Stiffer wheels: ideal for 27.5 and 29 - and especially Plus tires
In summer 2014, Trek tinkered with the rear triangle and rear hub for the new Remedy bike: The result was a 148mm wide hub, called Boost 148, with the hub flanges slipping 3mm outwards on the left and right, and thus also the brake mount. The result was a spoke angle that supports the rim more widely, making the wheel stiffer. This is generally important for good and direct transmission of steering, braking and drive forces - and is particularly important for wheels with a larger diameter (27.5 and 29 inches) and wide tires.

Another advantage of the wider rear hub and the modified chain line should be more tire clearance and more space for accommodating pivot and suspension technology on the rear triangle.

Plus-size tires need wider flanges
With the plus-size tire trend rolling in at high speed, the Boost formats come at just the right time. The tires with widths of 2.75 to 3.25 inches provide the mountain bike system with higher forces that act on the wheel. Wider flanges are the right medicine to make the wheel stiffer and more stable.

Boost also at the front: 15x110mm
The 15x110mm format is not entirely new, as the Rock Shox RS-1 29er upside-down fork already uses this installation width, albeit in a so-called predictive steering version. As with the rear triangle, the flange spacing has increased for the Boost 110 format, with the flanges each slipping outwards by 5mm compared to the now dominant 15x100mm standard. With the same advantages: The wheel becomes stiffer and steering, braking and drive forces are transmitted better.

What are the consequences of the two new hub standards? These are not backwards compatible...
Probably to the delight of component specialist Sram, which is pushing the Boost components, numerous new components are needed: To use such bikes with Boost 110 and Boost 148 hubs, you need a matching fork and a matching bike with a corresponding rear triangle. New cranks adapted to the new chainline are also needed. With the Boost rear hub, the cassette slips slightly to the right, so the crank is fitted with a spider with a 3mm offset. The familiar Q-factor remains with the Boost cranks.

The Boost forks could possibly cause confusion in combination with the Plus format. A 29er Boost fork offers space for a 27.5 Plus tire with a tire width of around 3 inches.

New standard with new brake rotor position
When Syntace invented the X-12 hub dimension and the bike industry had been using the standard on a large scale since 2008, it was possible to convert numerous hubs from the predominant 135mm format with end caps to the X-12 dimension with a width of 142mm. This means that the position of the hub flanges and therefore the position of the disc brake mount were the same. With the Boost format, however, the disc brake mounts also slide outwards with the flanges. For the time being, changing end caps cannot mediate between X-12 and Boost.

And another marketing term
Boost 110 and Boost 148, Plus Standard... and now Torque Cap on top. If you are not yet confused by the new standard shaft, you can also remember this term: The new Boost fork from Rock Shox is emblazoned with a mount for the so-called Torque Cap, which is designed to ensure that the frictional connection between the hub and fork is optimal due to a significantly larger contact surface.

In the second part, Ride presents the new Boost components from Rocks Shox in detail.

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