Alchemy Helios custom carbon frame

Alchemy's Helios is impressively fast whether the road points up, down or across. It's wonderfully comfortable as well, both in the geometry that is pitched towards the racier end of the scale, and the compliance afforded by the frame and fork that filters out vibration from rough roads.

Frame: Handbuilt in the US

You might never have heard of Alchemy, but they're doing something few manufacturers are doing; building their own carbon fibre frames in-house. They're based in Denver, Colorado and this Helios is the latest model in the range. They're carbon fibre specialists, though they do include two titanium road bikes and a steel cyclocross bike in their range. But it's carbon fibre they're known for.

And my they've done a superb job of building a beautiful frame. The carbon fibre construction, a tube-to-tube process with the joints carbon wrapped, shows through the transparent lacquer. It's delicately finished with understated decals. As with most custom frame builders, you can pay a bit more and specify the paint finish and decals and create a unique frame.

It helps that Alchemy produce their frames in their own facility, rather than outsourcing to another manufacturer. They started out by using Enve-sourced round tubes in the Xanthus, but the desire to get more creative than simple round tubes led them to acquire the ability to cut their own moulds, opening up a lot more creative freedom. The Arion was the first result of this new manufacturing potential, and they've followed up with the Helios.

Drawing on the aerodynamically shaped tube profiles of the Arion aero road bike, the Helios has a more pleasing stance with gently profiled and flared main tubes. It's a bit less mad looking than the Arion, yet offers some of the aero benefits of those shaped tube profiles. The main tubes have a distinct profile with a rounded leading edge and flare into the head tube, seat tube and bottom bracket.

Deep chainstays are joined by slender seatstays, the bottom bracket shell is oversized and in this case press fit. Up front is a tapered head tube with Alchemy's own fork sliding into the 1 1/8in and 1 1/2in headset bearings. The cables are routed internally, the rear brake inside the top tube and the gear cables inside the down tube. You could specify electronic routing if you were going to build it with an electronic groupset.

Although I didn't have the frame built for me, they do offer six stock sizes if you fall happily onto one of those. I did and this 56cm model fitted my really well. If you're looking to buy an Alchemy the nice people at Mosquito Bikes will give you a full bike fit, send those measurements off to Alchemy and you'll get a perfectly fitting frame, whether it's a custom or stock size.

For reference, this 56cm bike has a 56cm effective top tube, 50cm seat tube, 16cm head tube and 73 degree seat and head angles. Those numbers are what we'd expect of a bike pitched as a performance and race bike, ensuring flighty handling with fast responses, just what you want in a race situation. The short head tube favours a low riding position, but there's nothing to stop you specifying a taller head tube if you went down the custom route.

Build: Custom build with top-drawer parts

The Helios came with some top-drawer components for us to assess the frame. You can buy a frameset for £3,320, including an Enve 2.0 carbon tapered fork and headset, and Mosquito will happily build you a bike to any specification you want. There were no shortcuts in our build, which comprised a Shimano Dura-Ace mechanical groupset, Enve SES 3.4 carbon clincher wheels with 23mm Continental GP4000S II tyres, Enve handlebars, stem, seatpost and a Fizik saddle. If you wanted the same spec, the complete bike would cost you £8,200.

All very nice kit, but I won't dwell on the componentry too much. Suffice to say it was all flawless during the test. The wheels, a real highlight of the package and a good match for the frame, are superbly fast and coped just fine in blustery conditions. The braking performance, with Enve's own brake blocks, puts them right at the top of the carbon wheel pile when it comes to stopping. Lots of power, plenty of modulation, no squeaking and no sudden grabbing.

The Enve finishing kit is lovely stuff, though the single bolt seatpost is fiddly when fitting a saddle, but easy to adjust once you've got the rails around the cradle. I found the bars a touch on the wide side, but that's no problem because if I was buying the bike I would simply ask for a narrower handlebar. That's the beauty of a custom bike build, you can get exactly what you want, in the size you want.

Ride: Fast and wonderfully comfortable

All that little lot produced a 6.8kg build (14.99 lb), and that lack of weight you really notice riding the Helios. It really rips up the road when get on the power. Show it a climb, from a shallow gradient leg stretcher to a wall steep leg breaker, and it scampers up with little hesitation. There's a high level of stiffness around the bottom bracket area that transfers power very efficiently, and it feels very solid under power too.

There's a good level of stiffness at the front, and it does well to resist twisting forces from the head tube to the bottom bracket. This gives the Helios a slightly edgy and darty ride feel, especially coming off the Colnago c60 which is far more measured. That was the defining trait during my time with the Helios, a lively ride character that is very responsive to any sort of steering input. That makes it a thrilling bike to ride, fast-paced and energetic.

It's certainly not the stiffest carbon race frame, but neither is it remotely lacking in this department unless you're a big sprinter who can deliver some serious power to the cranks. Remember that the carbon layup can be completely tuned to your requirements, so you could build it stiffer if you really wanted. I found the ride as is nicely balanced in all situations.

It picks up speed briskly and demonstrates a good ability to handle a sudden injection of pace, which is handy for bridging gaps in a pace line or jumping across to the breakaway, or just getting the jump on your mates for the race to the town sign.

Where the Helios draws another ace card is in the comfort it provides. It's not just smooth, it's buttery smooth, in a way that only a small handful of other carbon frames are. The way it just floats over rough and broken tarmac and absorbs vibrations caused by crumpled road surfaces, such that these imperfections never unsettle the Helios. And that's with 23mm tyres as well, inflated to about 90 psi.

So it's beautifully composed and smooth on all manner of road surfaces, fast when the road points up, down or chasing wheels, gathers momentum with alarming ease, and is a real looker too with the full gamut of custom options available. For a race or fast performance bike the Helios offers everything such a potential customer is seeking. And being so comfortable that you can cruise along on it all day, and finish every ride feeling fresh, is a real attraction.

Yes, it's jolly expensive, but it's similarly priced to a clutch of top-end production bikes, yet offers the full custom treatment that such bikes just don't offer. And that's an appealing prospect if you've got this sort of money to spend on a carbon road bike. Plus there's the rarity value that it offers, which will be a draw for a lot of people.

Verdict

Fast and exciting yet comfortable and smooth, the Helios is a beautifully balanced US built carbon fibre racer.