Avalanche Downhill

Compression damping, rebound damping, high-speed damping, low-speed damping, preload adjusters, progressive bump stops, shim stacks, spring rates, ride height – probably not what’s on most riders’ minds as they plunge their bicycles down a rocky mountain slope at speeds approaching 50 miles per hour. In fact, most of these terms probably don’t even exist in the vocabulary of the average mountain biker. They certainly weren’t part of the vocabulary of the sport’s founding fathers, who braved local trails and fire roads on 1940s-era single-speed clunkers. But for a certain Eric Wold, these terms are everyday parlance.

Wold is the co-owner of Avalanche Downhill Racing, a company that manufactures high-end suspension components for downhill mountain bikes. And while Wold came to mountain biking nearly 20 years after the Fishers, Breezes and Ritcheys of the world, his contribution to the sport is no less notable: Avalanche Downhill Racing products represent the pinnacle of high-end forks and shocks for extreme downhill mountain bike racing and free riding.

Unlike those early pioneers, who were avid cyclists and successful road racers before discovering – nay, inventing – mountain biking, Eric Wold entered the sport rather reluctantly. Like most children, he always had a bicycle while growing up – he even did a bit of BMX racing as a kid. But adulthood brought with it a corresponding sense of responsibility: “I’ve got better things to do than ride a bike.”

It was a friend’s persistence in 1991 that showed Wold the error of his ways. “I had a few friends in town who were mountain bikers,” he relates. “One guy had two bikes and kept hounding me to go for a ride. He bothered me so much that I finally said, Okay, I’ll go! I didn’t even know what a mountain bike was. I loved it instantly!”

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Wold’s indoctrination into the world of downhill came about a year later, when a friend told him: “I hear you can go up to Killington [a ski area in nearby Vermont] and put your bike on the lift, and then ride down the mountain.”

“We decided to go one weekend,” Wold says. “We bought lift tickets and rode up and down the mountain as many times as we could. It was great! We were riding completely rigid bikes at the time, with no front suspension. Insanity!”

My arms and legs are all the suspension I need . . .was a common refrain among die-hard cyclists and traditionalists, who saw bicycle suspension as an unnecessary extravagance that just added weight. For Wold and friends, however, just one run down a bumpy ski slope was enough to convince them otherwise.

“We went back to our local bike shop and said, We need front suspension,” Wold explains. But the choices were few. The first RockShox front suspension fork had come out a year or two earlier, and Manitou had also introduced a version, but both forks were designed primarily for cross-country riding and provided only about 2 inches of travel.

It wasn’t much, but it was better than nothing. Wold bought a Manitou fork and headed back to the mountains.

“There was already a national circuit of about five or six downhill races, and one of them was at Mount Snow in Vermont,” Wold says. “That’s where we learned about more serious racing, and started seeing some of the bigger teams. We began to realize that the tracks were so rough that all of the suspension was inadequate.”

It was apparent that something more was needed to handle the rigors of downhill racing. It was also apparent, at least to Wold, that no one was filling that need. Taking things into his own hands – much like those early mountain bike pioneers – he decided to build a suspension fork of his own. At first glance, this might seem like a daunting proposition, but Wold was an experienced machinist and had a full manufacturing facility at his disposal. “I grew up in a machine shop,” he says. “My grandfather started Wold Tool Engineering in 1947, and my dad currently is the president of the business. I’ve been working there full time since 1987.” (In fact, Wold started working full time the day he graduated from high school.)

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Located in Moosup, Connecticut, Wold Tool Engineering, Inc. (WTE) is a contract machine shop that serves a number of manufacturers in the area. Among WTE’s customers are Moroso Performance, a manufacturer of racecar products, Linemaster Switch Corporation, which makes industrial foot switches, and Kenyon Marine, which manufactures stoves for marine applications.

For Wold, fabricating the components for his mountain bike fork was the easy part: It was just another machining job. The challenge was designing a fork that did what he wanted it to do. He readily admits: “I’m a machinist, not an engineer.”

Wold built his first prototype around 1995. “It was an upside-down fork with about five inches of travel,” Wold explains. “It was very small, and didn’t last very long, but I learned a lot.”

Wold raced his prototype fork through the season, and then spent the winter diagnosing what had worked and what hadn’t. “I took what I learned and applied it to a new fork,” he says. “I built three more prototypes, raced them during the ’96 season, and had much better luck than with the first one. By the end of the season, I was already thinking, Okay, I can improve this even more.”

In Wold’s mind, the solution was obvious. The motorcycle industry had already done what he was trying to do. Why re-invent the wheel?

