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How to Read a Jeep Tire Size: 285/70R17 vs 35x12.50R17
Guide · Updated October 23, 2026
Tire sizes on Jeep forums and tire sites come in two styles, and the numbers do not line up at a glance. This guide explains how to read both, converts common sizes to inches, and points you to the right tool when you are ready to compare setups.
Metric sizes
- 285/70R17: 285 is the section width in millimeters, 70 is the sidewall height as a percent of that width, R means radial, and 17 is the wheel diameter in inches.
- To get overall height in inches: (width × aspect ratio ÷ 100 × 2 ÷ 25.4) + wheel diameter. For 285/70R17 that is about 32.7 inches, often sold as a “33”.
- 315/70R17 works out to roughly 34.4 inches and is usually called a “35”. 255/75R17 is about 32 inches, and 245/75R17 is about 31.5 inches.
Flotation sizes
- 35x12.50R17: 35 is the overall height in inches, 12.50 is the section width in inches, and 17 is the wheel diameter.
- Flotation sizes are wider than their metric “same height” cousins, so they often need more clearance and wheel backspacing. A 35x12.50 is a common cause of rubbing on JK and JL builds.
- Real measured height can differ from the label by a few tenths of an inch, and it depends on the brand and wheel width.
Load Range and ply rating
- Load Range (for example C, D or E) shows how much load and pressure a tire is built for. Higher ranges are tougher and heavier, and usually ride firmer.
- Many owners choose Load Range E for heavy rigs, towing or rocky trails, and a lighter range for a mostly-daily-driver.
- Check the load index on the sidewall against your Jeep’s weight, bumper and gear.
Check what fits
Use the Tire & Gear Calculator to compare your current size with a new one, see speedometer error and highway RPM, and get a regear target. Then read our Will it fit? answers for your model, such as 33s on a stock JL or 35s on a JK with a 2.5-inch lift.
Gear that helps
- 35×12.50R17 Load Range E all-terrains (search) — check wheel width and backspacing first.
- JL all-terrain tires (search) — filter by your size and Load Range.
- JK all-terrain tires (search) — filter by your size and Load Range.
- Digital tire pressure gauge — airing down and back up accurately.
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Disclaimer: General information for enthusiasts, not a substitute for your owner’s manual, a licensed mechanic or your tire shop. Confirm fitment for your exact Jeep before buying.
FAQ
Is a 285/70R17 the same as a 33-inch tire?
It is close, about 32.7 inches tall, and many sellers list it as a 33. Always check the manufacturer’s measured diameter.
Is 315/70R17 the same as a 35?
Roughly. It is about 34.4 inches tall and commonly sold as a 35.
Will a wider tire fit better or worse?
Wider tires are more likely to rub on a Jeep, especially with the wrong wheel backspacing, so check clearance before you buy.
Do I have to recalibrate the speedometer after changing sizes?
Yes, taller tires make the speedometer read low until it is recalibrated.