 So welcome back or welcome to the Friday vlog series where once again we're going to break this video into two main parts. Number one we're going to talk about a very scary and alarming double carbon wheel fail. That's right both the front and the rear wheel failed almost simultaneously after being purchased 11 months prior brand new from a New York City bike shop and this occurred on the 5th of May 2020 at Bear Mountain in the New York City region. And number two I'm actually celebrating two years on YouTube this week so I'm going to take a small portion of airtime at the very end to thank everyone for your support. So number one it was a few weeks ago I received a message from a channel supporter on my Instagram account and this channel supporter he lives in New York City. He was asking me my thoughts on carbon wheel sharing a photo of a recent incident he had on a set of cosmic pro carbon UST's for rim brake bikes. As soon as I saw this Instagram message and the photos I was like bloody hell that is insane and very scary and while he was asking me questions about my thoughts on carbon wheels I had some questions for him. I wanted to know was he all right where and how did this happen and who's taking responsibility for what is essentially a near-death situation. Now I don't feel it's appropriate that I share this channel supporter's name with you so for the purpose of this video let's call him John. Now John kindly accepted to jump on a zoom call with me so I'll share a small portion of that conversation with you. He also kindly provided a number of photos which I'll share but please be aware that some viewers may find these photos alarming and just a heads up for the small portion of people that tend to get critical in these situations. Let's not ride a high horse and get judgmental on things that should have been done differently this is real it's happened and John has been kind enough to share his experience with us so we can all take learnings from this. Now the next person I teed up a conversation with was a renowned carbon fiber expert Raul Luscha who has a background in quality assurance and the aerospace industry before turning to the Australian Institute of Sport for five years working with the Aussie cycling team and then in 2008 transitioned solely to bikes with now over 10 years in carbon fiber design repair and quality assurance experience and Raul gives us an outstanding hypothesis of what most likely occurred in this instance. Just be aware that he's got his own YouTube channel as well which I'll link to below and many have probably seen him on other channels in the past such as the Cycling Mavens and Shane Miller's YouTube channels and lastly before we get into these two discussions I did find myself in quite a deep Mavic that being the company rabbit hole after these pictures were shared with me and for those of you who are unaware of what is going on with Mavic at the moment I'll share some interesting information with you following the two discussions so let's get into it first discussion with John just be aware that he's actually okay external to some bruises and some scratches and a concussion that he experienced after the incident he actually is walking right now in fact he went for his first bike ride a few days ago after the incident which is remarkable so let's get into the discussion we start descending and there's two sections so a past one section one section going down is about 10% and then the last section is a little bumpy so that has some potholes and I'm going about like 45 miles an hour and my back wheel completely like it breaks the tire blew out and then my front wheel while I'm pressing the brakes my front wheel hits another pothole and my rims completely shattered in three pieces so I end up landing on my fork and my friends are telling me that I did four or five flips all the way to I stopped and they told me that I was unconscious for like three minutes and after that I'll hardly remember what happened so pretty full on huh now just know that the photos I was able to share with you there were taken by John's friends who were cycling with him at the time and took them as material or evidence in case of worst-case scenarios but luckily for John he's actually okay now what is the likely cause of this situation let's hear from Ray All and what's interesting is I asked Ray All how many times have you seen this in your 10 plus year experience in the industry and what I found surprising is he said less than a handful so it is rare so let's get into the conversation and I've put some subtitles there just because the zoom recording wasn't overly clear so let's get into it well the highest the highest temperature that you're really going to get reliably out of these reds is about 180 degrees Celsius and you can get you can get 250-280 degrees Celsius with with breaking on a on a decent descent that that temperature compound that temperature needs to be dissipated and what happens is as you heat air it expands so you're getting you're generating more pressure at that at that tire bead interface as the the rim is losing structural integrity due to the the resin getting hot so and that so then what typically happens is the tire just blows off because the pressure increases the material gets softer and so the sidewall blows out then Ray All goes on to discuss two variables that increase energy number one is speed so as you know John was traveling at about 45 miles