2016 KTM 450 SX-F
It isn’t every day that I get to write about a “new” bike that already has podium time, but KTM produced a bike for its upcoming lineup that has done just that. Introducing the KTM 450 SX-F; newly redesigned for 2016, and newly crowned Supercross king. Those clever Austrians weren’t content to simply tweak the 2015 model, instead opting for more of a ground-up approach, a decision that seems to have worked out well so far. This ride has had such an auspicious start, I decided to take a look-see and find out why.
Continue reading for me review of the 2016 KTM 450 SX-F.
2016 KTM 450 SX-F
Bikes like this are purpose built, and as such are somewhat constrained by functional necessity. The design parameters are all well established, so what do you do to build a better mousetrap? KTM’s answer is to make it lighter, so they sent the 2015 to fat camp and trimmed just a hair under eight pounds off for a fighting weight of 224.6 pounds, plus fuel. The lines taper down to almost nothing behind the fuel tank, leaving the bike with a very narrow waist. This is a double-edged sword; while it has plenty of room to move about, the skinny barrel leaves riders with little to hang on to with their legs. Obviously, this isn’t a problem for guys like Ryan Dungey, but it may be uncomfortable for less-experienced riders.
KTM started from the ground up with the lightening project. The new frame is flexible in all the right places, and stiff in all the others for less energy transfer from the track to the rider. Rubber-mounted handlebars absorb even more energy-sapping shock and vibration, helping the rider save energy for the important stuff. Steering geometry received a small (0.4-degree) rake adjustment that shortened the wheelbase by 0.393 inch for a bit of extra agility; a move that, according to riders, helps the KTM corner even better than before.
The factory kept unsprung weight down with an aluminum swingarm (down 250 grams), and machined rims with hubs connected by lightweight laces and aluminum spoke nipples. Dunlop supplies the hoops with its Geomax MX32 racing tires.
WP suspension components provide the ride on 48 mm inverted front forks and piggyback monoshock. Both ends float on 11.8 inches of travel, and come with the usual arrangement of preload and compression/rebound damping. Specifically tuned for MX racing, the forks come with mudguards to protect the swept area of the fork tube.
As usual, Brembo provides the wheel bindage at both ends. The calipers pinch a 260 mm disc up front, and a 220 mm disc in the rear, both cut in a wave pattern to save weight and provide improved heat dissipation; another area where KTM trimmed a little fat.
Not even the engine was sacred; the newly-designed mill comes in a whole four-pounds lighter than its predecessor. To achieve this, the factory lopped 6 mm off the length of the cylinder, and lightened the head by 350 grams. The engine cases lost a bit of weight, and even the starter and battery were redesigned to be as light as possible and still get the job done.
The over-square mill displaces 449.9 cc, and cranks out 62 ponies, max. A short stroke of 63.4 mm keeps engine vibration low, and a counter-balancer in the engine takes care of the rest for a noticeably smoother windup. Water-cooled, the radiator is tucked away behind the fairing that both protects it, but also acts as a sort of ram scoop. The airbox is behind the left side cover both to protect it from becoming choked, but also to allow for quick filter changes trackside. A 44 mm Keihin throttle body controls the engine under the management of the Engine Control Unit (ECU), which provides press-button access to three, pre-programmed engine maps with different power-delivery curves. It also comes with a Launch Control function that limits rpm at start and gradually brings on full power to help prevent loss of traction in those first crucial seconds of a race.
A Damped-Diaphragm Steel (DDS) clutch couples engine power to the five-speed tranny, and comes with the designed-in benefit of shorter and easier clutch pulls. Bottom and top gears come with a treatment the factory claims increases reliability.
Both manufacturers made weight reduction central to their design efforts. The KTM weighs in at 224.6 pounds, ready to race but unfueled, and the Yamaha claims 247 pounds wet. Given the fuel capacity on the SX-F of 1.6 gallons, I’d say KTM wins the weight category by a mile.
Suspension travel is a skosh better on the YZ at just over 12 inches, front and rear. A slight difference, but an advantage all the same. Both bikes enjoy fully adjustable suspension.
Variable engine mapping and launch control is becoming rather ubiquitous nowadays, and neither bike gains an edge here as both run some version of these systems. Engine displacement is also close with a scant 0.9 cc in favor of the KTM.
Bottom line: while the weight difference is sure to help the KTM a bit, I think races between these two will come down to skill, and a dose of luck.
“As usual, KTM puts out a good product. Usually I have to wait and see how a bike performs, but not this time. This will definitely be one to watch this year, and I expect to see more podium finishes in the upcoming year.”
My wife and fellow writer, Allyn Hinton, says, "As the biggest bike in KTM’s MX stable this year, it has to be ready to go fast over some really brutal terrain. KTM says it redesigned 365 out of 378 parts to be lighter, stronger or more efficient in the 2016 model over last year. That sounds like they pulled out the microscope and gave every detail a good, hard look. It has more horsepower, improved low-range power and the lower center of gravity makes it that much easier to handle."
|Engine:||Single-cylinder, Four-stroke engine|
|Secondary Gear Ratio:||13:48|
|Clutch:||Wet, DDS multi-disc clutch, Brembo hydraulics|
|Frame:||25CrMo4 steel central-tube frame|
|Front Suspension:||WP USD 48 mm 4CS closed cartridge|
|Rear Suspension:||WP monoshock with linkage|
|Suspension Travel. Front:||11.8 inches|
|Suspension Travel, Rear:||11.8 inches|
|Front brake:||260 mm Disc brake|
|Rear brake:||220 mm Disc brake|
|Chain:||5/8 x 1/4 inches|
|Steering Head Angle:||63.9 degrees|
|Wheelbase:||58.5 ± 0.4 inches|
|Ground Clearance:||14.6 inches|
|Seat Height:||37.8 inches|
|Tank Capacity (approx.):||1.6 Gallons|
|Curb Weight:||224.6 Pounds|