What is Boost 141 or Boost QR

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Guide to Boost 141 or Boost QR

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Trailmech XC Front End Caps QR, legacy
Trailmech XC Front End Caps QR, legacy

The answer to the question on what really Boost 141 is about, may not be comfortable. As Boost 141 or Boost QR stands for an inferior version of the mainstream Boost standard. And we argue why here.

The original Boost 148 states the 12 mm thru axle for the rear. We covered its story and compatibility with the legacy non-Boost earlier.

Several bike manufacturers established that there must be a different option out there. We would not call it a better one, frankly because it is not. And so, we got Boost 141, or Boost QR. Sometimes also referred to as Boost 141×9, which is not precise definition. Instead of using the 12 mm axle, it uses 5 mm legacy Quick Release rod or skewer and same legacy end caps. So much for the story of stiffness, which is one of the buzz words in cycling. From performance point of view, there is nothing to hype about Boost 141. We believe that its existence is “operational efficiency” driven, of saying directly – desire to marginally reduce manufacturing per unit costs. A change from an alloy machined 12mm stiff and light thru axle, to rolled-steel 5mm skewer.

Only two hubs from our current lineup support the legacy 5 mm QR axle option or 135xQR – XCR and Gravel.

The forgotten 135xQR is “resurrected” with a new name Boost 141. Just add the 6 mm difference in the over dropout length and here you go – 141xQR. And so, it makes its way to some otherwise capable bikes, e.g Trek X-Caliber and alike.

Trailmech Rear End Caps. Left: Boost 141x10 Thru Axle. Right: Boost QR
Rear End Caps. Left: Boost 141×10 Thru Axle. Right: Boost QR

By omitting the support of genuine 12 mm thru axle, designers brought back the open dropouts. And by doing so, created a backdoor to yet another legacy tech – 10 thru axle option. Also known as the “thick” QR – 135×10 thru axle. Indeed, it is exactly the same concept, just 6 mm wider – 141×10 thru axle. But this is an aftermarket tech. You won’t find 141×10 thru axle in stock specs with your rig. Boost 141×10 is a solution to rectify the issue with the 5 mm thin QR skewer, which keeps your rear wheel attached to the frame.

Boost 141 thin skewer fits through the end caps. There is no attachment between skewer and hub’s axle. The skewer gets its support solely from the end caps, unlike for regular Boost. Majority of rear hubs have their internal axles machined to fit 12 mm thru axle, including our XCR, Gravel and Enduro. The latter slides in and directly supports hub’s axle and end caps. Making it an “effective” 17 mm axle which joins the bearings and bike’s frame.

Similar to the conventional “thin” skewer, 141×10 mm thru axle rests only on the end caps. However, with its double cross section diameter, it offers much better stiffness. Not as good as 12 mm, but better than 5 mm skewer. Besides, any open dropouts Boost QR frame accepts 141×10 thru axle – no modifications required.

The only good thing about Boost 141 that it is convertible to Boost 148. It is only the end caps that differ between the two standards. That is from hub’s perspective not the frame, though. The latter cannot be converted to Boost 148.

Done with Boost 141. You may be thinking, is there anything else we are missing in Boost family? Well, the industry got the answer. You may did not know it, but it is Road Boost.