How to Choose Correct Ball Mount for Tow Dolly
Question:
Hi, I have a 2017 Sunstar LX , class A motor home, and would like to tow dolly a car. The question is which type of ball mount should I use but with the following characteristic: since this is my first time that I am going to tow a vehicle and before I buy a tow dolly, I am renting a Uhaul tow dolly with the idea that when I find a good opportunity on a tow dolly buy it. My issue is that I do not know what would be the ideal drop for the tow dolly I am planning to buy, and I need a solution that will fit the Uhaul tow dolly. Per manufacturer the motorhome towing limits are: hitch capacity 5K lbs. max. and tongue weight 500 lbs. max. Another issue that I do not understand is explained in the attached picture.
asked by: Oscar
Helpful Expert Reply:
The tow dolly you are looking to rent or purchase should feature a recommended or maximum ball height for the hitch ball it will attach to. For example, the Roadmaster Tow Dolly # RM-2050-1 that we have available recommends a ball height of 18 to 20 inches. Since you do not yet have the tow dolly in hand, you can contact the seller and ask for its coupler height from the ground to see where the ideal hitch ball position will be on your Sunstar RV. You will then simply take a measurement from the ground to the top of the hitch receiver on your RV. The difference between these two measurements determine the amount of drop or rise you will need on the ball mount. If your RV hitch measurement is larger, you will need a ball mount with a drop. If the tow dolly coupler measurement is larger, you will need one with a rise.
I have attached a great article that further explains how to choose a ball mount that you might find helpful.
Since you will be renting a tow dolly and then potentially purchasing one down the line, you might be interested in an adjustable ball mount like the Curt # C45900. This sturdy ball mount allows for a maximum rise of 5-1/4 inches or a maximum drop of 6 inches. It also includes both a 2 inch and 2-5/16 inch hitch ball.
I have attached a short video demonstration on this product, along with a link that will take you to our available selection of ball mounts that you can look through.

Products Referenced in This Question
Channel Style Adjustable Ballmount - 2" & 2-5/16" Balls - 14,000 lbs
- Trailer Hitch Ball Mount
- Adjustable Ball Mount
- Two Balls
- 2 Inch Ball
- 2-5/16 Inch Ball
- Steel Shank - Gloss Black
- Drop - 6 Inch
- Rise - 5 Inch
- Fits 2 Inch Hitch
- 14000 lbs GTW
- CURT
more information >
Product Page this Question was Asked From
Roadmaster Tow Dolly with Electric Brakes - 4,250 lbs
- Trailers
- Tow Dolly
- Wheel Decks
- 4250 lbs
- Cars/Trucks/SUVs
- 8-1/2W x 12L Foot
- Powder Coated Steel
- Roadmaster
more information >
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