The problem with the KTM steering head design
The KTM style steering stem design is different from a "traditional" design used by Honda, Yamaha, Kawasaki, Suzuki, and others. Here are a couple photos of both designs:
The KTM design is much like modern bicycle headsets. There's a nut (it's really a bolt) on the top of the triple clamp that is used to preload the steering bearings. This bolt is not a structural part, its only purpose is to adjust the bearings and it doesn't get tightened very much. Once the bearings are adjusted, there's another bolt on the triple clamps that clamps the top clamp around the steering stem and locks everything together. The clamp itself is slit so the steering stem pinch bolt can clamp the stem when tightened.
This works really well on bicycles, but motocross bikes see much larger loads! The stem on a KTM is also a smaller diameter than a bicycle steering stem, and the bicycle stem typically uses two pinch bolts. KTM only uses one.
Under normal conditions, and when properly installed and maintained, the KTM style system is rather elegant, lightweight, and effective. But, take away the normal conditions and/or the proper installation and maintenance, and things can go really wrong. If the pinch bolt is compromised somehow and fails, then there's not much of anything holding the whole front end of the bike to the chassis. This is why Ripper's bike ended up in two pieces. That bolt broke, then everything else broke, and the result is what spread all over social media.
This isn't a scenario specific to Luxon parts, it's happened with many triple clamps of this style; both stock KTM/Husky/GasGas and aftermarket. Here are a few examples:
The “traditional” steering setup used by the Japanese manufacturers, and others, uses a non-slit clamp and a steering stem with a large nut to preload the bearings and a large nut on top to tighten it all together. This is a very strong and robust design. Even with improper assembly and poor maintenance, it would be pretty obvious that something was wrong before the front end of the bike broke off. The downside of this design is that it's a little heavier and not quite as easy to adjust. But we've never had any issue with our clamps of this design (Honda, Yamaha, and Kawasaki), and I've never seen anyone else's clamps have an issue in the steering stem area with this design either.
Great article ! I am a Luxon customer purely because of your dedication to innovation, and engineering transparency. None of the competition would put up a detailed engineering analysis of a high profile failure like this. Nor do they put out detailed blog posts on their design and analysis. Proper assembly and maintenance is incredibly important, especially when using parts that push the limits of design, performance, and mass reduction like Luxon's products. This can't be ignored or overlooked, which is likely what happened here. Anyone in the industry who disrespects the work Luxon does is clearly very narrow minded, ignorant, and simply doesn't understand engineering fundamentals. Keep up the good work Billy!
Read this blog post, great effort to show all the context as far as you can without having been there for that crash or any of the maintenance to the bike. It does seem the ktm style clamp requires more close attention and a bit more understanding on how it should be set up. The instagram mouth breathers certainly know jack so it’s funny to see their negativity come out of nowhere. It almost seems worth contacting KTM about their design choice!