He just needed to adapt motocross technology to mountain bike forks. He spent the winter figuring out how – searching the Internet and visiting local motorcycle shops for any information he could find on how motorcycle forks are built.

It was through this research that Wold met Craig Seekins, his partner in crime and the co-owner of Avalanche, in 1997. “Craig owned a motocross suspension tuning shop about half an hour from my house,” Wold relates. “I called him up, and we talked for a while, and then I went down there to show him my fork. He took the bike for a ride, just around his driveway, and came back and said: ‘Wow! The fork looks beautiful . . . but it works like crap.’”

While some might take this as an insult, Wold saw it as an opportunity. Seekins had the engineering skills and motocross experience to complement Wold’s own machining skills and mountain bike experience. It was a perfect match.

“Craig was already considering getting into the mountain bike market,” says Wold, “so we started talking about possibly modifying the fork that I already had, or maybe building something new. We decided to scrap the fork completely and start over. Since I’d already made the triple clamps, which were pretty large, Craig figured out that we could design a 43 mm fork that would work with the triple clamps.”

(Putting that size into perspective, Honda’s CBR954RR sport bike and XR650 off-road motorcycle both use 43 mm forks, while the current crop of mountain bike forks run between 28 and 32 mm in diameter.)

The choice of 43 mm was no accident: It’s a common size for motorcycle components. “We wanted to build a prototype as quickly and cheaply as we could,” Wold explains, “so we bought a lot of off-the-shelf motocross parts and adapted them to the mountain bike. We chose 43 mm because we could buy Honda seals and bushings, which were known to be high quality and long lasting. And since Craig already manufactured high- and low-speed compression adjusters for motocross forks and shocks, we could put his products right into the mountain bike fork.”

The result was unlike anything the mountain bike industry had ever seen: a fully adjustable motocross-style fork with machined aluminum triple clamps and a full 8 inches of travel – nearly double that of anything else on the market. It worked really well, but it weighed 19 pounds! It was a beast!

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In 1998, Wold and Seekins formed Avalanche Downhill Racing to manufacture the new creations. Working after hours at Wold Tool Engineering (his day job), Wold set about making the fork lighter, fabricating pieces for two new prototypes. But WTE was primarily a lathe shop, so “a lot of the mill parts were done by hand,” says Wold. “We had a bunch of Browne & Sharpe screw machines, and a CNC lathe that we’d bought around 1989, but we did the secondary machining operations, like drilling, tapping and light milling, by hand on Bridgeports.”


Once complete, Wold put one of the prototypes through its paces during the ’98 race season, and gave the second prototype to other riders to try out and provide feedback. After making some minor adjustments to the design, “We did a pre-production run of about seven forks and started a small race team,” Wold says. “Things went really well with them that year, so we geared up for a production run of 20 forks.”


Making prototype parts by hand is one thing, but making production parts is another. The more forks Wold built, the more he realized that WTE needed a CNC mill – and not just for the Avalanche work. “The triple clamps are definitely a CNC job, and the same goes for the lower lugs for the axle – definitely CNC work – but we also had all these secondaries coming off the lathe, and off the screw machines.”

With a little arm-twisting, Wold convinced his father to buy a CNC mill in the fall of 1998. After researching a number of different machines, they settled on a Haas VF-0 vertical machining center. “We really liked that Haas was an American company,” says Wold, “and the Haas machines were more affordable than any other machine we looked at. We went down to Hartford to the Haas Factory Outlet (a Division of Trident Machine Tools) for a demonstration, and bought a VF-0 with a Haas HA5C rotary indexer.”

In a way, Wold’s work at Avalanche Downhill Racing drove the decision to buy a CNC mill, but the benefits to Wold Tool Engineering were immediate. “It made every job so much more productive,” says Wold, “not only making the new parts, but also the secondaries we were doing on the Bridgeports. The cycle times were cut in half, and we had less operator fatigue, better accuracy and repeatability – everything.”

The benefits for Avalanche were also immediate. “We started making our own triple clamps,” says Wold, “and also the lower lugs, and we made our own slider tubes; it dropped the weight of the fork down quite a bit. The 43 mm fork became our first product.”

Dubbed the Mountain 8 (MTN-8), it was not a fork for the faint of heart . . . or for the faint of pocketbook. Despite the CNC-assisted diet, it still weighed in at a hefty 14 pounds, and only a few people would race with them. “Plus, the price tag,” says Wold. “That fork retailed for $3300 – but it was completely custom. It was built specifically for you, based on your weight, your riding style, whether you’re aggressive or light on the bike . . . the parts were all in stock and it would be totally assembled for you. Plus, we offered a 60-day setup on the spring rate and the valving, and a two-year warranty on wear and workmanship.”

