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Trek Fuels ABP Full Floater Design

Trek ABP

ABP Explained

Alrighty, class. Welcome to Suspension 101. In today's lesson, we're going to go over what ABP is, what it does for you, and how it works. Ready? Let's jump in.

ABP: What is it?
Pivotlocations The active brake pivot puts the rear suspension pivot concentric to the rear wheel axle, as opposed to Trek’s current design or the ‘Horst’ link where the pivot is located above (Trek) or Below (Horst) the rear axel.

What is the Benefit?
-The ABP keeps the suspension active and the rider in control while braking. Lock-up, or stiffening of the suspension under braking is virtually eliminated. Skidding is reduced; the tire stays in contact with the ground. Because the tire stays in contact with the ground, the brakes are more effective when they are used, and thus the time spent braking is reduced. Less braking also equals better handling and suspension by not loading the front fork.
Less time braking = more time going fast!
-Wide stance pivot bearings – same as the main pivot. Because the rear pivot bearings are spaced wider apart, the frame structure is torsionally stiffer.

How does it work?
The ABP allows the suspension to be active and independent of braking by separating the braking and drive-train components. The ABP allows the brake caliper to keep a near constant relationship to the brake rotor, so the caliper doesn’t rotate around the brake disk as the suspension moves through its range of travel.

What’s the science behind ABP?
Abp_explaination_revkb Think that claim sounds too much like unsubstantiated marketing speak? Here’s the real deal, in-depth explanation (in other words, most of us will now tune out, and simply go riding and experience a ride like never before…)
The ABP allows the brake caliper to keep a near constant relationship to the brake rotor, so the caliper doesn’t rotate around the brake disk as the suspension moves through its range of travel.
Huh?
Brake force occurs between the ground and the tire. There is a contact patch on the bottom of the tire that is in contact with the ground. All modern, current suspension designs move the rear axel in an arcing motion. So when the brakes are applied, the wheel has to move in an arcing motion because it is fixed to the swing-arm. What this means is that the ground and the tire don’t exactly move together.
If you look at the bike with the suspension fully extended (bike completely un-weighted), there is a contact patch the tire has with the ground at 6 o’clock on the tire. With the wheel (and the tire) fixed to the swing-arm because of the brake being applied, when the suspension tries to move in the arc we described earlier, that original contact patch the tire had with ground moves.
However, because of friction between the tire and the ground, this contact patch doesn’t want to move. The rider feels this as “suspension stiffening” under braking, or a skidding, skipping feeling as the suspension bounces over bumps.

All suspension designs experience this to varying degrees, and all suspension designs can be analyzed to measure and quantify the amount of “contact patch rotation.” The lower or smaller the amount of rotation, the more active the suspension will be under braking.
ABP has the lowest rotation factor – lower than single pivot, lower than VPP, lower than FSR.
However, because the movement of the wheel is still based on our proven R1 design, all this active suspension comes without unwanted suspension movement. The bike is still highly efficient, bob-free, and without the need for suspension lock-outs.

Small bumps, big bumps, braking bumps, fast bumps – full time smooth, active, efficient suspension.

Here's how the Fuel EX compares to some of its competition. The first comparison is at the mid-stroke of the suspension, or at 50% travel. This is the most important measure because it's a bit past sag, and where the suspension is most likely to be during braking, and especially braking during high speed bumps.

Comparison of Contact Patch Rotational Factors – Mid-Stoke of Suspension Compression

2008 Fuel EX  -  2.3 degrees
2007 Stumpjumper  -  3.1 degrees
2007 Blur LT  -  4.5 degrees
2007 Mojo  -  4.0 degrees

Remember again, the lower the rotational number, the more active the suspension under braking.

Comparison of Contact Patch Rotational Factors – Full Suspension Compression

2008 Fuel EX  -  6.0 degrees
2007 Stumpjumper  -  7.3 degrees
2007 Blur LT  -  6.3 degrees
2007 Mojo  -  9.3 degrees

ANSWER: It absolutely does just that more efficiently than a floating caliper mount. The most obvious way it's more efficient is that we don't have the extra weight of a separate floating mount. The floating mounts add about a half a pound of weight to a bike, not the mention the extra complexity of more parts, more bearings, and long brake rods that must be run through the frame.

When we started developing the ABP system, one of the bikes we tested it on was a Session 7. We already had a floating brake mount developed for this bike by Brake Therapy. Using the Session 7s as a test bed, we were able to directly compare the bike without any braking assistance, with the Therapy mount, and with ABP, giving a very "apples to apples" comparison. The ABP system was more efficient at keeping the suspension active under braking - and we showed this not only with the math and science behind ABP, but on the trail in real world testing conditions, on a bike we already had a lot of experience with.

Every good suspension system has to have a solid theory behind it based on math and physics. But it is ultimately the ride on the trail that matters above all else. This is where ABP really shines and proves the theory behind it. -DH

Full Floater

Full Floater Explained

Welocme again to Suspension 101. For this lesson, we're joined by Jose Gonzalez, as he can really explain how the Full Floater suspension really works, what its benefits are, and how it compares to the competition.

Full Floating Suspension - What is it?


Fullfloater_actionarrows2_k The Full Floater works in conjunction with the EVO Link and the shock to create a suspension ride with unparalleled tuning and performance. Instead of simply mounting one end of the shock to the rocker link and one end to the frame, the shock is held in a suspended state between the rocker link and a mounting point attached to the swing-arm. The shock “floats” on two suspended attachment points.

