175/70R15 vs 195/60R15: Tyre Size Comparison, Diameter Difference & Speedometer Effect

Comparing 175/70R15 with 195/60R15 comes down to four numbers for each size: diameter, sidewall, circumference and revs per mile. 195/60R15 is the shorter tyre: its diameter is 615.0 mm against 626.0 mm, -11.0 mm (-1.8%) smaller. The width changes by +20 mm (175 mm to 195 mm) and the sidewall by -5.5 mm. This page puts both sizes side by side, works out the diameter difference in millimetres and percent, shows the speedometer error in both directions at 30, 50 and 70 mph, and explains what the change means for ride, grip and clearance — so you can judge the swap with the actual figures in front of you.

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 -1.8% 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.

175/70R15 vs 195/60R15 side by side

Measurement 175/70R15 195/60R15 Difference
Overall diameter 626.0 mm (24.6 in) 615.0 mm (24.2 in) -11.0 mm (-1.8%)
Sidewall height 122.5 mm 117.0 mm -5.5 mm
Circumference 1966.6 mm 1932.1 mm -34.5 mm
Revolutions per mile 818.3 833.0 +14.7
Section width 175 mm 195 mm +20 mm
Rim diameter 15 in 15 in +0 in

Diameter difference between 175/70R15 and 195/60R15: -11.0 mm (-1.8%)

The diameter gap of -11.0 mm (-1.8%) is the number to carry away from this section. It is inside the plus-or-minus 3% guideline, and it shows up directly in the speedometer tables below. The circumference difference of -34.5 mm and the revs-per-mile difference of +14.7 are the same change expressed differently — the first is what the road sees, the second is what the car's sensors count. Neither is a safety judgement on its own; both are inputs to the fitment checks further down the page.

Speedometer error: 175/70R15 to 195/60R15 and back

Going from 175/70R15 to 195/60R15, the diameter grows by -1.8%, so the true speed is the indicated speed multiplied by 0.982. At 30 mph on the dial the car is really doing 29.5 mph; at 50 mph indicated it is 49.1 mph; at 70 mph indicated it is 68.8 mph. The speedometer therefore reads high after the change, which matters most at motorway speed, where even a small percentage is a real difference in miles per hour. Going the other way, from 195/60R15 back to 175/70R15, the error reverses exactly: the ratio becomes 1.018, so 70 mph indicated is really 71.3 mph.

Indicated speed Actual speed fitting 195/60R15 (from 175/70R15) Actual speed fitting 175/70R15 (from 195/60R15)
30 mph 29.5 mph 30.5 mph
50 mph 49.1 mph 50.9 mph
70 mph 68.8 mph 71.3 mph

Sidewall height and ride comfort: 175/70R15 vs 195/60R15

Look at the sidewalls next. 122.5 mm on 175/70R15, 117.0 mm on 195/60R15: a difference of -5.5 mm. That is the flexible part of the tyre, and it is the first thing that absorbs a bump. A shorter sidewall transmits more of the road to the driver, which feels more direct but less forgiving on rough surfaces. Aspect ratio (70% vs 60%) is simply the sidewall expressed as a share of the width.

Width, grip and fuel use: 175/70R15 vs 195/60R15

The width gap is 20 mm (175 mm against 195 mm). Going wider usually buys dry grip and a more planted feel, and it costs a little in rolling resistance and road noise. Remember that width also decides whether the tyre fits the rim: a 195 mm tyre needs a rim width within the range its maker approves, and a rim that suited 175/70R15 may not suit 195/60R15. That is a separate check from the diameter comparison, and it belongs on the list before anything is fitted.

Revolutions per mile and gearing: 175/70R15 vs 195/60R15

The revs-per-mile figures (818.3 for 175/70R15, 833.0 for 195/60R15) describe the gearing effect. 195/60R15 turns +14.7 fewer times per mile, so at any given road speed the engine turns slightly slower with 195/60R15 fitted — the gearing is effectively longer. That can make cruising a touch more relaxed and can trim fuel use slightly, but it also means slightly less acceleration from the same throttle opening, because each gear is effectively taller. The change is 1.8% either way, so the effect on everyday driving is subtle rather than transformative.

Will 195/60R15 clear after 175/70R15? What to check before fitting

Whether 195/60R15 physically fits is a question for your car, not for this table. The numbers say it is shorter by 11.0 mm and 20 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 195 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: 175/70R15 or 195/60R15

Weigh the four effects separately. Sidewall (-5.5 mm) for comfort. Width (+20 mm) for grip and rolling resistance. Diameter (-1.8%) 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 175/70R15 vs 195/60R15 comparisons and tools

Frequently asked questions

What is the diameter difference between 175/70R15 and 195/60R15?

195/60R15 is -11.0 mm (-1.8%) smaller in diameter than 175/70R15: 615.0 mm against 626.0 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 195/60R15 instead of 175/70R15?

The error follows the diameter ratio, -1.8%. At an indicated 30 mph the true speed would be 29.5 mph, at 50 mph indicated it would be 49.1 mph, and at 70 mph indicated it would be 68.8 mph. The full table in both directions is in the speedometer section above.

Is 195/60R15 wider than 175/70R15, and does that matter?

Yes — 195/60R15 is 195 mm wide against 175 mm for 175/70R15, 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 195/60R15 fit my car if 175/70R15 fits?

Not necessarily. 195/60R15 is shorter by 11.0 mm and 20 mm wider, and it needs a 15-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, 175/70R15 or 195/60R15?

Neither is better in general — it depends on what you want. 195/60R15 has a -5.5 mm sidewall difference, a +20 mm width difference and a -1.8% 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.