Th e litt le broth er to isaac’s muon isn’t as aggress ive but st ill packs a power punch
e’ve test ed Isaac’s brutally fast Muon superbike before but the cheaper, more forgiving and still damn fast Photon is actually likely to appeal to more riders. Especially those sandwiching their bike leg between a 2.4mile swim and a marathon.
Frame and fork
Unlike most ‘younger brother’ frames, the Photon doesn’t just use a cheaper carbon fibre lay-up in the same mould as the flagship frame. The designs are separate but they use the same High Modulus Nano Aero carbon. The front end is the most obvious difference between the two bikes as the Photon gets a conventional short head-tube and a low top-tube rather than the distinctive hunchback top-tube arrangement of the Muon. Interestingly, the Photon gets a set of TRP V-brakes hidden on the back of the forks while the Muon uses conventional brakes on the front. Which design aspect wins out in overall wattage saving we don’t know but it certainly makes the two closer in aero terms than if they both had hidden brakes. The rear brake is also a V-style unit sitting behind the aero seatstays rather than hidden under the chainstays. It’s no more convenient in practical terms as you still need to undo the rear brake or deflate the tyre to release the wheel.
The Photon back end is also fractionally longer and the bottom bracket is lower, adding stability. The kite section seat-tube design with wheelhugger cut-out and inset seatpost clamp is shared between the two designs. The sliding seat mast mount is also shared. While you might need to dismantle the seatpost head clamp rather than just slide it along, there’s 80mm of fore-aft adjustment for tuning the effective seatpost angle. The neat, light Ritchey clamp is easy to adjust for angle and the soft-nosed Selle Italia Tri saddle was liked by all our test team. Finishing touches include metal plates on the outside of the dropouts to stop clamping damage and neat vertically inserted internal cable routing behind the stem.
Our sample used 20-speed Ultegra 6700 but consumer bikes have already changed to the latest 22-speed 6800 set. Shifting is precise and the cranks add welcome stiffness when you’re putting the power down hard. What the one-piece alloy Vision tri-bars lose in adjustment they make up for in sleek aerodynamics, low weight and far fewer bolts to worry about loosening. The real gem of this component package is the Vision wheelset though. They’re far lighter than the other wheels on test (the rear wheel is barely heavier than the front wheels of the Raleigh and the Neil Pryde) but still add a bit of aero edge without affecting handling or braking. Smooth running, easily adjusted bearings mean they’ll make a trusty long-lived set of training wheels even if you upgrade to race wheels at a later date too.
The fact we were thinking of long-term plans for the Isaac as soon as we started riding it says a lot about the bike. With the saddle nudged to the front of the seatpost, we fell into a very natural feeling tuck position over the relatively short top-tube straight away. There’s plenty of propulsive stiffness right through the crank, BB and chainstays to the rear wheel. At this point the light wheels take the rich supply of wattage and translate it into seriously responsive acceleration. The result is a proper punch of speed and its belligerent
Size tested: 51cm
With 80mm of fore-aft movement, the seatpost top makes it easy to find an efficient and comfortable position
The light weight Vision T30 wheels look great, pick up speed easily and handle really well too