2017 KTM 300 XC-W and XPlor Suspension - Comprehensive Review

Kreft Moto's take on the redesigned 2017 KTM XC-W line, with particular attention given to the new XPlor suspension.

Bike Overview

KTM’s 2017 XC-W line received major design changes for the first time in years.  Among the changes are a new motor, new frame, and most interesting for us, new XPlor suspension.

If you’re familiar with past XC-Ws, you won’t have trouble adapting to the new one.  It retains most of the characteristics of the trail-oriented, wide-ratio transmission KTMs we are accustomed to.

The most significant improvement by far is the engine counter-balancer.  The motor is as powerful and responsive as ever, but has much less vibration than previous years.  I hopped on an older 300 for a quick side-by-side comparison and the difference is pretty amazing.

In terms of ergonomics, I felt completely at home with the new frame and cockpit layout.  It’s comfortable and narrow between the knees, and the bike has a nice lightweight feel. 

Suspension Overview

From a tuner’s perspective, the XPlor suspension looks like a cost-cutting measure for KTM.  The new shock body was downsized from 50mm to 46mm, which reduces fluid volume and could contribute to heat buildup and fade.

The fork is very similar to the previous generation open cartridge fork – the major difference being the split compression and rebound adjustment.  XPlor has a single rebound adjuster on top of the right fork and a single compression adjuster on top of the left fork, just like WP used on the more-or-less universally hated 4CS fork. 

 

XPlor CAPS.png

Dyno testing at our facility shows what the compression adjuster on the XPlor fork actually does.  The first chart shows the XPlor fork with the compression adjuster fully open, at the halfway point, and fully closed.  In comparison, here’s the adjustment range of the old open cartridge fork at the same three adjustment settings.  As you can see, the XPlor compression adjuster has very little impact on compression stiffness.

Most important of all, the XPlor adjuster has NO effect whatsoever in the low-speed range, shown here from 0-500 mm/second.  Your suspension is constantly working in the low speed range, and being able to make adjustments here is critical.  Making the adjuster more accessible doesn’t help if the adjuster doesn’t work properly.

Subjective Evaluation - Test Riding

This chart summarizes our impressions of the 2017 XPlor suspension compared to the 2016 XC-W suspension it replaces.  As you can see, we gave the 2016 model, represented in blue, higher marks overall.

 
 

Balance

XC-Ws are typically setup a little softer in the front than the back, and that setup makes sense for some applications, but 2017 takes that imbalance to a whole new level.  The new XPlor fork is softer than the model it replaced, and the shock is stiffer that the model it replaced.  I found myself constantly hanging out over the back of the bike trying to stabilize the chassis and reduce the effects of excessive fork dive.

Slow-speed impacts

The upside to the super-soft XPlor fork is that it offers good comfort in slow-speed rock gardens.  If you are new to the sport or spend most of your time riding very slow speed first-gear terrain, you are much more likely to appreciate the stock fork performance.

The cushy fork is somewhat offset by a shock that will occasionally deliver a sharp kick to the backside on square-edged obstacles.  Again, this is reminiscent of previous generation PDS shocks.  You’ll want to be sure to maintain a standing position when riding through sharp obstacles at any speed.

Mid/high speed impacts

Unfortunately, the Xplor fork’s slow-speed compliance completely disappears as the speeds increase.  Watch out for unseen rocks when clipping along in third gear, because the fork can feel completely solid on this type of obstacle.  After a couple close calls, I learned to back off and watch closely to avoid hitting anything sharp at speeds over about 12 mph.

Cornering

I give the 2017 300 XC-W low marks in cornering for three reasons:

  1. The suspension setup is unbalanced to begin with (see Balance above).
  2. The XPlor fork has the worst brake dive I have experienced in any modern performance-oriented dirt bike.  Fork dive cannot be reduced by adjusting the clicker due to the problems with WP’s split adjuster system explained earlier.
  3. The Xplor PDS shock still has the same top-out tendency we saw in previous PDS shocks.

Together, these factors cause a rapid and excessive weight transfer onto the front wheel when setting up for a corner, which can make the front end to knife or tuck instead of tracking cleanly.

Whoops

In the whoops, the chassis balance issue continues to haunt us.  The fork completely collapses on the face of every whoop, exaggerating the tendency of the shock to boot the back end of the bike up into the air.

Adjustability

Fortunately, the XPlor shock retains the same adjustment features as the previous PDS shock, with high-speed compression, low-speed compression, and rebound adjusters all working as they should.  The XPlor fork, with its split adjuster design, is another matter.  As we demonstrated in the video and explained with the dyno charts, the fork has very little compression adjustment range, and zero ability to adjust low-speed compression – where we need it the most.

Summary

In conclusion, the 2017 KTM 300 XC-W hit a home run with the new motor, but took some irritating shortcuts with the XPlor suspension.  It’s possible KTM is targeting the bike for beginners, but this is still an expensive, high-end dirt bike and I think a lot of serious riders will continue to buy XC-Ws for the wide-ratio transmission, link-less rear suspension, and headlight.

Kreft Moto is about half-way through our development program for XPlor.  We’ll be finalizing our design updates and fine tuning settings over the next few weeks.  We’ll post updates as soon as they become available. Thanks for reading!

