Click Photo Gallery for pictures of all the sleds on the scale. 

As has been well documented, the biggest predictor of any vehicle's performance is how much it weighs and how much power its' engine produces. With high speed vehicles like race cars, motorcycles, or airplanes, aerodynamics also plays a big role in determining top speed and high speed acceleration. In the case of snowmobiles, especially mountain snowmobiles, the weight to horsepower equation has proven over the years to be an almost flawless predictor of relative performance. At our riding speeds, aerodynamics is just not a big factor. We know that things like clutching efficiency, track design, and chassis setup all can make a big difference in performance characteristics, but weight and horsepower are still the basis of performance. Over time, the OEMs have generally gotten closer on the other factors, although they still manage to improve or degrade performance occasionally. For example, the Challenger Lite tracks found on the 2007 Summit X and XRS models were bad enough to give the sleds serious flotation issues in deep snow in spite of being lighter. We have proven over the past couple years as well that IQ based RMKs do float better and work better in deep snow than similarly powered Edge models, which means the chassis is more efficient. We have also observed over the years that certain sleds work better in certain circumstances. Dragon 700s out in the meadow proved to be very fast for the amount of horsepower they make. If you raced a Summit 800 and a Dragon across the meadow, more times than not, the Polaris was faster. But, if you pointed them uphill on a deep day, the Dragon was no match for the Summit and you could really see the extra horsepower do its job at those slower track and ground speeds. Likewise, the Apex shows lots of speed on the trail in spite of its monster track, but suffers more in the deep snow. Of course, when you turn the horsepower way up with the turbo, the equation changes entirely. Therefore, the data presented here should not be used as a performance guarantee but simply a starting spot to evaluate the realm of performance that could be expected from any model.

As many folks know, we have probably spent far more time, money, and effort building our dyno to accurately assess horsepower than we probably should have from a strictly business perspective. Unless noted as estimates, the horsepower numbers quoted below were all tested on our dyno and corrected to the same high altitude atmospheric conditions. In order to really get some great weight data, we invested in a new hanging scale this fall. We had been using a set of race car style floor scales but they required adding up three different weights and manually picking up the sleds and putting them on the scales. We also didn't also get great repeatability with them as we'd often see the weight vary a couple pounds between sessions. Given our excellent results with the S-Beam style load cell found on our dyno, using a similar setup with a remote display seemed like the way to go here as well. In order to weigh the sleds, we simply hooked the S-Beam to our forklift with a strap and then hooked the other side to the sled via a soft strap around the steering post and a steel hook. Lifting from the steering post gave us a single pick point and didn't require extensive rigging to make it work. As for repeatability, we weighed several of the sleds multiple times and found the scale to repeat to within 0.2 pounds.

As for the inevitable discussion about dry weight versus wet weight, we opted to weigh everything full of gas, oil to the full line, and coolant at the full mark as well. To be fair, we stuffed as much gas as we could in the sleds, just the way you'd normally leave the parking lot. Can we say with certainty that one sled didn't have a couple tenths more or less fuel? Absolutely not, but all the sleds were definitely "full" of fuel. It's possible to debate which weight is really the right weight to compare but from a field perspective, attaining dry weight is simply not possible to do with any accuracy. When the OEMs talk about a dry weight, they are often deducting things like shock oil, chain case oil, etc. in addition to the fuel, oil, and coolant we normally talk about. Trying to duplicate those conditions is simply not practical, nor does it really tell you much since you need all those fluids to ride the sled.

