Warning: Extreme Bike Geekery Ahead

I have received a few questions about the style of bike I’m taking to NAHBS.  This type of bike is usually called a dirtroad bike, all-arounder, or a rain bike.  A lot of what defines this bike is builder dependent, however suffice to say, it’s much more than a cyclocross bike with fender mounts.

• In general, the bottom bracket will be in line with a classic road stage race bike, around 70mm-80mm of drop.
• This lowers the rider’s center of gravity which increases stability when riding smooth tires on gravel roads.
•  The chainstays will be shorter than a cross bike, but longer than that of a road bike.  Mine are 420mm which is enough to clear fenders and tires, but still keep the wheelbase in check.
•  To counterbalance the longer backend, I slacken the head tube angle to 72.5 degrees and increase the fork rake to 46mm.  These two things maintain the handling characteristic of a normal road bike, but keep the rider centered between the wheels for even weight distribution.
• This provides a trail measurement of about 59mm with the appropriate tires, which is typical of a road bike.
• The slacker head tube/increase in fork rake combined with the longer chainstays help soften the ride on rough roads.

The most common tire size I see ranges from 24c to 33c.  This type of bike is also fitted with fatter 650b wheels if the rider desires more comfort.  I could also see shorting the cockpit  or raising the handlebar for a more upright fit. 

Brake style is also rider dependent and will vary between caliper, cantilever, or disc.  In the past I’ve always used canti’s, but I prefer longer reach calipers for both their aesthetics and lack of maintenance.  Cantilevers tend to work themselves into a squealing frenzy unless you constantly readjust the pads for toe-in.  For the most part, I find this to be true when it’s wet or cold and under hard front braking.  Not so much if its dry and hot, but that’s not when I ride a bike with fenders on it.  I also find calipers to have a firmer lever feel, but if maximum tire clearance is needed, cantilevers work best. 

Disc brakes provide the best braking in poor weather.  I have used them as well, but the pads have to be set close to the rotor because road levers don’t pull very much cable.  Even with the Avid road specific BB7’s, the rotors have to be perfectly true or the pads will rub.  Disc brakes add a fair amount of weight and look out of place on a road bike to me.

In my experience, you will out brake the traction of a road tire before running out of stopping power, regardless of brake used.  This is not true if conditions are excessively wet or muddy, in which case, disc brakes are appropriate.  See below for photographic evidence of the fine dirt roads that surround Bozeman.

No news on the framebuilding front because I don’t have any tubes to build frames with right now.  All of my funds were sucked into the vortex called NAHBS, so I just practiced welding on some seat tube cutoffs and such.

 I’m just about done with the second dirt road bike except for braze-ons.  The second one turned out a little better, so I will be sending it to spectrum in the next few days.  Some quick stats include OX Platinum 31.8mm DT and 28.6mm TT, both with .7-.4-.7 wall thickness for the front triangle.  The back half has true temper 16mm-11mm tapered seatstays and Columbus teardrop shaped chainstays.  A Columbus 1.1mm head tube and True Temper externally butted seat tube complete the frame.

Chainstays and Seatstays ready to be mitered.

It’s essential that the seat tube is perfectly aligned perpendicularly with the bottom bracket or the rider will be biased towards one side of the bike.  The rider will then have to rock his/her hips to compensate for this.  If it’s perfect the bar will slide in without having to push the seatube up or down.   It’s stepped for different size seattubes.

Checking for fender/tire fit one last time before I weld the rear triangle on.  At this point, it’s only tacked and can be adjusted if needed (read: break the tacks, bend or dimple stays, retack, recheck).  I can simulate this in the fixture to a certain extent, but I like to have the real thing fit before I weld the frame.  

The North American Handmade Bike Show is coming up at the end of February.  I had the opportunity to help out with Carl’s booth last year.  This year I will be attending NAHBS as an exhibiter.  I will be displaying a bike in the new builders section that was recently added. My page on the NAHBS website can be found at:

http://www.handmadebicycleshow.com/2009/12/alliance-bicycles/ 

Only one bike is allowed in the new builder section at the show.  It was really tough to narrow it down to only one frame because I like so many different styles.  I decided to build what I consider to be the quintessential Bozeman road bike.  Around here, the paved roads are straight and flat, as they surround large farm plots.  We jokingly call the most popular loops “around the block” or “the Bozeman track”.  If you want to make a ride longer you just make a bigger square.  However, we do have quality fireroads and footpaths as far as the eye can see.  The in-town singletrack and dirt roads don’t excite the mountain biker in me, or really require a mountain bike for that matter.  However, a bike with a pair of 28c tires allows me to ride all preseason long without going crazy. I just link all the good dirt sections with the pavement roads.  There are awesome mountain logging roads and singletrack trails with some good high-speed sweepers to keep it interesting.   It’s also about the only way to get some elevation gain.

The bike will be a built with a lighter tube set for me (about a 6 on the stiffness scale).  It’s based around long reach calipers to clear 28c tires with fenders, or 30c tires without.  I will be building two of the exact same bike and will take the better of the two.

The bike will also get the full treatment from spectrum powderworks, which I’m really happy about.  It has been hard not to paint any of my bikes because they look and feel unfinished.  My Dura-Ace 7800 grouppo, Ritchey/Bontrager cockpit, handlaced wheels mated to Challenge Paris-Roubaix tires, and a pair of Berthoud fenders comprise the tentative build.  The first bike is about half done.