Building A Supermoto Street Bob for Harley-Davidson’s Brewtown Throwdown

Assembling a custom motorcycle in two days and taking home the win

Customization is at the heart of Harley-Davidson ownership. Buying a bike is just the first step, and The Motor Company knows this very well, doing everything it can to inspire personalization and self-expression throughout the custom process. One way it does this is by inviting a group of influential industry types to Milwaukee once a year and pitting them against each other to build a bike on a chosen platform within clearly defined parameters—Harley calls it the Brewtown Throwdown.

final build
The final build from Team SuperBob on display at Mama TriedJosh Kurpius
Brewtown Throwdown
A little tribute to the Brewtown Throwdown competition on our side coversJosh Kurpius

Why would anyone try to build a supermoto out of a Street Bob? Because no one has. As our group started to assemble in emails and phone calls from across the US, the hot words from today’s custom scene kept popping up: ”scrambler,” “tracker,” “adventure build.” We were all on the same page in wanting to radically alter the bike—despite having only two days in the shop to do so—but I wanted to see something totally new. Something nobody had seen before. So we started gathering inspiration, looking at supermotos, bikes that have run Pikes Peak, looking at other Street Bob customs, and we began drawing.

I was representing Cycle World, head to head against one of my good buds in the industry, Wes Reyneke of Bike Exif. Motocross mega babe Dianna Dahlgren, actor Colin Owens, Alex Robinson of Thrillist, Milwaukee's House of Harley, and Phillip Birschbach of H-D engineering. It was a virtual dream team of moto-minded individuals here for one purpose: to build a bike that could smoke the other team's. The competition was fierce and the trash talking started weeks before we hit the ground in Milwaukee.

Flat Out Friday is a flat-track racing event that kicks off inside Panther Arena in Milwaukee on a slick concrete track that’s been sprayed down with Dr Pepper syrup for added sticky traction. This is where our bike was unveiled, and it’s where our bike was meant to perform. Over the two days we had in House of Harley, we not only installed the hand-fabbed custom tailsection, rear shock lift kit from Bung King, fork lift kit from Trackerdie, chain conversion from Speed-Kings, footpegs from Boosted Brad. but we also hopped up the engine. With the Screamin’ Eagle Stage II kit we put on a more free-flowing air intake, our handmade 2-1-2 exhaust system, and high-performance cams. We then dyno tuned the bike with the new setup, dialing in power at 88.6 hp and 98.36 pound-feet of torque. With the bike’s lifted stance, modified seat, and hopped-up engine, we were sure it had the chops to race at Flat Out, and maybe even take a win.

Flat Out Friday
The final SuperBob unveiled at Flat Out Friday in Milwaukee's Panther ArenaJosh Kurpius
Alex Vogel, Phillip Birschbach and Morgan Gales
House of Harley Service Manager Alex Vogel (right), H-D engineer Phillip Birschbach (middle), and Morgan Gales getting into the build on day oneJosh Kurpius
Lifted fork, fork boots, spoked 19-inch wheel, high fender, and a number plate all add to the Supermoto vibe of the SuperBobJosh Kurpius

Bill Davidson, great-grandson of one of H-D’s founding members, stopped by to see our build: “When you start with a clean sheet of paper or a clean canvas, which here is already a cool bike—I love the Street Bob—then you have the ability to customize within these certain parameters. To look back on what you started with and what you ended with—a lot of effort goes into it. A lot of studying of proportions and colors—what you’re trying to achieve, it’s all shown in the end product and it’s very rewarding.” We had him install our gas tank before he left, a significant little detail for us H-D fans.

J hands-on
J was giving hands-on instructions throughout the build, making sure everyone who wanted to got their hands dirty in the processJosh Kurpius
When you put a custom bike together in two days, it's okay for your pipes to be a little wonk-eyedJosh Kurpius

The day of the races we all met up at House of Harley for the final parts installs and to get to ride our final creation. It was tall, loud, blacked out with tons of killer little details. We had altered the Street Bob into our SuMo vision, and it was awesome. Now we just had to wait and see if everyone else thought it was as cool as we did.

Rich from House of Harley
Rich from House of Harley grinds off a part of the frame that interfered with the swingarm's line of motion after installing the lift kitJosh Kurpius
Chain conversion kit
Chain conversion kit by Speed-Kings with a matching blue chainJosh Kurpius

The bike was set on display at Mama Tried, right next to the competition, so being a fly on the wall to onlookers’ conversations shed some light on their perspective. Some more traditional fans dug the other bike’s style, but we saw tons of people who really jelled with the SuMo style we were chasing. After more than 15,000 votes online, we won by just under 300.

Powder-coated wheel hubs, engine parts, and a blue air filter helped carry our color theme throughout the bikeJosh Kurpius

Getting to work with such an amazing team to do so much in so little time was an incredible experience. Alex Vogel and his whole team at House of Harley bent over backward to make this happen, doing the prep work and halting progress in their shop so our group of hooligans could come in and move all their tools around. Huge thanks to Harley-Davidson and everyone involved, and Wes, better luck next year, bud!