It is also unfair to "penalize" the sleds that hold more gas for weighing more. When you look at the chart, you'll see a truly full weight and a weight without fuel. In order to get a feel for how the sleds would compare without fuel, we did take the full weights and backed out 6.1 pounds per gallon. However, only the Phazer and the M1000s would switch positions when they are ranked by weight without gas. One disclaimer here as well - we did not attempt to determine the actual capacity of the tank but simply used the listed capacities. Are the OEMs telling the truth about capacity any more than the typically do about dry weight? We don't know but we'll hope that they're close. The other question is really how much gas do you need to carry to cover a given distance? Yamaha argues that the four strokes are more fuel efficient and, therefore, the tank can really be smaller. We've known since the 1997 700 RMKs that the fuel mileage game with snowmobiles isn't really won or lost at wide open throttle but rather at part throttle. As much as we think we run around taped, the statistics simply don't bear that out and even a mountain sled spends most of its life at part throttle. Therefore, full power fuel flow numbers gathered on the dyno help us predict if we have enough fuel not to burn the engine down but do little to predict how much fuel the sled will actually use in normal riding. It does seem reasonable, then, that fuel injected sleds might do better on fuel since they can more precisely control and meter fuel than a carburetor. That gain, however, would be true on both a two or four stroke engine. It also seems likely that the lighter a sled is, the better it will do on fuel since it needs less power to keep it moving. It is then somewhat ironic that the lightest sleds (the new Summit 800s) still have carburetors while the heavier sleds are mostly fuel injected. If we find out that the Nytro rider really has to haul another 3 gallons of fuel on the sled to ride all day, that means that its' actual weight savings versus the Apex are not nearly what they seem and it may be considering the bigger Apex engine. If, however, it really takes less gas to ride all day, then the weight savings are really usable.

There are also one other set of numbers worth considering in the deep snow. Track FP (footprint) is simply the width of the track multiplied by the length. It does not attempt to predict how much track is actually on the ground, although with everybody using longer travel suspensions, the overall track length is a close approximation of the actual footprint. From there, we can figure the weight/footprint ratio which gives us a rough idea of what kind of flotation to expect. Again, this is only a mathematical guess and folks really shouldn't be deciding which snowmobile or track length to buy based on this one factor. However, if going straight uphill or not getting stuck on the worst days is a priority, this is a good metric to consider. It's also neat to see a sled like the Summit 550 Fan show us that flotation is possible without horsepower. We've all seen those light sleds with the kid riding that goes everywhere we do, just not as fast.

With all the data compiled, are there any big surprises here so far? It doesn't really seem so. It does seem that if you opt for a Sno Pro Cat, you should do so for the better suspension of the air shocks, not necessarily for weight as the standard and Sno Pro models are very close. It's also interesting that the gap between a 600 RMK 144 (carb) and a 700 RMK 155 (fuel injected) is almost 20 pounds. There is still some penalty for all that electrical equipment and the bigger engine, in spite of it being built on the same basic crankcase. As far as the Yamahas go, they've pointed out that their sleds are competitive with Cat & Polaris in the short track models in terms of weight. That would appear, looking at the mountain sled numbers, to be a function of the other guys getting heavier in the chassis designs rather than the four stroke engines really getting lighter. I absolutely think that if you want a mod sled, there's no better choice than a boosted four stroke, but a person has to realize that the sleds are still heavier and do handle differently because of that. Even the M1000, the sole survivor in the two stroke big bore class that couldn't support 900 RMKs or Summit 1000s, packs an approximately 30 pound penalty versus an M8. Sure, with a lightweight can and a little work, the gap can be reduced, but stock for stock, there's a difference. Thankfully, the difference is reasonable and the M1000 makes signficantly more power than an M8 - the Summit 1000 was at least 80 pounds heavier than the 800s and the 900 RMK was similarly heavy and low on stock horsepower. Finally, we included the data on Kellie Bayne's 600 RMK. It was weighed with no gas so keep that in mind when you look at the numbers. As many people know, Jon is obsessed with light weight and he's proven once again why their sleds work so well. With lots of weight removed and an RMX engine, Kellie's 600 should outdo a stock Dragon and be nearly 70 pounds easier to ride - that sounds like a fun combination.

The bottom line on 2008 is that there are lots of good choices. I believe that if we can do a good job matching a rider's style with the right machine, there's a fit for all of these sleds. The Ski-Doo looks hard to beat pointed straight uphill with its weight and power, but a lot of folks will opt for the Polaris and Cat simply because they like the chassis feel. For tree riders, that's more important than putting the high mark on the hill. For others, the Yamahas make a great place to start building big horsepower or the durability of the four stroke simply is more important than the weight penalty. At any rate, it sounds like it's going to be a fun winter.

Thanks,
Donavon

Please click the Photo Gallery to see pictures of all the sleds hanging from the scale.