INTO THE RIDE #94
Alterra 29er: Big Wheel Fun Ride
by Randy Schlitter & Tanner Marshall
The Alterra geometry in the 26″ MTB wheel has proven to be a very viable mountain bike. The slightly more upright seat angle, increased front end loading, and shorter top tube and wheel base combine to create a new generation of RANS Crank Forward geometry with great off-road performance. With the success of this geometry, it was natural to make a 29″ version. 29ers hit the main stream a few years back and to the surprise of many, are still gaining in popularity. I think the advantages of the bigger wheels out-weigh the drawbacks. The pros include greater traction, higher speed and better control on rough courses, greater tire selection, convertible to road and cross bike, and a softer ride. That conversion capacity may be a great attraction for some because a 29er with the simple change of wheels or tires can become a road or cross bike. As a touring or commuter setup, it should find no restrictions since there is plenty of room for fenders and eyelets for rear racks.
The cons are slower acceleration and a longer, heavier bike (unless you are willing to pay for lightness). However, in comparing our Alterra 29 to the Alterra 26, there is only 0.45 pound weight increase, less than a half pound! We selected light wheels and tires, and this pays off big in brisk acceleration.
Though the overall ride position of the Alterra 29 is similar to that of the Alterra, the differences are what make this 29er stand out. To create a 29er frame that performed like the Alterra, we first needed to decide what characteristics of the original Alterra we wanted to keep (i.e. bottom bracket height, seat crank relationship, cockpit length). Once we had these key points plotted, we continued our design like we do with all our other bikes. One key feature is the 51mm offset fork. The use of this offset allows us to keep the fork trail very close to that of a 26″ bike and thus improve handling characteristics immensely. The end result is a bike with the wheelbase and turning characteristics of a 26″ wheeled bike, and the supple ride and confidence of a 29er.
The frame is robust, as any 29er frame should be! We used large diameter tubing to assure good power transfer in climb, and a sturdy stable frame for winding single track. Even still, the length of the chain stays allows enough vertical compliance to take the edge off any nasty terrain.
The stock bike (rigid CrMo fork) weighs in at 28 pounds, and with the optional suspension fork, the bike comes in at 29.5 lb. By comparison the Alterra with the 26″ wheels and shock fork is 29.1 pounds. Check out the specs on the model page for the Alterra 29.
The Alterra seat is actually a trimmed down version of the stock CF seat, with a custom fitted cushion. Just for fun I trimmed the stock Alterra seat to less width, and cut out the bulb of the nose piece. I noticed when wearing riding shorts, the extra padding puts pressure on the perineum. I have ridden this seat several hundred miles and it is holding up, but there is not a lot holding the nose out there, so I am not expecting it to last. If I would do it again I would take less of the top out of the bulb, making it more structurally sound.
Wilson Lake, Kansas has a surprisingly technical trail. The big wheels proved true to theory. They took some of the punch out of the rocks. Keep in mind the trail is a repeating array of sandstone, sod, rock steps, and hair-pin up hills that will surprise most non-flatlanders. The greater tire contact area was good for climbs and aggressive braking. After several hours one thing was clear; the bike can climb and handle anything you are willing to ride over.
The next stop was Keystone, Colorado. We selected a fairly easy trail and were surprised at the ease of the climbs and nice rhythm to the climbs and dives. Speed was easy to keep up, and climbs, although often long, were never a lung burner. This was all taking place at 11,000 to 13,000 feet, on a trail that was well populated with cyclists. A few 29″ full suspension and hard tail bikes were in the mix. I was thinking either 29ers have come and gone, or they were not yet the rage. Tanner our engineer explained possibly why: a dual suspension 29 is costly to be light, and fewer choices exist. But both the test bikes we brought had straight forks, and only one high speed downhill was where I missed the shock fork. The bike remained easy to control, despite the beating my hands received. Mostly I let the big wheel take the brunt of the rough; occasionally I popped over the really obvious obstacles.
After taking on the mountains with the Alterra 29 my confidence in having a big-wheeled fun ride was high. Since then I have been making circuits around our test track and experimenting with different tire pressure. 25 is about my fav setting, offering enough grip, shock, and rolling ease.
Production of the Alterra 29 is proceeding and bikes should be in stock in 3 months with the rigid or optional suspension fork. Colors are not firm, although the “orange crush” is spectacular in person, and is stated as the spec color. For those who cannot see themselves on an orange Alterra 29 talk to Carl; I am sure we can be flexible and reasonable about a couple of other color choices. I hope you get a chance to test this bike at one of our dealers, or stop by the factory. We do have a test track that will allow you to give the machine a decent shake down. Try it! I am sure you will find the Alterra 29 is big-wheel fun with the great crank forward comfort! Until next month ride safe and stay into the ride!
To learn more please visit the related youtube links below.