Technical Features
Virtual Pivot Kinematics
The more suspension travel is offered by a fully, the bigger is the developers’ challenge to balance the sensitivity and neutrality of the chassis successfully. MERIDA has a very own answer to this complex question: „Virtual Pivot Kinematics“ (VPK).
During recent years, the full-suspension MTB sector has seen a lot of technological changes: The continuous reduction of frame and component weight has extremely minimized the total bike weight especially beyond the 120 mm category. So it’s not really surprising that 140 mm or 150 mm fullies effortlessly become partners for Alpine crossings or that even 160 mm enduros show a more than acceptable climbing performance. Great! Because fullies offer not only more comfort than hardtails, but also a huge performance plus – thanks to the fact that both wheels have nearly constant ground contact and that the handling can be controlled with perceptibly more precision. But the fact that also more and more “long-travel” fullies get constantly lighter and are therefore “pedalled” (moved by the pilot’s “kicks”) by a growing number of riders means that the creation of such bikes becomes even more challenging for R&D experts. Only some years ago, e. g. most 160 mm enduros still were carried uphill by funicular or car to perform their brutal “downhill dive” afterwards. In contrast, today’s enduro fans can get chassis systems which still offer top sensitivity for such challenging downhill runs – but also greatest possible neutrality during braking and pedalling uphill. The MERIDA R&D team has an ideal solution for this obvious antagonism: “Virtual Pivot Kinematics” (VPK).
“With VPK, we have developed a rearstay concept which meets all needs in the suspension travel sector of 140 or more millimetres.” Thomas Pfrommer, Bike Product Manager
18 Technical Features
The engineers’ respective trick might be simple in principle, but its successful transformation into a perfectly working system means the exact opposite: The rear stays of singlepivot respectively supported single-pivot systems feature a fixed pivot point which defines the wheel path. In contrast, developers of multi-pivot chassis systems with virtual pivot point have more freedom to be creative and to influence the individual characteristics of the chassis. “Anything which is necessary to ensure best possible functionality for a fully beyond 120 mm can be realized optimally by VPK,” MERIDA engineer Thomas Pfrommer explains. First of all, the virtual pivot point stands for premium downhill competence – because a sensitively working VPK chassis utilizes every single millimetre of the rear stay. Nevertheless, VPK performs without bobbing; even on the smallest chain ring, the system remains drivetrain-neutral (especially when the rider sits in the saddle) – exactly this is a theoretic weakness of virtual pivot points. MERIDA was also able to eliminate most of the notorious pedal kickback which is caused by rearward chain pull at the chain ring during strut compression. So there remains just the question about the undesirable chassis rigidity under brake load. Thomas Pfrommer: “Not existing, task completed.” Good to know.
Virtual Pivot Point Main frame and rear stay of all full-suspension bikes are connected via several pivots whose number depends on the respective concept. The shock unit mounted between the two elements defines the “final feeling” of the concept. Also dependent on the selected concept are the position of the rear stay’s pivot point and the respective rear wheel path (rear wheel movement during strut compression). In case of fullies with virtual pivot point, the latter can be configured more or less freely and individually via specific pivot positioning. Compared with other systems such as single-pivot constructions (which can nevertheless be highly advantageous for certain purposes), this outstanding concept allows for a more intense modification of the bike’s character. VPK: Application range Virtual pivot points especially make sense for bikes with 140 mm or bigger suspension travel: In this category, the typical downhill qualities of the sophisticated concept come more and more to the fore. That’s why MERIDA equips all ONE-FORTY, ONE-SIXTY and FREDDY 1-80 bikes of MY 2013 with “Virtual Pivot Kinematics“ (VPK) now. VPK: Advantages Besides its mighty “absorption potential”, VPK is especially not affected by brake influences. Dependent on construction, fully chassis systems can become rigid completely as soon as the rear brake is operated – particularly during tough downhills a disadvantage which is also relevant in terms of pilot safety. But VPK is different: The chassis remains active even under maximum retardation. Also with regard to the drivetrain, VPK fullies perform in a pleasantly neutral way: Pedal kickback and bobbing tendencies are reduced to an absolute minimum.