While in Taiwan for the Taipei Cycle Show, we spent a little extra time visiting factories, the beaches and other areas. This included a stop in Taichung, so I lined up a ride with Josh Culp, founder of Culprit Cycles, to get an early ride on his new RAD concept bike.
An acronym for Road And
Gravel DIRT, the frame and fork are designed to handle rough gravel roads, backcountry paths and smooth asphalt with equal aplomb. Our test ride stuck to the latter because those were the wheels he had mounted, but we managed to find some rougher pavement around an abandoned garden theme park high up a mountain to the north of town. Our ride was about three hours, here’s how it went…
Designed as a package to complement his also-available stealth stem, the RAD allows for cables, wires and hoses to enter the top tube directly behind the steerer (like many tri bikes) or remain completely internal by running them through the stem, into the steerer tube, and then into the frame. Either way, you’ll still be able to use the included bento box, which bolts to the top tube.
The result is a very clean appearance. The fork has a hidden fender mount behind the crown, and lower mounts that can be used for light cargo, too. Which brings up the key differences between the RAD and similar frames coming direct out of Asian factories. This is a point we don’t often make here on Bikerumor because smaller brands often use open molds for both frames and rims, throw their logos on them and mark them up in order to bring them into non-Asian markets.
The difference here is that, over the years, Josh has helped to design some of these bikes, which have then found their way into others’ portfolios. For the RAD, he had a smaller budget, so he found a frame design that met most of his goals, then modified it. The layup is different, cable routing is improved and has electronic shifting compatibility, and the finish is much better. How so? With many open mold frames, the exterior layer of carbon is not very pretty, so they’re virtually all painted with a black base coat to hide imperfections. Here, he worked with them to get a better finish that could be sold with only a clear coat. The result is a more modern looking frame that saves anywhere from 80g to 200g in paint weight.
The other upgrades Josh added that are exclusive to the RAD are more rack, bag and bottle mounts, as well as a warranty.
As for performance, the bike has excellent power transfer thanks to an oversized downtube and bottom bracket junction, followed by stout chainstays. For pure road, it delivers the acceleration and stiffness I would want. For dirt roads, larger tires would help mute the bumps and vibrations, and there’s plenty of tire clearance on offer.
While I’m not ready to convert to 1x for all of my road bikes, this setup worked well with a Praxis 1x chainring and carbon crankset chained to an XT 11-speed wide range cassette and rear derailleur.
The bike can be run with 700×45 or 650×2.1″ tires, which means tons of clearance for fenders with up to 700×32 road tires. Note the rack and fender mounts above and below.
Handling was spot on. The bike held its line on the curving mountain road descents and was stable in a straight line. My usual handlebar shimmy test showed a properly stiff front end, landing on the slightly stiffer than normal bit of the scale, but not so rigid as to feel dead. If you’re looking for a versatile bike, it’s worth checking our original coverage for more of the tech details and heading over to their crowdfunding campaign for more.