KTM broke in half.

Brent
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5838
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8/16/2006
Location
Temecula, CA, USA
4/18/2022 11:34am Edited Date/Time 4/18/2022 11:41am
GrapeApe wrote:
I'm curious, too. No need to provide details, just a brief description would suffice. You're the one that interposed the X-trig clamp into this thread, and...
I'm curious, too. No need to provide details, just a brief description would suffice. You're the one that interposed the X-trig clamp into this thread, and referenced "a couple specific reasons" why it would have fared better.

I will add I'm not trying to be mean, I'm genuinely curious. I, like many others on here, like to nerd out on this stuff.

Fair enough.

Background -

There are people with some money in Holland that want to work with me to try and start a small race team for the AMA nationals so that they can send EMX and Dutch Masters development riders to race in the USA. This will be an ongoing thing if it works, since the first time I did this last year didn't turn out too badly for the first rider.

A few riders and tech guys have been visiting here in Temecula off and on testing parts since last year.

We have been testing a lot of hard parts and other components made both both here and in Europe to determine what works, and we have had some things work well and some that break. I have one guy in particular that can break any part on a KTM just by riding it hard, so its been an eye opener.

If I start posting particulars about parts, I get a bunch of shit from anonymous people who don't have an idea about what they are talking about. I don't have to explain myself and why I have an opinion on stuff.

If anyone wants to ask questions about any of this, then go to the pits at Fox Raceway in May during the first national and find me - I'll be more than happy to hand you a beer and show you face to face what we think works on these bikes, and why.
10
16
Sandusky26
Posts
3421
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7/28/2021
Location
Eastern, NC, USA
4/18/2022 11:36am
I'll delete this thread for a free set of triple clamps.
12
4/18/2022 11:48am
McG194 wrote:
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to...
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to break but it will bend and stretch less. It will be nothing, nothing, nothing snap. I lower grade bolt you may have to retorque more often, but I'd rather have a bolt stretch than break.
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much...
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much? I assume the lower grade bolt has a cycle limit of #, or amount of stretch allowed. Does the higher grade bolt too? Do I simply change the bolt once a year to be safe? I can see the criticality of this bolt in the grand scheme of bike maintenance.

I'm sure I torque that specific bolt at least 10-15 times a year on each of our Austrian bikes and I've never changed it. Bolt comes out, gets cleaned on a wire wheel, upper clamp threaded part gets cleaned with brake cleaner and air compressor. Then fresh loctite on the bolt and torqued to spec on install every time. My boy is really picky about his headset "feel" and we touch the headset and clamps quite a bit.

Hammer
Get a set of calipers and google Young's Modulus. Have fun Laughing
2
McG194
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Location
Palm Coast, FL, USA
4/18/2022 11:49am
McG194 wrote:
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to...
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to break but it will bend and stretch less. It will be nothing, nothing, nothing snap. I lower grade bolt you may have to retorque more often, but I'd rather have a bolt stretch than break.
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much...
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much? I assume the lower grade bolt has a cycle limit of #, or amount of stretch allowed. Does the higher grade bolt too? Do I simply change the bolt once a year to be safe? I can see the criticality of this bolt in the grand scheme of bike maintenance.

I'm sure I torque that specific bolt at least 10-15 times a year on each of our Austrian bikes and I've never changed it. Bolt comes out, gets cleaned on a wire wheel, upper clamp threaded part gets cleaned with brake cleaner and air compressor. Then fresh loctite on the bolt and torqued to spec on install every time. My boy is really picky about his headset "feel" and we touch the headset and clamps quite a bit.

Hammer
I don't know the specific grade of bolt KTM uses but to me all of them look suspiciously like Torque to Yield fasteners even though I know they aren't. Those are one time use only bolts used in automotive. Tighten it once and if you remove it you throw it away. I would say that if you are re torquing it that often a once-a-year replacement is a good policy.
5
1

The Shop

LungButter
Posts
8684
Joined
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Location
Yellow Pine, ID, USA
4/18/2022 11:54am
Brent wrote:
Fair enough. Background - There are people with some money in Holland that want to work with me to try and start a small race team...
Fair enough.

Background -

There are people with some money in Holland that want to work with me to try and start a small race team for the AMA nationals so that they can send EMX and Dutch Masters development riders to race in the USA. This will be an ongoing thing if it works, since the first time I did this last year didn't turn out too badly for the first rider.

A few riders and tech guys have been visiting here in Temecula off and on testing parts since last year.