What is the Benefit?
The Full Floating suspension design allows the suspension system to be tuned more highly than ever before. The suspension system is tuned to work in harmony with the specific shock spring technology (air or coil) through-out the entire range of suspension motion.
What this creates is a suspension that is incredibly supple and active on small bumps, has excellent control through the mid-stroke, and has a gentle progression at the end of the stroke to handle big hits and drops.
However, this progression has been very painstakingly tuned to get the perfect balance of allowing full travel, without blowing through the travel too easily.
All this comes without compromising the legendary ride of R1 – that is, comfort and efficiency all without pedal feedback, bob or brake-induced suspension stiffening – and all without the need for lockouts or other suspension inhibitors.

The Full Floating Suspension is not just more travel – it is BETTER travel!

How does it work?

Full_floater_dualtuned The Full Floater allows the engineers and designers more control over the rates and tuning of the suspension than ever before. Because there are two moving mounts that can be controlled, the engineers can adjust the instantaneous ratios of the suspension system throughout its full travel range to do precisely what they want – keeping the suspension active over the small stuff, but with good control of the mid stroke, and precise end-stroke compression.

Want more info? The first graph shows the difference in the instantaneous leverage ratios of the 2007 Fuel EX (red curve) compared to the new 2008 Fuel EX (blue curve).

Fullfloatershockleveragegraph

What you see is the 2008 red curve offers a “flatter” rising rate with a slight “hook” (digression) at the end of its stroke. This allows the system to have supple and active suspension over small bumps while maintaining a controlled mid stroke feel. However, due to the flatter pitch of the curve, the mid stroke offers a very fluid, smooth and controlling effect that does not have that firming feel (too progressive) and allows for better use of the available travel without rear suspension “wallow”.  The slight hook at the end adds a digression (falling rate) to the system which allows the suspension to continue to compress after most of the energy has already been absorbed and dissipated, as well as to counter the progressive nature of the air spring found on the shock. This gives the sensation that the bike has more travel than it really does, offering a bottomless feel and a higher quality travel (better use of the travel instead of just adding lower quality travel).

Competitor Comparison

So how does this compare with the competition’s systems? The following graph shows the 2008 Fuel EX compared with some of the most notable suspension designs used by its competitors:

Ffshockleveragecomparegraph1 The Ibis Mojo with DW-Link and VPP bikes fall victim to their very small links – they simply cannot provide the control needed due to the dramatic swing amount and radius it covers during use. But they differ slightly in effect as follows:

Mojo with DW-Link – This curve has a pretty steep progressive rate initially that flattens out in mid stroke and quickly goes to a digressive rate for the last half of its travel. This curve makes it almost impossible to optimize the tuning of the shock as the first part of the curve requires that the shock have light spring force and damping but the second part of the stroke requires the opposite. If you set this system up to have decent small bump performance, it will blow through its travel, giving the bike a wallow feel and will bottom out easily. It is almost impossible to optimize the shock tuning to this curve due to its contradicting requirements and huge swing.

VPP – This curve has a steep, digressive rate for the first 1/3 of its travel and then goes to a steep progressive rate for the last 2/3 of its travel. Due to the nature of the design and the rear wheel path this system has, the digressive rate at the beginning of the stroke helps to mask the inherent lack of small bump performance this design has. It allows for a lot of suspension movement for a smaller bump. But that also creates a wallow effect. The steep progressive rate after mid stroke creates a very firm shock effect and does not complement an air spring curve (too much progression effect when combined). As with the Mojo with DW Link, it’s very difficult to tune a shock to this curve. On both the VPP and Mojo with DW-Link, these curves become more of an issue as travel is increased (meaning that it’s easier to get a 4” bike to function than a longer travel application). Keep in mind that the original multi-link designs, that these bikes are based on, were conceived when downhill bikes were using under 6” of travel!

The FSR bike, while it does have a pretty good curve, the overall ratio is much higher than the EX. This means that it will require higher shocks pressures, creating more stiction and producing higher forces on the system, and requires heavier compression damping effect to control rider input (chassis stability). This is why Specialized bikes require some platform, inertia or lockout feature for efficiency and pedaling. The higher initial pressure needed also means the spring curve of the air shock itself will ramp up much more, which combined with progressive rate of the system, gives it a firmer overall feel and does not offer as fluid of a suspension feel or use.

All the while, the R1i design allows the weight of the frame to be kept and low and centered, with easy rider access to all shock adjusters and air valves.
By centralizing the weight over the BB (referred to as Mass Centralization-as important as Center of Gravity), the Center of Gravity is brought to the middle of the bike, under the rider, where the rider feels it much less when throwing the bike around (in line with his own weight and point of moment). Although lowering the weight helps, just lowering weight doesn’t do as much.

By keeping the shock low and centered, we’re also able to keep it in front of the seat tube. This keeps the shock and all its seals and bushings well protected from mud, rocks and other debris that gets thrown off the rear tire. And giving the rider easy access to the adjustment knobs and air valves – well, that’s pretty self-explanatory.

This design further allows room for a water bottle, and a full seat tube, allowing the rider a large range of seat height adjustment depending on the terrain and rider preference. Seat tube adjustment and protection of the shock are major benefits over other designs that don’t provide for this