So how do manufacturers come up with track designs? SnoWest Magazine asked Yamaha some of these questions regarding its new 162-inch Ascent track found on the 2012 Nytro MTX 162 and not only did we get answers, Yamaha gave us a little peek at how it's done.
A Successful History
Yamaha and Camoplast have collaborated on more than one innovative track design over the years. Among the highlights is the Rip Saw, which has been one of the best short-lug tracks on the market since it debuted in 2005. As soon as the exclusivity agreement expired, pretty much every OEM had at least one trail sled that spun this track as a stock part.
Yamaha also worked with Camoplast to develop the Maverick deep snow track. The guys at Yamaha said the Maverick track worked very well for what it was designed to do, but suffered from poor public perception.
"The Maverick got a bad rap with the mountain guys, which was unfortunate," Yamaha snowmobile product manager Rob Powers said. "It's a great deep powder and soft snow track and it climbs like crazy in those conditions. But under extended trail and hard snow use, the lugs would bend and not give the traction some guys were expecting on acceleration."
It was a classic conundrum for product engineers: the very design aspects of the track that led to its sweet deep snow and climbing performance, the ability of the lugs to flex and bend, were the same ones that turned out to handicap its broader consumer acceptance. More specifically, the columns molded in the track didn't provide the forward acceleration riders were looking for on hardpack.
Back To The Collaborative Drawing Board
When Yamaha and Camoplast began work to create the Maverick's replacement, they knew they would have to eliminate the unpopular aspects of the track but not abandon the key design elements they felt made it work so well in deep snow.
In fact, there were many qualities of the Maverick they wanted to retain.
"When the mountain development team set out to design the next track, we knew we wanted to keep the Maverick's excellent soft snow performance, climbing ability and light weight," Powers said. "But there were definitely targets for improving the track as well. We needed to have better durability, especially in the base areas of the lugs, without losing that flexibility that works well in powder. We also felt we could have a more versatile, consistent track for riding on the trails when a guy is heading up to his favorite bowls and hills."
At its foundation the new track would have the same specs as the Maverick, a 3-inch pitch, 162-inch length and 2.25-inch lugs and it would be a single-ply design. Ideally the track would keep the lift qualities of the Maverick track lug, using the wide center belt of the track to provide lift, while improving forward acceleration and durability.
Track Science
There is more to designing a track than just sticking funky-shaped lugs on it. In fact, there's a definite science to it. For example, with the Ascent track the total area of lug surface was figured into the design. To increase lug durability the new design called for 400 square inches of lug surface vs. 338 square inches found on the Maverick. This basically spreads the load across a broader area, taking stress off each individual lug.
The rubber compound figures in too, and Yamaha took advantage of a new compound Camoplast had engineered that showed better performance regarding "lug set" while retaining the same durability. It was lug set that dogged the Maverick track. The lugs folded over to provide lift like they were designed, but over time they stopped wanting to return to their original shape. The new compound is also less prone to cracking or heat issues.
A larger factor in eliminating the lug set problem and hitting the lug durability target was a new V-shaped notch design at the tips of the lugs designed to fold back at a 20-degree angle but not take a set. The lug shape would also be designed so it would force snow to the center of the track for the most flotation. Lastly, the towers that supported the lugs on the Maverick would be redesigned to spread loads more evenly to mitigate cracking and tearing.
Performance Is In The Details
The Ascent is a track unlike any ever designed. The first thing you notice is the lugs reach from the edge of the track all the way to the center. There are no "center lugs" or "side lugs." The lugs are designed to force snow to the center of the track and the track actually builds its own dense base of packed snow to provide lift and acceleration in deep or soft snow.
One design element that is consistent from Maverick to Ascent is the 3-inch pitch.
"Our testing showed us that the wider pitch is the best design in terms of packing the snow for acceleration and flotation," explained Powers. "We also tried a 2.86-inch pitch version of the Ascent track and it did not perform as well."
The next thing you notice is there are no pronounced columns like the Maverick had; it looks like there are just lugs. But the lugs have support columns built into them that provide support on the base two-thirds of the lug for forward acceleration. This is a noted difference from the Maverick design which placed its pronounced columns only at the ends of the lugs. Also, the columns in the center of the Ascent track are designed to "migrate" to the edge to reduce stress at the base of the lug. Finally, the columns are only placed on the backside of the lugs to limit tension effects when the track is under load.
The top third of the lug controls lift. There are V-notches cut into the top third of the lug that allow the tips to fold back at a 20-degree angle to provide lift, but the notches and the lug are shaped such that the lugs will return to their original shape and not take a set. As for weight, the total package is every bit as light as the Maverick.
Proving It
Yamaha tested the Ascent side-by-side with the Maverick and what it considered the best competitive track, the Power Claw, and it consistently outclimbed both of them. Its deep snow performance was notably better than them as well. In fact, Camoplast and Yamaha reps both think the new track is a huge step forward in the world of mountain tracks.
"You ride the Maverick, the Power Claw and the Ascent side-by-side and you can feel how much better the Ascent works," Powers said. "Camoplast told us they feel this is the best mountain track they make. On our end, we made a big improvement with the Nytro MTX 162 basically with a simple track swap, so that's a big deal for us."
During the photo shoots last February and March, the SnoWest SnowTest staff was able to ride the 2012 Nytro MTX and we found the sleds to be the best-riding Yamaha mountain sleds to date and at the top of the heap for pure climbing machines.
What the Rip Saw track did for flatlanders, we think the Ascent is going to do for mountain guys.
Yamaha and Camoplast have set another highmark with the Ascent track.