Last season, the model year 2014, we listed the Ski-Doo XM RS Freeride, both in 146 and 154 lengths, as our Editor’s Choice for Mountain Snowmobile of the Year. In model year 2013 the newly minted XM Summit X 154 was our Editor’s Choice, although sharing it equally with Polaris’ RMK Pro, which offered its innovative Quick Drive belt drive system. Going back one year even further to model year 2012, the much-refined XP Summit X was our Editor’s Choice as Mountain Snowmobile of the Year. Over the past few seasons, we’ve given the Ski-Doo Summit quite a run as Mountain Sled of The Year.

Fast Facts

Engine Type:Horizontal In-line


Engine Stroke:2-Stroke

Valve Configuration:Reed Valve

Displacement:799.5 / 48.8



View Full Spec

Heading into model year 2015 we saw the XM Summit X, 146, 154 and 163 coming to market with few changes from 2014. We weren’t expecting much difference. Plus, the 2015 XM Summit X has a new in-house competitor where all the “big” news was going – the XM Summit X 163 and 174 with T3. These new T3 models spin three-inch tall paddles on the PowderMax 3 track. The tall-lugged T3 three-inch track retains its 16-inch width and FlexEdge technology.

With Ski-Doo giving birth to this new T3 Summit line, we fear the Summit X is a three-and-done nameplate; three model years beginning with year 2013. The XM Summit X laid the groundwork for the T3 Summit, which gives the buying public a solid and well-tested chassis. Could it be the snow gods will take their all-seeing eyes off the Summit X 146, 154 and 163?

Though we don’t have specific tracking-and-trending data, Rocky Mountain-area Ski-Doo dealers we spoke to said most pre-ordered Summit Xs during Ski-Doo’s Spring-time push, were T3 Summits sporting the 163 track. Some reported 80 percent of the Summit Xs were T3s with the remaining 20 percent, the Summit X. If I were to purchase an X-package Summit, I too would pass over the 154 or 163 XM Summit X for the taller-lugged 163 Summit X T3. The only reason I would purchase a Summit X 154 or 163 would be price; the Summit X is cheaper.

But, since ego drives mountain riders to have the best, Ski-Doo has given deep-powder pushers, three 800 E-TEC XM Summits – the SP, the X and the X T3. Thus, many 800-powered XM Summits are available to fit your mountain riding needs – based on price. We believe buyers will settle into two ends of the same spectrum, the SP – the least costly XM Summit – or the high-end T3. Buyers, generally western-market buyers, fall into budget, budget-performance or premium-performance. The middle, budget-performance, is often forgotten.

COMPARISON: Read our review of the 2015 Ski-Doo 800 Summit X 174 with T3 + Video

The XM Summit X, be it 146, 154 or 163, should not be passed-over nor forgotten as a mountain killer. Just because its Powder Max 2 track has a lug height of 2.5 inches and its spindle is not the cool updated RAS spindle, the XM Summit X remains a stellar, high-end uber steep-and-deep mountain snowmobile. Ski-Doo has created serious competition within its own ranks. For model year 2015, the Summit X 154 and 163 do not so much compete against Polaris’ RMK Pro and Arctic Cat’s M8000 Sno Pro, as it does against its own mother-company product, the Summit X T3.

If we were Ski-Doo, we’d build a 154 Summit X T3 and let the fast spinning 154 three-inch paddle track speak loud and clear its mountain mayhem intent. But, that’s just us simple folk who ride weekend-in and weekend-out from November through April.

What, then, is the XM Summit X 146, 154 and 163? Here’s the inside skinny.

The XM Summit X receives its “mojo” from a twin-cylinder two-stroke motor known as the Rotax E-TEC 800R. This motor uses direct-injection and builds approximately 164 horsepower. From our experience, this is an economical motor with an easy throttle pull. Its power delivery is linear with virtually no smoke or smell and provides one-pull starts.

The drive clutch is the TRA VII, whereas the driven clutch is the quick and easy adjustable QRS.

The front suspension has dual A-arms (upper and lower A-arms) with HPG shocks. Ski stance is adjustable from 35.7 to 37.4 inches. Skis are Pilot DS 2. The front end is coupled via a sway bar that can be quickly disconnected, hence the label, “Quick Disconnect.” We like this and frequently take advantage of quickly disconnecting the sway bar for more aggressive sidehill attacks.

The rear suspension is tMotion with HPG Plus shocks. The unique tMotion rear suspension has a ball joint hinge, residing between the rear arm, the drop link, and split flex points on the front arm, that allows it to swing two-degrees right or left, for a total of four degrees. This induces a controlled roll where more track footprint stays on the snow when sidehilling.

