It is not Boost 148mm. The Trail 429 uses a 157mm rear hub spacing in a configuration called Super Boost Plus 157. The rear hub spacing is the standard 157mm spacing available from every hub manufacturer in the world so any 157mm X 12mm hub is compatible with the Trail 429. Super Boost Plus 157 builds on the idea of wider flange spacing pioneered by Boost 148. Super Boost Plus spreads the flanges even wider (up to 14mm wider than a 142mm hub) and increases wheel stiffness substantially, which is a huge benefit on 29” enduro and 27.5+ wheels. Although any 12mm X 157mm hub can be used, the special Super Boost Plus versions developed with Pivot, DT Swiss, Industry 9, and Reynolds makes for a highly optimized 29er enduro and 27.5+ wheel combinations that take wheel performance to another level. SRAM also offers a similar concept 157mm hub in their standard XO line. Super Boost Plus Hub flange spacing is also available on wheels from Stan’s and hubs from Onyx. Most hub companies are adopting the Super Boost wider flange spacing to their 157mm hubs so if you have a particular brand of hub that you are looking at, its best to check with the manufacturer as to what they are running.