Shimano Carbon 1380 wheelset £249.99 front, £299.99 rear
First things first: Shimano’s Carbon 1380 wheelset, properly designated WH-7850-C24-CL, uses Dura-Ace hub bearing technology albeit with revised seals in sharply-styled, angular barrels, has 16 radial bladed spokes in the front wheel and wears a titanium freehub body compatible with eight, nine and 10-speed cassettes. Like all Shimano freehubs it occasionally skips but otherwise offers rapid take-up and a quiet ratchet. With the release of the 2008 range of Shimano wheels, the Japanese company’s spoke nipples have finally made their way from the hub to the rim.
The rear wheel showcases the latest efforts by Shimano to build a road wheel with the desired combination of radial resilience and axial stiffness. In search of this the wheel has tangent spokes on both drive and non-drive flanges. 20 in number, they locate in a rim with spoke holes offset by 3mm from the centre line in order to balance tension between the two sides of the wheel. Wider flanges contribute further to axial stiffness.
The really interesting stuff, however, lies in the ‘carbon composite’ rim, which might more comprehensibly be called carbon laminate. Key to the technology is a process reliant on phosphoric acid anodizing to ensure a tough, resilient bond between the carbon fibre and aluminium components of the rim. Aluminium provides an excellent braking surface, can be extruded to precise dimensions and is a convenient, reliable means of shaping the rim bead hook on which clincher tyres depend. Carbon fibre offers maximum stiffness for its weight; combining the two allows the designer to cut rim weight to the bone without compromising on strength, durability or rideability.
Thanks to the carbon cladding, the rim extrusion is slimmed down to a stunning 0.6mm for the box walls, with a conventional 1mm to 1.3mm for the braking surface and bead hook section. The sidewalls receive two layers of carbon and the top of the box four between spoke holes. However, around the spoke holes there are 30 layers of carbon to cope with the high tension forces applied by the spokes. The resulting rim is comparable in weight to an all-carbon construction at, according to Shimano, a lower price point.
For sure, these wheels are not super-expensive. Indeed, their weight is such that they feel, if anything, under-priced. Hefting in the hands indicates an exceptionally low rim weight and hence inertia, while the high spoke tension kept in check by aluminium alloy spokes promises a taut, responsive ride.
The 1380s do not disappoint. Shod with sub-200g clinchers, they simply fly along with a floating, supple ride sensation that makes light of even the rougher sorts of Tarmac found across central London. Acceleration is brisk at any speed, with a springiness that brings to mind a really top-end handbuilt – which is what they are. Every Dura-Ace wheel is built by hand, every spoke has its final tension measured and noted and each wheel has its own serial number to assist in quality control.
RCUK’s pair was a pre-production sample that required a touch of the reviewer’s spoke key prior to riding. No bad thing, this, as it gave me a feel for the tension required and the response of the rim to tweaking. Nice and predictable is the answer, with no further work needed in the 1000-odd miles ridden since. These include the Dragon Ride, London-Paris Cycle Tour and plenty of commuting, offering plenty of opportunity both to stress the rims and to assess their aerodynamic performance.
Shimano claims that the 21mm rim makes an ideal partner for a 23mm tyre; maybe so, although I have no doubt a carefully-shaped but deeper rim would do better. Shimano offers a deeper carbon laminate wheel, after all… But, with just 16 bladed spokes, the front wheel doesn’t offer much resistance to the wind, any more than the rim does to gaining altitude or speed. Top stuff and no mistake.