per hour down this hill that's about 72 kilometers per hour and he also weighs 100 kilograms or 220 pounds which is actually well within the advised will limits that Mavic suggests for these wheels so back to Ray All so the kinetic energy in that situation is is very significant so you're looking at a kinetic energy you're roughly 24 000 joules of energy now on the front wheel you've probably got a similar thing happening where once once the resin starts getting getting soft then the front wheel starts losing some of the structural integrity as well and and then you have the case where you know you hit you hit the pothole and you know which is a an overload situation which if if the rim was fully structurally sound it may survive that without any issues because now it's heat compromised then you start you start getting into dangerous territory and so with that impact you've basically got that that that impact energy and give you a ballpark when the UCI have a wheel impact drop test which the wheel needs to survive to to be able to be sold as a UCI approved wheel to be used in competition etc now that the energy the impact energy in that drop test is 40 joules so four zero joules you know you can see the energy that we're talking about the kinetic energy of a rider going down the road at that speed that mass you've got 24 000 odd joules that's just the reality of it you know things don't fail when you yeah when you're just taking it easy it's when you're pushing hard um there was a there was a famous um photo from uh I can't remember which race it was it might have even been the tour but it had Cavendish off the uh off the front in a like a bunch sprint coming into the finish and his wheels just folded in half and and he went down and brought the bunch down um yeah it sort of really highlights some of this stuff so I'll provide a link to the full discussion we had together but just know that rail goes on to talk about other variables such as braking techniques and the distribution of heat across both wheels and also the consideration of the structural integrity of the wheel before that particular day so there is a possibility that the wheel might have already had some damage which is a reminder to us all to examine our wheels and our bikes with our eyes before we go out onto the road although unfortunately carbon damage can often be internal so the only way you can fully examine internal structural issues is to visit someone like rail now as much as it pains me to say it based off a video I did on this channel about three weeks ago now about rim brake bikes rail did indicate that by running disc brakes the likelihood of this happening is significantly reduced he also indicated that alloy wheels are a much more structurally sound wheel particularly when the compromised situations occur such as heat and weight and certainly speaking with john he's indicated that moving forward he's probably going to be sticking with alloy rims and I did ask him about what's actually happening with mavic through his local bike shop and according to him mavic are moving factories so they're still yet to hear back about warranties and getting refunded or maybe getting a new set of wheels which is a little bit disappointing to hear because if I was in charge of mavic I would be getting on to this situation straight away and be sending a letter of care to john as well which takes me to my last point I don't mean to throw mavic under the bus here it just so happens that the company is currently in receivership and if you go online you'll find some interesting details about the french company that is roughly 130 years old cycling tips article as well indicates that there is some confusion who actually owns mavic at the moment as well so if you're looking to purchase some carbon wheels in the not too distant future I might consider exploring some other brands so I just wanted to thank John for sharing his experiences with us and it's remarkable that he's come out of it with hardly any injuries so thanks so much for sharing I've certainly learned a lot through this process John and also Ray All for coming on and sharing his expertise about what most likely happened here and ways we can mitigate this from potentially happening to us so that's pretty much it let's get in to the rest of the video just arrived home from dropping the kids off on the way to school we stopped at a coffee shop which you just saw and I've got this weird strategy with Ruby she doesn't like putting her shoes on at home so what I do is say grab your bags grab your shoes and we get in the car and then we put them on at the local cafe before school and it's weird and it's strange but it works so you know sometimes with young kids you just got to do weird and strange things if they work and that's one of my weird and strange things so two years on the channel gives me a small opportunity to reflect on what's been going on and really what I wanted to do here very quickly is just thank everyone for your support over on the channel it means a lot YouTube is great I love it a lot but it can be hard work at times and to have such a strong and growing contingent of channel supporters really keeps me motivated so that's pretty much it I'll leave you with the video the first video I published on the channel when I launched it it's my cycling story in under three minutes I'll put it up here somewhere if you want to watch that and I'll catch you all in the next video