We have been testing a lot of hard parts and other components made both both here and in Europe to determine what works, and we have had some things work well and some that break. I have one guy in particular that can break any part on a KTM just by riding it hard, so its been an eye opener.

If I start posting particulars about parts, I get a bunch of shit from anonymous people who don't have an idea about what they are talking about. I don't have to explain myself and why I have an opinion on stuff.

If anyone wants to ask questions about any of this, then go to the pits at Fox Raceway in May during the first national and find me - I'll be more than happy to hand you a beer and show you face to face what we think works on these bikes, and why.
L.O.L. Come on bro.... do you have a background in sales? Cause that was some good deflection there.

You came in here touting "go with what you know" and inferring that the XTrig was superior.

You pointed out in another post "a couple specific reasons."....

Since then you've been called out on "Why is it better?" and continually refuse to give those "specific reasons".

Why even bring it up if you aren't gonna back it up? It almost leaves one to believe that you don't have any reasons you just wanted to make yourself look superior....

All that to say, I'm truly curious about the reasons as are others. Not trying to be a dick but it's hard not to sound like one when responding to someone with such a superiority complex as yourself.

20
philG
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Joined
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Location
GB
4/18/2022 12:04pm
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much...
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much? I assume the lower grade bolt has a cycle limit of #, or amount of stretch allowed. Does the higher grade bolt too? Do I simply change the bolt once a year to be safe? I can see the criticality of this bolt in the grand scheme of bike maintenance.

I'm sure I torque that specific bolt at least 10-15 times a year on each of our Austrian bikes and I've never changed it. Bolt comes out, gets cleaned on a wire wheel, upper clamp threaded part gets cleaned with brake cleaner and air compressor. Then fresh loctite on the bolt and torqued to spec on install every time. My boy is really picky about his headset "feel" and we touch the headset and clamps quite a bit.

Hammer
Unless you know what it was in the first place, you cant know how much it has stretched, so you toss it in the bin.

Replace it with the proper bolt to the proper torque.

This is why the factory guys pull them apart every week and go though a shit ton of parts .

Good maintenance, is just that , taking it apart to see what is going on, checking for cracks etc.

Having spent enough time looking at failed parts in Motorsports and Aerospace, understanding that stuff just breaks, and legislating for when it does, is always better than trying to make stuff indestructable.

A Plane that would never break , would also never fly.



6
Brent
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Temecula, CA, USA
4/18/2022 12:05pm Edited Date/Time 4/18/2022 12:08pm
LungButter wrote:
L.O.L. Come on bro.... do you have a background in sales? Cause that was some good deflection there. You came in here touting "go with what...
L.O.L. Come on bro.... do you have a background in sales? Cause that was some good deflection there.

You came in here touting "go with what you know" and inferring that the XTrig was superior.

You pointed out in another post "a couple specific reasons."....

Since then you've been called out on "Why is it better?" and continually refuse to give those "specific reasons".

Why even bring it up if you aren't gonna back it up? It almost leaves one to believe that you don't have any reasons you just wanted to make yourself look superior....

All that to say, I'm truly curious about the reasons as are others. Not trying to be a dick but it's hard not to sound like one when responding to someone with such a superiority complex as yourself.

Because saying anything about other manufacturer's products on a public message board is not the best move. I like X trig stuff for a reason, and its not just my view.

You are welcome to see for yourself - We will be training around the SoCal tracks all month in May.

DM me for our schedule.
17
GrapeApe
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Location
Mc Kinney, TX, USA
4/18/2022 12:08pm
GrapeApe wrote:
I'm curious, too. No need to provide details, just a brief description would suffice. You're the one that interposed the X-trig clamp into this thread, and...
I'm curious, too. No need to provide details, just a brief description would suffice. You're the one that interposed the X-trig clamp into this thread, and referenced "a couple specific reasons" why it would have fared better.

I will add I'm not trying to be mean, I'm genuinely curious. I, like many others on here, like to nerd out on this stuff.

Brent wrote:
Fair enough. Background - There are people with some money in Holland that want to work with me to try and start a small race team...
Fair enough.

Background -

There are people with some money in Holland that want to work with me to try and start a small race team for the AMA nationals so that they can send EMX and Dutch Masters development riders to race in the USA. This will be an ongoing thing if it works, since the first time I did this last year didn't turn out too badly for the first rider.

A few riders and tech guys have been visiting here in Temecula off and on testing parts since last year.

