Tuesday, January 12, 2010

Fixed Mountain Biking

I thought I would cover one of may favorite bikes and an interesting and unique ride. The story is this, I needed a mountain bike. They are always good to have in a pinch, make for awesome snow bikes, and of course are perfect for that which they are designed. I started out with a 2005 Specialized Stumpjumper Hardtail Frame which is made of their M4 aluminum, a compound of aluminum alloyed with silicon, copper, magnesium, and vanadium.

Note: There is now a M5 Specialized Frame that is alloyed with silicon, manganese, magnesium and zinc. The difference being that the ultimate and yield strengths are both a touch bigger and also the ability of the the materials to retain their hardness and stiffness after welding such that less material is incorporated into the frame itself.

Next I acquired a 2008 Fox F-Series 120mm RLC fork with G2 Geometry. This was a very hard item to acquire, being that you cannot purchase this item in retail, as it is custom made for Gary Fisher and the geometry of their bikes. So, I called the rep, and he was kind enough to pull one off a bike for me. Lets just say this was going to be fun.

Note: The G2 Geometry implies that the offset of the fork is 51mm and exclusive to Gary Fisher bikes. As opposed to a normal offset of 38-44mm the fork is unusually raked forward, lengthening the wheelbase. Why did I need this? Well my frame is designed for 80mm of travel in the front, to put 120mm of travel on it I would need to shoot the front end forward.

I paired my find with a Red Chris King 1 1/8 NoThreadSet Original.

Then, I ran out of funds. Postponing the build for another 14 months, purchasing odds and ends when I could stomach them.

Come the Spring of 2009 I had had enough waiting. Although I had intended this bike to run 2x9 with a Sram 3.3 Stylo Team Crankset complete with Rock Guard - tear :'( -I opted to create my first Fixed Gear Mountain Bike.

My last big purchase/build was the rear wheel. The single vertical dropout provided the problem, my White Industries Eric's Eccentric ENO Disc Hub 32h solved that problem.
With the help of a great guy named Dustin at University Bicycles we laced it 2x to a Mavic 321 Disc Rim with DT Swiss Champion 2.0 Straight Gauge and Brass Nipples. Paired with aTomiCOG (which is the ultimate solution, laser cut type 304 stainless steel 1/2" pitch chain drive cog, cut to match a standard 6-bolt mtn bike disc rotor mount) I was set.

Parts List:
2005 Specialized Stumpjumper 19" M4 Frame
2008 Fox F-Series 120mm RLC G2
Avid BB7 Disc Brake and Lever
Chris King 1 1/8 NoThreadSet
WTB SpeedDisc Rim Laced to Deore 32h Hub
32h White Industries ENO Eccentric Laced to Mavic 123 Disc
Izumi Chain
Specialized Avatar Saddle
Generic Seatpost
Specialized XC Handlebars UNCUT w/ Specialized XC Locking Grips
Specialized 80mm 31.8 Stem Flipped and Shimmed at -16
175 Specialized Deore LX Crankset (Un Modified Tripple)
Maxxis Advantage Rear 2.25 Tire

Spec.'s aside this bike is so much fun. It rides great, weighs just about 22 lbs. So much fun on the trails, skidding on dirt throws a new meaning into control. Also a perfect commuter in its 42x16, mainly ridden in 32x16 on trails. Seen in haternation's PBR Poker Alley Cat.


Chris said...

Nice! It's the only way to ride offroad. So much fun!

This is my ride:


daileydarko said...

Very Nice...sounds like you guys have a bigger following then we do here in the states. I only know a few kids locally that are riding fixed off-road. I like the night ride photos, thinking about getting a light setup myself...

Chris said...

TBH there aren't many of us - most people think we're mad.

But they've never tried it!

How much chainlength adjustment do you get with the eno? Do you need to get a halflink?

It's the ultimate solution for low maintenance winter riding :-)