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When Should You Regear a Jeep for Bigger Tires?
Guide · Updated October 23, 2026
Bigger tires change how your Jeep accelerates, how many RPM it turns on the highway and how it crawls. Regearing swaps the axle ring-and-pinion gears to bring those numbers back. This guide explains when it helps and what to expect.
Why bigger tires hurt
- A taller tire acts like a higher (numerically lower) gear ratio, so the engine has less leverage and the Jeep feels slower, especially uphill or loaded.
- Highway RPM drops, which can cause the transmission to hunt between gears.
- Crawl ratio drops too, which matters off-road and when towing.
Common ratios (usually, depends)
- 33s: many owners are fine on stock gears, and some regear to around 4.10 or 4.56, especially with the earlier engines or an automatic.
- 35s: regearing is common, often to around 4.56 to 4.88, depending on the engine, transmission and how you drive.
- 37s: most owners regear, often to around 4.88 to 5.13.
- These are general ranges, not rules. Your engine, transmission and use change the best choice.
What else to budget
- Install is a precision job (setup, backlash and break-in). Many owners use a shop, and the quote is often the largest part of the cost.
- Plan on both axles, new fluid, and sometimes new bearings, seals and a locker or limited-slip check at the same time.
- Recalibrate the speedometer after regearing and tire changes.
Run your numbers
The Tire & Gear Calculator shows speedometer error, highway RPM and a regear target for your tire size. For your model, see Will it fit? answers, such as 35s on a JK with a 3.5-inch lift or 37s on a JL Rubicon.
Gear that helps
- JL all-terrain tires (search) — filter by your size and Load Range.
- JK all-terrain tires (search) — filter by your size and Load Range.
- Staun tire deflators — repeatable trail pressures.
- VIAIR 88P portable compressor — air back up before the highway.
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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
Do I always need to regear for 35s?
No. Some owners are fine, especially with a lighter rig and no towing, but many regear for better acceleration and highway RPM.
Is regearing the same on a JK and a JL?
The idea is the same, but axles, ratios and part availability differ. Confirm your axle model and the gears you need.
Do I regear both axles?
Yes, both axles must have the same ratio on a four-wheel-drive Jeep.
Does regearing hurt fuel economy?
Usually it improves or cancels the loss from bigger tires, but results vary with driving and tire weight.