We have been testing a lot of hard parts and other components made both both here and in Europe to determine what works, and we have had some things work well and some that break. I have one guy in particular that can break any part on a KTM just by riding it hard, so its been an eye opener.

If I start posting particulars about parts, I get a bunch of shit from anonymous people who don't have an idea about what they are talking about. I don't have to explain myself and why I have an opinion on stuff.

If anyone wants to ask questions about any of this, then go to the pits at Fox Raceway in May during the first national and find me - I'll be more than happy to hand you a beer and show you face to face what we think works on these bikes, and why.
Ok you tested some hard parts with some riders and X-trigs didn't break and presumably others did break. I was under the impression you have a couple of reasons, specifically, why you feel they didn't break. Design? Materials? Quality Control? Something we're overlooking? I don't care enough to travel from Texas to California for an answer, I'm just killing some time on a message board.
11
Luxon MX
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Location
San Diego, CA, USA
Fantasy
4/18/2022 12:10pm
McG194 wrote:
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to...
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to break but it will bend and stretch less. It will be nothing, nothing, nothing snap. I lower grade bolt you may have to retorque more often, but I'd rather have a bolt stretch than break.
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much...
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much? I assume the lower grade bolt has a cycle limit of #, or amount of stretch allowed. Does the higher grade bolt too? Do I simply change the bolt once a year to be safe? I can see the criticality of this bolt in the grand scheme of bike maintenance.

I'm sure I torque that specific bolt at least 10-15 times a year on each of our Austrian bikes and I've never changed it. Bolt comes out, gets cleaned on a wire wheel, upper clamp threaded part gets cleaned with brake cleaner and air compressor. Then fresh loctite on the bolt and torqued to spec on install every time. My boy is really picky about his headset "feel" and we touch the headset and clamps quite a bit.

Hammer
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see a good amount of load (obviously), and a lot of cycles of that load. So it's not a bad idea to change out the bolt every so often to reduce the odds of a fatigue failure.

Another reason to swap out the bolt is to maintain consistent torque. If you torque a new bolt, then remove it and torque it again, the resulting bolt tension will be different than the first time you torqued it. That's because the friction has changed - coating has worn off a little bit, the threads have "seated" a little bit, etc. If the bolt was installed dry, then that difference can be significant. See this reference for more info:
https://www.nord-lock.com/insights/bolting-tips/2020/reusing-bolted-joi…

Ideally, you'd swap out the bolt for a new one each time you take it apart (not each time you check the torque). That ensures consistent torque and significantly reduces the chance of a fatigue failure. If you're lubricating the bolt, then the torque-tension relationship is much more consistent (again, see above reference). You could get a few uses out of the bolt without replacing it without issue. The downside there is that the bolt is more likely to come loose being lubricated and you should double check torque more often (every ride, ideally).
11
LungButter
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Location
Yellow Pine, ID, USA
4/18/2022 12:17pm
Brent wrote:
Because saying anything about other manufacturer's products on a public message board is not the best move. I like X trig stuff for a reason, and...
Because saying anything about other manufacturer's products on a public message board is not the best move. I like X trig stuff for a reason, and its not just my view.

You are welcome to see for yourself - We will be training around the SoCal tracks all month in May.

DM me for our schedule.
I give up...

I'll just have to go about my life knowing that we are only smart enough to know that you think Xtrig is superior but we aren't quite smart enough to get your "specific reasons".

I appreciate the invite to the testing sessions as well, but at this stage in my life even the awesome motocross tracks aren't enough to convince me to step foot in Cali.

Best of luck with the race team.
13
Sandusky26
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Eastern, NC, USA
4/18/2022 12:20pm Edited Date/Time 4/18/2022 12:21pm
I don’t know who makes X-trigs, but this Brent guy should fight Adrian and Luxon so I can know for sure who makes the best triple clamps.
8
5
Hammer 663s
Posts
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Forest Grove, OR, USA
4/18/2022 12:21pm Edited Date/Time 4/18/2022 12:22pm
Luxon MX wrote:
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see...
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see a good amount of load (obviously), and a lot of cycles of that load. So it's not a bad idea to change out the bolt every so often to reduce the odds of a fatigue failure.

