This article originally published on BikeRadar
Praxis Works' impressive range of forged chainrings grows by several models for 2013. In addition to the new Shimano Dura-Ace 7900 and single-speed rings covered a few weeks ago, the company have released 130mm BCD time trial chainrings in 54/42-tooth combinations (with 55/42t to follow) and a new mid-compact, 52/36t set. Also in development are 29er-specific mountain bike chainrings with lower ratios to help offset the bigger wheels.
The company aren't only about chainrings, however – they also make the most thoroughly thought-out BB/PF30-to-24mm bottom bracket adapter we've seen yet. Far from just a pressed-in sleeve with threads for conventional cups, the Praxis Works adapter builds the sleeve and one of the cups as one piece. The end of the sleeve is internally threaded but also slotted several times around so that when the other cup – which is slightly tapered – is threaded in, the sleeve expands against the inside of the shell like a collet, locking it in place and preventing creaking like simpler press-fit designs. Larger-diameter PressFit 30 bottom bracket shells require only an additional aluminum sleeve, which is included at no additional cost.
New cranks, too
Praxis Works have a sister company, Turn, who design and manufacture their own cranks. New for 2013 are fully modular models with either hollow forged aluminum or carbon fiber arms, both of which can be used with different chainring spiders as necessary. Target weight for the hollow forged aluminum cranks is under 750g for a complete compact set with bottom bracket. Swapping in carbon arms will shave off 50g.
Far and away the most intriguing model in the range, however, are the prototype all-carbon Turn road cranks with huge arms, a massive chainring spider supporting a clever one-piece dual chainring, and a gigantic 35mm-diameter carbon fiber spindle rotating on externally located bearings.
According to Praxis's director of marketing and sales, Adam Haverstock, target weight for the all-carbon cranks is around 600g – about 100g lighter than the previous iteration, which was all machined aluminum. The real draw, however, will be their incredible stiffness. Pedaling efficiency should be among the best in the industry with the enormous arms and spindle but the stoutly reinforced spider arms – plus the hidden fourth arm design – combined with Praxis Works' well-engineered chainring pins and ramps should yield fantastic shifting, too.
Haverstock wouldn't even guess on a timeline for the all-carbon cranks and suffice to say we don't expect these will be cheap. That being said, we're still looking forward to trying them out someday regardless.
Target weight for Praxis Works' awesome-looking all-carbon road crankset is a feathery 600g with chainrings and bottom bracket