Effect on Hitch Tongue Weight Rating from Use of Hitch Adapter with Motorcycle Carrier

Updated 05/16/2017 | Published 05/15/2017

Products Featured in This Question

Curt Hitch Extender for 2" Hitch Receivers - 8" Long

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Curt Dual Hitch Extender for 2" Trailer Hitches - 8" Extension

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Erickson Re-Tractable Ratchet Straps w/ Push Button Releases - 2" x 10' - 1,100 lbs - Qty 2

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Question:

How much does a hitch extension increase the vertical weight of a motorcycle carrier relative to the hitch? Is there some sort of equation to calculate the variance in weight to the distance from the hitch? Thanks

asked by: Luke

Expert Reply:

You are on the right track in recognizing that use of a hitch extension or adapter changes the forces on the hitch. This in turn changes the hitch's tongue weight (TW) capacity.

In the same way that using a cheater bar on the end of a tire iron can give you more leverage to loosen a stubborn lug nut, using a hitch extension like # C45791 or an adapter like # D-192 will let the chosen carrier exert more force on the hitch tube. This is why use of any such item reduces the hitch capacity by 50-percent. Adapters also tend to allow more random motion of a carrier since there is now an additional mechanical connection point in the system. Use of tie down straps like # EM34416 can help to reduce this motion.

This 50-percent reduction is an industry standard that was adopted since doing the actual calculation for a specific application is beyond the math skills of most of us who are not mechanical engineers.

In your application with a hitch-mounted motorcycle carrier you could use an extender/adapter ONLY if the halved hitch weight rating is still enough for the combined weight of the carrier and motorcycle.

expert reply by: Adam R