26 vs 29 singletrack shootout: tie

Well now, (AHEM!), looks like I jumped the gun yesterday in revealing results.  That’s what I get for seat of the pants analysis.

The testing of 29er vs 26ers continues on.  Quick recap:  the first round of tests looked at how climbing on the Dos 29er compares to climbing on the Fuel 26er.  Those results showed a small but repeatable advantage to the Fuel for climbing dirt roads.  That wasn’t a big surprise to me, however, many took it as a direct attack on their lifestyle ;)  We’re just talking about a slightly larger wheel size, right?

This round of tests was done on a 3.2 mile singletrack loop in McDowell mountain park outside of Fountain Hills, AZ.  If you’ve done the Mesa NORBA nats, you’ve ridden this trail.  Swoopy, twisty, fast in spots, steep rollers, bad braking bumps in spots, a few very tight turns.  It starts with a ~ 3 min big ring climb, finishes with a more rolling but trending downwards section of whoops and twisties.  I call the latter section the “descent” in this analysis.

I did the rides on 2 different days separated by a 5 day period.  The first ride tested the 29er, the second ride tested the Fuel.  The results for each test are broken down by overall time, average power, and normalized power.  Here’s how it turned out: 

Other relevant data not reported in the above sheet:  energy expenditure was identical across bikes and runs at 185 kJ & 184 kJ for the Dos, 185 kJ and 182 kJ for the Fuel.

At first I thought based on average powers that the Fuel was significantly faster on the descent portion – which is completely non-intuitive.  The Dos felt like it held speed better in turns, so I expected the Dos to be faster on the descent.  If we just look at average power, that conclusion would stand.  However, normalized power comes to the rescue.  Normalized power was just enough higher in the Fuel tests to indicate I had a bit more snap in the legs on that day.  In rolling terrain, it is very important where you put the power down, and how much at a time.  On the Fuel’s day, I just had a bit more to give on the steep ups, and rested more on the descents.  The averages were the same, but Pnorm tells all…another factor that may have attributed to faster times on the Fuel was that I got 3 runs in on the Dos 5 days prior, so I was more familiar with the trail.  The Fuel did feel faster in the tightest terrain, oh wait, that’s subjective, nevermind.

Here’s a chart showing how the distribution of power changed between the two rounds of tests.  There’s a considerable shift to the right for the Fuel’s test, which simply means I was feeling better that day. 

As for the climb – look how tight the data is between the first run on the Fuel, and the second run on the Dos.  Looks identical to me.

Round 2 conclusion:  it’s a tie. 

So what’s next?

One test will be similar to this one, except at a much more relaxed pace.  These runs were at a XC like pace, far above that of an endurance race.  What happens if power spikes are much lower & most of the riding is in the saddle?  Will the bigger wheels conserve energy somehow in the twisty/rolly stuff under those conditions?  

How about some pure downhill runs?  There aren’t any around here I can think of, that’ll probably have to wait until late-spring back in Colorado.  The great thing about a bunch of downhill runs means I get to do a bunch of climbing :)

Signing out for now, fire away, but keep it civil.