Electronic Shifting
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BIKETEST | ELECTRONIC SHIFTING RICHARD HALLETT Technical Editor Bike test ELECTRONIC SHIFTING Just for racers or an upgrade for the rest of us? Richard Hallett reviews a Trek Domane SLR7 and a Specialized Tarmac Expert eTAP LECTRONIC DERAILLEUR gear entrant is SRAM, whose eTAP concept arrived FRAME & FORK shifting has come a long way in in 2015 to considerable acclaim both for its IsoSpeed is the name chosen by Trek for the the quarter of a century since wireless operation and for its highly original vibration-dissipating technology found on the E French manufacturer Mavic gave functionality. Wisconsin firm’s Domane endurance road the ZMS – or ‘Zap’ – system its prototype If there’s a common feature of road bikes bikes. The first generation Domane, launched debut at the 1992 Tour de France. Then that are specified with electronic shifting, it is in 2012, featured a rear ‘de-coupler’ with a little more than a curiosity, electronic shifting their cost, with eTAP-equipped cycles starting conventional (for Trek) all-carbon fork shaped is now widely reckoned to be superior in at around £4.5k and Ultegra Di2 a more for resilience. The current version has a operation, reliability, and prestige to the affordable £3k or so. Both groupsets can be de-coupler device in the head tube as well as various mechanical shifting systems offered found for sale at a grand or thereabouts and a new flex adjustment system at the rear. by the three main manufacturers. Having can be retro-fitted to an existing bike, making The de-coupler essentially allows the proven almost impervious to adverse riding the technology itself more accessible than relevant frame member – seat post or fork conditions, it is popular with cyclocross riders. the prices of complete cycles might suggest. steerer – to deflect under shock, semi- Its ease of use also makes it a great option Typical of the latter are the two cycles on test, independently of the frame or fork, in the fore- for long-distance riders and those with limited with the eTAP-equipped example some £400 aft plane while remaining accurately aligned to hand strength or movement. more expensive than its broadly comparable maintain torsional rigidity. At the rear, a slider Shimano’s Di2 was the first of the competitor. can be used to alter the length of the flexible ‘modern’ systems. It was launched in Dura- There are significant differences besides spar and tune the rear suspension. Ace guise a decade after Mavic’s Mektronic price and component choice. Trek’s Domane Lacking such complexity, the Tarmac groupset fell foul in 1999 of the Union SLR features frame technology designed Expert’s conventional high-end composite Cycliste Internationale’s then muddled to quell vibration, and is marketed as a thinking on technological advances. (The UCI comfortable machine for rough roads and banned Mavic Mektronic from competition, the long haul. Meanwhile, the Tarmac Expert dealing a fatal blow to its commercial from Specialized is easily identified as a potential.) Campagnolo’s EPS design came straightforward high-performance road bike, along shortly after Di2, and it too uses wires albeit one with a good helping of all-round to transmit control signals. The most recent ability. BOTH GROUPSETS CAN BE FOUND FOR SALE AT A GRAND OR THEREABOUTS AND CAN BE Above: The right shifter moves the rear derailleur to a smaller sprocket, the left moves it to a bigger one. Press RETRO-FITTED TO AN EXISTING BIKE both shifters together, the front mech moves up or down 64 CYCLE JUNE/JULY 2017 ELECTRONIC SHIFTING | BIKETEST SPECIALIZED TARMAC EXPERT ETAP eTap derailleurs are bulkier as they house batteries as well as wireless receivers TREK DOMANE SLR7 The single Di2 battery, linked to both shifters and derailleurs via wires, is hidden in the frame CYCLINGUK.ORG CYCLE 65 ELECTRONIC SHIFTING | BIKETEST Clockwise from left: IsoSpeed de-coupler gives fore-aft movement. Complex callipers. Di2’s shift setup is normal: RH lever = rear mech BATTERY LIFE FOR BOTH SHIMANO DI2 AND SRAM ETAP CAN BE EXPECTED TO EXCEED 1,000KM OF NORMAL RIDING chassis relies on a ‘size-specific approach internal brake and conventional gear cable suited to those comfortable with a more to frame construction’ to achieve its routing, double bottle cage bosses, and competition-orientated riding position. This performance goals, meaning that the fine provision for mudguard stay attachment. major feature aside, there was little difference details of carbon-fibre lay-up vary with frame The Tarmac’s cleanly-styled seatpost cluster, in ride sensation – steering response, comfort size to provide the desired balance of which houses a concealed binder wedge, – that could not be at least in part attributed stiffness and weight. compares with a busier area on the Domane, to the two bikes’ tyre selections. The two