Ultralight is cool again, and this disc-brake climber is out to prove why
Photos and words: Jack Lynch
RRP: $18,500
If you’d asked me 18 months ago if there was a purpose to Cervélo’s lightweight R5, I would have scratched my head.
Light weight bikes were swiftly becoming redundant thanks to companies (including Cervélo) producing aero rigs tipping the scales close to the UCI’s 6.8kg minimum racing weight. We saw Specialized, then Trek, combine their climber-bike offerings with sprint-bikes, reducing production costs and buyer confusion, while seeing many pundits smile and nod, proclaiming that it made sense in the current economic climate to stymie choice in favour of the middle ground.
In 2025 the wheel began to turn and light became cool again thanks to the non-racing consumer (i.e. 90% of road riders) wondering if we can ride something we can pick up with one finger again.
This sensation was relatively achievable in the rim brake era, but now discs are de rigueur it’s not so easy. We can all agree disc brake bikes offer a lot more in terms of handling and compliance, but they’re at least half a house brick heavier than their predecessors and the weight weenies of the world are getting itchy feet.
Cervélo has sought to ameliorate the colossal shortcoming of modern road bikes, joining Scott by presenting us with a sub-6kg production bike. It looks like a classic but is littered with forward thinking trends, and is sure to make waves in the local bunch.
Zero Compromises, just choices
Although we didn’t admit it at the time, those super-light bikes we made in the rim brake days all had their quirks or flaws. You’d sacrifice comfort, frame longevity and even braking performance in the quest for something featherweight. They were fun to ride but could also be described as tinny at best, or terrifying at worst.
Thankfully, gone are the days of nylon cables, padding-free saddles, tubular tyres (21mm) and paper-thin bar tape. Cervélo has engineered this atest generation of R5 to feel like every other
R5 before it. There are no spooky creaks or hair-raising skipping through corners; just a well balanced, consistent bike.
I don’t know how they can make something feel so stiff at this weight, but from the first ride I was hooked on the R5. Unlike aero frames, you can feel a light bike under your legs with every pedal
stroke, and given the extreme weightlessness of this package, that feeling doesn’t get old throughout a ride. Even when I was on my limit, the bike never dragged on me – and that can’t be said about bikes only 1kg heavier.
This, of course, isn’t just the result of the incredible frame and fork, which Cervélo says has shed around 100g from its previous version, but also Sram’s 1×13 Red XPLR transmission, which does away with the front derailleur in favour of a 10-46 cassette and 48-tooth front ring. I’ve been half in on no derailleur for about 10 years now (since the Aqua Blue Racing blunder…), building several roadies in 1x configurations, but only now with 13-speed does it feel like it’s manageable in different terrains at varying intensities. I live in an undulating area and there were only a handful of situations where the jumps between gears disrupted my rhythm.
I can absolutely recommend the 13-speed 1x for its simplicity, lighter configuration and appearance. The thing pops.
The compromise on the stock build is Cervélo’s choice to run with 26mm tyres and TPU tubes. This is despite the Canadian company saying the bike is optimised for 29mm tyres. I felt sure-footed on the stock tyres, but there’s little doubt they rattled me around more than 28mm or 30mm rubber,
This isn’t a theoretical statement. The paperthin Vittoria Corsa Pro Speed tyres lasted for about 300km before a sneaky double flat had me catching a train home on a solo ride. There had been a light sprinkling of rain, and whatever caused the WTB TPU tubes to puncture was undetectable when I changed to Vittoria Corsa Speed tyres, tubeless and 28mm wide.
It enhanced my experience of the bike with improved comfort and confidence. There was peace of mind on rougher surfaces, knowing that the tyres could withstand some road debris and bring a little extra cushioning for improved comfort and cornering. Adding a few grams of tyre rubber and tubeless sealant is definitely worthwhile.
The science of feeling
The benefits of an aero set-up – including bike, helmet, clothing, shoes, socks and more – are indisputable. Labs have been telling us that aero trumps weight for some time. And far be it for me
to disagree with what the scientists say – but I’ve always felt faster on a bike that’s lighter.
The R5 feels like it spins up faster than other bikes. In the real world, I’m constantly getting stopped by traffic lights or having my pace dictated by others in the bunch… and I certainly
don’t hit the high 40s as much as the big brands’ marketing material leads me to believe.
Surely, then, it’s more beneficial to have a bike capable of rolling over a hill faster than another. If I crest a climb faster on one bike, it must come down faster… right?
There’s an unmatched sensation of speed on the R5 and a tacit assurance that, if you want to, you can always go faster. In fact, the bike made me hunt local KOMs I’d previously not considered,
and I had more Strava PRs on this bike – ascents and descents – than any bike I’ve previously tested (including e-bikes).
The R5 just feels right across a variety of roads and conditions, and given I’m not racing, I’m down for the lightweight treatment.
In pursuit of pro
Perhaps one of the reasons this bike felt so perfect for me is its geometry matches the S5 – Cervélo’s aero offering, which has been a benchmark bike for aero, comfort and control for the better part
of a decade.
My size 51’s 38cm handlebars, 165mm cranks and short reach had me getting lower and narrower than had previously felt comfortable. It made me feel like a little bullet on the bike (although I’m sure that’s not how I looked!) who was punching out of corners and attacking small climbs.
Cervélo has given us a treat with the R5. It’s the perfect bike for me, and I guarantee anyone who rides anything with more variety than long, straight and flat stretches will find something to love about it.
I wish Cervélo would be more adventurous with its paint schemes, but if that’s the greatest criticism I have, this bike is the best I’ve ever ridden with daylight to second.
