Seven IMX 29er version 2.0, (Image credit: James Huang)
A couple of months ago, James Huangreported on the progress of a Cyclingnews project to get to the bottom of the wheel size debate in mountain biking. Advocates of the newer '29-inch' size (based on 700C wheels) claim it rolls better over rough terrain, increasing speed and saving energy. To test this idea, we set up two bikes that were as near to identical as possible, but used different wheel sizes. We were deluged with feedback from the 29er and traditional camps, which has led to some changes in the bikes and test protocols, as James reports:
If I've learned just one thing from this project so far, it's that 29er aficionados are a rather, er, passionate bunch. After posting Part One of this series, we received gobs of mail, both good and bad, logical and occasionally nonsensical. If you're reading this looking for our conclusions you'll have to accept our apologies as we're still not there yet. However, we do have some revisions in our test setups to tell you about with which we think you'll all be quite satisfied, regardless of your own personal choice in wheel size.
One common theme of many of your emails was the need to add power meters to our pair of Seven IMX test sleds. The people have spoken, and we concede. The folks at Ergomo and Gita Bike, Ergomo's US distributor, pitched in with an ISIS-compatible power meter for each bike plus a head unit to share between the two. The Ergomo is a particularly interesting unit for this project because it measures power at the bottom bracket, rather than the rear wheel or in the crank. That made it an elegant solution to the problem of measuring power on our bikes.
We're still in the learning phase in getting these things setup and dialed in, but it'll clearly add a very useful additional parameter with which to complete our analysis. The handlebars on these bikes are getting awfully crowded, though; that Garmin Edge 305 GPS unit and the Ergomo head take up a lot of real estate! The pair of little electronic boxes also provides a dizzying array of data points to analyze. Sheesh, I feel like I'm in grad school again.