framesets exhibit similar basic due to the rear IsoSpeed bearings and Trek’s characteristics, including sweeping transitions external seat mast design. WHEELS & TYRES at junctions and massive sections around Many of today’s carbon fibre road frames Both machines sport wheelsets in the the head tube and bottom bracket. Both use have very wide top tubes. That of the Domane contemporary fast(ish) road bike style, which press-fit bottom bracket bearings, the Tarmac is the wider of these two and, at 48mm near means a low spoke count (18/24 and 20/24 choosing a version of BB30 that requires a the middle, was too wide for me to ride in for the Trek and Specialized respectively) and remarkably unlovely plastic spacer inboard comfort; the Tarmac Expert’s was just about sturdy rims designed primarily for durability. of the left-hand crank, while the Domane acceptable. For many potential purchasers, Both wheelsets are tubeless-ready, with the employs Trek’s now-venerable BB90 system, this may seem a personal quibble, which in a Trek rolling on tubeless Bontrager R3 28mm which is compatible with Shimano’s 24mm sense it is. But for anyone who finds a wide rubber and the Tarmac on 24mm innertubed axle. It also means a 90mm wide bottom top tube uncomfortable, it may well be a deal- Specialized S-Works Turbos. Whether thanks bracket shell, which leaves little room for breaker. to the fatter tyres or IsoSpeed, the Domane a displaced chain. Despite the fitting of a The Domane’s frame geometry may also felt marginally the more isolated from rough chain keeper, the chain of the test bike was influence your choice. Its front-end geometry road surfaces. jammed between the inner chainring and might be described as ‘short and high’, and is frame on delivery, requiring removal of the designed for those who don’t want too much EQUIPMENT chain set to free it. of a stretch to the handlebar. The Specialized Other than seatpost arrangement, the only Details on both frames include ports for is a different beast entirely, with proportions notable difference in general component OTHER OPTIONS Canyon Ultimate CF Boardman SLR 1 SLX 8.0 Di2 £3,599 2 Endurance 9.9 Carbon-fibre frameset, Ultegra Di2 £5,300 Boardman’s transmission, Mavic Ksyrium Exalith Endurance geometry teamed wheels and a 6.7kg weight make this up with Zipp wheels and a competition-orientated option. Men’s finishing kit and eTAP shifting. & women’s models. canyon.com boardmanbikes.com CYCLINGUK.ORG CYCLE 67 BIKETEST | ELECTRONIC SHIFTING Tech Specs Dimensions 730 in millimetres 554 and degrees 73.3˚ 780 36 525 686 48 600 420 130 622 71.9˚ 172.5 265 28 61 1005 TREK DOMANE SLR7 PRICE: £4,600 11-speed Di2 with SIZES: 50, 52, 54, 172.5mm cranks, 56 (tested), 58, 60, 50-34 chainrings, 62cm 11-28t cassette, WEIGHT: 7.4 kg (no Trek BB90 bottom pedals) bracket. 22 ratios, FRAME & FORK: 32-120" 600 Series OCLV BRAKING: Bontrager Carbon frame with Speed Stop direct front IsoSpeed mount rim brakes and adjustable STEERING & rear IsoSpeed, SEATING: Trek hidden mudguard integrated sealed BB30 with plastic mounts, 3S chain cartridge bearing spacer. Note unused keeper, DuoTrap S headset, 1-1/8" gear cable exit hole compatible, Ride top, 1.5" bottom Tuned seatmast, bearings; Bontrager Domane full carbon Pro 31.8mm 7° fork with direct stem, Bontrager Pro specification is in braking. Where the Tarmac can be hard to distinguish with gloved fingers, mount brakes IsoCore VR-CF drop sticks with regular SRAM Force dual-pivot occasionally resulting in mis-shifts. WHEELS: Bontrager handlebar with gel callipers, the Domane gets direct-mount Just as impressive as eTAP’s functionality Paradigm Comp cork tape. Bontrager Tubeless Ready Ride Tuned seat Bontrager Speed Stop rim brakes. These is its use of wireless signal transmission, wheels, 28-622 mast with 20mm employ a fantastically complex-looking which is done between shifters and mechs Bontrager R3 Hard- offset, Bontrager arrangement of struts, eccentrics, and using a proprietary wireless protocol. Case Lite tyres Affinity Elite saddle TRANSMISSION: with titanium rails bearings and allow braking power to be Batteries are contained within the mechs and Shimano Ultegra trekbikes.com adjusted to take account of rim width. shift levers, the latter using standard CR2032 A close look shows that there is a rising buttons, while the shifters have identical rate effect to the mechanism, which in turn rechargeables, allowing a swap should one Dimensions 700 in millimetres 565 means, as Bontrager’s own fitting instructions flatten while riding. With no wired connections, and degrees 73.25˚ concede, that power is reduced on wider rims the look is clean and installation both quick 785 34 501 such as the Trek’s. The net result is that and easy. 680 there’s nothing to choose between the two: Di2 is powered by a single rechargeable 43 595 405 130 622 both bikes have smooth, effective stoppers.