Canadian manufacturer, Guru, launched the Photon in 2010. This, the Photon SL, is the updated edition.
A 750-gram chassis in 54cm is available with custom geometry. Our test machine is an off-the-peg model with a 535mm top tube and a seat tube that measures 53cm from bottom bracket centre to top. It tipped our scale at 16lbs on the nose, or 7.25kg.
The fork is a full carbon Enve Road 2.0, fast becoming the default selection for premium chassis. The Photon SL, one built by hand with tube-to-tube construction, rather than baked in a mould, certainly meets that description.
The Photon SL’s most notable visual characteristic is the comparatively modest diameter of its tubes. Guru is clearly content not to be a competitor in the my-downtube-is-larger-than-yours arms race consuming much of the cycle industry. The headtube, for example, is a stock 1-1/8”, rather than the increasingly standard tapered offering. This comparatively svelte unit leads into a similarly modest downtube.
It’s an understated aesthetic that continues throughout the frame (the flattened wishbone that unites the seat stays, for example) and one that strikes us as a conscious attempt not to sacrifice comfort for stiffness. We’ll find out. This design philosophy is bucked only by the chainstays, which look more robust and suited to the job of power transfer.
The press fit 30 bottom bracket is our one area of concern at this early stage. The adaptor kit deployed to accommodate the 24mm axle of the Shimano Ultegra chainset has an unsightly plastic shim that doesn’t inspire confidence. We’re hoping our fears are misplaced, however. Everything else about the Photon SL oozes class.
The aforesaid Shimano Ultegra groupset is the 6770 Di2 variety, one that’s performed well in tests on other chassis. The Photon SL, it’s worth noting, is compatible with electronic or mechanical groups.
The Ritchey finishing kit appears competent (the minimalist clamp on the seatpost is very pretty), and the Prologo saddle comfortable, but it’s the Reynolds Assault wheels that threaten to steal the component show. Our 46mm, sub-1500 gram hoops are clinchers (1265g tubulars also available), and shod with Michelin’s highly-rated Pro 4 Service Course rubber.
Our test bike is supplied in an understated black and white finish, but custom colour options are part of the Guru offering for those seeking something more eye-catching.
We’re looking forward to seeing what Guru’s slightly off-message approach can bring to the table with the Photon SL. Check back soon for a full review.