#95 STARLING CYCLES STURN
This UK-made 29er downhill bike shuns carbon ibre, complex linkages and even gears, for the quickest, quietest descent possible
Starling Cycles is Joe McEwan, a former aerospace engineer with a background in carbon fibre research who’s taken to building custom steel frames in his Bristol workshop. Joe’s design philosophy is to-the-point: “I aim to make simple, silent and fast mountain bikes.” The type of bike that we’re sure is at the top of every rider’s wish list. Shown here is Joe’s latest creation, the Sturn (from the Latin for starling, Sturnus vulgaris) – a full-on downhill bike, built for the race track or the bike park, but with some pretty unusual features.
Man of steel
Before getting the lowdown on the bike, we had one burning question to ask Joe. Why would someone with nearly 20 years of experience with carbon fibre – what the bike industry and most people would consider cycling’s most desirable material – turn his attention to steel?
“If we understand that a more laterally compliant frame adds grip and control with negligible impact on pedalling efficiency, then it becomes the best option, because of the inherent flex in steel frame designs,” explains Joe. “There is a small weight increase, but for all but the skinniest of XC racers, this is a negligible tradeoff worth putting up with.”
Single & ready to mingle It’s not just the raw steel tubing that jumps out at you on the Sturn, but the striking singlespeed drivetrain set-up. The non-driveside chainring and secondary chain (1) make it visually unique, not to mention the lack of a chain guide, rear mech and cassette (2).
The singlespeed concept isn’t new to Joe. “I sold my last downhill bike a few years ago, but when I did ride DH, I always built my bikes up singlespeed,” he says. “But this was always a bodge, using tensioners to correct chain growth.” What was the reasoning behind this?
“In DH you rarely change gear,” he explains. “For me, the gears acted as a distraction from ‘getting into the zone’ and riding well. Also, removing gears allows you to be much more free with the suspension design.”
Drive time
Another benefit, Joe points out, is that getting rid of the gears means that the drive system has “minimal impact” on the suspension action, when combined with the Sturn’s jack-drive design. The way this works is that the non-driveside chainring and secondary chain turn a jack shaft that runs through the suspension pivot. This then powers the rear wheel, via a driveside sprocket and chain. Because that sprocket is concentric with the pivot, there’s none of the chain growth that can afflict highpivot bikes as they move through their travel, but you still get all the benefits, including a rearward axle path.
Joe claims that the lack of gears, jack-drive design and careful positioning of the single pivot (so as to give the best balance of anti-rise and anti-squat through the full stroke) mean that rider weight movement, pedalling and braking have the “least possible impact” on the suspension, resulting in a “balanced, predictable ride”. “There may be some tracks where singlespeed just isn’t competitive,” he admits. “But recent chainless World Cup wins and podiums help reinforce my confidence that singlespeed is the way to go.”
So, where did Joe get his inspiration from for the Sturn? “I’d definitely acknowledge the old Brooklyn Machine Works bikes and SuperCo Silencer as influences,” he says. “But I’ve tried to take their designs, simplify them and make them more elegant.”
Speed machine
The Sturn’s geometry can be tweaked to your needs. If you know what you want, you can have it, and if you don’t,
Joe will help you decide. The head angle, reach, seat angle and head tube length can all be customised.
This is a machine built for speed, and Joe believes 29in wheels are the way to go here. There’s room in the rear triangle for tyres up to 2.7in wide. The frame is made from Reynolds 853 tubing, with a custom-butted down tube and plate gussets behind the head tube for extra strength (3). A complete build with coil shock and DH tyres weighs 36lb (16.3kg).
So how does all this translate to speed on the trail? “The Sturn’s been given to Brett Wheeler, of Wheeler’s MTB holidays, in Portugal,” says Joe. “He’s only had it a few months and has already won his first two races and beaten lots of local track records. It’s fast!”
Contacting Joe is the best way to get hold of one of these unique bikes for yourself. But as he’s very busy, delivery times may not be as fast as the bike!
SPECS
Price £TBC (contact Joe for pricing info)
Contact www.starlingcycles.com
Also try Sick Gnarpoon (180mm-travel steel freeride rig), £1,850 (frame), https://sickbicycle.co