Another reason to swap out the bolt is to maintain consistent torque. If you torque a new bolt, then remove it and torque it again, the resulting bolt tension will be different than the first time you torqued it. That's because the friction has changed - coating has worn off a little bit, the threads have "seated" a little bit, etc. If the bolt was installed dry, then that difference can be significant. See this reference for more info:
https://www.nord-lock.com/insights/bolting-tips/2020/reusing-bolted-joi…

Ideally, you'd swap out the bolt for a new one each time you take it apart (not each time you check the torque). That ensures consistent torque and significantly reduces the chance of a fatigue failure. If you're lubricating the bolt, then the torque-tension relationship is much more consistent (again, see above reference). You could get a few uses out of the bolt without replacing it without issue. The downside there is that the bolt is more likely to come loose being lubricated and you should double check torque more often (every ride, ideally).
Thanks. Yeah, 20 nm isn't a whole lot of pressure applied at install. The loctite will act as a bit of a lubricant as well. I do follow the manual when torqueing as they often spec dry, engine oil, or loctite type and I always make sure both male and female threads are clean and dry to start.

I will get a hand full of new bolts and just change them every 6 months. Cheap insurance. Tonight I will check the torque on all the front end fasteners since we were hammering on the bikes all weekend on a jumpy SX-style track and they sure took some stress!

Hammer

PS I did Google Young's Modulus and while I get the physics (and less so the math) I'm just a Dad Mechanic. Smile
6
#434
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DE
4/18/2022 12:28pm
McG194 wrote:
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to...
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to break but it will bend and stretch less. It will be nothing, nothing, nothing snap. I lower grade bolt you may have to retorque more often, but I'd rather have a bolt stretch than break.
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much...
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much? I assume the lower grade bolt has a cycle limit of #, or amount of stretch allowed. Does the higher grade bolt too? Do I simply change the bolt once a year to be safe? I can see the criticality of this bolt in the grand scheme of bike maintenance.

I'm sure I torque that specific bolt at least 10-15 times a year on each of our Austrian bikes and I've never changed it. Bolt comes out, gets cleaned on a wire wheel, upper clamp threaded part gets cleaned with brake cleaner and air compressor. Then fresh loctite on the bolt and torqued to spec on install every time. My boy is really picky about his headset "feel" and we touch the headset and clamps quite a bit.

Hammer
I don’t think you have to worry about it one bit, if you regularly torque it to spec. That bolt will only fail if it gets massively over-torqued or is ridden loose and gets shock loaded by big impacts.
4
350ss
Posts
30
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12/24/2016
Location
Houston, TX, USA
4/18/2022 12:51pm Edited Date/Time 4/18/2022 12:55pm
350ss wrote:
why would ktm design the part asymmetrically like it is? if the bolt fails or is mistorqued than the left side is basically handling all the...
why would ktm design the part asymmetrically like it is?

if the bolt fails or is mistorqued than the left side is basically handling all the load (with a longer torque arm), whereas if it was symmetric and split in the middle like the suzuki pic above, if the bolt fails at least both sides would share the load with shorter torque arms increasing the safety factor. could even go with a two bolt design

maybe putting the split in the middle causes more load to be handled by the bolt as opposed to the clamp

would be cool to see the FEA on this
Luxon MX wrote:
Your proposed design would indeed be stronger, although it may not have enough extra strength to make a difference. If we were to implement that, though...
Your proposed design would indeed be stronger, although it may not have enough extra strength to make a difference. If we were to implement that, though, it would be nice as we could add a locknut instead of threading directly into the aluminum. This would help keep things from coming loose. There's not enough room for two M8 bolts, though, so the bolt size would need to drop down to make that work; definitely don't want to do that.

So initially that sounds like a good plan. However, KTM does it the way they do to keep a low profile. A bolt where you propose would interfere with steering dampers and possibly other aftermarket parts. So that alone eliminated the idea as we have to support aftermarket steering dampers.


is there a reason the split and bolts couldn't be on the number plate side? probably sees more load on that side of the steering shaft though

that could avoid the steering damper problem. seems like it would be easy enough to access with an extension to check it without removing the number plate and you could even get the bolt and lock nut you would want, two bolts, etc.


1
philG
Posts
11000
Joined
5/12/2012
Location
GB
4/18/2022 1:02pm Edited Date/Time 4/18/2022 1:25pm
Thanks. Yeah, 20 nm isn't a whole lot of pressure applied at install. The loctite will act as a bit of a lubricant as well. I...
Thanks. Yeah, 20 nm isn't a whole lot of pressure applied at install. The loctite will act as a bit of a lubricant as well. I do follow the manual when torqueing as they often spec dry, engine oil, or loctite type and I always make sure both male and female threads are clean and dry to start.

I will get a hand full of new bolts and just change them every 6 months. Cheap insurance. Tonight I will check the torque on all the front end fasteners since we were hammering on the bikes all weekend on a jumpy SX-style track and they sure took some stress!

