Montana Trailer Brake Laws 2026: 3,000 lb Rule
State towing-law summaries are educational only and are not legal advice. Verify your trailer type, actual weight or GVWR, and equipment requirements with official Montana sources before towing.
Quick answer: 3,000 lb gross weight
In Montana, trailer brakes are currently listed at 3,000 lb (gross weight). Breakaway equipment and safety chains may also be required depending on trailer type, weight, and coupling. Always verify with official Montana sources before towing.
| Requirement | State rule | Applies when | Source | Last checked |
|---|---|---|---|---|
| Trailer brakes | 3,000 lb | gross weight | Verified | 2026-07-13 |
| Breakaway switch | Required for trailers, semitrailers, and pole trailers over 3,000 lb gross weight manufactured or assembled after January 1, 1966; brakes must apply automatically and remain applied for at least 15 minutes. | Trailer type and weight may matter | Verified | 2026-07-13 |
| Safety chains | Needs verification | Conventional trailer couplings | Verified | 2026-07-13 |
| Speed / lane rule | Needs verification; follow posted limits. | Posted roads and vehicle combinations | Verified | 2026-07-13 |
| Double towing | Needs verification with Montana Code Annotated. | Multiple-trailer combinations | Verified | 2026-07-13 |
Official source links
Montana requires brakes on all wheels except for trailers, semitrailers, and pole trailers not exceeding 3,000 lb gross weight when the trailer wheel weight is no more than 40% of the towing vehicle gross weight and the combination meets performance requirements.
Compliance checklist
- Verify trailer GVWR and loaded weight before the trip.
- Check whether brakes are required under the 3,000 lb.
- Inspect brake controller, seven-way connector, and trailer brake function.
- Confirm breakaway battery, switch, cable routing, and pin condition.
- Use properly rated safety chains and attachment points.
- Check posted speed limits, lane rules, and trailer tire speed rating.
Related towing tools
Montana towing law FAQ
Are trailer brakes required in Montana?
Montana currently lists a trailer brake threshold at 3,000 lb gross weight. Always verify the official state source before towing.
What weight requires trailer brakes in Montana?
The current data lists 3,000 lb gross weight as the brake threshold.
Is a breakaway switch required in Montana?
Required for trailers, semitrailers, and pole trailers over 3,000 lb gross weight manufactured or assembled after January 1, 1966; brakes must apply automatically and remain applied for at least 15 minutes.
Are safety chains required in Montana?
The safety-chain rule for Montana needs verification with official state sources.
Can I tow two trailers in Montana?
Needs verification with Montana Code Annotated.
What is the safest speed when towing in Montana?
Needs verification; follow posted limits. Even where no special towing speed is verified, reduce speed for trailer tire ratings, grades, wind, and stopping distance.
Do RVs and travel trailers follow the same rules in Montana?
Many brake rules apply by trailer type and weight, but RV, travel trailer, boat trailer, and utility trailer definitions can differ. Verify your exact trailer type with official state sources.
Where can I verify Montana towing laws?
Use the official source links on this page first. Prefer state DOT, DMV, legislature, highway patrol, or public-safety pages over summaries from private websites.