2021 Merida Reacto IV revealed: a fourth-generation aero bike

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Between the Olympics and the Tour de France, 2020 was always going to be a big year for new bike releases. And while things haven’t gone to plan, that hasn’t stopped a swarm of new bikes hitting the market. On the road, the common themes are disc-only aero bikes becoming lighter and more well-rounded, and disc-only well-rounded race bikes becoming more aero. Merida’s new fourth-generation Reacto sits firmly in the former camp.

We’re yet to throw a leg over the 2021 Reacto but here’s what we know of this new ride so far.

Still an aero bike

Merida’s Reacto aero bike has long offered a healthy balance of aerodynamics, stiffness and seated comfort. And in many ways, Merida was one of the first to produce an aero bike that was comfortable for all-day use. The new 2021 Reacto IV aims to retain that comfort while dropping weight, increasing frame stiffness, and cheating the wind just a little more than the Reacto III.

Imagine a brand releasing a new aero bike in 2020 with an exposed cable. Thankfully no such controversy exists here.

The Reacto IV is clearly still an aero road bike with truncated airfoil profiles throughout, and it’s intended to sit alongside the lightweight Scultura in Merida’s lineup. Merida admits to having made some aero compromises in order to achieve more all-round benefits from the Reacto, but according to the company, those aero losses have been more than offset elsewhere.

Up front, the most obvious improvement is a move to entirely hidden and internally routed cables. And where much of the competition has achieved this feat through proprietary systems, Merida has simply adopted FSA’s ACR system, something already used by the likes of Bianchi and De Rosa. This system includes an assortment of FSA/Vision handlebars and stems designed to fit with a specific headset and compression plug which are all designed to keep the cables (including mechanical shift cables) concealed from the levers through to the frame.

FSA’s ACR system sees the front brake hose run through the special steerer compression plug, while all other cables are routed in front of the steerer tube. The design requires a deeper-shaped head tube (one of the claimed aerodynamic losses) to provide room for the cables, but in turn allows the use of a regular round steerer tube. Like similar designs, it offers split headset spacers for easy stack adjustment, too. However, changing stem lengths or headset bearings will be tricky with the cables running through both.

Further gains are seen with a new fork design that now more smoothly integrates with the frame. Merida has also widened the space at both the seat stays and fork crown for better airflow between the wheels. And like so many others, those seat stays have been dropped further, too.

Merida’s disc cooler fins (similar in concept to Shimano’s finned brake pads and rotors) receive a tweak on this new bike.

Smaller improvements include Merida’s disc cooler fins moving from the side of the fork blade to behind it, which now also somewhat mimics an aero covering, too. The cooling fins at the chain stay also share a similar design to the front, while the bolt-on thru-axles are now countersunk into the respective dropouts. Worthy of note: the Reacto no longer uses Focus’ R.A.T keyed thru-axle design and instead has moved to a simpler threaded system.

All told, Merida is claiming the new Reacto saves one watt of power at 45 km/h when compared to the previous version (210 versus 209 watts), and remains one of the very best in the wind tunnel according to German-based Tour Magazin’s testing protocol. Or in other words, it’s competitively fast.


Merida will offer the new Reacto in two tiers of carbon frame: the premium CF5 and the mid-priced CF3. Merida claims that aerodynamics, ride comfort, and stiffness are unchanged between the two, with the key difference being seen on the scales. The new CF5-level frame is quoted to weigh 965 g for a painted medium frame, with the matching fork at a not-so-light 457 g. The cheaper CF3 frame is quoted at 1,145 g while the fork sits at 490 g. These figures are certainly not class-leading, but it’s worth noting that Merida often prices its bikes substantially lower than the likes of Specialized and Trek (more on this below).

Another difference between the CF5 and CF3 frames is that the former is intended for use with electronic drivetrains only, while the latter accepts everything. This difference likely has more to do with the selected cockpit than it does the frame.

No changes to the geometry.

There are no changes to the geometry of the new Reacto, numbers that provide quick handling and an aggressive reach. However Merida has shuffled the labelling of its sizes around. The middle-ground S/M and M/L sizing labels are now S and M respectively, while a new XXS size has been added, too.

Merida is still equipping its new Reacto bikes with 25 mm wide tyres (which is still what most of the WorldTour races on), however, the new frame does offer room for 30 mm rubber. And as always, those published figures typically provide some breathing room.

The seat binder wedge is now sleeker.

According to the Taiwanese mega-manufacturer, further aerodynamic gains could have been made by elongating the seat tube and seat post but comfort won over. The new Reacto sticks to the same S-Flex seatpost design as the previous version, albeit with a modified and cleaner-looking frame wedge. It’s a design that I’ve personally found to do an admirable job of smoothing the ride.

The S-Flex seatpost retains the switchable head design for a huge adjustment range to the saddle fore-aft position. It’s a design that’s shared with Merida’s Warp TT bikes and, perhaps showing the Reacto’s worth as either a road or triathlon racing bike, it allows the saddle to be used in an extremely forward non-UCI-compliant position.

Other details include an integrated rear light (with no further details provided), the use of a direct mount derailleur hanger on all Shimano bike models, and a PF86 bottom bracket shell (previously BB386EVO). That last element is our preferred choice amongst the sea of press-fit options, and is what Giant and Scott use too.

Prices and specs

Merida’s model naming can be somewhat confusing and the exact transition from bikes with the CF5 frame to the CF3 version is a little murky. At least for Australia, the Reacto Team-E frameset and 8000-E bike feature the lighter frame, while the other models use the CF3. Models using the CF5 frame are equipped with the Vision Metreon 5D ACR one-piece cockpit.

Specific models will vary from country to country, however below we have the known models for the UK and Australia. As with all Merida Bikes, they’re simply not available in the United States.

  • Merida Reacto 4000: £2,250 / AU$3,499 (Shimano 105 mechanical with Merida Expert wheels)
  • Merida Reacto 6000: £2,800 / AU$4,199 (Shimano Ultegra mechanical with Fulcrum Racing 800 wheels)
  • Merida Reacto 7000-E: £3,600 / AU$5,499 (Shimano Ultegra Di2 with DT Swiss P1800 Spline wheels)
  • Merida Reacto Force: £4,400 / AU$6,499 (SRAM Force eTap AXS with Reynolds AR 58 wheels)
  • Merida Reacto 8000: £5,500 / AU$NA (spec TBC)
  • Merida Reacto 8000-E: £NA / AU$7,799 (Shimano Ultegra Di2 with Reynolds AR 58 wheels)
  • Merida Reacto Team frameset: £NA / AU$3,999


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