The suspension is a key element in any mountain bike, providing greater comfort and control on uneven terrain. Although it is mainly associated with MTB, its use has also started to extend to other disciplines such as gravel, and even in some road bicycles designed for long distances and uneven surfaces.
In recent years, the cycling industry has developed advanced suspension systems that significantly improve the experience on the bike. These technological innovations not only increase impact absorption, but also optimize pedaling efficiency, allowing for better performance on any type of terrain.
Suspension manufacturers are constantly working to offer more customizable, intuitive, and efficient systems, with revolutionary technologies that have changed the way cyclists tackle trails and roads. Notable examples include the Brain system from Specialized, the famous Lefty forks from Cannondale and the electronic suspensions from leading brands like Fox and RockShox.
Below, we review the main suspension technologies for mountain and road bicycles, designed to take comfort and control to the next level.
Specialized Brain
It is one of the most successful technologies from the Californian brand. It arrived in 2001 with the first Specialized Epic and the collaboration of Fox, and since then it has never left the model or the brand. In more than 20 years of history, it has evolved into a practical and comfortable lockout technology that does without the handlebar lever function. The Brain uses an inertia valve in the hydraulic circuit of the suspension. This valve blocks the oil flow by default (when pedaling on flat ground, climbing, etc). But when it receives an impact from below (rocks, bumps), it moves, allowing the fluid to pass and the shock absorber (or front suspension fork) to compress. Currently, Fox has been replaced by RockShox for its development. Its size has been considerably reduced and its integration into the rear axle and inside the fork has improved. Likewise, its adjustment options have increased, offering up to 5 positions.
📺 Surely this video will interest you: learn about the Brain technology from the Specialized brand itself.
Cannondale Lefty
Let's now talk about another great suspension innovation launched at the beginning of the century and which has reached our days. The single-arm Lefty fork from Cannondale continues to attract attention when mounted on an F-si or a Scalpel. This technology dispenses with one of the stanchions and legs, reinforcing the remaining one with needle bearings, a double crown, and inverting the suspension stanchion to gain rigidity and stability. In this way, controlled and effective absorption is achieved. Currently, the Lefty has adopted the surname 8 and has become a more conventional MTB XC suspension fork, maintaining its essence: the single-arm structure. Now it is much lighter (almost equal in weight to the RockShox SID or Fox 32 competition forks) and dispenses with the double crown superior to become compatible with other MTB frames, beyond the Cannondale brand.
Scott TwinLoc
Scott TwinLoc is a suspension lockout technology that allows, at the same time, to change the suspension travel and the bike's geometry simply by operating a remote lever. From this lockout remote, with two or three levers, the rider can switch between up to three positions (descent, traction control, and lockout), also changing the inclination of the seat tube angles or the bottom bracket height from the ground. To do this, it uses a total connection between the control lever, the fork, and the shock absorber. By pressing the levers for the open or descent position, one of the two air chambers of the suspension is closed. In this way, the travel is reduced (from 120 to 80 mm in the case of the current Spark). It can also be fully locked in the lockout option. Everything is done simultaneously, in addition to moving the linkage to slightly modify the seat tube angle and adapt the biker's position to the terrain.
📺 Do you want to know more about the TwinLoc system from Scott?
We can find the TwinLoc system on MTB models such as the Scott Spark, Genius, Ransom, or the electric Scott Genius eRide or Patron eRide.
Trek IsoStrut
It arrived with the Trek Supercaliber in 2019. The competition MTB that, thanks to this technology, preserves its structure and behavior of a hardtail bike with the absorption of a full-suspension. For this, it uses a semi-integrated shock absorber in an extension of the seat stays towards the superior tube. A mini shock absorber manufactured in collaboration with Fox, offering 50 mm of travel. It is complemented by the flex of the structure that houses it to provide an extra 10 mm.
📺 Watch this video to get to know the IsoStrut system better.
With this system, up to 700 grams are saved compared to the brand's classic short-travel double, the Top Fuel. In addition, the design of wide and flat seatstays on this Supercaliber allows the frame to flex vertically in this area, together with the shock absorber, to absorb terrain irregularities and achieve a better and more comfortable bike response on technical sections. Besides the Trek Supercaliber, this system has also been extended to its electric variant called Trek E-Caliber.
RockShox Flight Attendant
There have been several attempts by RockShox in recent years to move towards autonomous suspensions; that is, controlled electronically and not manually, with levers or dials. And it seems that since 2021, they have succeeded with their Flight Attendant. This is a system that uses SRAM's AXS technology (SRAM is RockShox's parent company) to implement it in suspension control and adjustment. Thus, the new electronic suspension does away with cables for adjustments, requiring the purchase of electronic versions (with integrated control modules) of forks and shocks, which will be connected (via wireless) to a sensor installed on the bottom bracket axle.
