Wind tunnel tested: The UCI-illegal Merida Reacto One was designed to beat the wind tunnel tests – it failed, but that's only half the story

The Merida Reacto One is a bike that confuses me. It sort of proves you can't always judge a book by its cover. But then again, it sort of proves you can.

Let me explain.

With its narrow handlebars, one-by (Classified-equipped) groupset, deep wheels and aero tubes, it looks as if it was designed to 'win' the wind tunnel tests performed by ourselves and other media.

It should have been a prime candidate for the top spot in our aero bike wind tunnel testing, but it fell remarkably short of the current leaders, Factor's One and Cervélo's S5, landing a disappointing result; the details of which are below.

It was better than the older Reacto we tested in 2025, but despite being a full-house bingo card of go-faster tricks that make it UCI-illegal and are undoubtedly an unfair advantage compared to other bikes, it barely scraped the top 10.

But then when I climbed aboard it and rode it in earnest, I liked almost everything about it. The position was great, the handling was superb, it was plenty responsive under power, and it was decently comfortable.

The bike explained

The Merida Reacto One is the black sheep in the wider Reacto range. All of the other Reacto Models are 'normal' in that they come with two-by groupsets from Shimano or SRAM, and handlebars that are UCI-legal in their width.

The One – not to be confused with the Factor One (or even the Trek Mad(One)) – is a showcase of what the product team can create when they're let a little loose.

The Taiwanese brand partnered with some revered European brands to kit the bike out with the set menu from the aero playbook. DT Swiss supplied its ARC 1100 Dicut 65mm deep wheels, Continental supplied the Aero 111 front tyre, and Classified chipped in its Powershift rear-hub gear system, which in turn meant Rotor could supply a 1x aero chainring alongside its InSpider power meter chainset.

Perhaps most pertinent of all, though, is that Vision supplied a super-narrow, special edition Merida Team CW 1P cockpit that measured a grand total of just 22.5cm between the Shimano Dura-Ace hoods. And no, I've not got the hoods set up tilted inwards like a 2022 WorldTour pro.

It's an off-the-shelf version of what I think I'd build for the type of crit racing that suits me best – flat, fast and tightly packed, rather than hilly or too punchy. Deep wheels, one-by groupset, big chainring, small cassette, narrow bars and aero frame. The Classified groupset is a nice touch, and one that means you get the aerodynamics of one-by without compromising on gear range or steps, meaning you can actually live with it and ride it at the weekend without messing about with swapping wheels or cassettes around. I like it. It's well thought out.

Notably, and this perhaps goes some way to explain why it didn't storm to victory in our wind tunnel test, that narrow cockpit is mainly achieved through a massive flare from the tops to the drops, as the outside-to-outside measurement down there is actually 42cm.

When we test in the wind tunnel, we do so with our hands in the drops, meaning the narrow bars didn't really have an opportunity to shine. If I'd performed the same test in more of an aero position with hands on the hoods, horizontal forearms and elbows bent to 90°, the narrowness would have probably made a difference.

It would have also been less comparable to other bikes and thus, less of a fair test.

Also, I can't hold that position for more than a few minutes at a time, and I'm going to bet that not many others can either. On the flip side, it only takes a few minutes at a time to make the difference in a race sometimes, so you can spin it that way if you prefer.

Elsewhere, the bike promises 32mm tyre clearance front and rear. The 29mm Aero 111 tyre up front measured at exactly 29mm on the DT Swiss wheels, and the clearance measured amply at 12mm either side, so you could easily go wider if you wanted.

At the rear, the 30mm GP5000 S TR tyre measured at 31mm, with 6mm of room to spare on either side according to our calipers, so you could probably get away with a little more than claimed, but not much. Perhaps 34mm if you're in need of cobble-smoothing comfort.

And while I'm on the subject of measuring, the Reacto One tipped our scales at a not-bad-but-not-excellent 7.73kg (weighed without pedals, computer mount, or bottle cages).

Wind tunnel performance

Okay, I've dallied long enough. Time to get stuck into the stuff you're really here for.