COMPARISON: Read our review of the 2015 Yamaha RS Viper M-TX Turbo + Video

Secondly, the tMotion works in tandem with the Powder Max II track. The 16-inch wide track with 2.5-inch tall lugs has flexible edges. The track has – from center out, at a length of 12 inches – fiberglass reinforcing rods. With the center 12 inches reinforced, the track’s outer non-reinforced two-inches, flex up ever so slightly (to match the hill’s slope angle). This allows the track’s edges to flex up when a sidehill roll is initiated. The track with FlexEdge technology is 16 inches wide and come in lengths 146, 154 and 163.

Gear Ratios

For the small sprocket:

• The 146 has, for sea-level calibration, 23 teeth and for high-altitude, 21 teeth;
• For the 154 and 163 in sea-level configuration, 21 teeth; and for high-altitude configuration, 19 teeth

For the large sprocket:

• The 146 and 154, both sea-level and high-altitude configurations are the same, 49 teeth;
• The 163 for both altitude configurations have 51 teeth.

The drive sprocket for all track lengths and the two altitude configurations uses an eight-tooth driver.

The XM Summit X has pushed-forward handlebars and skis (pushed forward from the XP), side panels that are cut out by the footwells, and footwells that are deeper to align the rider with the handlebars and track drivers. We’ve learned these add to the XM Summit’s easy roll personality.

The S-36 package fitted to these sleds accommodates the tMotion rear suspension and track while the Pilot DS2 ski aggressively bites into a hill.

Ergonomics are well laid out. The handlebars have a natural curve that allows the driver’s arms and wrists to retain a natural bend. Heat controls are located on the console. The controls that remain on the bars, RER and motor kill, are positioned or protected to prevent inadvertent activation.

The XM Summit X comes equipped with a multi-function digital/analog gauge that peers up to the rider – reflecting the fact that most mountain riders are in a standing position, The gauge reports all engine vitals and tracks altitude. We’ve come to appreciate its easy-to-read numbers and wide face.

Located behind the gauge is a glove/goggle box. We appreciate storage. To have a place to stuff an extra pair of gloves or goggles is much appreciated.

The seat is nicely sculptured with a tactile texture. It does not hinder most foot swings from one board to the next. But really, the XM Summit X can be masterfully ridden by keeping both feet planted on its respective platform. The seat does have some rear seat storage. Not much, but enough to appreciate.

The painted tunnel prevents snow from flash freezing to it. Rigid footboards with wide evacuation holes dump snow and ice with ease. The tunnel can utilize Ski-Doo’s LinQ system as many optional storage devices can be added to the tunnel with ease.

COMPARISON: Read our review of the 2015 Arctic Cat ProClimb M8000 HCR

In “Summation,” the XM Summit X is a satisfying mountain snowmobile. For 2015, Ski-Doo also offers Summit X versions for sea-level riders who want a long, lean, and mean trail machine that will give miles of comfort and mind-blowing off-trail meadow bashing in deep powder.

From our experience, the XM Summit is feathery light through the handlebars. For handlebar position, factory is best. We’ve learned the XM Summit X, when sidehilling through some previously laid down trenches or hard packed trenches, has some nose bounce and wants to dive down off the slope as impact energy kicks the bars down. This is not nearly as bad as the XP Summit of yore, but it is still present and can be a nuisance.

The XM Summit X can, on occasion, trench down through light and fluffy snow more than we like; the T3 Summit fixes this. Simply standing closer to the bars, or adjusting the limiter straps to control weight transfer through power-on situations can mitigate some of the effect. Every mountain snowmobile has quirks and this is one we find in the Summit X.

With all the above, the XM Summit X is a highly popular mountain snowmobile, but it’s giving up its spotlight to the T3. Yet, the XM Summit X will does make mountain riding confidence riding.

2015 Ski-Doo Summit X 163 Specs
Engine Rotax 799.5cc, two-stroke twin; liquid-cooled; Electronic direct injection; new lightweight tuned muffler
Horsepower 160-plus
Drive Ski-Doo/Rotax TRA VII with QRS driven; electronic reverse
Front Suspension Ski-Doo dual A-arms with spring over HPG Plus gas shock; up to 8-in travel
Rear Suspension Ski-Doo tMotion parallel slide rail with HPG Plus shocks center & rear; up to 16.0-in travel
Length 135.6 in
Width 44.3 in
Height 53.0 in
Ski Stance Adjustable: 35.7 to 37.4 in
Track 16 x 163 x 2.5 PowderMax II Flexedge
Brake Brembo racing brake with stainless steel braided brake line
Weight 464 lbs (claimed)
Fuel Capacity 10.6 US Gal (Premium unleaded recommended)
Features Standard: REV-XM chassis; S-36 handling package; Pilot DS2 skis; aluminum handlebar with J-hooks; multi-function gauge; REV-XM lightweight seat with rear storage; 5.1-inch riser block; electronic reverse; 12-inch windshield
Optional: rearview mirrors; storage bags; electric start
MSRP US$12,899