Nationals Bike: Kira Mullins’ 2x Junior Nationals-Winning SP-Cycle Bike

We're continuing our tradition of looking at many of the 2019 USA Cycling Cyclocross National Championships-winning bikes. While we see many similarly-built Crux and Boone models, it's often the more unique race bikes of younger Juniors and Masters that capture our attention. Today we take a look at one such bike.

For younger riders, finding a bike for cyclocross racing can be more of a challenge than simply going to the local shop. Off-road worthy rigid bikes built for kids are hard to find and many are too heavy, especially relative to their riders, for serious competition. Without readily available options from the likes of the UK's Islabikes, in the United States, parents often resort to building interesting machines for their children.

We have seen these tiny, rigid mountain bikes converted to cyclocross race bikes under Kaya Musgraves in Hartford and Haydn Hludzinki in Asheville, partly because the lower standover of a mountain bike is useful for young racers, and partly because many kids are more confident in technical sections using a flat bar.

This year, Kaia Mullins kept the flat bar tradition alive in the Junior Women 11-12 category, taking the win on her eBay carbon SP-Cycle mountain bike frame and fork.

Kira Mullins won the Junior Women 11-12 National Championship in Lakewood. Junior Women 11-12. 2019 Cyclocross National Championships, Lakewood, WA. © A. Yee / Cyclocross Magazine

Mullins races mountain bikes and cyclocross using the same frame with a different fork for each discipline. "For mountain biking, all we do is switch out the fork for a suspension fork and change the tires and it becomes her mountain bike," Mullins’ father told Cyclocross Magazine.

Earlier this year Mullins won Mountain Bike Nationals on the same bike and that familiarity paid off when the multi-discipline rider lined up in Lakewood. "I don’t think I could have done the descents with drops," Mullins told us after her victory.

With her win in Lakewood, Mullins and her bike hold two National Championship titles. We caught up with her after the race to get a closer look at her winning machine.

Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

Kira Mullins' Nationals-Winning SP-Cycle Bike

Mullins’ frame is an unbranded carbon mountain bike from SP-Cycle, a direct from factory seller that specializes in carbon frames and components. In addition to her frame, SP-Cycle also manufactured her handlebar, seatpost and the rigid carbon fork she uses for cyclocross. The company offers combo kits in different colors in addition to selling the frames by themselves.

Mullins uses a rigid SP-Cycle fork for cyclocross but substitutes a suspension fork for mountain bike racing. Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

Her drivetrain was a mix of Shimano and SRAM with a well-worn 165mm Shimano XT crankset in the front, onto which Mullins’ father mounted a blue anodized 32t Dymoece Narrow-Wide chain ring.

Mullins used a well-worn Shimano XT crankset in Lakewood. Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

In the back, she used an 11-42t Shimano XT cassette, paired with a SRAM chain and SRAM X1 mountain rear derailleur.

Mullins used a Shimano XT 11-42t cassette on her SRAM 11-speed drivetrain with a SRAM X1 mountain derailleur. Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

Mullins' derailleurs and Shimano XT post mount disc calipers paired with Shimano XT shifters.

Shimano XT brakes feature an external reach adjustment knob. Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

While Mullins’ bike may have been budget carbon, her wheels were pricey Roval Control tubeless mountain bike wheels that were acquired from a family friend. The wheels achieve an impressive 1,370 grams using DT Swiss Revolution spokes and feature DT Swiss 240 hub internals. While the wheels are an older pre-boost version, the 100mm front, 142mm rear spacing means that she can keep the wheels for future cyclocross bikes.

At 22mm internally, the Roval Control SL 29 rim is on the narrow side for mountain bikes now. Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

Mullins changes her tires between cyclocross and mountain bike racing, but she also made an unplanned tire swap before the race. "She pinch flatted the rear yesterday," Mullins’ father said. In a pre-ride the day before her title race, she cut the rear tubeless tire on her bike and left her parents scrambling to find a replacement.

Ultimately, running around through the expo at Nationals, they were able to locate a mismatched pair of tires, a Vittoria Terreno Mix in the back to replace her cut tire and Maxxis All Terrane in the front for good measure.

Mullins' Terreno Mix was a last-minute replacement. Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

Although the pairing almost looks deliberate with the All Terrane’s more aggressive knobs on the front wheel, the setup came completely by chance. "These are random, free tires we found in the expo," her mother said.

While she only cut her rear tire, Mullins raced on a new front tire as well. Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

Mullins' cockpit largely featured parts from SP-Cycle, with the company’s carbon seatpost and handlebar on display, although the stem was a rather short aluminum Kalloy Uno 0 degree model. Mullins’ contact points came in the form of Chromag locking grips, Crankbrothers Eggbeaters pedals and a Bontrager saddle.

Mullins' Kalloy Uno stem offered little in the way of reach. Kira Mullins' Junior Women 11-12 winning bike. 2019 USA Cycling Cyclocross National Championships bike profiles, Lakewood, WA. © A. Yee / Cyclocross Magazine

For a closer look at Mullins' drop bar, mountain bike cyclocross bike, see the photo gallery and specs below.

For more coverage from Lakewood, see our 2019 Cyclocross Nationals archive.

Photo Gallery: Kira Mullins' 2x Nationals-Winning SP-Cycle Bike