Canadian manufacturer Guru used NAHBS (North American Handmade Bicycle Show) to unveil their lightest ever frame to date, the 670g (size 54cm) Photon HL. Standing for ‘Hyperlight’, the HL required the development of a new carbon fibre layup and new tube profiles to push the weight as low this, and was two years in development, a complete redesign of the old Photon.
The frame uses new profile tubes, with a squared off shape (we’re thinking Cervelo here with their squoval tubes) which because of the increased surface area means less carbon can be used, therefore reducing the weight without any loss of strength or stiffness. The frame is constructed using a tube-to-tube process, a similar method used by other high-end carbon frame manufacturers like Parlee.
Quantum Carbon Concept is the name given to the special carbon fibre layup used in the frame. Strips of carbon fibre are carefully laid in a special arrangement at key areas of the frame to strengthen it where needed, likened to stiffening ribs. And there’s barely any metal in the frame, in fact just the removable mech hanger is made from metal. The bearings cups in the frame are all made from carbon, and the rear dropouts are carbon too. Clean internal cable routing, or Internal Adaptive Routing to use Guru’s name for it, makes the frame fully mechanical and electronic compatible.
Proving the lengths they’ve gone to keep the weight down, Guru even developed a brand new proprietary sub 5 gram clearcoat dubbed Specter. They’ve also shunned the trend for tapered head tubes and given the Photon HL a regular 1 1/8in head tube. A trend they have opted to go with is that of a 27.2mm seat post, which not only is light but should provide a little comfort. A PressFit 30 bottom bracket is specced.
Guru offer full custom geometry on every frame and it costs $8,500, and that includes an Enve 1.0 Road fork. There are other paint options available if you don’t want the special 5g finish.
You’ll be able to see the Guru Photon HL at Bespoked Bristol on the Cyclefit stand. It’s sure to be turning a few heads.
David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.