Are the days of a metal welded suspension nearly over? Fabricators at Levis, Quebec’s AD Boivin Design Inc. think so.
AD Boivin, the makers of the Expert suspension, have a new release: a composite rear suspension. Yes, that’s right, a suspension made primarily of plastic.
Jeff Couture, tech support at AD Boivin, said that these are the first questions people ask about the new ZX2: Is it strong? What does it weigh?
The answers, he said are “Yes” and “53 pounds.”
Then, he goes a step farther.
“I ask them if they would go back to a steel ski after being on a composite ski for the past 10 years,” he said. “They laugh, and their worries go away.”
The ZX2 suspension is a proprietary AD Boivin design. It’s made primarily of composite plastic material with two side-by-side shocks in the rear of the suspension. There are two swing arms, 12 idler wheels and a short limiter strap in the front.
The ZX2 suspension has three unique components: the material, the G-Force shocks and the Revolver System of adjustment.
The composite material comes from PPD Group in Sherbrooke, Quebec.
The rails are made from a “secret recipe” composite from PPD. “We don’t know what’s in it, we just know it’s really strong,” Couture said. The remainder of the suspension is made from the same UHMW plastic found in skis.
Couture said the composite has some inherent advantages. “The good thing about the composite is that it acts like a damper. It absorbs energy and vibration,” he said.
Another advantage, he said, is that snow won’t build up on the composite. “There may be snow on it, but nothing compared to a regular suspension,” Couture said. “There’s a reason why those arms are designed that way, and it’s to prevent snow from getting into the suspension.”
Overall, the ZX2 weighs between 52 and 53 pounds. “People think it looks big and heavy, but it’s light,” Couture said. Depending on the suspension it’s replacing, it can be as much as a 30 pound difference.
Two G-Force shocks sit side by side in the rear of the suspension. The shocks are mainly Kayaba parts, but are patented by AD Boivin.
“They’re the heart of the suspension,” Couture said.
The first 75 percent of the piston stroke works in the small to medium bumps got a touring-style ride. The upper 25 percent of the stroke hits different valving, tuned for big bumps, Couture said.
“The main problem with a suspension is that when it’s set to have smooth performance, it will bottom out in the big bumps,” Couture said. “The G-Force shock will kick in on the big g-bumps and prevent you from bottoming.”
Couture said an effort was made to develop a user-friendly, simple-operating suspension.
For comparison, he said, AD Boivin’s Expert suspension has 152 parts. There are 51 parts on the ZX2. Of those 51 parts, 12 are identical bolts.
Components are all standard, readily-available sizes and mounting kits are designed with simplicity in mind.
“We’re hoping to cut a four to 5 hour job to an hour, hour-and-a-half,” he said.
The suspension adjustment features, called the Revolver System, is also modeled on ease, he said. The plate at the rear of the suspension has five holes and two pins. Two of the holes are for a weight transfer adjustment; the other three are for coupling.
Another unique feature is that there’s no extra oil or grease necessary since the UHMW itself has enough lubrication, Couture said.
A special promotion, which expires May 31, puts a $899 USD/$999 CND price tag on one unit. After the promotion expires, they will sell for $1,199 USD/$1,299 CND. Mounting kits will sell for $99 USD/$149 CND. There will be mounting kits for 26 different snowmobiles.
The composite suspension has been in the works for nearly 10 years. In 1998, Denis Boivin, a mechanical engineer, came up with the idea of a plastic suspension.
He suggested it to his brother and business partner, Alain, who agreed with the approach.
Denis built several prototypes and tested the concept for two years.
“In the beginning, we started with plastic to see if we could save weight,” AD Boivin’s owner, Denis Boivin, said, adding that low cost was the second goal.
He experimented with nylon — which was stiff but not tough — and with UHMW — which was tough, but not stiff. The first prototypes where machined — not the molded product that the ZX2 has become.
“The new-technology composite was not there,” Boivin said. In the end, the project was abandoned, but not forgotten. Boivin patented the idea.
By 2005, plastics technology had caught up to Boivin’s concepts and prototypes recommenced.
“I’m so satisfied with the product,” Boivin said of the final result. “It will be a revolution in snowmobile suspensions.”
Boivin said he was looking for particular advantages that plastic could offer over the standard aluminum suspension frame.
Welds, he said, can fail especially in extreme low temperatures. Fatigue can stress and crack the rails.
“With UHMW composite, there is no more problems like this,” he said. “As you can see with the ski, it’s a good toughness, up to minus 70 degrees C, and it will still stay flexible. There’s no welding, no heat treatment. It’s an integral material.”
Boivin said the suspension is tough, but stops short of calling it the Titanic of snowmobile suspensions.
“We’ve never had any failed or broken parts up until now,” he said, noting that it was tested under severe conditions. “I don’t want to say that it’s indestructible because then we’ll have customers trying to destroy it. But let’s just say that it’s tough — tougher than metals.”
This isn’t the only industry that uses these types of composite materials. Couture said that Formula 1 cars use composites in the motor connecting rods, and that it’s common in the aerospace industry.
Boivin is a bit coy as to the potential of composite products in other snowmobile applications. “I think that there are other parts of the snowmobile where this product can be used, but for not we will put our time into promoting our new suspension,” he said.