Hammer

PS I did Google Young's Modulus and while I get the physics (and less so the math) I'm just a Dad Mechanic. Smile
You dont want to go down the rabbit hole of thread lubrication affecting torque settings.

Metallurgy is a bottomless pit of fun, used to run a rig that would strength test bolts... i pushed the button and a clever bloke watched the screen. When stuff goes, it goes with a bang.

*********
Just had a You Tube advert for Gedore Torque wrenches halfway through a video..

*********
2
rbm33
Posts
450
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4/1/2008
Location
Duncan, OK, USA
Fantasy
4/18/2022 1:10pm
McG194 wrote:
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to...
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to break but it will bend and stretch less. It will be nothing, nothing, nothing snap. I lower grade bolt you may have to retorque more often, but I'd rather have a bolt stretch than break.
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much...
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much? I assume the lower grade bolt has a cycle limit of #, or amount of stretch allowed. Does the higher grade bolt too? Do I simply change the bolt once a year to be safe? I can see the criticality of this bolt in the grand scheme of bike maintenance.

I'm sure I torque that specific bolt at least 10-15 times a year on each of our Austrian bikes and I've never changed it. Bolt comes out, gets cleaned on a wire wheel, upper clamp threaded part gets cleaned with brake cleaner and air compressor. Then fresh loctite on the bolt and torqued to spec on install every time. My boy is really picky about his headset "feel" and we touch the headset and clamps quite a bit.

Hammer
Luxon MX wrote:
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see...
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see a good amount of load (obviously), and a lot of cycles of that load. So it's not a bad idea to change out the bolt every so often to reduce the odds of a fatigue failure.

Another reason to swap out the bolt is to maintain consistent torque. If you torque a new bolt, then remove it and torque it again, the resulting bolt tension will be different than the first time you torqued it. That's because the friction has changed - coating has worn off a little bit, the threads have "seated" a little bit, etc. If the bolt was installed dry, then that difference can be significant. See this reference for more info:
https://www.nord-lock.com/insights/bolting-tips/2020/reusing-bolted-joi…

Ideally, you'd swap out the bolt for a new one each time you take it apart (not each time you check the torque). That ensures consistent torque and significantly reduces the chance of a fatigue failure. If you're lubricating the bolt, then the torque-tension relationship is much more consistent (again, see above reference). You could get a few uses out of the bolt without replacing it without issue. The downside there is that the bolt is more likely to come loose being lubricated and you should double check torque more often (every ride, ideally).
And add in the fact that if the bolt is lubed or even has locktight it can effect the torque vale around 30%. however the original specs from the owners manual my call out locktight and 30nm of torque, if not adding locktight can cause significant over torqueing of the bolt... (depending on the type of coating) and then there is the very real possibility of hydrogen embrittlement which could possibly be the root cause of many of these failures.
Deadric
Posts
387
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Location
Walden, CO, USA
4/18/2022 1:18pm
McG194 wrote:
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to...
The loads may be later but the point I was making is the bolt will bend less before catastrophic failure. It may take more force to break but it will bend and stretch less. It will be nothing, nothing, nothing snap. I lower grade bolt you may have to retorque more often, but I'd rather have a bolt stretch than break.
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much...
I'm not an engineer but I am a good mechanic, so got a question. So, how do I know when a bolt has stretched too much? I assume the lower grade bolt has a cycle limit of #, or amount of stretch allowed. Does the higher grade bolt too? Do I simply change the bolt once a year to be safe? I can see the criticality of this bolt in the grand scheme of bike maintenance.

I'm sure I torque that specific bolt at least 10-15 times a year on each of our Austrian bikes and I've never changed it. Bolt comes out, gets cleaned on a wire wheel, upper clamp threaded part gets cleaned with brake cleaner and air compressor. Then fresh loctite on the bolt and torqued to spec on install every time. My boy is really picky about his headset "feel" and we touch the headset and clamps quite a bit.

Hammer
Luxon MX wrote:
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see...
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see a good amount of load (obviously), and a lot of cycles of that load. So it's not a bad idea to change out the bolt every so often to reduce the odds of a fatigue failure.

