Sunday, June 23, 2013

Bike #64 Intro: OS Blackbuck 29er

Just to be clear, I don't currently have 64 bikes. Even my ever-patient wife would be giving me the evil eye way before that point. The Blackbuck is my 64th bike since I started biking as an adult (since 1990, basically), but "only" the 7th I have in the garage currently. Even at seven, I'm getting itchy to start unloading... but there's always one more out there, isn't there?

Anyway, after my less than enthusiastic reception of a Canfield Nimble 9, I was ready to try something different. Where the Canfield has a notably slack front end, the Blackbuck is notably quick. Blackbuck offers three forks lengths, and this is the shortest (I think of it as the "baby bear") fork available: at 435mm axle to crown, it's a touch shorter than most 26" forks, and it has more rake to boot. All of this will reduce the trail and sharpen the front steering. More on this later.

Oddly, this is the second Blackbuck I've had. I bought an early arrival of the 2nd generation two summers ago, but with the "mama bear" middle fork (455mm):

As it happened, I ended up selling that Blackbuck that same summer, when I had a brief affair with a titanium hardtail. I've had some seller's remorse since then, because the Blackbuck has so many things I like in a bike:

- it's a steel 29er

- with skinny, not too-stiff oversized tubes

- with a pinch bolt eccentric bottom bracket, maybe the best way to tension a single speed out there

- and a tall head tube, so I can use less spacers (150mm on the large frame)

- and, of course, that quick front end. Check out that minimal gap over the front tire:

But, the Blackbuck's signature elements, the curvy seatstays, still look kind of odd to me. I think this is part of the reason I unloaded it earlier-it never fit my traditional idea of what a mountain bike should look like. But how does it ride? Today I hit P2 to find out.

Handling: Very quick. Not as quick as my old Rawland Sogn 650B with low trail geometry:

but plenty quick. It is very, very easy to place this bike on the trail. See a 2" gap between a root and a rock? You can nail it with the knobbies scraping on either side. It's good for a rider who likes to read the trail and pick a good line. The Rawland was kind of like this too, but in the Rawland's case, if you let your eyes wander for a second, you'd find yourself three feet off the trail. The Blackbuck gives you some margin to make up for any mistakes.

Acceleration: As hard as I can pedal, this bike will go. But that's pretty much true of any bike.

Ride Comfort:  Just OK. If you think those curvy seat stays offer some compliance, well, maybe they will for you, but I don't detect any benefit from them. My Soma Juice is smoother, but again, that's about the smoothest hardtail I've ridden.

Build Quality: Pretty good. The paint is maybe too thick, and tends to chip off around wear areas (dropouts, seat clamp so far). But more importantly, the EBB is solid, squeak free, and easy to set up. Many types of single speed mechanisms I've tried can't nail those three requirements.

Oddities: the down tube has three bottle braze ons. I understand this was intended to fit the  (no longer available) Blackburn Bomber cage, but it also fits the Salsa Anything cage. Which would be great, but doing so blocks out the seat tube water bottle:

Also, and I need to get a picture here, but the downtube has a pair of cable stops near the head tube, then a line of single hose attach points running down the down tube. Mark Slate (the Blackbuck guy) tried to explain this to me, but I can't see any logic here. If you use the cable stops, there's no start point for the other end of the cable. If you use the clamps for full length housing, you have to share one clamp for up to three cables.

I mentioned trail earlier. Let's dive into that a bit more. In general, more trail makes a bike more stable (less willing to change direction, harder to knock off a line), while less trail does the opposite. There are many other factors that affect steering (wheel inertia, rider position, wheelbase, tire size, etc), but trail is a big factor in front steering. I've had bikes with a broad range of trail. I calculated the values from here:

Canfield Nimble 9 at 100mm: 95mm (unsagged), ~81mm (sagged)

Soma Juice, rigid: 74mm

Blackbuck, mama bear: 60mm

Blackbuck, baby bear: 53mm

Rawland Sogn: 39mm

In my experience, the sweet spot seems to be right around the Blackbuck with the mama bear. The Rawland was too nervous to be truly enjoyable. Baby bear is much better than that, but I don't see any real benefit here from what I remember from the Mama bear--that was a sweet handling bike. The Juice at 74mm is pretty good, but not razor sharp. And of course the misnamed Nimble 9 didn't really work for me at all.

I'll give the Blackbuck some more seat time this summer, but so far, I like my Juice a bit better. I'm also starting to think that I might be getting old for a rigid single speed. During today's ride, my mind wandered some to the FSR hanging in the garage. But when I eventually get tired of the complexity of a full sus, then what? Maybe a Surly Krampus. Something for me to chew on while I try to find a demo ride.

And Happy Birthday to my brother Jason! Go Huskies!


  1. I wanted a Gen 1 when I first saw it, but I'm 5'9" and that frame was just too big. I bought 1 of the (only) 4 650B frames ever made. I enjoyed that bike a lot. After riding it rigid, I decided there was no point in 650b front wheel if trying to be more comfortable, so I used a 29er wheel instead. I enjoyed the bike and it's handling traits very much, but eventually sold it. I wouldn't mind owning another one, but like you I'm feeling a little old for all the time rigid riding. Nice bike nonetheless.

    I have heard other say the Juice rides nice, but I don't think I like the dripouts enough to ever give it a try.

    1. Huzzah, my first comment! A nice way to start a Monday morning. Those 650B Blackbucks are pretty rare birds. Like you, I've tried 650B and found more advantages in 29er. But maybe a 650B rear for the short stays and a 29er front is a good way to go...

      Don't be scared by the dropouts on the Juice. They hold solid and don't squeak at all. Also, if you slide them back all the way, there's clearance to mount a normal rack with a disc brake through one of the dropout eyelets. You can see this here:


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