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Wednesday, 18 January 2017

Tech Talk: Pivot Switchblade 29"

Pivot Switchblade 

The Switchblade is Pivot’s first frame compatible with both 29″ and 27.5+ wheels, the two wheel sizes have inherently very different ride attributes, so effectively two different bikes can be built from one frame. Two wheel sizes in one model of bike is not a new concept but two wheel sizes with one frame is. What’s most interesting is how two Switchblades can built with the different wheels resulting in nearly identical geometry, leaving the different ride characterise to be determined by the wheels only.

The Switchblade took five years to develop. Pivot had four prototype frames on-hand to illustrate the evolution of this bike. In the bike’s first iteration, clevis shock mounts were used to get the chainstays short, while generation two saw larger pivots and beefier links. Despite the changes, it still wasn’t as stiff as Pivot wanted it to be. As the third generation started taking shape, it gained an upper link similar to the one Pivot’s Phoenix downhill bike uses and Boost spacing. The bike was getting close to meeting Pivot’s standards—and then plus-size tires came along. 

Comparison between standard hub with super boost plus 157

To accommodate those bigger tires and still achieve the company’s stiffness and geometry goals, Pivot’s engineers needed to think outside the box. Enter Super Boost Plus 157. Super Boost Plus 157 optimizes existing standards to create what could just be a better mousetrap—especially for long travel 29ers and plus-tire-compatible bikes. It uses the existing 157x12mm rear hub spacing and the chainline that’s used for downhill bikes, but pairs that to a standard trail bike bottom bracket for 6mm more tire clearance—twice that of Boost 148. DT Swiss, Industry 9 and Reynolds are already on board, and SRAM are offering a similar 157 mm hub concept that’s also compatible.


Spacer under headtube

To ensure the BB height isn’t too low when riding with plus-size tires, Pivot delivers the bike with a spacer under the head tube. Interestingly, the same spacer can be used to slacken the head angle when running 29er wheels. According to Pivot’s founder Chris Cocalis, this offers 12mm of tire clearance and allows for super short chainstays, all while creating a stiffer, stronger wheel and frame. Q-factor remains essentially the same too. And there’s even front derailleur compatibility for 2x setups.

Q factor comparison

Super Boost Plus 157 cranks can use a PressFit 92mm or threaded 73mm bottom bracket shell. According to Pivot, several other manufacturers will also have compatible cranks available soon.The carbon front end is paired to a one-piece carbon rear triangle with a double wishbone, which Pivot claims provides excellent stiffness. Comes in at a featherlight claimed weight of 2,900 grams and shows off its descending potential with a humongous reach and a slack 67.25° head angle. Every frame size except the XS can accommodate a water bottle inside the front triangle. If you flip the shock body, you can fit an even bigger bottle.

Internal route cable

Besides the rear hub, it’s clear the Switchblade has been designed with a keen eye for detail. The internal cable routing and guides are well thought-out and there is a removable chip on the underside of the down tube near the bottom bracket for a Shimano Di2 battery. To protect the shiny carbon there are integrated rubber chainstay and down tube protectors and a metal plate to fend off chain slap.


Highlight:

  • Compatible with 1x or 2x chainring
  • Super Boost Plus 157 Freehub
  • Di2 ready
  • Can use it with 29" or 27,5+" wheels
  • Super Boost Plus 157 Crank
  • Adjustable head angle



Glossary:

Bottom Bracket: The bottom bracket on a bicycle connects the crankset (chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle that the crankset attaches to, and the bearings that allow the spindle and cranks to rotate. The chainrings and pedals attach to the cranks. The bottom bracket fits inside the bottom bracket shell, which connects the seat tube, down tube and chain stays as part of the bicycle frame.

Downtube: The down tube connects the head tube to the bottom bracket shell. 

Chainstay: The chain stays run parallel to the chain, connecting the bottom bracket shell to the rear dropouts


Source:
http://www.bicycling.com
http://enduro-mtb.com
https://dirtmountainbike.com
http://www.singletracks.com
http://flowmountainbike.com


Ride On!

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