zer0dayexploit Posted August 25, 2023 Share Posted August 25, 2023 Hey all, just had a freak (albeit very minor) accident on my inmotion v12, where the entire pedal on the right side snapped off at the bolt connection. The heads of all 4 bolts seemed to just pop off. I have never taken this wheel off-roading or jumping, I’m relatively lightweight, and I know that these were tight but not over tight because I checked them after some recent rain. see the pictures below it’s crazy. I was only going about 5kph and hopped off a curb and that’s when it completely snapped 2 1 Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 25, 2023 Author Share Posted August 25, 2023 Is this a common issue for people? I mean I’ve seen people beating the crap out of their v12HT’s and the pedals are fine. Quote Link to comment Share on other sites More sharing options...
Clem604 Posted August 25, 2023 Share Posted August 25, 2023 I haven't seen this myself but that's pretty surprising. Good thing you were going pretty slow when that happened. 1 Quote Link to comment Share on other sites More sharing options...
Circuitmage Posted August 25, 2023 Share Posted August 25, 2023 Just some thoughts; Do you have a foot you favor (always keep on the wheel)? It could be that pedal gets the most stress. I tend to always keep my left foot on and lightly use my right foot, for example. Just curious from a strain stand-point. Has anyone else used your wheel? How many miles on on your wheel (pedal look pretty new)? Maybe warranty issue and repairable if you have a local dealer? Have you checked the other side? Quote Link to comment Share on other sites More sharing options...
Hellkitten Posted August 25, 2023 Share Posted August 25, 2023 Anyone know if the hangers are cast or machined? Quote Link to comment Share on other sites More sharing options...
Rawnei Posted August 25, 2023 Share Posted August 25, 2023 I've swear I've heard of this happening before? Perhaps the screws are not strong enough, wonder what grade they are? 2 Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 25, 2023 Author Share Posted August 25, 2023 2 hours ago, Circuitmage said: Just some thoughts; Do you have a foot you favor (always keep on the wheel)? It could be that pedal gets the most stress. I tend to always keep my left foot on and lightly use my right foot, for example. Just curious from a strain stand-point. Has anyone else used your wheel? How many miles on on your wheel (pedal look pretty new)? Maybe warranty issue and repairable if you have a local dealer? Have you checked the other side? My weight is actually predominantly on the other side (left) and I only use my right foot lightly. Nobody else uses my wheel, and the only time it’s been laid on its side is when I put it in a car. I have about 3000kms on this wheel now, and the other side seems in fantastic. I’m slightly concerned that this is just prolonged wear on an inferior grade bolt, as the threads on the wheel itself are holding onto the rest of my bolts very snuggly :,) All 4 bolts giving out at the same time as well is something kind of crazy. Quote Link to comment Share on other sites More sharing options...
Mono Posted August 25, 2023 Share Posted August 25, 2023 24 minutes ago, zer0dayexploit said: All 4 bolts giving out at the same time as well is something kind of crazy. I don't know how you could determine whether they did give in at the same time. Chances are that one snapped first an the others followed suite due to the increased stress only afterwards. 1 Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 25, 2023 Author Share Posted August 25, 2023 Fair point haha 13 minutes ago, Mono said: I don't know how you could determine whether they did give in at the same time. Chances are that one snapped first an the others followed suite due to the increased stress only afterwards. I did check them about two weeks ago for rust because of the recent rain but they could have each separately snapped Quote Link to comment Share on other sites More sharing options...
Mono Posted August 26, 2023 Share Posted August 26, 2023 10 hours ago, zer0dayexploit said: Fair point haha I did check them about two weeks ago for rust because of the recent rain but they could have each separately snapped yes, when I wrote "only afterwards" I wasn't necessarily thinking of days or weeks (though this is possible too), but also about seconds or even milliseconds but still as a causal chain of events which isn't surprising. When a rope tears apart, there is no surprise that many of its fibers brake at almost the same time, it's just an expected chain of "catastrophic" events that are bound to happen when the first few fibers start to give in. Having said all that, obviously what happened should never happen. To me, the bolts look reasonably sized, so my first suspicion would be that they are just not made of durable enough material, or, worst case, the construction in itself allows too high shearing forces on the bolts. Quote Link to comment Share on other sites More sharing options...
Punxatawneyjoe Posted August 26, 2023 Share Posted August 26, 2023 12 hours ago, zer0dayexploit said: I did check them about two weeks ago for rust Is it at all possible you over tightened them? Maybe when you "checked" them you tightened them enough to hair line crack one or two. Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 26, 2023 Author Share Posted August 26, 2023 7 hours ago, Punxatawneyjoe said: Is it at all possible you over tightened them? Maybe when you "checked" them you tightened them enough to hair line crack one or two. I don’t think so, I only tighten enough that is comfortable in the hand with a regular Allen key. What’s strange is I just checked the left side which has undergone more stress and tightened exactly the same, and the bolts seem completely fine. I’m going to buy some higher grade bolts for this and replace both sides. This is probably a freak accident but I felt like posting this so if anyone else has this issue happen to them they can tag along and see if its a recurring problem 1 1 Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 26, 2023 Author Share Posted August 26, 2023 9 hours ago, Mono said: yes, when I wrote "only afterwards" I wasn't necessarily thinking of days or weeks (though this is possible too), but also about seconds or even milliseconds but still as a causal chain of events which isn't surprising. When a rope tears apart, there is no surprise that many of its fibers brake at almost the same time, it's just an expected chain of "catastrophic" events that are bound to happen when the first few fibers start to give in. Having said all that, obviously what happened should never happen. To me, the bolts look reasonably sized, so my first suspicion would be that they are just not made of durable enough material, or, worst case, the construction in itself allows too high shearing forces on the bolts. 100% understand lol, it’s wild that the bolts were existing on such a fine margin that they all catastrophically failed together Quote Link to comment Share on other sites More sharing options...
