The vid of driving in a creek near the end reminds me of a buddy of mine who passed me, (he was going fast), in a flooded 2 track, hydroplaned enough to lose it. I can see nothing but one end of the handlebar sticking up out of the water, and he picked it up so fast it didn't stall. :)
With the two top air slots on the top of the F5, it does not surprise me that the sledge hammer had an easier time with it. I guess it was to be expected.
I also noticed with the hammer, the hits on the sides of the helmet would squish the helmet quite a bit, and it would rebound back up into the air. But with the helmet sitting on its collar, there was no compression of the shell or rebound. The weakened structure (because of the vents), was taking a lot more peak/sudden force.
@@DmitriyAdv I agree. I thought the vid may be just destruction, but I learned things from it, (and do have engineering degrees). If you are going to continue, it would be nice to know the "force on what size area" to put some numbers to the experiment. A simple drop stand, (experiment with weight and height) could give valid numbers. Would be able to measure foam crush also if you put a bowling ball in it. :) In 5 years,---you can make DOT obsolete by charging much less for testing in your garage. :)
Damaged yes, but the sand bags were unharmed. From manufacture vids of how those tubes "crush", (top down, like the world trade centers), it looks like the sand bag test barely crushed them, just at the tops. They looked like they only absorbed about 15% of the energy (or duration) that they are capable of. I think they are interesting, with new possibilities for construction and maybe replacement parts.
I bet it is still the foam that takes the big hits, and that foam, (after out of the helmet), I don't think was squished from the sand bags. The tubes do not take more energy to keep squishing like the foam does. It is almost like we can use the destruction of the tubes, (how far down they are squished), to gauge how bad the foam is squished.
@@EarthSurferUSA Koroyd is pretty strong if the force is applied in the correct direction. I think I put it in the video where I can stand on it and it does not compress. If I stand on the EPS, it does compress (a little bit, but it does). The "correct direction" is one limitation that Koroyd does have. Which perhaps limits it's application somewhat. I've smashed up a few different helmets (see my other video) and overall I'm pretty impressed with how durable they all are. I definitely feel a lot safer wearing one after seeing how much abuse it can take, and don't feel like it's necessary to replace one if one falls out of my hands on the ground.
@@DmitriyAdv Thinking about the Koroyd more, I can see it being pretty rigid as long as the force is directly on top with the forces straight down the tubes sides, (like standing on a flat piece). I have heard stories about a piece of straw, (the biological kind), after a tornado, stuck straight into a telephone poll like a knife. I think I figured out why is crushes from the top down. With a force other than vertical, the edge opening of the tube goes out of round and crinkles. So it crinkles from the top down as the tube is deformed there by the hard force that is not quite a direct vertical force. Hmm, if my head hits the ends of the tubes perfectly square, will they stick in my head like the piece of straw in a telephone poll?
I just got the F3 Carbon Pro in. Nice helmet, but 2 small finger tip like smudges of what looks like a dark gasket sealer that is cured to a cheek pad/showing material. Excellent customer service over there at Klim. By phone with a real conversation, E-mailed her some pictures and details of the helmet, and they are sending me a new cheek piece. Direct good service. Did not have to back track to the retailer (Dennis Kirk) that I bought it from. But I do have this one request from you, if you will. Since you busted through the shell, you can tell. The carbon fiber strands we see through the clear coat are hand laid (individually), and not a tight weave, or even a weave at all, just strips laid in by hand. I think they are just decoration, and there is a real mat of carbon fiber under it. I did read/hear from one advertisement about a matt called "Prepreg", which is a matt we once worked with in the bicycle industry. I want to know if there is at least one layer of real carbon, tightly woven mat in there, because if not, this helmet has a pretty tough resin. What we see does nothing for structural integrity. I hope it is just decoration, (even though real mat is hard to beat for decoration). Carbon fiber mat is harder to bend into corners than fiberglass, so you might find a mixture of both real mat over the round area's with resin and decorative mat in the chin bar. guessing. You can tell. :) Doug in Michigan
Ohh, I am not a big fan of the liner fasteners (snap in devises). Hard to line up to connect, and some release very easily now only after a few cheek piece removals. They reflect "made in china" as historically proven over the last 4 plus decades. The snaps on their pants (that I have) would work better. But I think for cheek pieces, easily removable with magnet fasteners is a good type of direction that would also fix the issue. The helmet is pretty tough to get off with those cheek pieces in, if the helmet is fitting snugly.
Glad you got good customer service from Klim! I've been dealing with them for years, and some times are better than others. I think like many businesses, they had some rough patches around Covid. Unfortunately I don't have the helmet around anymore to tell you anything about the layers. Klim advertises 12k carbon fiber construction, which are the wide strands we can see (vs the more typical 3k carbon fiber). Around the 4:10 mark you can actually see that the wider 12k strands are visible inside the shell as well, for what it's worth. That's definitely not there for decoration since it's not generally visible. I'm not an expert in carbon fiber by any means, but my understanding is that while there are a lot of variables, 12k is generally considered preferable to the more traditional 3k.
