KTM’s Direct to swingarm Shock v’s Husqvarna Linkage Shock
KTM’s offroad range (EXC and XC-W) utilises the WP ‘Xplor’ shock. This unit runs a direct mount to the top of the rear swingarm. It is most commonly referred to as the Xplor shock and is effectively a ‘PDS’ shock (Progressive Damping system). Whilst belonging to the same parent company, Husqvarna’s equivalent ‘FE’ range features the Xact Linkage Shock matched to an under swingarm mounted linkage system. This shock is also standard fitment on all KTM and Husqvarna MX models.
After spending many hours riding and testing the KTM ‘Xplor’ setup since its release in 2017 we have learned this version of the venerable PDS shock is now a very good unit whilst featuring some downside in comparison to a linkage-equipped bike. We have personally tested the Xplor shock on the KTM 350, 450 and 500 EXC four strokes and both 300Exc and 300i two strokes.
More recently, we have commenced testing on the Husqvarna linkage-equipped Xact shock, revealing interesting differences between these otherwise very similar motorcycles.
We’ve collated a lot of data in stock trim and set about modifying both of these setups to deliver an optimum setting.
PROS & CONS
KTM Xplor - EXC XC-W
Lightweight, compact and extremely straight forward to remove and replace in the chassis. This shock, featuring a direct mount to the swingarm, has exceptional ground clearance due to the absence of a linkage hanging in front of the rear wheel. Encounter a huge log to wheelie over? No problem, an Xplor bike will glide over it most of the time whether you wheel tap it correctly or frame bash onto the log. The lack of linkage allows forward momentum, no friction and an easy glide over such obstacles. With less moving parts (no linkage) its less maintanence and lighter.
Due to its compact size and small shock body the first issue is somewhat obvious; it holds less oil. In fact, only around 260ml. This factor combined with the short stroke and more leverage, the shock by nature has to be set up with firmer damping, ultimately resulting in more heat being generated. Less oil, more heat and you can see where this is going. The result is a shock that heats up quickly and fades fast. Although not a huge problem on low speed terrain, it quickly becomes a bigger issue on long high speed, severely chopped out surfaces, fading far beyond any real clicker control.
Xact Linkage Shock - Husqvarna FE
It has a linkage! It is the same shock available on all Husqvarna and KTM motocross models. It results in suspension that is both soft at the start and firm at the end. It also runs nearly 100ml more oil than the Xplor shock and reaps the associated benefits from this. It has a much softer damping rate due to the linkage and is much gentler on the oil. In standard form across the 2020 FE range this shock provides a soft action right out of the box.
It has a linkage! Yes, its biggest strength is also its biggest weakness; especially in the bush. Trying to bulldoze your way across fallen trees with average-level skills will probably end badly. This bike will hang up and stop fast, Really fast. The linkage hangs low and prevents the rear wheel getting any further traction, leaving you spinning on top of these obstacles. By design, a linkage has several pivots that also hang low down in the mud and slop and will be constantly rammed full of dirt and debris. You can also bet on a little extra weight to go with the extra maintenance and careful cleaning.
OEM feeling out of the box
After riding several of these bikes in absolute stock trim it is amazing the similarity you get from both of these configurations across all bike sizes. Whether it’s a KTM 300tpi or a KTM 500 Exc, the Xplor shock feels like an Xplor shock, and an Xact will be instantly identifiable if you were to jump on each bike without looking underneath.
The Xplor shock probably has the most distinctive feeling. Hard and wooden-like to get moving, combined with a fast-rebound return action. We tested this combination on some big fast high-speed rollers and chopped the throttle on purpose. We only did this once with the OEM Xplor shock! On smaller chop it was acceptable when it was ‘undersprung’ (ie, a 90kg rider on the OEM 75kg spring) but once a rider weight-appropriate spring was fitted (based on WP’s recommendation list), the harsh feeling was evident across small choppy ground. The fast-rebound action was also increased matched to a stiffer spring rate.
The Xact shock feels soft in comparison to the Xplor, especially at the start of the stroke. The shock feels plush and after a few hours of run in time, almost too soft and very springy. Great on low speed terrain but with little control on big downhills or across large whoops. Although we feel compression is not the major issue here for most, adjusting the rebound rate (via shim setting change) to match your shock spring transforms the ride all over.
After upgrading both of these shocks we feel one is as good as the other for most riders. There are still Pros and Cons but these differences are much smaller when modified appropriately. The vast majority of riders are not hard enduro guns or expert level motocross guys riding on the trails, so setting either of these shocks up to deliver great results is quite achievable. Both settings will improve rider feeling with a controlled, comfortable ride that feels safe.
Although our Xplor setting changes and modifications are more involved, the results we can achieve out on the trails are outstanding on either. If we had to choose between Xplor and Xact in absolute stock trim, we would likely lean towards the linkage setup Husqvarna and put up with the linkage in the bush.
In modified form though, we can ride hard on both bikes with just the same confidence, speed and trail times! With the lack of under hanging linkage and the light weight rear end this decision would be much harder to choose from.
Krooztune WP Offroad recommended Upgrades
Free Bleed Modification - Modifying the shock internal system allows for a plush initial feeling from the beginning of the stroke.
Rebound setting - we achieve a shock that can be tuned to 'sit in' the stroke and drive accross chop or tuned via the clicker to be 'fast acting' enough to gain traction on slippery conditions.
Compression- Multiple settings to suit various skill levels. Soft/Plush or medium to firm.
Nitrogen Bladder Kit – Less moving parts internally, more oil volume, less heat and you guessed it less fade. More small bump compliant.
Spring Rate - Matched to rider weight. We follow with Ktm’s recommendation on spring rates. There OEM progressive spring mimics a linkage setup and it works. From Soft to Hard. Riders outside normal weight range may benefit from a linear straight rate spring setup. (i.e 120kg + gear)
Rebound Setting – Dyno and trail tested rebound setting that is designed to work through out the service range. We feel OEM rebound setting is ok for an hour, then fades to a bouncy shock quickly. A simple shim setting change to match spring rates transforms the rider feeling in the rear.
Compression Setting – Shim setting changes to suit all riders. A Cloud like setting to a MX style firm is easily achievable on these super popular rear shocks with easy shim setting changes.
Nitrogen Bladder kit – Same as Xplor, less moving parts , more oil, less heat and fade. More small bump compliant.
Spring Rate – Linear spring rates available for all weight ranges. Again Husqvarna / WP have the spring rate guide correct. We agree and use similar spring rates to suit our setup.