at full lock.

Will 175/60R13 fit my car if 155/70R13 fits?

Not necessarily. 175/60R13 is shorter by 7.0 mm and 20 mm wider, and it needs a 13-inch rim. Check the wheel arches, suspension and steering lock at full lock in both directions, with the car loaded, and confirm the load index and speed rating against your door-jamb placard. A tyre professional can confirm fitment on your vehicle.

Which size is better, 155/70R13 or 175/60R13?

Neither is better in general — it depends on what you want. 175/60R13 has a -3.5 mm sidewall difference, a +20 mm width difference and a -1.3% diameter difference, so the trade-offs are comfort, grip and instrument accuracy respectively. If the diameter is within the plus-or-minus 3% guideline and the clearance check passes, the choice is a matter of preference; if not, resolve those two points first.