Posted on October 28, 2016 .

WP AER 48 fork

FIRST LOOK

 

 

WP's new air-spring fork is already available on European KTM motocross models, and it will likely be introduced in the US on 2017 KTMs. The new design is a major departure from their controversial 4CS fork.  WP ditched the forward-thinking design for one that is, in many ways, much more conventional.  The fork is filled with design features we are accustomed to seeing on Japanese products.  For example, it uses a spring and floating piston reservoir pressurization system, large pistons with heavy shim stacks, and of course the appearance of an air spring in place of steel coil springs. 

The new design divides the spring and damping duties into separate legs.  The left leg contains an air spring cartridge, while the right leg houses all the damping components.  Separating the suspension functions like this is nothing new in motocross, or mountain bikes for that matter.  When the fork, triple clamp, and wheel are all bolted together they function as a single unit.

On the negative side, the new fork will require a little extra track-side maintenance.  You will need a special tool to accurately set air pressure (I got the Works Connection Digital Shock Pump).  Forget about pumping it up with a compressor and using a pressure gauge to bleed off excess air - the air pressure setting is way too sensitive.  It needs about 150 psi and even a couple psi change makes a big difference.

On the positive side, the new fork is really lightweight.  It's easy to feel the difference when riding.  More importantly, unlike a stock 4CS, it actually absorbs bumps!  With a reasonably compliant feel and good bottoming resistance, this is easily the best performing production fork to date from WP. Still, it's not perfect.  It has a bouncy feel at the top of the stroke that gives it a wiggly turn-in feel.  It also has lots of brake dive for a motocross fork. And to be fair, I have not yet tested it in any really demanding conditions.

We have a ton of testing yet to do with the AER 48, but so far it looks like a step in the right direction for WP.

 
Posted on August 20, 2015 .

2015.5 Factory Edition KTM

I've spent a ton of time lately aboard KTM's new 250 SX-F Factory Edition.  There is no other way to say it - it's awesome.  Here are some of the details that struck me about this bike.


Ergonomics

Throw one leg over the new Factory Edition bike and you will instantly notice major ergonomic revisions.  The handlebar is low, the seat is flat, and the gas tank is tiny.  The juncture of the seat and tank is seamless and therefore very easy to get your weight forward in a corner.  The new layout feels a little odd putting through the pits – but completely natural once you lean it into the first corner.


The new 4CS has no bottoming control system.  

The new 4CS has no bottoming control system.

 

Handling

The new frame has had a significant impact on the handling feel of the bike.  Previous generation KTMs, particularly when the sag setting is a hair off, sometimes feel like they are on the edge between railing a corner and knifing the front wheel.  The front wheel on the new bike is more predictable and forgiving, giving the rider confidence to lean a little farther.  On flat hardpack turns it is even possible to skate the front wheel a bit without completely loosing control.

 

Fork

The new shock piston uses three sets of paired compression ports.

The new shock piston uses three sets of paired compression ports.

The 4CS fork has minor changes from last year.  It is an incremental improvement, but remains mediocre overall.  It has a soft feel, but nevertheless can become quite sharp as the track gets worn in.  There is no hydraulic bottoming control system in this year’s fork, so WP relies on a high oil height to control the big hits.  That gives the fork a springy feel and harsh response in a situation where the fork is already compressed and then hits a bump.  Bottoming resistance is acceptable, but will clank hard if you come up short on a longer table top.

 

Shock

The shock is all new with a longer stroke, revised linkage, extra chubby nitrogen reservoir, and much lighter spring rates.  The 2015.5 250FE, for example, comes with a 45 N/mm spring whereas the standard 2015 250 SX-F came with a 54 N/mm spring.  The shock’s main piston has also been redesigned with six small oval compression ports instead of three giant ports.  As delivered, the shock falls through the initial travel easily, but somehow does not bottom hard on big jumps.  The new linkage may include an aggressive rate increase deep in the stroke.  The shock performs superbly in whoops, but struggles in acceleration chop despite its soft initial feel.

 

Motor

As delivered, the 250F engine did not live up to my expectations.  The dyno horsepower numbers published in the magazines are extremely high – yet I was shifting and slipping the clutch constantly to keep the bike up to speed.  Later I discovered a steel screen in the silencer tip, presumably installed for noise reduction, and removed it.  The bike came to life with a massive boost in power across the range.  It seems reasonable to assume KTM removed the offending screen prior to delivering test bikes to the magazine editors.

 

Nitpicking

I may be nitpicking here, but the new right side cover is downright dangerous when used with my Sidi Charger boots.  The ankle support strap catches on the plastic panel constantly.  I resorted to using zip ties and duct tape to hold the ankle support piece flush with the rest of the boot.  Eventually I tried a pair of Gaerne boots and did not experience the problem.


Bottom Line

I have really enjoyed this bike.  It makes me feel like a better rider – and that’s a feeling any dirt biker would love.  The new chassis and ergonomic configuration are a big win, at least for motocross and supercross.  It is only getting better as we bring the suspension up to our standards.


What do you think?

Have you ridden one of the new Factory Edition bikes?  Let me know what you thought about it!  Email me at adam@kreftmoto.com.

Posted on May 16, 2015 .