B-Side (v.2) (27.5″ / 650b)

(RETIRED: Replace with new version) 650b (27.5") is the tire size halfway inbetween 26" and 29" tires. 650b tires roll over obstacles better and are more stable at speed than a 26" wheel. But it has less of the unwieldy feel some say 29ers have. Our re-designed B-Side has an improved geometry and the addition of snazzy Tange/IRD Sliding Dropouts so you can go single-speed or geared.

- Tange Prestige heat-treated butted CrMo steel; butted CrMo rear end
- Disc brakes only (no canti studs)
- Tange/IRD Sliding Dropouts allows geared and single-speed builds with easy wheel removal
- S-bend seatstays and chainstays
- Low sloping top tube/short seat tube
- Rigid CrMo steel disc fork in black available
- Geometry adjusted for the White Brothers 650b 80mm travel fork (will also work with some 100mm travel 26” wheel forks)
- 1-1/8” size headtube
- 27.2mm post size/28.6mm frt. der. size/29.8mm(or 30.0) seat collar
- Recommended tire size: 1.95 - 2.4”
- Color: Gunmetal Blue Matte
- Wt: 4.5 lbs.
- Sizes: Sm(14.5"), Md(16.5"), Lg(18.5"), XL(20.5") - Compatible with Paragon Machine Works replacement dropouts (Rohloff, Single Speed, Direct Mount, Thru Axle)


B-Side (v.2) (27.5″ / 650b)

  • Is it hard to get 650b MTB tires?

    In 2009, the list was pretty short, but in 2013 there are a solid number to excellent riding treads ranging from fast-rolling small knob XC to fat all-mountain 2.4's:
    Partial list:
    Pacenti Quasi-Moto
    Pacenti Neo-Moto
    IRD Fire 650b 2.1
    Schwalbe Racing Ralphs 2.25
    Kenda Nevegals
    WTB Wolverines 2.2
    Hutchinson Cougars 2.2/2.4
    Hutchinson Cobra 2.1
    Maxxis Ardent 2.25
    Maxxis Cross Mark 2.1

B-Side (v.2) (27.5″ / 650b)

  • Suits this guy better than 29ers

    “I’ve been riding a Soma B-Side for a couple of months now. It is a sweet, sweet ride! For the past 4 years, I’ve ridden a Turner Flux (26″ x 4″ XC bike). I have loved my Turner since the day I bought it. During that time, I’ve owned a JET9, SIR9 and Kona Unit. Not one of those bikes were fun to ride. I live in an area where 29ers should work best. It’s pretty smooth and flowy. God knows that they are popular around here. Alas, I have no love for the big wheels. Perhaps it my relatively short stature (I’m 5′ 7″) or point-and-shoot riding style. There are lots of people much shorter than I who love their 29ers. Although, I can’t fathom how based on my experience with them. Back to the B-Side. It is a bike that, like my Flux, just “feels right.” The wheels roll suprisingly better than 26ers. Sure, it doesn’t roll over things like a 29er, but it also doesn’t try to hide freight-train handling behind overly steep head angles and jacked fork offsets. What a fun bike this is to ride!”

    CH, ,

  • B-Side

    “ The geometry is A LOT like the classic KONA hardtail geometry. Which i LOVE. I run a setback post on most other frames but seem to not need on this and the mentioned KONAs. The frame has ample crotch clearance and feels very nimble. The Rear derailleur cable routing is abit hard with my shimano XT shadow RD. I don't know if it is just the derailleur but the housing passes right across the slider bolt heads making it difficult to access. also the housing ends up resting on the flange portion of the dropout which is sharp and just seems like if i crash on that side just right it is likely to crimp the housing. hasn't happened yet but seems likely. Overall frame feels great! this is my first ride on a 650b and i am in love. I really only noticed goods differences from my 26er. the frame retails for $450ish and is a great deal! i kinda wish i would have set up as a single speeder first because it seems like it would SHINE utilizing the sliding dropouts The paint is pretty but THIN!!!! i wore through a 3in patch on the chainstay from my muddy pants. I have since covered the chainstay with a layer of electrical tape to protect it from further rubbing and chain slap.”

    Dr. Braunson, ,

  • B-Side: One Year Review

    “(This review was for a first generation B-Side) though I haven't been able to ride it as much as I'd like, the B-Side is definitely the mountain bike for me (at this moment). The steering seems neutral with a 90 degree stem (may seem slow at first if you're coming off a 26er), the big wheels roll over quite a bit more than I expect without feeling like flywheels or being slow to accelerate. I got the gear ratio just about right for most climbing and flats (32x18). The steel frame and fork and the big 2.3" Pacenti Neo-Moto tires handle enough of the bumps and trail chatter that I don't regret going with a fully rigid setup. Overall, this is a simple mountain bike that makes me feel confident and though it's not the ideal bike for everyone everywhere, it can certainly handle the rocky, rooty northeast trails. There are, of course, limits to a fully rigid singlespeed, but not as many as you might think until you've tried one. I'm happy with it. ”

    Doug, ,