What Gear Ratio For Towing A Trailer With A Harley-Davidson Road Glide?

Gearing For Grunt and Towing

Towing a trailer with a motorcycle

Towing A Trailer With A Motorcycle

Rick Brebner tows a trailer with his 2011 Harley-Davidson Road Glide Ultra and wants to gear down for more grunt.©Motorcyclist

Q. I have a 2011 Harley-Davidson Road Glide Ultra. I tow a trailer with it and would like a little more "grunt" coming off the line. Does anyone make a rear pulley that would lower my final-drive gearing but that doesn't require fitting a longer drive belt?

Rick Brebner
Aspen, CO

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A. Last question first: The stock final gearing on your bike is 32/68 (2.13:1). There are countershaft pulleys available with 30 teeth and rear sprockets with 70. Doing just the rear should be within the range of the axle adjusters so you don't have to replace the belt. But you're going to shorten the gearing only slightly, to 2.19:1 or about 3 percent. Using the 30-tooth front pulley with the 70-tooth rear will get you a 2.33:1 final ratio, or a shortening of about 10 percent. Certainly that will help with performance and will work with the stock belt.

But there's a catch. The labor to replace the countershaft pulley can be substantial. Because Harley's Big Twins have the pulley behind the primary drive, you have to remove the primary chain, sprockets, and clutch, plus the housing itself. Longtime Harley mechanics can do this in their sleep, but it's probably more than a garage-floor project for someone without that experience. A simpler alternative is to shorten the primary ratios with a different sprocket set; due to the easier access, a lot of Harley owners go this route over changing wheel pulleys. It should also be noted that increasing engine power—via a big-bore kit, exhaust and intake upgrades, plus a re-tune of the ECU, for example—might also help you pull the load.