5DEV Heavy Metal Downhill Spindles

The 5DEV Heavy Metal Downhill Spindles are crank spindles made from 17-4 stainless steel in San Diego, and they are heavy on purpose. Most spindle upgrades chase grams. These add them at the bottom bracket, the lowest and most central point on the bike. World Cup downhill teams have been putting weight there deliberately, because mass kept low and in the middle settles a bike at speed without the handling cost of weight carried high or out at the ends. The spindles weigh 616 grams in 29x139mm and 649 grams in 29x145mm.

They started in the 2025 World Cup season, when downhill racer Neko Mullaly asked 5DEV to make a batch of steel spindles for the Frameworks team bikes. For 2026 he agreed to let 5DEV sell them. In his words: "Adding weight low and central on the bike has been a trend over the past few years and is very common among World Cup Downhill teams right now. This spindle adds 500g exactly where you need it." Read that 500g as the extra weight over an aluminum spindle, not the weight of the part itself. The 29x139mm length (SB+, short for SuperBoost Plus) is what the Frameworks bikes run. 5DEV added the 29x145mm length (DH) to cover the rest of the downhill market, so check which one your frame and cranks call for before you order. These spindles fit 5DEV's own analog cranksets only, meaning their standard cranks as opposed to their e-bike cranks. They are not compatible with SRAM crank arms or with any other aftermarket crank maker.