The PVP Design
Searching for the ultimate MTB rig is an endless pursuit, especially for those XC Cross Country purists and racers. However, speed , efficiency, and lightness always seem to be on the opposite poles of control, comfort, rigidity and weight: when you gain a little more here, you lose a little more there. The "Dream Bike" that provides the comfort and control of a suspension bike but retains the speed and pedaling efficiency of a hardtail has eluded this Holy Grail since the Mountain Bike was born.

The industry has tried many approaches to achieve this goal. Here are some major milestones:

1. Shock Lockout: This is the simplest way to turn a FS into a hardtail, but also the most stupid method. When the shock is locked out, the suspension bike immediately becomes a portly hardtail that flexes too much, still carries the weight penalty, and is prone to damaging the critical parts of the suspension system. When locked out, you get the worst of both worlds. Unless you are riding on flat asphalt, shock lockout shall be the last idea to ride your bike.


2. Suspension Lockout:
Next, GIANT rolled out NRS. They called it as "No Resonance System". NRS's virtual pivot is placed both far and high, so every pedaling force induces a measurable force that virtually locks out the rear linkages. Joined by GIANT's intentional "NO SAG" shock setting, the NRS is virtually a bike that can lockout itself under pedaling, but still active to bumps when not pedaling. It sounds fantastic in the beginning: a bike that behaves like a hardtail when pedaling, and a FS when not pedaling. However, when you really think about it, this philosophy
GIANT NRS

is FUNDAMENTALLY FLAWED!! We need the comfort and control from a FS not only when we are not pedaling ; we also need the suspension's benefits when pedaling. It is a BAD compromise to sacrifice half the comfort and control of a FS like this. In addition, with NRS, your pedaling force locks out the rear linkages, which results in your legs always "fighting" against the bumps from the ground. The semi-active NRS can NEVER provide the quality comfort, traction and control of a premium FS. The NRS also suffers a lot on brake induced jacking ; the rear suspension is dramatically pulled down from the braking forces. The NO SAG air adjusted setting is sick ; the suspension will "knock & punch" the rider's back mercilessly every time when it encounters a bump before it hits the "threshold". Then it compresses, and rebounds to its place giving a gittery suspension feel that is only a slight improvement over a hard-tail. Admittedly the NRS is one of the most saleable bikes on the market, but it is also one of the most over- hyped bikes in history. The success of NRS just shows the MTB rider's desire for speed. It's recent demise in the face of better alternatives proves the NRS is definitely not the true, right and healthy approach to the dream.


3. Intelligent Lockout: Next, SPECIALIZED introduced their BRAIN system, and FOX introduced their TERRALOGIC fork. The BRAIN system is more of an intelligent lockout design added to
SPECIALIZED's highly regarded FSR (Horst Link) system. The FSR system has been famous for its high pedaling efficiency and neutral & independent suspension behavior. The BRAIN system uses an inertia valve to determine when the bike encounters bumps from the ground. When the terrain is flat and smooth, the BRAIN lockouts the suspension automatically ; when the ground is bumpy, it activates the oil circuitry of the shock and lets the suspension fluidly absorb the bumps. This idea sounds good, but the bike still suffers the same problems of a locked out suspension bike, and the same problems of an active suspension when it is not locked out. The BRAIN is no more than a smart genie who helps you switch the lockout lever on and off, but the system still suffers between the "locked out" and
GIANT NRS
"un-locked" modes. Besides, the weight center of BRAIN bikes usually lean a bit backward, which is unattractive to racers and purists; let alone the little weight penalty.

4. Pedaling Platform Technology: Progressive's 5th Element was the first in the industry to roll out the "Pedaling Platform Technology", then MANTIOU's SPV made it a big homerun hit in the market. The pedaling platform technology did radically change the MTB world by effectively eliminating the minor bobbing induced by pedaling, but the suspension is fully active and free traveling when the rear wheel encounters an adequate bump.
In addition, The "Pedaling Platform's implementation is pure and simple. It's like a normal shock but aided by invisible magic. The technology (or concept ; as some other makers achieved the same goal with some alternative methods) instantly excited the MTB world. The magic of pedaling platform technology transformed a poor bike to a good bike, and a good bike to a better bike.However, good and effective the platform figs
pedaling platform technology is, it still sacrifices some degree of the smoothness and plushness compared to conventional suspensions due to the "THRESHOLD ZONE".MTB riders still have to be very cautious about their pedaling manner ¡V when the pedaling force is too big or rude, the platform will still interpret it as a ground bump and activate the shock. In other words, the Pedaling Platform technology is more of a remedy and not a radical solution to the Ultimate Dream.

