Use the live comparison above to see the exact diameter, circumference, revs/mile, and speedometer error between 285/70R17 and 33x12.5R17. Change either size to explore a different pairing, or open the full Tire Size calculator to start from scratch.
Tire Size Comparison
285/70R17 vs 33x12.5R17
Diameter, circumference, revs/mile, and speedometer error for 285/70R17 vs 33x12.5R17, with a to-scale visual.
Metric (285/75R16) or inch (35x12.50R17)
Past +10% diameter, budget for a regear. Use the Gear Ratio calculator to check.
Tire Size Results
First Tire
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stock diameter
Second Tire
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new diameter
Speedo Error
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speedometer error
| Measurement | First | Second |
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285/70R17 vs 33x12.5R17: What Changes
Both of these get called "33s," but a metric 285/70R17 and a flotation 33x12.5R17 are not identical; the flotation size states 33 inches on the sidewall while the metric size measures a hair under that. This comparison shows exactly how the two stack up on diameter and width so you can pick the one that fits your wheels and fenders.
Frequently Asked Questions
Is a 285/70R17 the same as a 33x12.5R17?
Close, but not exact. The flotation 33x12.5R17 is a nominal 33.0 inches; the metric 285/70R17 comes in slightly shorter and a bit narrower. The results above show the precise difference.
Which is wider, 285/70R17 or 33x12.5R17?
The 33x12.5R17 is wider (12.5 inches of section width versus about 11.2 inches for the 285), which matters for fender and wheel-backspacing clearance.