Timbersled Snowbike Dirt Bike Conversion

Oct. 17, 2011 By Matt Allred

There are crossovers and then there are crossovers. This is a crossover that covers multiple seasons. We are talking about Crosstours, sport utes, dual-sport motorcycles or crossover snowmobiles. What we at Off-Road.com are whacked out about is a snowbike – a two-wheeled dirt toy that morphs into a ski and track snow toy.

Timbersled Products Inc., of Kootenai, Idaho, has produced a rear suspension kit that takes the common off-road motorcycle and transforms it into a mountain-mauling, deep-powder machine with a single front ski. Big-bore four-strokes are the best choice for this conversion.

Timbersled is not a motorcycle shop that took a Frankenstein approach to create a rear suspension that mates to a motorcycle’s existing chain drive system. Nor is Timbersled a snowmobile shop that thought a motorcycle’s chassis is inferior to a mountain snowmobile chassis. Timbersled’s owner Allen Mangum colors outside the lines, but he had enough restraint not to color off the page – he saw the off-road motorcycle as a machine with untapped potential. He and his staff went to work and created a fully functional snow rod that also returns to a savvy dirt bike.

Timbersled is a company that specializes in long-travel deep powder front and rear suspensions for mountain-specific snowmobiles. They also have other trick parts for motors and tunnels. Needles to say, Timbersled is a forward-thinking, ahead-of-the-curve fabricating company that has built a solid reputation for quality and long-lasting products.

While attending the Jackson Hole World Championship Snowmobile Hillclimb in March 2011,Timbersled was wooing the crowd with its display of Mountain Horse snowbikes. In front of its booth were three amped-out bikes, a Honda CRF, a Yamaha YZF and a 2011 Kawasaki KX 450F fuel-injected wonderbike. After seeing these Mountain Horse snowbikes I knew I needed a fix. We contacted Timbersled and sealed a ride to maul the mountains near Swan Valley, ID.

Before I ink out rider impressions, let me lay down some technical background about the Mountain Horse. The Mountain Horse uses Timbersled’s lightweight Mountain Tamer rear snowmobile suspension, which drives the track at the front, not the rear, and has a 20-degree approach angle to the snow. The track is a Camoplast Challenger that is 121 inches long, 12.25 inches wide and utilizes lugs that are 1 3/4 inches high.

The front suspension uses a spindle adapter which mates to a Simmons dual keel flexi ski; gone is the tire.

Now, you must be aware the rear suspension and track add about 60 pounds to the bike, hence your fully fueled 450 will grow to a 300-pound linebacker. With that said, it is still 150 to 200 pounds lighter than a dry two-stroke mountain snowmobile.

The rear suspension’s subframe is a tubular unit that is light yet strong. The tunnel is a three-piece unit that bolts to the subframe, which has all the mounting points for the rear suspension and drive system. The tunnel assembly provides foot protection and real-estate for a gas can and/or cargo bags.

Here is the sweet information: the sub-frame and tunnel assembly bolt the bike’s swing arm pin using the factory locations and are supported with a solid aluminum strut-rod that mounts in place of the factory back shock. The assembly bolts do not move up and down like the stock motorcycle back suspension – it is rigid.

The Mountain Tamer suspension system does not use the traditional dirt bike mono-shock configuration; it uses a front and back shock to evenly place pressure on the ground between the front and back portion of the track, and it is able to automatically adjust independently from the front to the back portions of the track. This keeps the track contacting the snow on uneven terrain and provides a smooth ride with superb traction. The Mountain Tamer rear suspension delivers 13 inches of vertical travel.

Front Spindle & Ski Mount
The front spindle is a heavy-duty welded aluminum adapter that replaces the tire. It mounts on a Simmons dual-keel Flexi Ski. This ski is stable, gives excellent steering, keeps the snowbike afloat and will not wash out when cutting a side-hill swath or when laying out a wicked turn.