¡´ So, until now, the problem is somewhat remedied but still not radically resolved in all the facets listed above. We are still looking for a better solution, so that we can enjoy these ultimate suspension charateristics:

1. No need for a lockout, be it manually or automatically.

2. Pedal with the same efficiency and direct power transfer as on a hardtail.

3. Embody the true and premium suspension quality of a great conventional suspension bike.

Are these ideals too lofty and unrealistic?

Here comes the VPP. A groundbreaking idea, first quietly introduced by OUTLAND more than a decade ago but wildly promoted with great fanfare by SANTA CRUZ and INTENSE in recent years. This came close to attaining the Holy Grail more closely than all other previous attempts.
The so-called "VPP" (Virtual Pivot Point) design uses a pair of counter-rotating links, which results in a very dedicated ¡¥S'-shape rear wheel path to achieve an all-new riding experience that was never experienced before. The rear wheel is set at its "nearest" position to the bike when the suspension is "sagged-in". When the rear wheel is not at this place; upper or lower, compressed or extended, then there will be torque from the chain to pull the rear wheel back to this place. The further the rear wheel is away from this "sweet spot", the bigger the chain torque will become to
VPP
pull back the wheel. In other words, there is an intelligent chain-torque on the VPP system that is automatically generated to adequately counter the force from the rider's input, which normally induces the bobbing effect. That means MTB riders can finally ride on a truly active FS without a lockout device or pedaling platform technology, yet gains better pedaling efficiency than with these previous two designs.More important is that the rider can finally pedal the "active suspension bike" as freely and efficiently as on a hardtail, without the fear of the bike bobbing or diving in return. The VPP system counters the improper force from the rider's pedaling automatically, intelligently, quietly and beautifully but still lets the suspension to be open and active to any kind of rough terrain. FINALLY, high-pedaling efficiency and premium suspension qualities can live together harmoniously.

So, is the VPP the ultimate solution that fulfilled our long-awaited dream? HELL NO! Well, at least the designers at XTENSION don't fully agree. The VPP's tendency to effect the chain length during active suspension travel results in pull-back forces on the pedal that is annoying to experienced riders when the suspension is working. The brake still induces noticeable brake jacking on the VPP suspension, and the overall stiffness of the rear suspension is still not really satisfactory.

Inspired by the positive traits of the VPP system, XTENSION has rolled out our own solution: the PVP system. PVP means "Parabolic Virtual Pivot". That means the virtual pivot is like a rising ball when the suspension runs into its travel. Unlike VPP's use of chain torque to counter the rider's uneven pedaling input, XTENSION's PVP uses the virtual pivot location to counter the rider's pedaling forces. The more forceful the rider's input is, the higher the virtual pivot adjusts to offer a counter force to cancel the bobbing effect. At the same time, our PVP system still maintains a very vertical rear-wheel path, which provides a very neutral and independent suspension characteristic similar to the time proven FSR/Horst-Link bike. The pedal and the suspension do not interfere with each other. The rider feels quite neutral and there is no kick back from the pedals regardless of how the rear suspension is
working. The VPP 's strong "pull-back" feel from the pedals is eliminated. Furthermore, there is no noticeable suspension movement under hard braking. Our Xtension engineered linkages deliver a more stable and controlled characteristic than the VPP can offer. The PVP looks similar to the VPP but in reality they perform very differently. Both systems allow the rider to pedal freely and even harshly as on a hardtail, but our PVP system eliminates the major flaws of the VPP suspension design, while retaining and even improving all the great characteristics.
VPP
The pedaling efficiency of the Hardtail along with the comfort, control, and traction of rear suspension has finally been achieved with , XTENSION's PVP.

The Holy Grail of the Mountain Biking world is now a reality.

The Gold Standard has been set.

Come Xperience Xtension's PVP.