Luxon Triple Clamp Failure!?

Billy Wight, President, Luxon MX

March 9, 2023

Ripper Broken Bike
This image and similar ones were shared all over social media

You may have seen a photo of a KTM broken in half about two weeks ago that had Luxon triple clamps (Riley Ripper at Arlington press day before Supercross). Multiple photos were shared across social media; a bike broken in half is pretty spectacular looking! What those photos lacked, though, was context. What broke and why? Well, that's what this blog is all about!

There are a lot of details below, but there are two important points to make immediately:

Riley Ripper is fine. He was a little sore after the crash, but otherwise OK. He put on another set of Luxon clamps and raced the next day.
The clamps broke because Ripper crashed, the clamps did NOT break and cause the crash. We've had a small handful of parts break over the years, but all were either the result of hard crashes and/or improper installation and maintenance. There is no issue with any of our products, past or present, when ridden under normal conditions (no massive crashes) and with correct installation and maintenance.
Someone on Instagram posted multiple lies stating that we "blocked" Ripper and his mechanic. This isn't true at all. I talked with them directly on the phone, then sent them a new set of clamps at no cost that same day.

So, what happened?

I called and spoke with Ripper and his mechanic not long after the crash. Ripper told me that he hit a jump, got a little out of shape, but went for the next triple anyways. But he didn't make it and had a big crash. When went to get the bike, it was in two pieces. I specifically asked him if the clamps broke because of the crash or they broke and caused the crash; he said that they broke because of the crash. This is a very important detail!

Here's Ripper himself describing his crash in an excerpt from the BigMX Radio Podcast:

Parts break in a crash, that's just the nature of this sport. And when a professional level Supercross rider crashes on a triple, it's going to be a big crash. In this case, it was our clamps that broke, or more specifically, the steering stem pinch bolt that broke. In countless other cases this year, and in years past, it has been other parts (bars, subframes, wheels, etc.).

Something special about this crash, though, is that the whole front end of the bike came off! That's not ideal… Why did that happen?

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.

What are the details of the Luxon clamps that broke?

The Luxon clamp on Ripper's bike broke after the steering stem pinch bolt broke. And, as explained above, when that bolt breaks, the whole front end comes off. But why did that bolt break? There are a few reasons why that bolt broke:

The bolt on Ripper's bike was a titanium pinch bolt. It's plenty strong for the job, but being titanium, it requires some special care:

Anti-seize needs to be used on the threads and under the bolt head
The correct torque needs to be applied with a quality torque wrench and checked often

This torque is lower than a standard bolt. Torquing this bolt to the standard level will result in an over-stressed bolt

We don't know if the bolt was properly prepped and torqued or not in this case, but if it wasn't then it can certainly lead to what happened.

The titanium bolt (and all bolts really) should be inspected, or better yet, replaced, after a hard crash.

Privateer Supercross riders crash more often than the top pros; and they often crash hard! Enough hard hits and parts fatigue faster and can break, in particular, that pinch bolt. The clamps that broke were about a year old. How many crashes has Ripper had on them previously? We don't know, but I suspect there have been a few.
There's definitely been one, as it's on video. And it's a big one. This crash was just two weeks prior at the Houston Supercross. Take note of how hard the bike hits the flat, rather solid, ground - the end of the bars hit, and with the full force of the bike. The bars act as a big lever arm that's in just the right direction to put a lot of force into that pinch bolt.

Ripper's Big Crash, Two Weeks Prior

The pinch bolt did not break in this crash, but it was not replaced afterwards either. This crash very likely compromised the bolt, which can significantly reduce its strength.

Can we make the design better?

We already have, about a year ago. As we do with all of our products, we're constantly updating our designs to increase performance, reduce weight, add robustness, etc. As mentioned, Ripper was on an earlier revision of the clamps (about a year old). Since then, we've made two revisions to increase the robustness of the steering interface:

We changed that titanium bolt to a higher strength steel bolt. It's only about 4% stronger, but it's also a bit more resilient to torque variation and allows us to use thread locker which helps to ensure it doesn't come loose.

This bolt also requires a 12-point socket to tighten, which is one step closer to ensuring the mechanic uses a torque wrench. No more t-handles.

We revised the slit in the top clamp to reduce the load it sees in common crashes. It's a small change, but every little bit counts.
We've always had thorough instructions that come with our parts, but we made it even more clear that the pinch bolt is critically important in the newer revisions of the instructions for these clamps.

Unfortunately, we've found that some of the “professional” mechanics are more likely to ignore instructions and do “what they've always done”. Which can be very wrong!

Though we've made these changes, it isn't to say that the previous design wasn't any good! We have hundreds of these clamps out there, many ridden hard by professional level riders. The previous design was used from 2017 through early 2022. Freddie Noren and Garred Steinke are just a couple of riders who used the same clamps as Ripper in 2022 without any issue and they're both significantly faster than Riley. Faster guys are harder on equipment in aggressive racing conditions and the titanium pinch bolt and clamp held up just fine for them as it has for many riders in the four years prior.

Wait, didn't this happen before?

Alves Broken Bolt
Broken bolt on Ramy's clamps, Atlanta SX 2022

It did, actually. Last year Ramy Alves also had the pinch bolt break, which resulted in a similar broken bike. Here's what happened with that situation:

There are no photos or video of that crash available to review, unfortunately.
Despite the team stating that they would send the clamps back to us and that they'd send an email with their thoughts with more information, neither of those things happened, even after multiple reminders.
I have seen a video on Instagram of that team's mechanic torquing the top and bottom triple clamp bolts to the same level. This is incorrect and I messaged them as such. This doesn't build confidence that they torqued the pinch bolt correctly.