For Wold and Seekins, though, the goal was never to sell mass quantities of product. The goal was to build an ultra-high-end mountain bike fork that was the absolute highest quality available and completely indestructible. That accomplished, it was time to tackle the back end of the bike.

“There are only about four manufacturers in the world that make shocks for mountain bikes that are at least decent,” says Wold. “But they all shoot for the OEM market and try to keep the cost very low. We wanted to build the highest quality, high-end shock, without regard to weight or price – just to prove to people what we could do.”

Thus was born the Mountain 3 (MTN-3) – a very large, motocross-inspired shock that, like the MTN-8 fork, was completely custom-built for each rider. “It was eleven and an eighth inches eye-to-eye,” says Wold. “The spring alone weighed two pounds – more than any other shock out there. We had a high- and low-speed compression adjuster on it – again, right from a motocross shock. It was very high-end, indestructible.”

The problem was, “You couldn’t just slap that shock on someone’s bike,” says Wold. The shock was so large that Avalanche needed a manufacturer willing to build a frame around it. Prototype in hand, Wold and Seekins headed to the 1999 Interbike Show (an annual trade show for bicycle and parts manufacturers) in Las Vegas to drum up some interest.

Unlike most manufacturers, who consider their designs proprietary and keep them tightly under wraps, the Avalanche crew put theirs out for everyone to see. “We pulled our shocks apart to show people the internals,” says Wold. “This isn’t a secret; this is technology that every motocross company uses.” Maybe so, but the folks from Brooklyn Machine Works – a small frame builder in New York – were amazed, nonetheless. “They came from a motorcycle background, and had just been waiting for someone to make a shock like this,” says Wold. “We sent them a prototype, and they immediately started building a bike around it.

“At the same time,” Wold continues, “we asked another company, Cortina, to build custom bikes for our team. They had a bike I felt could easily be modified to fit our shock. We were rolling on those bikes in the ’99 race season.”

Armed with full-on “works” bikes – Cortina DH Extreme-8 frames with Avalanche MTN-8 forks and MTN-3 rear shocks – the Avalanche race team hit the slopes. “We wanted to have the team out there so people could see and try out our product,” says Wold. “You can have the best product in the world, but it takes time for people to have confidence in it.”

By the end of 1999, confidence was building: The Avalanche Downhill Racing team had amassed more than 20 visits to the winner’s podium.

“At that point,” says Wold, “we felt we had really established a good reputation, and we decided we needed to start making some money. Up until then, the business had basically been an expensive hobby for us. We did it in our spare time – nights, weekends, things like that.

“We decided to come out with a rear shock that would fit the majority of the downhill bikes out there,” Wold continues. “We felt that the shocks on the market still were not up to what the downhill and free riders were doing. It was a perfect market for us.”

Avalanche began developing their DHS shock during the summer of 2000. Essentially a scaled-down version of their MTN-3 shock, it “was difficult to design and manufacture,” says Wold, “because it’s so small, and you have to cram so much into such a little space. We’d build 10 prototypes, and as we were fitting the parts, we’d find a problem: Oh, the shaft is crushing the hole for the rebound adjuster, we need to move that a millimeter. Now we have to gain a millimeter somewhere else in the shock.”

With the CNC capabilities of Wold Tool Engineering at their disposal, such changes were easy, even during production. “The Haas machines are so versatile – quick, easy to set up – that we can make quick changes on the machines for even minor problems.”

As Avalanche geared up for a production run of 500 DHS shocks in January 2001, it became apparent that Wold Tool Engineering didn’t have the capacity to handle the extra work. “We were getting really backed up,” says Wold. “We needed another lathe.”

More mill work was coming in the door as well, thanks to an employee with a penchant for custom cars. “Our foreman met a guy who manufactures parts for custom cars,” Wold explains. “He was having problems with his suppliers – one guy couldn’t ship on time, one guy was too expensive and another guy gave him bad parts – so he threw us a job . . . and then threw us a couple more. The next thing you know, we’re doing all his work.” The Haas VF-0 began to back up as well.

More machines clearly were in order, and this time, no arm twisting was required.

“We found a used Japanese lathe – one year old – that suited our needs, but it was expensive,” says Wold. “So, of course, we went to look at the Haas lathes. At the same time, the Mini Mill had just come out, and what a great price tag on that! We could buy a used lathe for $98,000, or we could buy a new Haas lathe and a Mini Mill – with options even – for the same price. It was pretty much a no-brainer.”

