Frame Build Info

So you wanna build up your Black Mountain Cycles road or cross bike by yourself.  Here’s the info you’ll need to build it and more.

Road and Cross
Headset:  You’ll need a 1 1/8” threadless headset.  I like the Cane Creek or the Chris King models.

Front derailleur:  The seat tube diameter where the front derailleur attaches is 1 1/8” or 28.6mm.  It seems that Shimano and SRAM don’t have this specific size these days so what you’ll need in that case is a 31.8 with a shim.  Shimano 31.8 derailleurs are supplied with the shim.  SRAM 31.8 doesn’t come with a shim.  Wheels Mfg. makes one that works pretty good.  An alternative is to use a braze-on type front derailleur with a braze-on adapter.  Problem Solvers and Shimano make nice ones.  I’ve got them in stock if you want to buy one from me.  I’ve also got Wheels Mfg. 31.8 to 28.6 shims for sale too.

Seat post size:  27.2 for both models. 

Seat post clamp:  Both frames are supplied with seat post clamps, but if you want to get yourself a different one, you’ll need a 30.0 size because the top of the seat tube is a bit thicker than the lower section of the seat tube to account for some extra strength in a high stress area where the seat stays and top tube are welded. 

Bottom bracket:  Both frames sport a 68mm wide bottom bracket that’s threaded with British threading.  Basically standard.  Axle length is determined by crank used.

Bottom bracket and head tube:  The bottom bracket has been faced and tapped prior to painting.  Refacing and tapping isn’t necessary, but there may be some residue from paint.  This applies to the head tube as well.  A little clean up with a piece of emory cloth should clean up the opening nicely and allow components to fit as they were designed. 

It may also be necessary to tap some of the threaded bosses because of paint.  If you are unsure about this, your local bike shop can assist you with this.  At least, I hope they can because I sure would. 

Road specific info
Brakes:  You need standard reach (47mm – 57mm) brake calipers.  There are options from Tektro or Shimano that work nicely.  The Tektro R539 is a great brake that opens wide for those 33mm tires.  I’ve got several brake options available for sale with your frame. 

Rear spacing:  130mm.  Use road 130 spaced hubs.  Don’t try to squeeze a 135 in or squeeze the dropouts down to your 126 hub.

Cross specific
Brakes:  Cantilevers are just so nice and simple.  There’s lots of them out there.  The Avid Ultimates are pretty neat.  You can also use v-brakes and the new TRP mini-v brake is sweet and has plenty of stopping power.  Paul Components make just about the best cantilever and mini-v brakes you can get your hands on.  Just make sure to use the appropriate lever with your brake of choice.  The exception is the mini-v which is compatible with a standard drop bar brake lever. 

Front derailleur:  There is a roller included so you can use a standard pull derailleur.  But if you want to use some old top pull front derailleur, you can remove the roller and route your cable straight to the source.

Cable hanger:  If you are running a cantilever brake up front, you’ll need a cable hanger that hangs off the steerer tube or bolts to the fork crown.  I've got both types in stock for sale.  I like the fork crown model when using lower profile canti brakes. 

Cranks:  I recommend either a 50/34 with around a 45mm chainline like Shimano’s, or a 24/34/46 triple such as one from Sugino (or any old school triple) with a 47.5mm chainline.  You can always go wider on the chainline, but  narrower may put the rings into the chainstay.  Because the frame is designed for fatter tires, the chainstays are widened making fitting large road sized rings (38 and larger) not a good idea.  Stick with a crank with a 110 bolt circle at the largest. There are some cranks, such as Dura Ace FC-7950, Ultegra FC-6750, and 105 FC-5750, which are not compatible with the cross frame.  The width of the arms is too narrow and will be too close to the chainstays.  Read this blog post on crank compatibility for more information.  Frame weights are available here at this page.

Rear spacing:  The first production run of frames were made with 132.5 spacing that allowed either 130 or 135 spaced hubs.  Sounds good, but dedicating the rear spacing to one or the other is best.  For the second run of frames, the spacing is a dedicated 130mm.  Because the frames (except for the 65cm size) are heat-treated, respacing the frame to 135 by coldsetting is not recommended.

And if all else fails, call or e-mail me.  My warranty is simple.  If there’s something wrong with the frame that’s my fault or the frame maker’s, I’ll make it right.  And if you have any questions, call or e-mail me.

There’s lots of great frames out there.  Thanks for choosing one of mine.