As with all our wind tunnel tests, we took the Reacto to the Silverstone Sports Engineering Hub, tested it back-to-back against our baseline bike (as well as a handful of other competitors on the same day), to measure how aerodynamic it is. Using its comparison against that baseline bike, which remains unchanged between tests, we can also measure it against bikes we've tested in years gone by.

We test every bike in three separate setups: the bike on its own first, then the bike with a rider, then finally we swap in a 'control' wheelset to isolate the differences found in the frame/fork and cockpit.

We test each of these setups across seven distinct wind angles – -15°, -10°, -5°, 0°, 5°, 10°, and 15° – for a total of 21 different measurements.

And we test at a wind speed of 40km/h, for either 15 or 30 seconds per measurement, depending on whether it's with or without a rider.

Everything that can be controlled remains unchanged between tests, including the tyres, the bottles, the clothing and so on, and we do our best to ensure the bike setup and rider position are the same across all tests, no matter what bike is being tested.

Starting with the raw measurements for the two tests without a rider. This doesn't tell us too much, aside from that the DT Swiss Wheels tested slightly faster than our Enve SES 4.5 control wheels, especially at higher yaw angles. Hardly a surprise given the depth difference.

From here, as we do with all our tests, I've run some calculations and applied weightings to land on an average that's relevant to real world conditions. From here, we can then see how many watts the Reacto One saves against our baseline.

As suggested at the top of this review, I'm pretty disappointed to see it down in 11th place. Don't get me wrong, that's still a reasonable result and one that puts aero bikes like the Giant Propel, Canyon Aeroad and X-Lab AD9 to shame, not to mention its own predecessor, but I was expecting more for a bike that pulled out all the aero tricks.

The Reacto One is exactly four watts behind the Factor One, and very much on par with the new Enve Melee v2, which is much more of an all-rounder in its design.

Next up, things don't really get any better when we swap in our control wheels…

We only introduced the control wheel test in 2025, so some of the older bikes are missing, but the Reacto is still mid-table, approximately five watts behind the Factor One. The Cannondale SuperSix even climbs ahead, which is another all-rounder.

We're splitting hairs, of course; it's still 35 watts better than our baseline bike, but I can't help but feel disappointed with its result.

Next up, let's check what happens when we chuck a rider on the bike.

At first glance, things start to look a little rosier here. At certain wind angles, the Merida is actually faster than the Factor One, which remains our benchmark (even though the Cervelo S5 snuck ahead by a fraction once the weightings had been applied).

But this only really happens at the wider yaw angles, which we know aren't seen anywhere near as commonly in the real world. Therefore, when we get to the averaged result, the rankings are as follows.

The big caveat to this data is that our error margin is bigger than many of the differences between the bikes, so the Reacto could lay claim to a victory, but it could also be right near the bottom of the table.

But taking the results as they come, the Reacto One is once again around five watts behind the leaders, in 10th place.

When it first arrived at CN HQ, I was reluctant to test the Reacto in our wind tunnel test at all. Clearly it's a bike designed to be aero, and part of me feared it would win the test and I'd forever have to caveat that "of course it won, it was specced with 22cm handlebars." But when it came to measuring up, the bar width at the drops was no narrower than our baseline bike. 42cm outside-to-outside.

The 1x groupset is still a bit sneaky, but Merida does sell the bike like this, so why should I leave it off the test? Factor was radical and progressive when designing the ONE, and we tested that. Merida kept things relatively sane when designing the Reacto frame, but then applied that progressive mindset to the spec. Two routes to a similar end goal, really.

If the Reacto One stormed to victory, I would be caveating this write-up heavily, saying you could also just fit a 1x groupset or narrow bars to any other bike, so the test was unfair and so on.

And, well, you can, and that's pretty damning for Merida. Despite having a significant spec advantage, the Reacto still didn't challenge the top spots.

But – and this is a very large but – I don't care.

Real riding experience

As it happens, I went from reviewing the Factor One straight onto the Merida, and while I appreciate I'm probably a bit boring for saying this, I'd take the Merida almost every time.

