We communicate to the person in command of growth for WP’s suspension elements, Sebastian Wolfgruber, to get the nice oil on WP’s all-new XACT Closed-Cartridge fork (which seems on the 2024 enduro fashions from KTM and Husqvarna), and the “full new vary of WP Professional Parts” within the pipeline!
TM: Sebastian, you began out as a designer for WP’s off-road suspension division some seven years in the past, and also you’re now the Venture Supervisor for WP’s off-road R&D program, proper?
SW: Sure. For the previous 4 years, I’ve managed the off-road R&D program for WP’s Professional Parts – our aftermarket elements – and the event of the suspension elements used within the KTM group’s off-road manufacturing fashions. That’s what brings me right here to Lesotho for the worldwide media launch for KTM’s 2024 enduro fashions.
Whether or not we’re speaking about KTM’s or Husqvarna’s 2024 enduro fashions, 95% of their elements are new. And but, a better majority of the market’s consideration has been centered on only one part: these bikes’ all-new WP XACT Closed-Cartridge fork. Why do you suppose that’s?
As a result of the first-time fitment of a fork that makes use of a closed-cartridge system is huge information for each manufacturers’ enduro fashions. Additionally, the demand for a closed-cartridge fork on these fashions has been very excessive, so shoppers are completely satisfied about this improve. We knew the demand was excessive as a result of we bought a whole lot of our WP 6500 Cartridge Kits prior to now couple of years.
WP’s XPLOR Professional 6500 Cartridge-Package fork has been out there for a few years now and sells for about $2000 in Australia (and, by the way in which, has been extensively praised). However when it comes to design, how comparable is WP’s all-new ‘manufacturing’ XACT CC fork and the 6500 Cartridge-Package fork?
Other than a number of variations within the internals (resembling a change in diameter of their base valve – 34mm on the CC versus the 30mm on the 6500 equipment) and some totally different supplies, the 2 are literally very comparable. The CC fork additionally shares some elements with the XACT air fork that’s used on the motocross fashions for each KTM and Husqvarna as a result of that additionally makes use of a 34mm diameter base valve.
The 2024 KTM fashions’ all-new high-grade solid triple clamps create a way more even clamping floor on the outer stanchions of WP’s 48mm XACT CC fork to make sure a smoother fork motion. Pinch-bolt torque settings for the decrease and higher triple clamp are upped to fifteen and 20Nm, respectively.
Additionally, the ‘manufacturing’ CC fork doesn’t come commonplace with exterior spring preload adjustment, however the 6500 Cartridge-Package fork does. Appropriate?
Sure, that’s proper. However it’s straightforward so as to add exterior preload adjustment to the CC fork by becoming a WP Professional Parts half. This really provides preload to the bottom valve’s stress spring, moderately than to the primary fork springs themselves (keep in mind that, on each the XPLOR open-cartridge fork and the 6500 Cartridge-Package fork, the exterior preload adjuster provides stress to the primary fork springs). Preloading the stress spring – which sits on prime of the bottom valve within the cartridge – is one thing we got here up with throughout the growth part with this CC fork and it gives an enormous enchancment. Mainly, including preload on this approach permits the rider to nonetheless regulate the front-to-rear steadiness of the bike, however with out affecting the consolation of the trip over small bumps – that ‘plushness’ in that first a part of the stroke.
What are the foremost enhancements the CC fork gives, and why?
The foremost factor with the closed-cartridge system is the actual fact the oil is pressurized throughout the cartridge. This stops the oil from foaming, which is what’s going to trigger a lack of damping. So not solely does the CC fork provide you with improved efficiency; it additionally ensures the efficiency stays persistently excessive, even after the bike is ridden exhausting for a very long time. The opposite profit is that, whenever you change between the compression and rebound stroke, the damping reacts in a short time with the closed-cartridge system. Additionally, the brand new hydro-stop system within the fork offers it rather more management and bottoming resistance on the finish of the stroke.
