I’ve spent plenty of time riding a full-suspension 650b bike over the course of this summer, but I had yet to see how the tweener wheels handle in a hardtail package. So, when I wandered over to the KHS booth and noticed the beautiful carbon frames rolling on WTB Laser Disc 650b wheels, I had to grab one and take it for a spin.
The KHS SixFifty 608 frame is a beautiful full carbon monocoque with a tapered headtube in the size large and greater frames. The top tube is a flattish squared tube that meshes beautifully at the headtube junction with the rounded downtube. The bottom side of the downtube features a long indention, allowing the cable housing to be recessed back into the frame. I found the red and white paint scheme to be a welcome change from the tired black matte frames that everyone has been running for years.
A SRAM 2×10 drivetrain cobbled together from a combination of X-9 and X-5 parts provides forward motion, Avid Elixir 1 brakes provide stopping power, and on the front end there’s a 100 mm X-Fusion Velvet RL.
Out on the trail the super light, very stiff carbon frame was incredibly responsive! The smaller (than 29er) wheels made me feel like I could flick the KHS to my heart’s content and place the wheels wherever I wanted them. Climbing was superb, and descending was great as well. The tire spec was too narrow (at least on the front) for my taste, but with all of the 650b tires coming to market that can easily be resolved.
This was a gorgeous bike that handled superbly, but KHS also produces a 29er model of this exact same bike. While I had a great time on the 650b hardtail, I don’t think I’ll be trading in my 29er anytime soon. I could feel the very tangible increased rollover power, extra momentum, and larger contact patch benefits when switching back and forth between 650b and 29er today. Especially in a hardtail package, 29er wheels aren’t that hard to control, even in tight terrain.
After riding 26” wheels, 650b (27.5”) wheels, and 29” wheels at Outdoor Demo, I honestly think that 650b is much closer to 26ers in how it handles than it is to 29ers. Is that good or bad? I’m not sure, but I think perhaps some marketers are trying to overhype the benefits of 650b wheels over 26ers. As I mentioned in my Jamis review, I still think the wheel sizes will filter out by application. We shall see…
The KHS SixFifty 608 is a gorgeous race-ready carbon fiber hardtail that, with a few key upgrades, could shed even more weight in a hurry! However, if you’re already a 29er fan, they also produce this bike in the big-wheeled variety. Unless some serious science comes around to tell me why a 650b wheel works better in a hardtail package, I’m going to stick to my wagon wheels for all cross country applications.