13-inch vs 14-inch rims · tyre size comparison
155/70 R13 vs 165/55 R14
165/55 R14 is 10.1 mm (0.4 in) shorter than 155/70 R13, a -1.85% difference in overall diameter. That is inside the ±3% limit commonly used to screen a tire size change; it is a nominal calculation, not a fitment approval.
- Diameter difference
- -10.1 mm
- -0.4 in · -1.85%
- Indicated 70 mph
- 68.7 mph
- Actual speed on 165/55 R14, if the speedometer was accurate on 155/70 R13.
- Sidewall height
- -17.75 mm
- 108.5 mm to 90.75 mm.
Dimensions side by side
| Measurement | 155/70 R13 | 165/55 R14 | Difference |
|---|---|---|---|
| Overall diameter | 547.2 mm21.54 in | 537.1 mm21.15 in | -10.1 mm (-1.85%)-0.4 in |
| Section width | 155 mm6.1 in | 165 mm6.5 in | +10 mm+0.39 in |
| Sidewall height | 108.5 mm4.27 in | 90.75 mm3.57 in | -17.75 mm-0.7 in |
| Circumference | 1,719.08 mm67.68 in | 1,687.35 mm66.43 in | -31.73 mm-1.25 in |
| Rim diameter | 330.2 mm13 in | 355.6 mm14 in | +25.4 mm+1 in |
| Revolutions per mile | 936.17 | 953.77 | +17.6 |
| Revolutions per km | 581.71 | 592.65 | +10.94 |
Calculated from the nominal size codes, without load or tread wear. Real tyres vary by model, rim width and pressure, so the exact tyre's published dimensions take priority.
Speedometer with 165/55 R14
If the speedometer was accurate on 155/70 R13, fitting 165/55 R14 means the car is travelling 1.85% slower than it shows, and the odometer over-records distance by about the same amount.
| Speedometer shows | Actual on 165/55 R14 | Difference |
|---|---|---|
| 30 mph | 29.45 mph | -0.55 mph |
| 50 mph | 49.08 mph | -0.92 mph |
| 60 mph | 58.89 mph | -1.11 mph |
| 70 mph | 68.71 mph | -1.29 mph |
| 50 km/h | 49.08 km/h | -0.92 km/h |
| 100 km/h | 98.15 km/h | -1.85 km/h |
UN ECE Regulation 39, used in the UK and EU, does not allow a speedometer to show less than the true speed, so many read slightly high from the factory. A shorter tyre adds to it. Calibration varies by car; these figures are the tyre-size effect only.
What changes from 155/70 R13 to 165/55 R14
Wheels
These sizes need different wheels: 13-inch for 155/70 R13 and 14-inch for 165/55 R14. The larger wheel usually weighs a little more; the smaller one must still clear the brake calipers. Check rim width, offset and load rating for whichever wheel you fit.
Sidewall and ride comfort
165/55 R14 has 17.75 mm less sidewall (90.75 vs 108.5 mm). A shorter sidewall usually sharpens steering response, but rides noticeably firmer and leaves the rim more exposed to potholes and kerbs.
Contact width
165/55 R14 is 10 mm wider in nominal section width (6.5%). A wider tyre usually puts a wider, shorter contact patch on the road, which can help dry grip, but it may follow ruts more, clear standing water less readily and add some rolling resistance.
Wheel well clearance
Ride height changes by about -5.1 mm, and the top of the tyre moves the same distance away from the arch. On the same wheel width and offset, each sidewall moves about 5 mm further out towards the arch lip and further in towards the suspension. Check clearance at full steering lock and full suspension compression, especially on a lowered car.
Gearing
The effective final drive changes by +1.88%: 3,000 rpm at a given road speed becomes about 3,060 rpm. Gearing gets slightly shorter, so acceleration in each gear sharpens and cruising revs rise.
ABS, stability control and AWD
These systems compare wheel speeds. Fit the same size on both ends of an axle; with a 1.8% diameter gap, never mix 155/70 R13 and 165/55 R14 on an AWD car, and follow the car maker's rolling-circumference limits, which can be much tighter than 3%.
General tendencies from the nominal numbers, not a test of any tyre. Load index, speed rating, tyre construction and the car's approved sizes matter more than these rules of thumb.
Explained in our guides
- Plus-sizing wheels: tyre diameter and speedometer changesWork through a 17 to 18 inch wheel change, compare tyre diameters and speedometer effects, and understand why a 3% rule cannot approve fitment.
- Staggered vs square wheels: tyres, rotation and AWDCompare square and staggered wheel setups, calculate front-to-rear tyre diameter, and understand rotation limits and all-wheel-drive requirements.
- How to read a tyre size, load index and sidewall markingsDecode tyre width, aspect ratio, rim diameter, load and speed markings, then calculate sidewall height and diameter using a 225/45 R17 example.
Cars in our guides using these sizes
Factory trims and popular community setups from our fitment guides. A popular setup is not a factory approval; each guide explains its trims, axles and clearance limits.
155/70 R13
165/55 R14
- Suzuki Swift / Cultus sedan 2nd gen (SF) (1989–2003)Popular setup
More comparisons
165/55 R14 compared
Questions
Can I use 165/55 R14 instead of 155/70 R13?
Only on 14-inch wheels, not the 13-inch wheels that take 155/70 R13. The diameter difference is -1.85%, inside the ±3% screening limit. That does not approve fitment: check the car maker's approved sizes, load index, speed rating, rim width and clearance first.
How much bigger is 165/55 R14 than 155/70 R13?
Overall diameter is 10.1 mm (0.4 in) smaller: 537.1 vs 547.2 mm. Section width is 10 mm wider, and the sidewall is 17.75 mm shorter. These are nominal figures; real tyres vary by model and rim width.
Will 165/55 R14 change my speedometer reading?
Yes, by 1.85%. If the speedometer was accurate on 155/70 R13, an indicated 60 mph would be about 58.9 mph on 165/55 R14, and an indicated 100 km/h about 98.2 km/h. You would be going slower than the speedometer shows.
Which is better, 155/70 R13 or 165/55 R14?
Neither in general. 155/70 R13 has the taller sidewall, which usually rides more comfortably; 165/55 R14 usually steers more sharply. 165/55 R14 is wider, which can help dry grip; the narrower size is usually better in standing water and snow. The size listed for your car's trim, on its placard or in the handbook, is the safe default.
Check the exact tyre
Size codes give nominal dimensions. Before buying, confirm the size is approved for your car and check the exact tyre's load and speed ratings and published dimensions.