Another reason to swap out the bolt is to maintain consistent torque. If you torque a new bolt, then remove it and torque it again, the resulting bolt tension will be different than the first time you torqued it. That's because the friction has changed - coating has worn off a little bit, the threads have "seated" a little bit, etc. If the bolt was installed dry, then that difference can be significant. See this reference for more info:
https://www.nord-lock.com/insights/bolting-tips/2020/reusing-bolted-joi…

Ideally, you'd swap out the bolt for a new one each time you take it apart (not each time you check the torque). That ensures consistent torque and significantly reduces the chance of a fatigue failure. If you're lubricating the bolt, then the torque-tension relationship is much more consistent (again, see above reference). You could get a few uses out of the bolt without replacing it without issue. The downside there is that the bolt is more likely to come loose being lubricated and you should double check torque more often (every ride, ideally).
While we're on this subject I got a set of Luxon Gen 2 clamps on my 21 350SXF and really like them, been running them for about a month now. I do loosen everything up every weekend (And after crashes) and retorque just to make sure everything is in line. Should I consider replacing that pinch bolt once a year just to be on the safe side with how often Im doing this? Im guessing that would probably be a bit over kill seeing as Im not putting anywhere near the stress on that thing that pro riders would be putting it through. The only thing I have torqued higher than the recommendation is the stem nut because I like a bit stiffer steering (Probably to the point I should just go with a stabilizer to be honest).

Love the clamps though! I was getting real sick of the constant binding with the stock KTM triple clamps and these have eliminated that problem.
3
NotCore
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Location
Alpharetta, GA, USA
4/18/2022 1:35pm
soresammy wrote:
So four "freak accidents" happen in the last two weeks that involve your parts in the failures. I don't think anyone is ganging up on you...
So four "freak accidents" happen in the last two weeks that involve your parts in the failures. I don't think anyone is ganging up on you ( actually most on here are sticking up for you ), but if you don't feel there is an issue then there is a bigger problem. This isn't a small issue. This could be life ending or life changing. Instead of getting defensive and being a wise ass, it would probably be a good thing if you put your energy into figuring what is going on. If someone gets seriously injured ( or worse ) your responses on here are going to Bury you in court. Can you imagine Mitch Payton responding the way you have been ( the owner of Luxon, I'm assuming)??? I actually had to scroll back in the other thread to makesure It was really the responses of Luxon. Super unprofessional, and actually shocking.

I think the post you are referring to was full of useful information and I learned something. I applaud the guy for coming on site and responding with specific detailed information in a timely fashion. You may object to him being too 'familiar' with the place or being witty or sarcastic, but I thought the post was well done, topical, timely, and competent.
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4/18/2022 1:40pm
Luxon MX wrote:
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see...
The bolt in question is not torqued to a point where it will permanently deform (stretch, etc.) from the installation torque alone. But it does see a good amount of load (obviously), and a lot of cycles of that load. So it's not a bad idea to change out the bolt every so often to reduce the odds of a fatigue failure.

Another reason to swap out the bolt is to maintain consistent torque. If you torque a new bolt, then remove it and torque it again, the resulting bolt tension will be different than the first time you torqued it. That's because the friction has changed - coating has worn off a little bit, the threads have "seated" a little bit, etc. If the bolt was installed dry, then that difference can be significant. See this reference for more info:
https://www.nord-lock.com/insights/bolting-tips/2020/reusing-bolted-joi…

Ideally, you'd swap out the bolt for a new one each time you take it apart (not each time you check the torque). That ensures consistent torque and significantly reduces the chance of a fatigue failure. If you're lubricating the bolt, then the torque-tension relationship is much more consistent (again, see above reference). You could get a few uses out of the bolt without replacing it without issue. The downside there is that the bolt is more likely to come loose being lubricated and you should double check torque more often (every ride, ideally).
Thanks. Yeah, 20 nm isn't a whole lot of pressure applied at install. The loctite will act as a bit of a lubricant as well. I...
Thanks. Yeah, 20 nm isn't a whole lot of pressure applied at install. The loctite will act as a bit of a lubricant as well. I do follow the manual when torqueing as they often spec dry, engine oil, or loctite type and I always make sure both male and female threads are clean and dry to start.

I will get a hand full of new bolts and just change them every 6 months. Cheap insurance. Tonight I will check the torque on all the front end fasteners since we were hammering on the bikes all weekend on a jumpy SX-style track and they sure took some stress!

Hammer

PS I did Google Young's Modulus and while I get the physics (and less so the math) I'm just a Dad Mechanic. Smile
Well, now you know that it is not a realistic calculation for our purposes and I think that's the answer you were looking for haha.
NotCore
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4/18/2022 1:40pm
GuyB wrote:
This is an example of one of the things that used to be super-frustrating to me. People want insider info. But then an insider comes here...
This is an example of one of the things that used to be super-frustrating to me.

