2nd Place of the 2018 450 MX Shootout: KTM 450 SX-F
The KTM 450 SX-F received only a few changes for 2018, but they were enough to bump it up to second place in our shootout ranking, up one spot from the year before. The changes made to KTM’s flagship motocrosser include a new air piston, air seal, and rebound spring in the left leg of the WP AER 48 fork while the right side, which handles damping, gets a sintered piston to replace the plastic piece found on the ’17 models. The other (and most visible) change is the orange frame.
The 450 SX-F’s bottom-end power seems mellow in comparison to the Honda, which makes the orange bike a bit easier and more manageable to ride in this part of the powerband. The somewhat mellow by comparison bottom-end power transitions into a strong midrange where the power hits hard and transitions into an explosive top-end and over-rev. The KTM works best when left in gear until nearly hitting the rev limiter as the engine never seems to sign off in the upper part of the rpm range. Overall, the meaty midrange and hard-hitting top-end power and over-rev make the engine suit more of an aggressive and/or faster rider.
The 450 SX-F comes standard with two engine maps and traction control, all of which can be adjusted on the fly via the unit mounted on the left side of the handlebar. Map 1 (stock) was more than enough for most test riders whereas Map 2 (aggressive) proved to be too much power for most and seemed to be best utilized at the beginning of the day when the track was deep and loamy. Traction control is very noticeable and takes away some of the hit throughout the entire rpm range and came in handy for the test riders who opted to use it toward the end of the day. Traction control can be used on Map 1 or Map 2. Most of our test riders felt that the KTM was on the quiet side, and a component that was highly praised by nearly every tester was the hydraulic clutch as it was consistent, smooth, and didn’t fade during a moto.
If there was one area that held the KTM back in the overall rankings, it was suspension. The WP AER 48 fork is unquestionably the best air fork to come on a stock production bike, but it is on the stiffer side in stock form and rides higher in the stroke. The beauty of air forks is that the spring rate can essentially be changed with an adjustment in air pressure, so most test riders opted to either decrease the air pressure or go softer on the compression, both of which helped gain the desired feel for their weight and riding style. Although it should be noted that most of our testers were on the lighter side of what manufacturers intend their target weight range 450 rider to be.
Even with adjustments to the air pressure and clickers, the fork doesn’t offer the comfort and plushness that are felt with Yamaha’s KYB SSS spring fork and Honda’s Showa 49mm spring fork. The KTM fork left some test riders feeling the fork could use some improvement in choppy braking bumps. Further down in the stroke, the bottoming resistance is excellent and nearly every tester had positive comments about how well the fork handled the bigger and more sudden impacts.
The WP shock had somewhat of an opposite feel as the fork in the way that it seemed fairly plush in the upper part of the stroke but was on the soft side on bigger impacts such as jump landings. An area where the shock shined was on rollers and choppy bumps, but some test riders felt that it was harsh when riding over square-edged bumps.
The 450 SX-F chassis has a very nimble, lightweight feel. The bike came in at only 234 pounds on our scales, the lightest bike in the test, and the weight, or lack thereof, is apparent on the track. Similar to the Honda, it’s very easy to throw around and responds very well to rider input, making it easy to put exactly where you want it. Cornering is an area where the 450 SX-F excels as it leans intuitively into corners and is easy to trust and have confidence that it will continue tracking. In addition to being able to corner very well, the KTM has great straight-line stability despite feeling so light and flickable, which are oftentimes a trade-off but not in this case.
The 2018 KTM 450 SX-F is a great choice for a racebike as it is lightweight, has a strong yet smooth engine with on-the-fly mapping and traction-control adjustments, and a nimble feel on the track. However, it doesn’t feel quite as lightweight or flickable on the track as the Honda despite the fact that it’s 14 pounds lighter than the red machine. One thing in particular that held the KTM back from taking the win was its suspension as some test riders felt the air fork lacked comfort, plushness, and progressiveness. On top of that, checking the fork’s air pressure is one extra thing to handle before a ride. A few even mentioned they think the bike would be better both performance-wise and in terms of pre-check steps with a spring fork, but they agreed the new AER fork is a better fork than the WP 4CS units that came on the bike in 2016 and prior.
“The KTM has a great engine that can be revved to the moon or lugged a gear high in any corner.” —BJ Burns
“The KTM 450 SX-F is light on the scales and feels very much so on the track.” —Andrew Oldar
“Maybe the KTM can borrow a KYB shock…” —Ricky Yorks