Customised Specialized S-Works Aethos: The world’s lightest functional road bike?

While pro bikes are restricted by the UCI’s 6.8kg weight limit, everyday riders can go below that, in some cases absolutely smashing that barrier. The pursuit to make a bike as light as possible leads to some unique designs and customisations, like this highly-customised Specialized S-Works Aethos that Ollie Bridgewood recently got his hands on. It weighs only 5.45kg, a weight that’s been achieved through some very creative adaptations to a bike that’s already one of the lightest road bikes commercially available - according to Specialized, the complete build in a size 56 weighs as little as 5.9kg.

Shedding half a kilogram off of that doesn’t sound like much, but on a bike that is specifically designed to be as lightweight as possible, it’s no mean feat. Even so, Oleg from Twisted Wheels - who is the brains behind the seriously lightweight build - has found a way.

Interestingly, in customising the bike, Oleg wanted to ensure that the bike remained fully functional. He didn't want to produce one of those weight-weenie builds we're used to seeing at hill climb competitions.

Custom internal cable routing

The thing that immediately caught our eye wasn’t any of the bike’s weight-shedding measures, though, but the internal cable routing. Anyone familiar with the Aethos will know that it doesn’t usually have internal cable routing, but Oleg has achieved it by upgrading a few components, including swapping out the fork for an internal routing-compatible one from Deda. The new fork is teamed up with a custom Bjorn handlebar which has a hole at the rear, allowing the cables to be fed through the steerer and down the fork.

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The new Deda fork supports internal cable routing.

Of course, moving to internal cable routing leaves unsightly holes in the form of cable routing ports where externally-routed cables are fed through. Not content with this, Oleg stripped the paint, sanded down any excess material around the holes, and then applied a layer of carbon fibre over the top to cover them up. After a new lick of paint, you’d never know that the ports were ever there.

Everything lightweight

Now to the lightweight stuff, and things actually get off to a bad start as the internal-routing solution comes with a 100g weight penalty, although it likely boosts aerodynamics.

There are some weight benefits to the cable routing changes with the new minimalistic paint job only weighing around 35g. That’s even with Eddy Merckx’s famous ‘Ride as much or as little, or as long or as short as you feel, but ride’ quote printed on the top tube.

Many of the weight savings on the bike are achieved through smaller things. The titanium bolts and washers used to clamp the SRAM Force shifters save 12g on each shifter, for example. The Wahoo Speedplay pedals have similarly undergone a titanium revamp, with new titanium axles and bolts.

All of these little things add up, but the biggest weight saving is delivered by Oleg’s custom wheels, tipping the scales at only 845g a pair. You’ll struggle to find a commercially-available wheelset that gets below 1000g, let alone anywhere near 845g. Following modern trends, these are tubeless and use Light Bicycle rims, which don’t require rim tape, lowering the weight. With carbon spokes and super-light hubs, it’s a featherweight combination.

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Super-light hubs help to reduce the weight of the wheels.

Elsewhere, there are changes to the braking system, including the addition of six-bolt disc brake rotors which, linking back to the wheels, have lighter hubs than their centre-lock alternatives.

In a move that is on trend within sections of pro cycling, the bike uses a 1x version of SRAM’s Red groupset with a 42-tooth chainring paired with a 10-36t cassette. Shedding the extra chainring is an easy way to cut grams. On the matter of functionality, this setup is roughly equivalent to having a 50/34t crankset paired with a 12-29t cassette.

It’s a seriously impressive custom build and definitely one of the most unique and painstakingly constructed bikes we’ll encounter this year.