People want insider info. But then an insider comes here, speaks openly, and spends what was probably a fair amount of time crafting a perfectly reasonable explanation. Then he gets told he's wrong. Eventually, the insider(s) stop responding, and the vacuum is filled with nonsense from people who are speculating, rather than speaking from actual experience.
Nice of you to come out of retirement to share. I think there is a whole thread or two (probably deleted) of the things people around here found super frustrating about how you ran the board.
2
8
soresammy
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4/18/2022 2:10pm
Sandusky26 wrote:
I'll delete this thread for a free set of triple clamps.
I'm shocked it's still around honestly. Lol
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GuyB
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4/18/2022 2:11pm
NotCore wrote:
Nice of you to come out of retirement to share. I think there is a whole thread or two (probably deleted) of the things people around...
Nice of you to come out of retirement to share. I think there is a whole thread or two (probably deleted) of the things people around here found super frustrating about how you ran the board.
Yet you kept coming back.

I'm perfectly okay with not everyone liking how I ran things. 😄


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forensic
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4/18/2022 2:17pm
Luxon MX wrote:
I'm glad the internet engineers have already found the problem and concluded that our product is junk. Can't wait for the internet lawyers to jump in...
I'm glad the internet engineers have already found the problem and concluded that our product is junk. Can't wait for the internet lawyers to jump in too!

I'm not at Atlanta, but from what I can tell at this point is that the pinch bolt at the stem failed, which caused the top clamp to fail, and then the bike to "break in half".

The KTM design uses the top triple clamp to clamp around the steering stem with a pinch bolt instead of the "standard" Japanese bike design where the top clamp is sandwiched between the adjuster nut and the lock nut. It's a pretty elegant design, but if the bolt fails, then the assembly becomes very weak and the clamp will fail. This is the same design that KTM/Husky/GasGas use on all of their stock clamps and factory clamp and multiple aftermarket companies use on their clamps for these bikes.

Here's the actual broken part from today:



You can see the broken bolt on the right, which allowed the clamp to break (on the left). Note the fresh break of the clamp and that there's no fretting or other evidence of a previous crack. That shows this happened all at once and the clamp itself wasn't the problem, it was the bolt. We use bolts that are stronger than the stock KTM bolts (random samples tested to failure for each batch we receive), so either the bolt was over-torqued to the point that it was on the edge of failure, or it came loose and that allowed things to give way.

This is the first failure of this kind for us, but it's not all that uncommon with this general design. Multiple other aftermarket clamps and stock KTM clamps have all failed in the same way. Not because the clamps are bad, but because the bolt failed; most likely because it was over torqued or came loose.

Regardless, we'll take a closer look at the clamps when we get them back to see if there's anything that I'm missing from the photos, but it seems pretty clear cut. If this were a design problem, we'd see this a whole lot more instead of this one incident. Freddie Noren has been on this same setup all year successfully and finished 11th in the 450 class today.

Here's a few examples of the same failure, stock and aftermarket, I'm sure there's plenty more I don't have photos of:








how can you tell from the photo that the bolt failed and then the clamp, as opposed to the bolt and clamp failing in one overload event?
1
Luxon MX
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Fantasy
4/18/2022 2:21pm
Deadric wrote:
While we're on this subject I got a set of Luxon Gen 2 clamps on my 21 350SXF and really like them, been running them for...
While we're on this subject I got a set of Luxon Gen 2 clamps on my 21 350SXF and really like them, been running them for about a month now. I do loosen everything up every weekend (And after crashes) and retorque just to make sure everything is in line. Should I consider replacing that pinch bolt once a year just to be on the safe side with how often Im doing this? Im guessing that would probably be a bit over kill seeing as Im not putting anywhere near the stress on that thing that pro riders would be putting it through. The only thing I have torqued higher than the recommendation is the stem nut because I like a bit stiffer steering (Probably to the point I should just go with a stabilizer to be honest).

Love the clamps though! I was getting real sick of the constant binding with the stock KTM triple clamps and these have eliminated that problem.
Thanks, glad you're happy with the clamps!

The steering stem nut on the Austrian bikes doesn't really have a particular torque (despite the manual calling one out), it's an adjuster more than a structural bolt. It should be torqued to the bearing preload that's correct, and as you say, you like a little more preload, so you torque it a bit more.