Given all that, there's nothing to do but come to a conclusion based on the evidence I have. Clearly, the stem bolt broke in that situation, but why? There's evidence of them torquing the other bolts incorrectly. None of our other clamps have broken like this, even with much faster racers on them; three years of these clamps prior to Ramy's crash, without a problem. So, my best conclusion based on the evidence we have is one of two scenarios:

They over-torqued the bolt, which caused it to break in a high stress scenario, which caused a crash.
There was a big crash and things broke, as they do in big crashes.

Unfortunately, that's all we could go on. But in response to that, we made the design changes I mentioned earlier. Regardless, either version of our clamp has been shown to have no issues when properly installed and maintained.

So why not just change it to the “traditional system”?

Well, it's not that simple, unfortunately. There's only so much room to work with there. KTM doesn't use a locknut like the Japanese bikes, so there's no room for it in the head tube of the chassis. If you were to convert the design over to a “traditional” style like the Japanese bikes use, everything has to get thinner. The top triple clamp on the previous generation KTM was about 26 mm thick. On the latest generation, it's thinner at about 23 mm. The adjustment nut takes up about 10mm of thickness, which leaves you with only 13 mm (1/2 inch) of triple clamp at that point. That's not terribly strong either.

So, we could make a raised section in the middle of the clamp with a longer stem to get the thickness we want, but that pushes the bar mounts up a good amount. With that change, you lose compatibility with aftermarket bar mounts, steering stabilizers, etc., so it really reduces the value of the clamps to a lot of riders.

We are looking into alternatives to get around this, but like I said, it's not straight forward. Our new Gen3 triple clamp bar mount design makes this easier than with the previous design, so we will likley have something different there. The current KTM style pinch bolt design, though a weak point, does work fine so long as it's properly installed and maintained.

What about Garrett Marchbanks at Daytona 2022?

You might remember when Garrett had his bar mounts break off at Daytona Supercross last year. This was a completely different scenario than the KTM clamps, but I'll summarize what happened here. Garrett crashed in Daytona and his bars hit the ground hard. Here's a video:

The Garrett Marchbanks Crash, Daytona SX 2022

Garrett had a pretty good crash, and the bars hit the ground hard. You can see how far they dig into the dirt in the slow motion replay. That put a ton of force into the bar mount bolts and they snapped.

Some key points to make about this:

The bar mount bolts broke because of the crash, they were not the cause of the crash.

Garrett initially reported that they caused the crash. But when the video was reviewed, it was obvious that it was the other way around! A lot happens really fast in racing and crashes and we don't blame him for this at all. We're just trying to make sure everyone gets the real facts.
The crash wasn't super hard, but everything aligned just right to put all the load into the bar mount bolts.

Garrett was running a non-standard bar mount setup that wasn't as resilient as the standard setup we send to our customers (he had solid cones instead of rubber and was using risers on the bar mounts).
The fix to this breakage was $18 worth of bolts. Had those bolts held up, something more expensive would have bent or broken, like the handlebars, as we've commonly seen from other crashes.
We've revised the design for Garrett to be stronger, which will help avoid a DNF like this again (he later qualified for the main event in the LCQ, so this didn't end his night).
This scenario is a complete non-issue for our customers.

In conclusion

A few people have commented that Luxon products fail a lot. Well, I guess that depends on how you define “a lot”. All of the big failures of our products have been detailed above; all three of them!

So why do you see our parts breaking "a lot"? Simple. We sponsor a lot of riders. This year we have over 30 professional Supercross, motocross, and MXGP riders on our parts. Last year we had 44 of them. Fifteen the year before that. And a few in the years before that. All of those riders are privateers or privateer team guys. And those are the guys who crash a lot, particularly when they're trying to push hard during a race. And when that's happening, it's also on TV or during a well publicize event.

So, lots of riders and lots of crashes is going to mean a few broken parts, and those will get a lot of press as there's a lot of people around. I'd say the small handful of broken bolts over five years of hard racing isn't bad at all. And we've taken measures to minimize that going forward.

Bottom line, things break in a crash. When you have a lot of riders who crash hard fairly often, you're going to see things break. There is no issue with any of our products, past or present, when properly installed and maintained. Thousands of sales and customers have proven that. For the few that happen to break one of our parts in a crash, we have a crash replacement policy to get you up and running for a good discount.

One more thing...

There are some negative comments about online, on Instagram, and other places. These people are posting wild speculation and sometimes just outright lies about us.

We even received an email from a "customer"the day after Ripper's incident claiming that he broke his clamps in a whoop section. Strange that their name didn't exist in our database. And when asked for an order number, name, or photos of the supposedly broken parts, there was no response.

Yet another was claiming our parts are made in China. Here's a walkthrough of our facility if anyone has any doubt about that: Shop Walkthrough Video

We're engineers. We present facts, not wild speculation. And in the absence of available facts, we use the best evidence we can to draw conclusions. There are critics out there with little to no engineering knowledge or background, spreading false information to the community, and impacting an innovative, USA based moto company in the process. Please ignore them and if you happen to see a negative post, direct them to this blog for some facts.

This should clear things up, but if anyone has any questions or concerns we'd like to hear from you, so please contact us!

Blog Comments

Comments (2)

Mitch:

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!

28 April 2023 17:57

Scott:

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!

10 March 2023 22:54