The Flight Attendant takes advantage of SRAM AXS wireless technology to eliminate cables.
Thus, the suspension will stiffen or open depending on the terrain conditions, which will be detected and interpreted by the bottom bracket axle sensor. But also, from the modules on the suspensions themselves, you can choose from several operating modes to customize them to the rider's preference: Auto, Normal (manual), or Override (quick change). For now, this technology is only available on long-travel RockShox suspensions, mainly for Trail or Enduro.
Fox Live Valve
Fox has developed a similar system for its suspensions: the new generation Live Valve. However, this system still relies on cable connections to give both the fork and shock an autonomous and intelligent operation. 
This means that the cyclist does not have to manually lock or open the suspension when needed. Thanks to a special valve integrated in each suspension and a sensor, the bike is able to read the type of terrain it is riding on. In a matter of milliseconds, the sensor sends the information to a central controller installed on the frame's down tube. Right after, it issues the order to open or close the hydraulic cartridge to activate or lock the suspension as needed.
The Fox Live Valve can only be found on certain bikes prepared for its installation.
The entire system operates powered by a rechargeable lithium battery, installed inside the controller, with an estimated autonomy of between 16 and 20 hours. However, the main barrier to its large-scale popularization comes from its high price, around 2,000 euros, and its availability only in certain factory builds and for specific prepared bikes. Currently, Giant and Liv are partnered with Fox and offer models such as the Trance X, Reign, or Anthem Advanced with Live Valve as standard.
SR Suntour Electronic Suspension
We wrap up the chapter on electronic suspensions with the system from a legendary brand like SR Suntour, still in the prototype phase. From what little has been seen in photos on the bike of the current Olympic MTB champion, the Briton Tom Pidcock, it appears to be a system similar to the Fox Live Valve, although in this one no motion sensors are apparent on the fork and shock; all the work seems to be done autonomously, or with integrated sensors. We'll have to stay tuned: Will it finally reach the market? Will it remain limited to competition use?
📺 Don’t miss this video to learn more about the technology developed by SR Suntour.
Integrated Suspensions: Scott-Bold and Cannondale
The technology and design of today’s bikes are moving towards the integration of components. Cables, bolts, and other parts of the b have only been developed for competition.ici blend into the frame to reduce weight, gain aerodynamics, or improve aesthetics. The shock absorbers, rather heavy and bulky components, have already managed to be integrated inside the frame thanks to technologies developed by Scott or Cannondale. In the first case, it was actually the Swiss brand Bold that was the first to present mountain bikes with integrated shocks, back in 2015. An innovation that caught the attention of a giant like Scott, who purchased and shared part of the patent with this brand. In this way, Scott also integrated the shock of its Spark (or the new e-bike Patron) inside the seat tube or the down tube.
Bold was the first brand to mass-produce mountain bikes with a shock inside the frame, back in 2015
Cannondale is another brand that has recently tried integrating the shock to improve suspension performance and aesthetics. The result: the launch of their new Enduro bike, the Jekyll. Unlike the Bold-Scott solution, Cannondale leaves the shock partially visible and more accessible to facilitate adjustments. But it is still a component installed inside the frame structure (inside the down tube). In addition, this new location brings proven improvements in the suspension’s kinematics and distributes its weight to improve the bike’s stability.
Other technologies: micro-suspensions and elastomers
The integration of suspension into the bike itself is not something new. Already in the nineties, numerous systems were tested that merged the frame and suspension, with some degree of success in certain cases. The HeadShock steering damper from Cannondale, the predecessor to the Lefty, is one of them. Likewise, the popularization of 29'' wheels with increasingly lighter and stiffer carbon frames brought with it the introduction of elastomers or more flexible materials in key areas of the bike to provide a certain amount of absorption. This is the case of the SAT system from Lapierre or the MTT micro-suspension on the rigid MTBs from BMC, which has been revived today by their new Gravel URS LT bike.
Micro-suspensions, originally found in rigid MTBs, are making a comeback today in models from Gravel and long-distance Road bikes.
They are much lighter systems than a conventional shock or fork. In addition, they allow flexing and absorbing small bumps and vibrations for greater comfort, without an excessive increase in weight. Another successful system in recent years has been the Trek IsoSpeed. A small bushing that connects the top tube and the seat tube, and that has autonomy to provide some flex in the area. It is featured on the current Trek Domane road bike, both under the seat and in the head tube, or the Trek Pro Caliber MTB. 
There are other successful road bikes with micro-suspensions, such as the Specialized Roubaix with the Future Shock steering damper, which is also found on the Specialized Diverge from gravel. Or the Cannondale Topstone Carbon from gravel, with the Kingpin system with flexible seat stays and a pivot point at the junction of the seat stays with the front triangle.