Ram 1500 tire size on the current DT truck is a 275-section family until you get to the 22-inch Limited. Tradesman and Big Horn often wear 275/65R18. Laramie and many Limited 20-inch trucks wear 275/55R20. Rebel wears 275/70R18. The 22-inch Limited wears 285/45R22. TRX is a different truck (325/65R18) and is not this table.
Stock sizes by trim
These are the common North American DT (2019+) packages. Classic (4th-gen) Rams used 265/70R17 and 275/60R20 in a lot of years. If the title on the registration says Classic, this table is the wrong generation.
| Trim / package | Stock size | Wheel (in) | Diameter (in) |
|---|---|---|---|
| Ram 1500 Tradesman / Big Horn 18-inch | 275/65R18 | 18 | 32.1″ |
| Ram 1500 Laramie / Limited 20-inch | 275/55R20 | 20 | 31.9″ |
| Ram 1500 Rebel | 275/70R18 | 18 | 33.2″ |
| Ram 1500 Limited 22-inch | 285/45R22 | 22 | 32.1″ |
Why the sticker beats the chart
Ram puts the same 275 width on three aspect ratios and three rims. That is why "just order 275s for a Ram" still fails. Aspect ratio and rim have to match the wheel you have.
A Ram 1500 can leave the factory on more than one size. Export markets, mid-year packages and previous-owner plus-sizes all disagree with a chart. Read the driver-door placard. Match width, aspect ratio and rim together.
Swapping to a different size
275/65R18 is about 32.1 inches. 275/55R20 is about 31.9. 275/70R18 is about 33.2. 285/45R22 is about 32.1. Rebel is the one that already sits in the 33 band. Stepping a Big Horn to a 275/65R20 (34.1) is the same argument as the F-150 20-inch trucks. See 275/65R20 vs 275/60R20 for the height math, then check the well.
Rebel is the factory 33
275/70R18 at 33.2 inches is why Rebel owners have a shorter conversation about "going to 33s" and a longer one about 35s. Load range still matters. An LT all-terrain at the same stamp is a different tire than the highway 275 the Big Horn started on.