Why has it taken KTM and Husky so lengthy to maneuver to a CC fork when, as you say, the demand for the improve has been so excessive?
Effectively, we nonetheless imagine within the open-cartridge system. And in reality, throughout the growth of the brand new XACT Closed-Cartridge fork, we additionally examined a number of variations of the XPLOR open-cartridge fork and had been in a position discover efficiency enhancements with it too. Which is nice, as a result of each manufacturers nonetheless use WP’s XPLOR fork on a number of of their different fashions. However this new XACT CC fork gives a better step up in efficiency once more. And, as I’m positive the product managers at KTM and Husqvarna could have defined to you, this new CC fork was particularly launched concurrently with the all-new body design idea so the 2 would work in concord with one another.
Now that the XACT CC fork is fitted to KTM’s and Husky’s enduro and cross-country ranges, solely the motocross fashions proceed to run the air-sprung fork. So, even from an economies of scale perspective, does that imply the MX bikes may also transfer to a model of WP’s coil-sprung CC fork sooner or later?
We are able to now produce the closed-cartridge spring fork effectively in massive numbers, so it might be doable for us to develop it for motocross. However that may rely completely on what these manufacturers’ product managers request from WP.
Exterior preload adjustment might be added to the CC fork by way of a WP Professional Parts half. This provides preload to the bottom valve’s stress spring, moderately than to the primary fork springs themselves – the good thing about which is that it permits the rider to regulate the chassis’ front-to-rear steadiness, with out affecting plushness over small bumps.
Other than WP growing forks and shock absorbers for the KTM group’s manufacturers, WP Professional Parts can be an vital a part of the enterprise. And I can think about that this new XACT CC fork goes to cannibalise the gross sales of WP’s XPLOR Professional 6500 Cartridge-Package fork bigtime.
For positive, it’ll. However there’s something else to come back from WP Professional Parts. Keep tuned.
Okay … are you able to say any extra about this? Are we speaking a few new aftermarket fork that’ll sit someplace between WP’s $2000 6500 Cartridge-Package fork and the $5000 XPLOR/XACT Professional (cone-valve) forks?
Maybe. Let’s simply say that, earlier than too lengthy, you will notice a full new vary of WP Professional Parts.
KTM’s all-new XPLOR PDS shock is 20mm shorter, but it surely retains the identical 103mm of shaft stroke. There’s additionally a brand new hydro-stop system to enhance bottoming resistance, a CFD-optimised asymmetrical primary piston, and hand-adjustable clickers all-round.
With all of the concentrate on the brand new CC fork, many appear to have neglected that the 2024 KTM enduro fashions additionally get a very new PDS shock!
Agreed. And that shouldn’t be neglected as a result of the shock additionally gives an enormous step up in efficiency. For his or her 2024 enduro fashions, KTM’s chassis growth group requested that we produce a shock that was shorter between its two mounting factors, however retained the identical stroke; the identical rear wheel journey. That was fairly a problem, however we made it occur. At 403mm, the brand new shock is about 20mm shorter, however the shaft’s stroke continues to be the identical 103mm. And this new PDS shock makes use of an analogous system to the fork to forestall bottoming out. What’s additionally fully new on the shock is the CFD-optimised primary piston, which gives a really plush preliminary trip after which has extra management via the stroke.
The shock piston’s new asymmetrical ports permit this, proper?
Precisely. This design directs the oil in a approach that opens just one aspect of the shims initially, earlier than the whole floor space of the shims progressively come into play. That is one thing we found throughout our CFD [Computational Fluid Dynamics – Ed] simulations, and the advantages had been confirmed by check riders within the discipline. We imagine this gives a major efficiency achieve.
What suggestions did you get after the media launch for the 2024 KTMs?
