Shimano Ultegra SL wheelset £89.99 front, £169.99 rear
The layout of Shimano’s recently-released Dura-Ace Carbon 1380 wheels suggests that the Japanese company may be moving away from the hub-mounted nipples seen on its top-end wheels since the very first set almost a decade ago. If so, then the format of the WH-6600 pair represents the ultimate expression of the idea, which undoubtedly offers advantages over the conventional positioning of the nipple in the rim. Not only is the weight of the nipple moved away from the periphery of the wheel, where it hinders acceleration but a larger nipple can be used allowing greater spoke tension.
Nevertheless, and perhaps because a hub mounted nipple requires the builder to think carefully when tweaking, the idea has never really found favour with the buying public. Expect it to quietly disappear from Shimano’s thinking over the next couple of years as the new Dura-Ace layout trickles down.
That doesn’t really answer the question of whether these wheels are any good. They are. High spoke tension, bladed spokes and a semi-deep rim with curved sides add up to a nicely stiff, taut ride with good air penetration that can be felt most noticeably on fast descents. The rear wheel has an asymmetric rim with spoke holes offset to the non-gear side to even up spoke tension. Being tangential, the non-drive side spokes do the job of driving while the radial spokes on the drive side just sit there, but the hub has a massive barrel well up to the task of transmitting drive torque.
This particular pair has done several sportives including the 2007 Southern Sportive and 2008 Dartmoor Classic, has been used for a fair amount of commuting and has even been given an outing on the cobbles of Flanders for SHIFT magazine, and has come through with flying colours. The only question mark over long-term reliability derives from an older, structurally similar pair of WH-R550 wheels tested by the reviewer, which lost a rear non-drive side spoke to fatigue at the thread. That said, they were being used for light touring and the rebuild at least proved that this potentially important aspect of wheel ownership is not beyond the skills of a regular home builder. In any case, the asymmetrical rim of the newer wheel, by offering a better balance of tensions, should go some way to minimising the chance of the same occurring with the WH-6600. The wheels come with a pair of oversized aluminium nipple keys to make the task easier.
Except for the slate-grey finish, which is found across the Ultegra SL groupset, the wheels are identical to the standard Ultegra WH-6600 model. This means a claimed weight of under 1700g per pair, a 16/20 spoke count front and rear, clincher only rim format, an aluminium freehub body with high splines and Shimano’s usual excellent skewers. Unfortunately, the freehub will only accept 10-speed cassettes; older nine-speed Shimano cassettes won’t fit over the splines. Otherwise, light, stiff, aero and a great complement for the Ultegra SL group.