Sunday, November 16, 2008

More Cross Bike Tech

My close friends know that I can't jump into anything halfway and so during my first season of cross racing I have made it a point to learn about what pieces makes up a good cross bike.

In my mind, the three key pieces are crisp shifting, reliable braking, and the delicate balance between rolling resistance and traction.

For someone starting from scratch, the "Easy Button" is to purchase one of the of very nice complete cross bikes being offered by Jamis, Cannondale, or Kona. No worries about gearing or compatibility because it comes out of the box ready to rock. Done.

The Jamis Super Nova is a sweet bike

If you are like me, and already have some parts to contribute, you may want to buy a frame and build it up from scratch and this is when you will realize that there are not a ton of options for cross-specific cranksets outside of FSA.

GEARING
Being a Campy fan, I decided to try and use a Campy Centaur Compact crankset thinking I could simply buy a set of 110 BCD (industry standard) Specialites TA chainrings in 36/46 gearing and be done with it.

Do NOT try to dremmel your new chain rings!

When my rings showed up I was surprised to see that the bolt holes didn't perfectly line up with my Campy CT crank arms. Fack! So out comes the dremmel tool and I proceed to ruin a perfectly good set of chain rings in an effort to go "custom". Evidently Campy decided to ignore the 110 BCD standard and 4 out of 5 holes on their CT cranks are at 110 BCD while the 5th hole is at 112/113. WTF!

Compact Crank Options
SRAM - 110 BCD
FSA - 110 BCD (available in 36/46)
Truvativ - 110 BCD
Shimano - 110 BCD
Campy - 110/112 BCD

I ended up pulling the Campy standard crank off of my road bike since 42T rings are easy to find in 135 BCD and now I am running the sinlge 42T ring with a light bashguard. Having recently ridden a bike with the SRAM Force shifter, I am glad that I stuck with Campy for its crisp, positive rear shifts.

BRAKES
Setting up cantilever brakes is part science and part voodoo. They never seem to be "perfect" and there is always some variable to address which bugs the shit out of me. Squeal, chatter, and clearance all seem to be moving targets.

TRP Eurox Mags, 103 Grams per wheel and dead sexy - $299

I opted for the economical and perfectly functional Tektro CR 720s. Although boring looking, I really can't say anything bad about them.

Tektro CR 720, 161 Grams per wheel and boring - $59

At least I got the tire & whhel thing right on the first try. My MC-built, Stans 355 wheelset, one scoop of Stans goo, and Hutchinson Tubeless Ready cross tires are also like the "Easy Button". I have been able to run low PSI and have had no flats. (knock on wood) Stan's Raven CX tires look promising too.

2 comments:

Ed said...

Dave - move slowly, put the Dremel tool down, take a deep breath....

They should put a warning on those tools about how quickly a good idea can go awry :-)

Ed

Dave Byers said...

Ed, even after my successful ovalizing of the 5th hole, I was foiled by the overall thickness of the new rings. The new rings are thicker and don't sit perfectly flat on the crank arm and therefore they wobble. Argh.