Carrying Class III Bike Rack Using Class I Trailer Hitch Installed on 2010 Mercedes-Benz S550

Question:

I have a 2-bike car rack that mounted into the 2inch Class III receiver on my old Jeep Grand Cherokee. The Jeep has now been replaced with a Mercedes S550 4Matic sedan. I see that you sell a Class I hitch/receiver for the S550, model 11828. Is there a suitable alternative frame-mounted hitch that provides a 2inch receiver to fit my existing bike rack? Thanks for any tips or suggestions of alternatives.

asked by: Dave M

Expert Reply:

There is not a 2 inch receiver available for your Mercedes, but you can still carry bikes if you install the Curt Class I hitch, part # C11828.

You could use an adapter like part # HTAD, but doing so will have its downsides. Because the adapter moves the load of the rack and bikes further away from the hitch, the leverage applied to the hitch will increase significantly. Because of that fact, using an adapter will LOWER the tongue weight capacity of the hitch by half, from 200 lbs to 100 lbs. This means that the two bikes and the rack they're carried on cannot exceed 100 lbs.

The other downside is that adding another fixture in between the hitch and the bike rack will cause more bounce and wobble because of having an extra piece in between. This can be somewhat combatted using anti-rattle devices like # RM-061 for the connection between the rack and the adapter and # RM-061-125 for the connection between the hitch and the adapter, but you'll still have some bounce.

From a convenience standpoint, I'd recommend you replace your existing bike rack with one that's compatible with a Class I hitch. The Swagman Trailhead, part # S63360 is a quality rack that's available at a decent price. A hitch/cable lock is available separately as part # S64031.

If you'll be transporting women's bikes or bikes with sharply-angled top tubes, you might also consider a frame adapter bar like part # 64005. The bar spans the distance between the handlebar gooseneck and the seat post, which provides a secondary attachment point for the bike rack. This allows the bike to be carried level, which maximizes ground clearance. I'll link you to a video showing how the adapter bar works.