For years I’ve been riding my beloved, custom-built, blue and black 2017 Salsa Mukluk with a set of DT Swiss 350 Big Ride-based wheels. This fall I noticed a very small crack in a non-critical part of the frame and Salsa quickly swapped me to a new 2019 Mukluk frame. Along with the new frame came a bit of an upgrade; Salsa’s Kingpin Deluxe fork.
In looking at photos of the fork, test fitting with end caps, and as confirmed by Salsa directly, the Kingpin Deluxe has 31mm dropouts designed to fit the SRAM-developed Torque Cap end caps. Originally intended to make suspension forks less prone to twisting, the larger 31mm OD end caps, instead of the standard 21mm OD, strengthen the wheel/axle interface. This is well documented elsewhere, and end caps are available for most higher end wheel sets (I9, DT Swiss, etc), but it only appeared on non-fatbike RockShox suspension forks… until now.
It’s not clear to me why Salsa chose to put 31mm dropouts on the already-stiff, rigid, carbon Kingpin Deluxe fork, but they did. My guess is they saw potential for dynamo hubs — which generate power via forces between the still axle and moving hub shell — to use Torque Caps so they have a larger interface with the hub. After all, one of the new features of the Kingpin Deluxe fork is internal routing for dynamo hubs.
The only downside to including 31mm dropouts is that without Torque Cap end caps on the hub the wheel won’t self-center on the axle making wheel installation a little bit fiddly. In practice this isn’t a problem, and Newmen made stick-on Torque Cap Fork Reducers to mitigate it, but I wanted to see if I could get some actual Torque Caps for my DT Swiss 350 Big Ride Center Lock hubs (H350DCIXR32SA6259S) to do it right.
After a bit of email with Logan, one of the ever-helpful folks at DT Swiss, I learned that unlike all their other hubs, these have equal-length end caps and until now there weren’t any fat bike forks with 31mm dropouts, so DT doesn’t have a Torque Cap kit for these hubs. Logan suggested that I pick up two of the HWGXXX0009100S kits for regular 350 hubs, then use the longer pieces on each side of the hub, figuring this should fit. While this was a bit pricey (~$65), it felt like the right choice so the wheel would match the fork.
The kits arrived and just as Logan had calculated these caps dropped right in and now the end caps and fork match. Hopefully in the future DT Swiss will offer a kit that has just the necessary parts so others won’t have to buy two as well.