Objectively, by a true performance yardstick, the Factor does most things better, particularly power transfer, sprinting, aerodynamics, steering directness, and holding pace when tanking along flat ground. But, subjectively, I still preferred riding the Reacto. I had a much nicer time on it every time I rode it, and whatever performance I was probably giving away didn't really feel worth stressing about.

Power transfer felt plenty enough, albeit this is what stood out the most when comparing the two, mainly because it's so insanely good on the Factor. The narrow cockpit was easy to get used to, despite my inability to hold an aero-hoods position for more than a few minutes. The comfort through the bars made it a much better bike to ride, so I was more confident on descents, and I was able to ride for longer without feeling beat up. I couldn't go more than an hour without aches and pains on the Factor, but I did multiple four-hour rides on the Merida without issue.

This isn't a head-to-head between just two bikes, but even compared to other bikes I've ridden lately, which includes the Tarmac SL9, the Merida is the one I've enjoyed most. It strikes a solid balance between being race-ready, something you can ride to the cafe at the weekend, and something you can do your intervals on after work in the evenings.

It wasn't completely without fault, though. For one, I had a terrible time with the Aero 111 tyre up front, puncturing three times in a single ride and five times overall in my two months of testing. It's hard to say whether that's due to the narrowness of the DT Swiss wheels, the fragility of a TT tyre, or just a coincidental streak of bad luck.

I also struggled to get on with the Classified Powershift drivetrain, which wasn't running as smoothly as I'd experienced before. The shift itself is instant, but there's still a small delay after you press the shift button. I found that sometimes it didn't register the click, and during that small delay, there's no feedback to confirm whether it's registered. So it was a case of click, wait, nothing, click again, shift! It's a first-world problem, but it was annoying no less.

The one problem I can actually attribute to Merida, though, was that the plastic cap that sits over the steerer tube and cockpit bolts didn't fit properly. On one fateful trip over a cattle grid (aka Texas gates for those outside the UK), it came off and went on a little journey to the wrong side of the road, where it was duly run over by a passing car. I retrieved it, but you'll see how bent it is in the photos.

And finally, to round off the negatives, the little metal grills that Merida insists on putting over its brake calipers are, to put it nicely, the devil. I have scars on my left ankle from repeatedly catching it. The best thing about them is that they're removable, and should be the first thing you do if you buy this bike. Sorry to the Merida designers reading this, but in your defence, it's a small thing to find so irksome, so the rest of the bike must be pretty good.

Value

At £9,500, for a bike with a progressive top-spec build, competitive (albeit not quite leading) aero performance, and a reasonable weight, I don't think you can complain too much, given the price of the aforementioned competitors.

Here in the UK, it's £2,499 cheaper than a top-spec S-Works Tarmac SL9 - currently £11,999. Or £2,699 less than the Factor ONE (£12,199).

It's still an inordinate amount of money to spend on a bike, but if you're in the market for a top-tier bike, it's a pretty good option as long as you're not going to want to upgrade your wheels anytime soon, as the Classified Powershift hub locks you into using the DT Swiss ones specced.

It's not the cheapest in its class, though. For a comparison in the other direction, you can get a Canyon Aeroad CFR with Dura-Ace and very similar DT Swiss wheels (the same but 55mm instead of 65mm) for £1000 less. Having not ridden the latest Aeroad, I can't comment on a direct comparison, but it is a more 'normal' build with UCI-legal bars.

Conclusions

Overall, I really liked the Reacto One. I like that a brand known for being safe, good value – dare I say boring? – has the wherewithal and panache to sell a bike with a UCI-illegal 22cm handlebar, rather than just selling it as a frameset and forcing people to make their own fun.

And in execution, I think it has pulled it off. It's a bike that sits in a nice sweet spot between everyday liveable, race-day ready, and a little bit mad.

Maybe, just maybe, I'm seeing a bike that's otherwise a little underwhelming through rose-tinted glasses because of its aero-ification and the excitement factor that it brings. It's hard to say whether I'd have enjoyed riding the 10K or Pro models, with their more common specs, as much as I did this.

But I think sometimes the objective comparison is allowed to give way to the subjective opinion. Aerodynamically, the results are okay. Top ten, not bad. Nothing to write home about, but the Merida Reacto One is a good bike.