I would recommend leaving the bolts alone unless you know something is twisted up. And in that case, it's no problem to loosen everything up and re-torque. You'll want to make sure there's plenty of anti-seize on all the bolts, both on the threads and under the bolt head, as that will help keep the torque/tension relationship consistent (and one of the reasons we specify using it), plus all of our torque specs are based on that, which is why they're lower than "normal".

Regarding the stem clamp bolt, so long as you're torqueing that correctly, using anti-seize, and not taking it apart a lot of times, it should be fine. It is cheap insurance to replace, though, should you feel better about that.
3
Luxon MX
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Fantasy
4/18/2022 2:24pm
forensic wrote:
how can you tell from the photo that the bolt failed and then the clamp, as opposed to the bolt and clamp failing in one overload...
how can you tell from the photo that the bolt failed and then the clamp, as opposed to the bolt and clamp failing in one overload event?
I can't really, but it would take an absolutely massive overload to break them both at the same time. So it's much more likely that the bolt failed first, then the clamp. It actually takes a serious overload to break just the bolt, which is why I'm thinking it was either over-torqued or loose which caused the break.
6
soresammy
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Red Hook, NY, USA
4/18/2022 2:29pm
soresammy wrote:
So four "freak accidents" happen in the last two weeks that involve your parts in the failures. I don't think anyone is ganging up on you...
So four "freak accidents" happen in the last two weeks that involve your parts in the failures. I don't think anyone is ganging up on you ( actually most on here are sticking up for you ), but if you don't feel there is an issue then there is a bigger problem. This isn't a small issue. This could be life ending or life changing. Instead of getting defensive and being a wise ass, it would probably be a good thing if you put your energy into figuring what is going on. If someone gets seriously injured ( or worse ) your responses on here are going to Bury you in court. Can you imagine Mitch Payton responding the way you have been ( the owner of Luxon, I'm assuming)??? I actually had to scroll back in the other thread to makesure It was really the responses of Luxon. Super unprofessional, and actually shocking.
NotCore wrote:
I think the post you are referring to was full of useful information and I learned something. I applaud the guy for coming on site and...

I think the post you are referring to was full of useful information and I learned something. I applaud the guy for coming on site and responding with specific detailed information in a timely fashion. You may object to him being too 'familiar' with the place or being witty or sarcastic, but I thought the post was well done, topical, timely, and competent.
I agree with everything you said... And I do have to add the "other thread " has magically disappear. I'd say it was probably the smart thing to do too. I think after he calmed down it was clear that thread could have been bad for him ( Luxon). I do think it was great that he got on here and spoke up and did it in a timely manner. I have absolutely nothing against the company and personally think his products seem awesome. Unfortunately we're not talking about a gasket failing, we're talking about an issue that if unless fails after the crash can be catastrophic for the rider.
12
forensic
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Location
Madison, WI, USA
4/18/2022 2:38pm
Luxon MX wrote:
I can't really, but it would take an absolutely massive overload to break them both at the same time. So it's much more likely that the...
I can't really, but it would take an absolutely massive overload to break them both at the same time. So it's much more likely that the bolt failed first, then the clamp. It actually takes a serious overload to break just the bolt, which is why I'm thinking it was either over-torqued or loose which caused the break.
That could be likely. It would be nice to see a video of how he crashed. If he went nose down into the face of a landing, that would be some serious stresses. When sport bikes hit another vehicle it is not uncommon to see the top clamp "pop" like this due to the overload.
4/18/2022 2:52pm
Technical discussions on vital offer an interesting insight into how many of us ingest information in the current world. People with expertise and technical background posting alongside people just winging it and going with their gut. Both sides being completely confident, makes it very hard to discern what’s based on sound technical reasoning unless you already have expertise in the field. Sort of a catch 22
17
Bruce372
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USA
4/18/2022 3:15pm
Technical discussions on vital offer an interesting insight into how many of us ingest information in the current world. People with expertise and technical background posting...
Technical discussions on vital offer an interesting insight into how many of us ingest information in the current world. People with expertise and technical background posting alongside people just winging it and going with their gut. Both sides being completely confident, makes it very hard to discern what’s based on sound technical reasoning unless you already have expertise in the field. Sort of a catch 22
Lol, try being an actual real medical scientist this last 2 years!
12
1
Yz229
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San Diego, CA, USA
4/18/2022 3:34pm
Freak accidents happen all the time motorsports.

I wouldn't bet against Billy's ability to produce the best parts in this sport. Thanks for the excellent replies, Billy, always enjoy hearing your inputs.
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