Double Up! | H-D 49mm Single-To-Dual-Disc Conversion

Tech | Under Budget

Double Up! | H-D 49mm Single-To-Dual-Disc Conversion - Hot Bike Magazine

01. We first replaced the stock fork lowers with a new H-D dual-disc set from an FXDF with help from our friends at Race Tech. This first required removing the legs from the bike.

02. Once the legs were off the bike, the upper springs were taken out. The oil was then drained from each tube and the lower legs removed.

03. The new black dual-disc lowers were covered with masking tape so as to not scratch them. The fork tubes were then reinstalled.

04. While we had the legs off of the bike, we decided to install an upgraded spring kit from Race Tech ($279) and lower the fork an inch as well. Here you can see the difference in length.

05. The new dual-disc legs were reinstalled on the bike and tightened to factory specs.

06. The front wheel on the Street Bob came from the factory with a dual-disc-ready hub which allowed us to easily mount the new matching H-D right-side rotor.

07. The wheel was then reinstalled on the bike and the new H-D right-side caliper was installed.

08. Since the brake lever is going to actuate two calipers instead of one, a larger 11/16-inch bore master cylinder was used over the stock 9/16-inch unit.

09. We also had to employ a dual-disc brake line with a junction block under the fork's bottom tree. Wanting a blacked-out look to match the new lowers, we chose a set of Black Pearl lines from Magnum Shielding, which LA Harley also had in stock.

10. Once the new master cylinder and brake lines were mounted, we added DOT 4 brake fluid and checked for leaks.

11. With no leaks and a pair of stoppers up front, we were ready to try the bike out. We found that the extra caliper and rotor up front made the bike stop much better and with a more balanced feel on deceleration. We also liked the sportier, yet factory look of the H-D dual-disc setup.

When I purchased my '10 Dyna Street Bob I knew that I wanted to do a few things to it, and setting it up with two stoppers up front was job one. As I was rolling my new bike out of the dealership, a Dyna Fat Bob caught my eye. It was there I spied the needed parts for my single-to-dual conversion. Knowing then that all of the parts could be easily had from my local H-D dealer, I accosted the guy at the parts counter and quizzed him about just what parts were needed. After some searching, we figured out that I needed a set of 49mm dual-disc lowers legs ($300), a right-side caliper ($185), a larger bore master cylinder ($112), a new brake line ($75), and a matching rotor ($225).

What makes this such an easy conversion is that all of these items can be attained at your local H-D dealer, and the parts have been proven to work since they have already been on thousands of bikes. Follow along as we show y'all how to double your braking fortune for about $900.


Los Angeles Harley-Davidson
(562) 408-6088

Magnum Sheilding
(585) 381-8380

Race Tech
(951) 279-6655