woke rider Posted August 27, 2023 Share Posted August 27, 2023 This is absolutely ridiculous. I hope my pedals don’t fail too. 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted August 28, 2023 Share Posted August 28, 2023 They all failed at the same point. Could it be that they weren't torqued equally and so they fatigued in turn one by one? Replace with steel bolts and use a torque wrench, is what I would do. Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 28, 2023 Author Share Posted August 28, 2023 2 hours ago, alcatraz said: They all failed at the same point. Could it be that they weren't torqued equally and so they fatigued in turn one by one? Replace with steel bolts and use a torque wrench, is what I would do. Most likely. These bolts seem to be one of those high tensile strength bolts like a grade 10.9 or higher, potentially making them brittle compared to malleable. Are you recommending a “softer” albeit more compliant bolt? Quote Link to comment Share on other sites More sharing options...
alcatraz Posted August 28, 2023 Share Posted August 28, 2023 1 hour ago, zer0dayexploit said: Most likely. These bolts seem to be one of those high tensile strength bolts like a grade 10.9 or higher, potentially making them brittle compared to malleable. Are you recommending a “softer” albeit more compliant bolt? I don't know. I'm thinking compliance is bad. As you said, high tensile strength steel and torqued equally. I'm guessing that western branded bolts should match or outperform the chinese in tensile strength. 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Shadalf Posted August 28, 2023 Popular Post Share Posted August 28, 2023 It happened to me five months ago, going 22-25 mph, All the bolts of the right pedal broke at the same time. I ended with my right shoulder damaged, but not broken. Still very painful. The wheel at the time had 4300 km without issues. I changed all the bolts on both sides for 12.9 grade ones. No issues after that, now with 7700 km on the wheel. Maybe a preventive change of the bolts is in order every 1000 or 2000 km, I don´t know. I recovered the confidence on the wheel, but It took a while. Still I would prefer fixed pedal hangers. I Never change the height of the pedals anyway. 4 Quote Link to comment Share on other sites More sharing options...
UniVehje Posted August 29, 2023 Share Posted August 29, 2023 On 8/25/2023 at 10:48 PM, Rawnei said: Perhaps the screws are not strong enough, wonder what grade they are? The problem with China is that it doesn’t matter what grade they want in design and order for manufacturing. What matters is whether their supplier provides fake bolts or not. Inmotion already had a problem with fake bolts on the V13. Best option is to change the critical bolts to ones from a reliable supplier. Changing the intended grade might not be a good idea if they designed it correctly. 1 1 Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 30, 2023 Author Share Posted August 30, 2023 @UniVehjevery good point. Does anyone know what the intended grade of bolt is? Quote Link to comment Share on other sites More sharing options...
Rawnei Posted August 30, 2023 Share Posted August 30, 2023 4 minutes ago, zer0dayexploit said: @UniVehjevery good point. Does anyone know what the intended grade of bolt is? Just go with 12.9 if you are buying replacements yourself? Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 30, 2023 Author Share Posted August 30, 2023 1 hour ago, Rawnei said: Just go with 12.9 if you are buying replacements yourself? 12.9 for sure, but if it’s engineered for a softer more compliant bolt that could possibly make it worse. Brittle but strong vs slightly weaker and malleable. Could be the difference between a hard snap vs a bend and break 1 Quote Link to comment Share on other sites More sharing options...
Rawnei Posted August 30, 2023 Share Posted August 30, 2023 2 minutes ago, zer0dayexploit said: 12.9 for sure, but if it’s engineered for a softer more compliant bolt that could possibly make it worse. Brittle but strong vs slightly weaker and malleable. Could be the difference between a hard snap vs a bend and break Maybe I'm not knowledgeable enough in steel but somehow this doesn't make sense to me at all, stronger bolt will hold better in my opinion, I don't see how 12.9 grade would be more brittle or why they would be designed to bend in the first place. Quote Link to comment Share on other sites More sharing options...
Planemo Posted August 30, 2023 Share Posted August 30, 2023 The area in question isn't engineered for a 'compliant fastener' at all. 10.9 would be more than adequate but if 12.9 are available then may as well. I still can't believe this even happened. Just as I thought I'd seen everything. Out of interest, whats the diameter of the bolt? Quote Link to comment Share on other sites More sharing options...
zer0dayexploit Posted August 30, 2023 Author Share Posted August 30, 2023 1 hour ago, Rawnei said: Maybe I'm not knowledgeable enough in steel but somehow this doesn't make sense to me at all, stronger bolt will hold better in my opinion, I don't see how 12.9 grade would be more brittle or why they would be designed to bend in the first place. I am not knowledgeable in steel either, I’m just proposing potential reasons for why a bolt grade that is much higher may not be a good idea. Another concern is if the bolt is of a much stronger steel than the thread it mounts into, that it ends up stripping the mount threads. None of this is grounded in personal experience/research I’m just asking so that someone smarter than me on the forum can correct/inform me Quote Link to comment Share on other sites More sharing options...
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