monocog commuter build and pics

                                                                                                                                    some basic maintenance tips
Build
Frame:          2008 Redline Monocog 29er
Fork:            Surly Karate Monkey 29" (more here)
stock bits:     wheelset (Alex), cranks
stem:            Easton 110mm 5deg
brakes:         Avid BB7's mtn 160 front, Avid SDn7 V-brake rear, both work with Tektro RL520 "road" style levers
seatpost:       Thomson elite 26.8mm diameter 400mm length
saddle:          Brooks B-17 Imperial
chainring:      Rennen SS 44t
Other bits:   
Shimano UN-54 square taper bottom bracket, Schwalbe Big Apple, Wellgo MG-1 platform pedals, Cane Creek S1 (in keeping with the steel theme),  Shimano 15t cog.

Old Man Mountain Sherpa front Rack (perfect for 29ers w/ disc brakes and (therefore) empty brake bosses.

Rear Rack Trials

Wood Fenders from Cody in Oregon (Woodysfenders.com).  Required drilling into the seat stay bridge and bottom chain stay bridge.

The Midge bars (std. review here) work as advertised so far.  The drops work well for commuting, though I needed a lot of wrap tape to get them comfortable enough.  The Midge bars needed a lot higher rise stem, which a Salsa SUL provided, but I needed even more...so an uncut Surly KM fork went on the 'cog with a normal stem.  Reach wasn't such a problem because the stem before was 130mm long.  I ended up with a 20mm shorter effective reach.  I think the geometry would not have worked if I had a shorter reach to begin with.

Huge balloon tires are justified here.  Basically lower pressure is possible=no suspension needed. 

2.0" in the rear to keep acceleration quicker.  2.35" in the front to absorb impacts.


bridge

The Midge bars aren't as flat as the picture shows....this picture shows their shape a little better:


These are some old pics from when I ran Ergon grips on broomstick bars, and a sprung Brooks.





If you're into statistics see this report utilizing excel's ANOVA capabilities with an experiment my group carried out in statistics class, trying to pin down if tire pressure or tire size affects rolling speed more.  For the highlights, read the summary below:

Since the p-value for the interaction term is less than α, we reject the null hypothesis and retain the interaction term (full model).  We believe this to be primarily attributable to the larger (29”) tires, which appeared to have a more significant interaction effect with pressure changes on our experimental unit.  The interesting point that this makes in terms of application relates to the traction versus speed conundrum within the mountain biking community.  While lower tire pressure may be desirable for improved off-road traction or “softer ride,” we believed that it would also reduce rolling speeds.  Our data seems to confirm this, but it also demonstrates a potential benefit provided by 29” tires.  Potentially, a 29” tire could be run at lower pressure to provide a “softer ride” but still provide the same rolling speed as a 26” tire with significantly higher inflation pressure.  Our interaction plot depicts this rather clearly.

Our inferences are limited to a very small subset of 26” and 29” tires, as our objective states.  Realistically, our experiment only demonstrates the effects of tire pressure and tire size on the time it takes a Redline Monocog (make/model of the bike) weighing 28.5 lbs (30.5 lbs with 29” wheelset) with a rider of similar shape and size to our own rider, Nils, using 26” WTB Velociraptor 26ers (on Mavik 117 rims) and 29” WTB Exiwolf 29ers (on Alex  D19 Rims) to roll down the same parking lot hill that we used, on a day with similar ambient weather conditions.  If we were to expand this study to a larger population, we would hypothesize that the larger tires would continue to have a greater interaction effect with varied inflation levels. 

Before running this experiment, we expected that lower pressures would have slower run times as a result of increased surface friction.  However, that expectation did not manifest itself noticeably with the smaller (26”) tires.  We would posit that this is simply a confirmation of the Ideal Gas Law, PV=nRT.  In words, the Ideal Gas Law states that Pressure x Volume equals the number of mols of gas x R (the universal gas constant) x Temperature.  Our assumption is that as Volume is increased with the larger tires, we see the multiplicative effect with respect to pressure changes.  In other words, in a tire with greater volume, the effects of pressure changes are more pronounced.  Additional experimentation would use an expanded sample of experimental units (varied bikes and tires) in an effort to confirm the 29” tire and pressure interaction effects that we observed.  We would also want to determine conclusively whether or not the 26” tires produce a significant interaction effect with similarly varied pressures in different experimental units.