The drive system is simple. First, there is a drive chain from the motor to a jackshaft. Second, the jackshaft transfers power to the outside of the tunnel. Third, a secondary chain drives from the jackshaft to the driveshaft. Fourth, the system drives off the front of the track. Chain tensioners on the two drive chains provide adjustments for gear and ratio options. The secondary chain drive system is inside a sealed chain case. The drive system uses O-ring chains, 4140 chromoly steel axles, CNC-machined sprockets and bearing cages, and oversized sealed axle bearing. Braking comes by way of disc brake with a Wilwood caliper.

Riding Impressions
Well, as a die-hard mountain snowmobile junkie, I can give my oath to a high court judge that the grin on my face after tromping the mountains on a Mountain Horse was freakishly and stupid fun. It was a different kind of winter fun.

The Mountain Horse snowbike will traverse nasty terrain and will snake through trees that would turn a snowmobile into a heap of chromo.

Riding the Mountain Horse is a sitdown affair. Like you, I have a dirt bike, a KTM 300 MXC. When single track riding in the Rockies, I spend half my time, maybe more, standing. Yet, for a snowbike, sitting tall is the in-control position. Oh, standing is needed to kick star the Horse, unless sweet electric start is on the snowbike.

The riding style requires a new approach – it is part motorbike and part snowmobile. The mental algorithm to turn off is leaning into a mountain side. Ratcheting through the gears is also a different mindset. A snowmobile is squeeze and go, a motorcycle is clutch, shift and twist. Yet, this all comes in about 45 minutes of banging the drums.

A big 450 likes to motor along in second and third gear; first gear is low and slow. The 12.25-inch track smartly hooks up on the snow because it receives packed snow from the Simmons ski; this is a beautiful thing to have packed snow as a freebie at all times.

When bringing the snowbike to a stop, no kickstand is needed. It patiently stands, waiting for command. Now, I admit at one point I did pull my foot off the right peg, in habit, to lay the bike down on its right side, and down it went on a hillside and buried deep. Oops. Let the bike settle into the snow and it will hold its position.

Being Economical
Ok, the economy has the flu, but you love the outdoors in the Rockies. Yet the boss hates you and has cut your hours and is making rent is tough. This is what you do. Buy a used 450 of whatever color for $3500, maintain it well, ride hard in the summer and plunk down $5K for a snowbike kit. Think this through … you could lay down another 11K to 13K for a new mountain snowmobile, add a tuned pipe, aftermarket skis, an EFI controller and be knee deep in 15 to 16 grand of money-draining payments for a short-season off-road vehicle. Ouch. For $3500 plus another $5000 (a total $8500), you can enjoy summer and winter, and all the seasons in between at half the cost.

Don’t forget, a 450 snowbike is a fuel miser and a little snow melt does not hurt the dirt rod.

The Present and Future
Currently, Timbersled has sold approximately 350 of these kits and are building more. This is a good number for its first season. According to owner Allen Mangum, the Snowbike will have a sibling suspension, a Snocross version. It will be designed to allow a rider to compete on a Snocross course with a suspension designed for the chicanes, doubles and triples. Several Snocross snowbikes will compete in the Mountain West Snocross circuit this year. Follow this new development on the company’s website.

Speaking of competitions, the Mountain Horse has pulled some exhibition runs in snowmobile hillclimb competitions and motorcycle hillclimb competitions. At the dirt climbs, the front tire was used. According to Mangum, the bikes tore up the courses in rapid times.

I’ll do it. I’ll ride the snowbike and enjoy the winter. But, be snowbike smart. Snowbiking and snowmobiling are different “snowmobiling” types. The two kinds of fun don’t mix well. Snowbikers ride with ‘bikers, snowmobilers ride with ‘bilers; they attack the terrain in different ways. Yet, at the end of the day, it’s all grins and giggles.

For more information, visit http://www.timbersled.com/. There you will find a plethora of pictures, tech data, engineering speak and all the needed knowledge to amp up your enthusiasm.

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