Updated October 2026
Winter tools
Chain laws change by state, and the "how many" answer is different for carrying vs. installing. This tool runs the multi-state math: pick your rig setup and the states you'll run, and it tells you how many chains to carry, how many to install at each severity level, where they go, and what to buy. Numbers sourced from Caltrans, CDOT, and the 2025 FreightWaves chain-law guide.
Answer 5 questions. Get your carry count, install counts by severity, a placement diagram, and a buy list. The math re-runs as you change answers.
Default: tandem. Most Class 8 sleeper tractors run 6x4.
Check your sidewall. 295/75R22.5 is ~28% of new-truck fitment (USTMA). Chain fitment follows tire size — pick wrong and the chains won't seat.
Trailer drag chains go on the rear trailer axle — one per side.
Pick every state on your route. The tool takes the strictest requirement across all of them — that's your legal carry minimum. Default: CA + OR + WA (the strictest corridor).
Default: link chains. When a checkpoint says "chains required," link chains are never the wrong answer.
Your numbers
Assumptions shown. Chain-law minimums are sourced from published state DOT requirements as of October 2026 — see the state notes above. Tire-size market shares from USTMA via WorkTruckOnline. Prices in CAD, checked September 2026. Chain laws change: always verify current chain controls for your route before you roll — Caltrans QuickMap, CDOT COtrip, and each state's DOT site. When in doubt, carry more chains, not fewer.
Research-based. Chain-law minimums from published state DOT requirements (Caltrans, CDOT, FreightWaves 2025 chain-law guide). Tire-size shares from USTMA. We did not test these chains hands-on.
Carry is the legal minimum inventory — the strictest state on your route sets it. California at R3 wants 8 chains on a standard tractor-trailer; Oregon wants 6; Colorado wants 4 drive tires chained. Washington adds its own twist: installed chains plus 2 spares.
Install is what goes on the tires at each severity level. Light (CA R1 / CO Code 15): 4 chains on the drive axle(s) — outer duals on a tandem, all four tires on a single drive axle. Moderate (CA R2): add 2 trailer drag chains, one per side on the rear trailer axle. Severe (CA R3): maximum — 8 chains including 2 spares in the side box.
Tighteners run 1 per pair of chains, rounded up. A loose chain at highway speed destroys fenders, air lines, and your day.
A standard tractor-trailer needs 8 chains to satisfy the strictest US state (California at R3): 4 on the drive axles, 2 trailer drag chains, and 2 spares. If you never run California, 6 covers Oregon and most mountain states, and 4 is the practical minimum for drive axles. Use the finder above — it takes the maximum across every state on your route.
On a tandem-drive tractor: the two outer tires of each drive axle (4 chains). At moderate severity and above, add one drag chain per side on the rear trailer axle. Never put chains on the steer axle. Spares ride in the side box — Washington legally requires them.
At CA R2 (moderate) and above, yes — one drag chain per side on the rear trailer axle. At R1 / light conditions, drive axles only. Bobtail (no trailer) skips the drag chains entirely.
Usually, but not everywhere at every severity. California accepts cables at lower chain-control levels, but severe conditions (e.g. Donner Pass at R3) can require link chains. If you run CA in deep winter, carry link chains for the drives.
California accepts AutoSocks as an alternative traction device, and they're far easier to install. But some severe-condition corridors still specify link chains — check the specific corridor's requirements before relying on them alone.
Read your sidewall — 295/75R22.5 and 11R22.5 are the two most common drive sizes. Chain manufacturers size by tire dimensions, and a wrong-size chain won't seat. The finder above matches your tire size to verified products; for unusual sizes, match chains to your exact sidewall markings.
Chain laws change. This tool reflects published state DOT requirements as of October 2026, but always check the current chain controls for your route before you roll — Caltrans QuickMap (quickmap.dot.ca.gov), CDOT COtrip, and each state's DOT site. When in doubt, carry more chains, not fewer.
Related: best tire chains for semi trucks in Canada · winter trucking gear guide · winter idling payback calculator