175/65R13 vs 185/60R13: Tyre Size Comparison, Diameter Difference & Speedometer Effect

If you are choosing between 175/65R13 and 185/60R13, the first question is how far apart they really are. 185/60R13 is the shorter tyre: its diameter is 552.2 mm against 557.7 mm, -5.5 mm (-1.0%) smaller. The sidewall goes from 113.8 mm to 111.0 mm (-2.8 mm), the circumference from 1752.1 mm to 1734.8 mm, and the revs per mile from 918.5 to 927.7. 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.

Taking 175/65r13 vs 185/60r13 as the case in point: Before the tables, keep the context straight. These are nominal new-tyre dimensions, computed from the size codes: real tyres vary slightly by brand, model, wear and inflation pressure. A -1.0% difference is within the plus-or-minus 3% guideline that is commonly used for speedometer accuracy, and the speedometer tables below show exactly what that percentage means at real road speeds. The rest of the page covers sidewall, grip, gearing and the clearance checks that decide whether the larger size can physically fit.

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.

175/65R13 vs 185/60R13 side by side

Measurement 175/65R13 185/60R13 Difference
Overall diameter 557.7 mm (22.0 in) 552.2 mm (21.7 in) -5.5 mm (-1.0%)
Sidewall height 113.8 mm 111.0 mm -2.8 mm
Circumference 1752.1 mm 1734.8 mm -17.3 mm
Revolutions per mile 918.5 927.7 +9.2
Section width 175 mm 185 mm +10 mm
Rim diameter 13 in 13 in +0 in

Diameter difference between 175/65R13 and 185/60R13: -5.5 mm (-1.0%)

A -1.0% diameter change is small enough to sit inside the commonly used plus-or-minus 3% guideline, so the speedometer error it introduces stays modest. The circumference changes by -17.3 mm per revolution, and the revs per mile change by +9.2, which is the same story told from the car's point of view: the instruments count revolutions, so fewer revs per mile means the car travels further per revolution than the instruments assume. That drift also affects the odometer, so recorded mileage moves by the same percentage over time.

Speedometer error: 175/65R13 to 185/60R13 and back

Here is what the speedometer does in practice. Fit 185/60R13 where 175/65R13 was, and the dial understates or overstates speed by 1.0%: indicated 30 mph is really 29.7 mph, indicated 50 mph is really 49.5 mph, and indicated 70 mph is really 69.3 mph. Swap back from 185/60R13 to 175/65R13 and the error flips sign — 70 mph indicated becomes 70.7 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 185/60R13 (from 175/65R13) Actual speed fitting 175/65R13 (from 185/60R13)
30 mph 29.7 mph 30.3 mph
50 mph 49.5 mph 50.5 mph
70 mph 69.3 mph 70.7 mph

Sidewall height and ride comfort: 175/65R13 vs 185/60R13

For 175/65r13 vs 185/60r13, the point is this: Sidewall height moves by -2.8 mm between these two sizes (113.8 mm to 111.0 mm), and that is enough to feel. A taller sidewall flexes more, which softens sharp impacts and gives the tyre more give over potholes; a shorter sidewall flexes less, which sharpens the steering response and leaves the rim closer to the road surface on a hard hit. Which of those you get depends on the direction of the change — here the sidewall shrinks — and on the aspect ratio shift from 65% to 60%.

Width, grip and fuel use: 175/65R13 vs 185/60R13

On this page, 175/65r13 vs 185/60r13 is the case in point: Width changes by +10 mm, from 175 mm to 185 mm. A wider tyre puts a broader contact patch on the road, which generally helps dry grip and braking, but it can also increase road noise and rolling resistance, and it needs more clearance around the suspension and arches. Fuel use moves with rolling resistance, so a wider tyre can cost a small amount of fuel over time — the effect is real but modest for a change of this size, and it is not something this page can put a precise number on without knowing the exact tyre models involved.

Revolutions per mile and gearing: 175/65R13 vs 185/60R13

Think of the gearing change as the diameter change in disguise. The revs-per-mile gap is +9.2, which is 1.0% 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 1.0% and no more. Small percentages mean small effects, which is another reason the plus-or-minus 3% guideline is a useful yardstick.

Will 185/60R13 clear after 175/65R13? What to check before fitting

Whether 185/60R13 physically fits is a question for your car, not for this table. The numbers say it is shorter by 5.5 mm and 10 mm wider, and those are the dimensions that decide clearance — but the actual gaps depend on your arches, suspension and steering geometry. Check at full lock both ways, check with the suspension compressed, and check with the car loaded. Check the placard for the load index and speed rating, and check the rim width for a 185 mm tyre. A tyre professional can confirm all of it in one visit, and that confirmation is the step that turns a comparison into a fitment.

Which size suits which priority: 175/65R13 or 185/60R13

The decision comes down to priorities. Comfort follows the sidewall (-2.8 mm here). Grip follows the width (+10 mm here). Instrument accuracy follows the diameter (-1.0% here). Gearing and cruising engine speed follow the revs-per-mile change (+9.2). None of those is large in this comparison, which is why the practical checks — clearance, load index, speed rating, rim width — deserve as much attention as the numbers. Get those right and the size choice becomes a matter of preference rather than a risk.

Related 175/65R13 vs 185/60R13 comparisons and tools

Frequently asked questions

What is the diameter difference between 175/65R13 and 185/60R13?

185/60R13 is -5.5 mm (-1.0%) smaller in diameter than 175/65R13: 552.2 mm against 557.7 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 185/60R13 instead of 175/65R13?

Taking 175/65r13 vs 185/60r13 as the case in point: The error follows the diameter ratio, -1.0%. At an indicated 30 mph the true speed would be 29.7 mph, at 50 mph indicated it would be 49.5 mph, and at 70 mph indicated it would be 69.3 mph. The full table in both directions is in the speedometer section above.

Is 185/60R13 wider than 175/65R13, and does that matter?

Yes — 185/60R13 is 185 mm wide against 175 mm for 175/65R13, a difference of +10 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 185/60R13 fit my car if 175/65R13 fits?

Not necessarily. 185/60R13 is shorter by 5.5 mm and 10 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, 175/65R13 or 185/60R13?

Neither is better in general — it depends on what you want. 185/60R13 has a -2.8 mm sidewall difference, a +10 mm width difference and a -1.0% 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.