Wis. Admin. Code Department of Transportation Trans 308.10 - Trailer and mobile home classification and standard minimum strength requirements of hitch and coupling

(1) HITCH DEFINITION. The hitch is that part of the connecting mechanism, including the coupling platform and its attaching members or weldments, which is attached to the towing vehicle.

(2) COUPLING DEFINITION. The coupling is that part of the connecting mechanism, including the coupling and its attaching members or weldments, which is attached to the trailer or mobile home and by which connection is made to the hitch.

(3) TRAILER AND MOBILE HOME CLASSIFICATION. Trailers and mobile homes shall be classified according to the following gross weights, which gross weight shall include the weight of the vehicle and the actual load carried.

(a) Class 1-All vehicles whose gross weight does not exceed 2000 lbs.

(b) Class 2-All vehicles in excess of 2000 lbs. gross weight but not exceeding 3500 lbs. gross weight.

(c) Class 3-All vehicles in excess of 3500 lbs. gross weight and not exceeding 5000 lbs. gross weight.

(d) Class 4-All vehicles with gross weight, in excess of 5000 lbs. but not to exceed 10,000 lbs.

(e) Class 5-All vehicles with a gross weight in excess of 10,000 lbs.

(4) STRENGTH RATING FOR TRAILER AND MOBILE HOME COUPLINGS AND FOR CLASS 5 VEHICLE HITCHES.

(a) The trailer or mobile home coupling shall be of such design as to conform to the minimum strength requirements set forth in par. (b). Where a ball-and-socket type of coupling is used, the ball must conform to the minimum load ratings of the mating coupling.

(b) Minimum strength ratings for the coupling used in conjunction with specific classes of trailers and mobile homes and for the hitch used in conjunction with Class 5 vehicles.

Vehicle Classification	Minimum Breaking Point Requirements of Coupling and of Class 5 Vehicle Hitch
Class 1	Longitudinal tension .......... 6,000 lbs.
Longitudinal compression ...... 6,000 lbs.
Transverse thrust ............. 2,000 lbs.
Vertical tension ............... 2,500 lbs.
Vertical compression .......... 2,500 lbs.
Class 2	Longitudinal tension ......... 10,500 lbs.
Longitudinal compression ..... 10,500 lbs.
Transverse thrust ............. 3,000 lbs.
Vertical tension ............... 4,500 lbs.
Vertical compression .......... 4,500 lbs.
Class 3	Longitudinal tension ......... 15,000 lbs.
Longitudinal compression ..... 15,000 lbs.
Transverse thrust ............. 4,000 lbs.
Vertical tension............... 7,000 lbs.
Vertical compression .......... 7,000 lbs.
Class 4	Longitudinal tension-gross weight of trailer-type vehicle in pounds x 3. Longitudinal compression-gross weight of trailer-type vehicle in pounds x 3. Transverse thrust-gross weight of trailer-type vehicle in pounds x 1.
Vertical tension-gross weight of trailer-type vehicle in pounds x 1.3.
Vertical compression-gross weight of trailer-type vehicle in pounds x 1.3.
Class 5	Strength rating of hitch and coupling for trailers over 10,000 lbs.-Each coupling system, other than safety chain or cable, shall have a minimum longitudinal strength, in both tension and compression, no less than 130% of the gross weight towed by the coupling system. The coupling system shall include not only coupling devices such as tow bars, pintles, and tow bar eyes, but also all the members, means and attachments used to fasten or to secure the coupling device to the motor vehicle.

(5) COUPLING, MOUNTING. Each coupling is to be mounted to the attaching member by bolting, welding or riveting in such manner that the maximum loading required for the coupling designation shown in sub. (4) (b) is safely and adequately transferred to that member.

(6) REQUIRED MECHANISM. Each hitch and coupling, regardless of classification, must be equipped with a manually operated mechanism so adapted as to prevent disengagement of the unit while in operation.

(7) STRENGTH RATING FOR TRAILER AND MOBILE HOME HITCHES.

(a) The hitch and its coupling platform shall be of such design and shall be so attached to the towing vehicle as to safely and adequately handle the gross load of trailer or mobile home including contents thereof.

Notes

Wis. Admin. Code Department of Transportation Trans 308.10

Cr. Register, July, 1968, No. 151, eff. 8-1-68; emerg. am. (3) (a) to (d) and (4) (b), Cr. (3) (e), r. (4) (c), eff. 4-14-80; renum. from MVD 8.10 and am. (3) (a) to (d) and (4) (b), Cr. (3) (e), r. (4) (c), Register, September, 1980, No. 297, eff. 10-1-80.