The media’s suggestions was very optimistic; saying the whole suspension package deal was noticeably firmer, but in addition labored significantly better than it beforehand did. We’re very completely satisfied about that as a result of it confirmed our perception that we’d made an enormous step ahead. Each the fork and shock have made enhancements within the consolation of their trip on small bumps, and but the damping management on the finish of the stroke can be significantly better. And that management all through the stroke is what offers the bike stability and security and predictable dealing with. I used to be additionally very happy to listen to that check riders had been dialling the fork’s compression clickers in each instructions – not simply including extra compression, which has been what’s occurred prior to now with the open-cartridge fork. That is encouraging as a result of it tells me that the suspension settings we’ve used for these 2024 fashions is way, a lot nearer to what riders need and it gives a wider vary of adjustment.
The brand new shock’s design improves serviceability too, proper?
It does. Not like prior to now, the eyelet’s bearing and seals on each the higher and decrease shock mounts are actually the identical. That’s a bonus for servicing and ordering elements. Plus it’s rather more handy that clickers on each fork and shock are actually all hand-adjustable.
With the brand new anti-squat chassis pushing the rear wheel more durable into the bottom throughout acceleration, what are the implications for the brand new XPLOR PDS shock’s spring and damping settings?
The transfer to the anti-squat chassis meant we not had to make use of overly agency settings to carry the shock up in its compression stroke; as a result of the body geometry did a lot of this for us. In different phrases, we not needed to compromise consolation within the rear-end, so this new chassis really made the shock set-up simpler for us.
In contrast with KTM’s 2023 EXC/EXC-F fashions, the 2024 enduro body is between 20 and 30% extra inflexible, relying on which axis you’re speaking about. WP’s new 48mm XACT CC fork was particularly launched concurrently with the all-new stiff body design idea so the 2 would work in concord with one another.
With the brand new stiff body idea used on each KTM’s and Husky’s 2024 enduro bikes, you would argue that the suspension settings are actually extra essential to make sure a compliant trip in off-road terrain.
Sure, a extra inflexible body does imply there’s a better emphasis on the suspension to create that ‘off-road compliance’ folks typically discuss. However keep in mind that the fork and shock settings are simply considered one of a number of ways in which a extra forgiving and compliant character has been constructed into these 2024 fashions. It’s additionally performed by way of adjustments to sure solid sections of the body, together with altering the flex traits of issues just like the triple clamps and engine mounts. The vital factor is that each one these design components work collectively to enhance one another, and I believe that’s what’s most spectacular about these new bikes.
I perceive that each KTM and Husqvarna have moved to particular fork and shock settings for varied 2024 enduro fashions. Are you able to inform us what every capability now will get?
Sure, they now use totally different springs and damping settings as a result of every of the totally different capacities has a unique weight, totally different front-to-rear weight bias, totally different engine braking traits, totally different rotating lots, etcetera. For each manufacturers’ forks in 2024, the 150cc two-strokes use 4.0N/mm springs; the 250/300cc two-strokes and 250cc four-strokes use 4.4N/mm springs. And the 350/450/500cc four-strokes all use 4.6N/mm fork springs. The spring charges and damping for the shock absorbers are additionally totally different for the 2024 fashions, and the spring charges will clearly differ between KTM’s no-linkage PDS and Husqvarna’s rising-rate linkage. For KTM’s PDF shock, a 63N/mm spring is used on the 150EXC; a 69N/mm spring is used on the 250/300EXC and 250EXC-F; and a 72N/mm spring is used on the 350/450/500EXC-F. For Husqvarna, a 39N/mm shock spring is used on the TE150; and a 45N/mm shock spring is used on the TE250/300 and FE250/350/450/501.
Thanks on your time, Sebastian. And for that tantalising perception into what’s within the pipeline for WP Professional Parts!
No downside, Andy. It’s really been nice to come back alongside to this KTM launch and communicate straight with impartial check riders from the media as a result of these 2024 bikes include a really totally different WP suspension package deal. And it’s been very gratifying for me that the suggestions has been so optimistic.