OS Bikes Blackbuck: On Test
January 22nd, 2008 by Guitar Ted
Twenty Nine Inches will be testing this frame (and a rigid fork) in the upcoming months from OS Bikes. As we have reported before, the frame only comes in one size, and it just happens to fit me. Since that was the case, I went ahead and ponied up for the frame and fork option. (The Blackbuck is also available as a complete single speed with a Reba suspension fork.)
The obvious feature of the Blackbuck is the gracefully arching seat stays, but there is a lot more going on here. The frame appears to be very well constructed and attention to detail is evident throughout. The attachment point for the seat stays to the seat tube is a good case in point.
The chainstay mounted disc brake will be another unique feature and the minimalistic look is different from the usual braces and whatnot that seat stay mounted calipers usually entail. The drop outs are also pared down versions of the old Breezer type and look dainty compared to alot of drop outs I’ve worked with on 29″ers. (Note: The two holes in the driveside drop out are for the optional pinned derailluer hangar which comes with the Blackbuck.)
You have your Bushnell type EBB’s and your “pinch bolt” type EBB’s, now I’d like to introduce you to a split shell EBB! Yep, it is an old idea that has been around a long time, and the Blackbuck utilizes it. I’ll be interested to see how it holds up to off roading and if the dreaded creaks come calling. Only time will tell!
Here is the idea Mark Slate, OS Bikes creator, had for a head tube reinforcement. His belief is that this needs to be done due to the ratio of short head tube to long fork leg that causes more leverage to be exerted on the lower part of a 29″ers head tube. I don’t think I’ll be having a problem here!
I’ll be setting the OS Bikes Blackbuck up with parts swapped over from another single speed that I own. I will be using several different forks on the Blackbuck to acertain the effects of different off sets and axle to crown lengths on the handling of this particular 29″er. Specifically of interest will be the 440mm axle to crown Blackbuck fork, which at first glance looks to be a wrong choice for this bike. I have been assured that it works really well, so I will be very interested in the results of using this fork/frame combination. Other forks I will be testing on the Blackbuck include the Reba, an On One Superlight Carbon fork, and a RST M-29 80mm fork.
Of course, I’ll be passing along my thoughts on the Blackbuck and most importantly….riding it alot!
Stay Tuned!
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Since I’m in your neck’o the woods Mark, I’d be more than happy to lend a few opinions of that there frame for ya!
Marty: Yeah, you’ll be seeing this up close and personal sometime when it warms up and the trails clear out.
Looking forward to reading your take on it. Nice pick up!
That is a pretty sweet rig! I can’t wait to hear how she rides.
The placement of the EBB slot and bolts is a little strange though. I would think that the chainstay joints might be more susceptible to cracking with the slot that close to them, plus the added stress of the bolts tugging at the welds.
What sizes does it come in?
neener-niner: Yeah…..I can see your concern. I think the idea is that the bottom part of the shell gets drawn into the rest of the EBB by the bolts. There is a lot of support there, so I think it isn’t too big a deal. Besides, as I mentioned, old tandems have utilized this very same approach with no ill affects. I think it should be fine, but we’ll find out.
The size would be much like alot of folks 20″ rigs, although I would venture some folks that fit 18″ frames may want to take a look too. It’s got something just above a 24 inch long effective top tube length. I’ll double check it later.
Cool. I’ll be interested to see how that chainstay mounted disc brake mount holds up over time. Will it restrict the type of brakes you can use on it? It is cool lookin and I think that has to be one of the longest offset (non-custom) rigid forks out on the market right now right?
Very well thought-out design! Thank god a hangar was included, can’t wait for the ide results.
GT - Can you weigh that frame for me before you build it up? Thanks!
MMcG: Right, I believe that is correct.
NHNiner: The frame, EBB, and seat collar weighed 5.6lbs on my digital scale.
the pics don’t do it justice. In person it looks even better. the thought process on this frame fixed every problem I had a with a bike that can be single speed or geared. When single, you would never know it could be geared. very nice indeed.
The bike really is sweet! Hmm, I wonder what I can sell off to afford one of these things?
Where are they made? The one size thing is kinda strange though???
asta lumbego,
NN
neener-niner: The frame and rigid fork are done up in Taiwan. It was described to me as the “go-to” factory for 29″ers there. Apparently several steel 29″ers come out of this particular factory there.
Mark Slate picked the size most likely to sell. He told me if the bikes sell through he has plans for a smaller size on the drawing boards.