The vid of driving in a creek near the end reminds me of a buddy of mine who passed me, (he was going fast), in a flooded 2 track, hydroplaned enough to lose it. I can see nothing but one end of the handlebar sticking up out of the water, and he picked it up so fast it didn't stall. :)
I try not to go through unknown water too quickly, never know when there is a big hole in there waiting to send you over the bars 😅
With the two top air slots on the top of the F5, it does not surprise me that the sledge hammer had an easier time with it. I guess it was to be expected.
I also noticed with the hammer, the hits on the sides of the helmet would squish the helmet quite a bit, and it would rebound back up into the air.
But with the helmet sitting on its collar, there was no compression of the shell or rebound. The weakened structure (because of the vents), was taking a lot more peak/sudden force.
As unscientific as it was, this was an interesting experiment. I will probably repeat it with any helmets I retire, just out of curiosity.
@@DmitriyAdv I agree. I thought the vid may be just destruction, but I learned things from it, (and do have engineering degrees). If you are going to continue, it would be nice to know the "force on what size area" to put some numbers to the experiment. A simple drop stand, (experiment with weight and height) could give valid numbers. Would be able to measure foam crush also if you put a bowling ball in it. :) In 5 years,---you can make DOT obsolete by charging much less for testing in your garage. :)
Damaged yes, but the sand bags were unharmed.
From manufacture vids of how those tubes "crush", (top down, like the world trade centers), it looks like the sand bag test barely crushed them, just at the tops. They looked like they only absorbed about 15% of the energy (or duration) that they are capable of. I think they are interesting, with new possibilities for construction and maybe replacement parts.
I bet it is still the foam that takes the big hits, and that foam, (after out of the helmet), I don't think was squished from the sand bags. The tubes do not take more energy to keep squishing like the foam does. It is almost like we can use the destruction of the tubes, (how far down they are squished), to gauge how bad the foam is squished.
@@EarthSurferUSA Koroyd is pretty strong if the force is applied in the correct direction. I think I put it in the video where I can stand on it and it does not compress. If I stand on the EPS, it does compress (a little bit, but it does).
The "correct direction" is one limitation that Koroyd does have. Which perhaps limits it's application somewhat.
I've smashed up a few different helmets (see my other video) and overall I'm pretty impressed with how durable they all are. I definitely feel a lot safer wearing one after seeing how much abuse it can take, and don't feel like it's necessary to replace one if one falls out of my hands on the ground.
@@DmitriyAdv Thinking about the Koroyd more, I can see it being pretty rigid as long as the force is directly on top with the forces straight down the tubes sides, (like standing on a flat piece). I have heard stories about a piece of straw, (the biological kind), after a tornado, stuck straight into a telephone poll like a knife. I think I figured out why is crushes from the top down. With a force other than vertical, the edge opening of the tube goes out of round and crinkles. So it crinkles from the top down as the tube is deformed there by the hard force that is not quite a direct vertical force. Hmm, if my head hits the ends of the tubes perfectly square, will they stick in my head like the piece of straw in a telephone poll?
I just got the F3 Carbon Pro in. Nice helmet, but 2 small finger tip like smudges of what looks like a dark gasket sealer that is cured to a cheek pad/showing material. Excellent customer service over there at Klim. By phone with a real conversation, E-mailed her some pictures and details of the helmet, and they are sending me a new cheek piece. Direct good service. Did not have to back track to the retailer (Dennis Kirk) that I bought it from.
But I do have this one request from you, if you will. Since you busted through the shell, you can tell. The carbon fiber strands we see through the clear coat are hand laid (individually), and not a tight weave, or even a weave at all, just strips laid in by hand. I think they are just decoration, and there is a real mat of carbon fiber under it. I did read/hear from one advertisement about a matt called "Prepreg", which is a matt we once worked with in the bicycle industry.
I want to know if there is at least one layer of real carbon, tightly woven mat in there, because if not, this helmet has a pretty tough resin. What we see does nothing for structural integrity. I hope it is just decoration, (even though real mat is hard to beat for decoration). Carbon fiber mat is harder to bend into corners than fiberglass, so you might find a mixture of both real mat over the round area's with resin and decorative mat in the chin bar. guessing. You can tell. :) Doug in Michigan
Ohh, I am not a big fan of the liner fasteners (snap in devises). Hard to line up to connect, and some release very easily now only after a few cheek piece removals. They reflect "made in china" as historically proven over the last 4 plus decades. The snaps on their pants (that I have) would work better. But I think for cheek pieces, easily removable with magnet fasteners is a good type of direction that would also fix the issue. The helmet is pretty tough to get off with those cheek pieces in, if the helmet is fitting snugly.
Glad you got good customer service from Klim! I've been dealing with them for years, and some times are better than others. I think like many businesses, they had some rough patches around Covid.
Unfortunately I don't have the helmet around anymore to tell you anything about the layers. Klim advertises 12k carbon fiber construction, which are the wide strands we can see (vs the more typical 3k carbon fiber). Around the 4:10 mark you can actually see that the wider 12k strands are visible inside the shell as well, for what it's worth. That's definitely not there for decoration since it's not generally visible. I'm not an expert in carbon fiber by any means, but my understanding is that while there are a lot of variables, 12k is generally considered preferable to the more traditional 3k.