2026 Rivian R1T: the quick answer
The 2026 Rivian R1T ships with 275/55R21 tires on the base trim — that's an overall diameter of 32.9″. The 275 mm width and 55% sidewall ratio give you 151.3 mm of sidewall cushion between the rim and the road.
Tire fitment
2026 Rivian R1T tire size
The 2026 Rivian R1T base tire size is 275/55R21 — 275 mm wide with a 55% aspect ratio on 21″ rims. 4 OEM sizes are available across trims.
2026 Rivian R1T
275/55R2132.9″ overall diameter · 151.3 mm sidewall · ~613 rev/mi
| Trim | Tire size | Rim | Diameter | vs Base |
|---|---|---|---|---|
| 21" Road ★ | 275/55R21 | 8.5×21″ | 32.9″ (835.9 mm) | — |
| 20" All-Terrain | 275/65R20 | 8.5×20″ | 34.1″ (865.5 mm) | +3.54% |
| 20" All-Season (Gen 2, 2025+) | 275/60R20 | 9×20″ | 33″ (838 mm) | +0.25% |
| 22" Sport | 275/50R22 | 8.5×22″ | 32.8″ (833.8 mm) | -0.25% |
No-charge standard wheel; the 20" All-Terrain was a paid upgrade.
Before you buy tires
Match the load index and speed rating from your door-jamb placard — not just the size. If you're switching sizes, keep the overall diameter within ~3% to avoid speedometer error and potential ABS/traction-control issues.
Factory fitment for the 2026 Rivian R1T; verify against your door-jamb placard or owner's manual.
FAQ
What tire size does the 2026 Rivian R1T use?
The base 2026 Rivian R1T uses 275/55R21 tires — 275 mm wide, 55% aspect ratio, on 21-inch rims. The overall diameter is 32.9″ (835.9 mm). Higher trims use different sizes — see the table above. Confirm against your door-jamb placard.
Can I use a different tire size on my 2026 R1T?
Yes, within limits. Keep the overall diameter within about 3% of 32.9″ to avoid speedometer error and clearance issues. A wider tire may improve grip, but match the load and speed ratings your R1T requires.
What is the overall diameter of 275/55R21 tires?
275/55R21 tires have an overall diameter of 32.9″ (835.9 mm), with a 151.3 mm sidewall height. That's about 613 revolutions per mile.
The 2026 Rivian R1T tire sizes shown are OEM factory fitments. Confirm your exact tire size, load rating, and speed rating against the door-jamb placard or owner's manual before buying tires.