Tire size comparison
305/55R22 vs 35x12.50R22
35x12.50R22 is −0.6% shorter than 305/55R22: 35.0 in vs 35.2 in (−0.21 in), and 0.5 in wider. With 35x12.50R22 on a vehicle set up for 305/55R22, the speedometer shows 60 mph at an actual 59.6 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 (35x12.50R22 instead of 305/55R22) · Different situation?
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.
Size you're considering
305/55R22 vs 35x12.50R22: full comparison
| 305/55R22 | 35x12.50R22 | Difference | |
|---|---|---|---|
| Overall diameter | 35.21 in | 35.00 in | −0.21 in (−0.6%) |
| Width | 12.01 in | 12.50 in | +0.49 in (+4.1%) |
| Sidewall height | 6.60 in | 6.50 in | −0.10 in |
| Circumference | 110.6 in | 110.0 in | −0.7 in |
| Revs per mile (nominal) | 573 | 576 | +3 |
| Wheel diameter | 22 in | 22 in | ±0 in |
| Diameter in mm | 894 | 889 | −5 mm |
Speedometer difference
Your speedometer is calibrated for 305/55R22. Fitted with 35x12.50R22, the actual speed is the reading × 35.00 ÷ 35.21.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 19.9 mph | −0.1 mph |
| 30 mph | 29.8 mph | −0.2 mph |
| 45 mph | 44.7 mph | −0.3 mph |
| 55 mph | 54.7 mph | −0.3 mph |
| 60 mph | 59.6 mph | −0.4 mph |
| 70 mph | 69.6 mph | −0.4 mph |
| 80 mph | 79.5 mph | −0.5 mph |
Real tires: published diameters
305/55R22: 35.24 in published by 1 maker; 35x12.50R22: 34.5–35 in published by 5 makers. Calculated figures assume a nominal tire; the exact difference between two specific tires depends on their models.
More about each size: 305/55R22 · 35x12.50R22
Related comparisons
FAQ
Which is bigger, 305/55R22 or 35x12.50R22?
35x12.50R22 is −0.6% shorter than 305/55R22: 35.0 in vs 35.2 in (−0.21 in).
How much will my speedometer be off with 35x12.50R22 instead of 305/55R22?
The speedometer is calibrated for 305/55R22. With 35x12.50R22 it shows 60 mph when you are doing 59.6 mph, and 70 mph at 69.6 mph (−0.6%). Your speedometer also has its own factory tolerance.
Can I replace 305/55R22 with 35x12.50R22?
The diameter difference is −0.6%. 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.