An SL-20 lathe and a Mini Mill were installed in short order, and immediately put into production. Wold had 500 shocks to build.

“I turn the shock bodies in one shot,” says Wold. “I start with the material close to the chuck and do all the ID work. Then I pull the material out, put a plug in the end and bring the tailstock up, so I can do the OD work. The Haas has the ability to use multiple work offsets, so I can do it all in one program. I use an M00 to stop the program, and then pull the bar out for the rest of the operations. With the Haas control, I can put messages on the screen – you know, pull the part out 8 inches.

“The secondary machining takes place in the two mills,” Wold continues. “With the exception of the triple clamps and the lower lugs for the forks, we can pretty much do every other job on the Mini Mill.”

The lower lugs, Wold says, are probably the most complex Avalanche component he makes, requiring a total of seven setups – two on the SL-20 and five on the VF-0.

Each lug starts as a block of 6061 aluminum approximately 2" x 4" x 2.75" (depending on the lug, the left and right are slightly different). The material goes into the VF-0 first, where a “lathe nub” – 1.75" diameter by 0.75" high – is milled on one end, so the part can be mounted in the SL-20 lathe.

The first operation in the SL-20 comprises the ID work for the area where the fork tube attaches. The lug is drilled, rough bored, finish bored, the ID is threaded and then an O-ring groove is cut on the ID. The part is then flipped (using a fixture threaded into the end), and the nub is cut off and the part is faced to length. A pocket is then bored in the end to accept the compression adjuster.

Once the lathe operations are complete, the lug goes back to the VF-0. First, the bottom profile is cut, and then the lug is flipped and the top profile and the mounting boss for the fork guard are machined. The lug is then mounted on its side and the profiles of the axle clamp and the disc brake flange are cut. A pocket is milled to lighten the lug, and then mounting holes for the disc brake are drilled, and the hole for the axle is drilled and reamed to size. A serial number is also engraved at this point using the G147 command.

For the final operation, the lug is fixtured in the HA5C indexer. A series of holes are drilled and tapped on two sides, and then the axle clamp is completed using a slotting saw.

“I actually program the machines and do all the Avalanche machining myself,” says Wold. “Craig does all the engineering, and I handle the machining. We use Mastercam to program the mills, and I actually do quite a bit of on-the-control programming, especially for simpler parts. The Haas machines are so easy to program that, a lot of times, it doesn’t make sense to go to the CAD/CAM. We don’t have a lathe module – we haven’t really found a need for it – so I program all of the SL-20 parts at the control.”

For Wold and Seekins, this hands-on approach is the only way to do business. “We’re not looking to sell massive quantities of forks and shocks, and mass produce them,” says Wold. “We want to produce custom shocks and forks specifically for the customer. No one else does what we do.”

A successful approach, it seems. “Our shock sales have been excellent,” Wold says. “The DHS shock has become our mainstay product. It’s durable, it works well, it’s custom built for the rider – people love it.” Avalanche has also introduced a 37 mm version of their fork, the DHF-8, which is much lighter than their 43 mm fork, but still provides 8 inches of travel and has all the same adjustability and features.

While light weight has never been the driving force behind Avalanche, it is a concern for most riders. But rather than compromise safety and durability to shave a few ounces, Wold and Seekins design Avalanche products for strength, and look to other ways to reduce weight. “We’ve come out with a titanium version of the DHF fork,” Wold explains, “that has a titanium spring in one leg and the valving in the other leg, rather than two steel springs and two oil cartridges. It’s 2 pounds lighter, but it’s still very strong.” For riders wishing to shave additional weight out back, Avalanche also offers titanium springs for its shocks.

Of course, there are lighter forks and shocks out there, but that’s not what Avalanche is about. “We really don’t want to compete with them,” says Wold. “Our plan is to stay small, at least for the time being, and sell the high-end product. We like what we do.”

But Wold likes his day job too, and has no plans to quit the family business. “I still love the machining side of it,” he says. “Owning Wold Tool Engineering (Eric’s dad plans to retire soon and hand over the reins) keeps a lot of the overhead away from Avalanche, and lets me control the quality and delivery of the parts.” At the same time, Avalanche Downhill Racing – no longer an expensive hobby but a paying customer – provides WTE with a steady flow of work.

“For me, the two go hand in hand,” says Wold. “We’re a job shop at Wold Tool, and it is a difficult business, but I do enjoy it.”