WhyFi

Ha! FWIW, looking at his views and subs, this guy isn't making any youtube money, but yes - point taken. I'd add that, personally, when the someone touts "the truth" or that they "tells it like it is," more often then not, they're saying what their audience wants to hear rather than actually being objective.

Dean V

Rather than try and wade through the theory and science which the design engineers have already done.
Just look at the end result.
A light carbon frame is around 700gms and a light aluminium frame is at least 200gms more.
Both will use a carbon fork.

woodcraft

Carbon fiber fabric- somewhat stiffer than your t-shirt.

chaadster

Hey, that’s the one where he references Warren Buffet’s 5 hour live stream treatise on crank arm length from The Berkshire Crank Length Review of Q1 2020. [see vid from 5:36]

Carbonfiberboy 

Which has zip to do with anything. It's the tensile strength and elongation coefficient which are its valuable materials properties.

woodcraft

I didn't make the video, but just watched part of it. He seems to be saying that carbon fiber is stiffer than aluminum,

but it's not really as stiff as they say because they're measuring the CF composite but the resin doesn't add stiffness over the fibers themselves.

This is like saying that sand and gravel are stronger than concrete because the cement doesn't add anything.

My piece of CF is about .3mm, about the same thickness as three layers of aluminum foil. The foil is stiffer.

I think watching this video puts one in danger of being stupider at worst, and more ignorant at best.

phrantic09

Watched video, immediately threw both of my carbon bikes in the trash. I can’t believe I thought they were nice bikes!

aplcr0331

I watched the full video from the OP finally, and it's not what I was expecting and certainly wasn't bagging on Carbon. I mean he rides carbon bikes anyway. But now I can tell who didn't watch the video by their crybaby comments lol.

Anyway I mentioned before that his other vids are pretty good. That one about crank length and how cool the modeling he used for that one super interesting.

I've shared his video on the Specialized SL7 release hype to all my club friends...that's a great one. My buddy in the UK didn't watch the full video on Titanium. Cause he's a *****, lol. I don't think it's as bad as he thinks.

It's weird how one guy says something you don't like about your preferred bike type or material and you throw a hissy fit?

Oh well, his other videos are interesting and I'll certainly watch those over the lame "paid promotion" GCN videos and that loud mouth Hambini guy.

bruce19

I am watching his vid on aero positioning and he mentioned that he is a mechanical engineer.

Symox

I skimmed through most of it. The summary I got is builders need to know what they are doing to get the most out of carbon fiber. (That is true of any material btw).

he goes on to rant about generalities of carbon vs aluminum and how they are “rubbish”

I tend to think bike builders have learned a lot over the years in how to work various materials and do their best to get as much performance as they can if for no other reason than competition.

I look at bicycle frames like acoustic guitars. The builder who is skilled can use almost any material to make a great guitar/bike. The choice of material is complex and comes down to cost, performance, durability, consistency and sell ability.

I choose bikes based on which fit and feel the best within my price range. If the frame has a lifetime warranty and the builder a good reputation then I trust they know what they are doing. I don’t really care if it is CF or not.

having said that, in general I’ve found CF bikes to be more expensive and lighted than aluminum and my favorite bikes in my price range have been carbon fiber.

Carbonfiberboy 

The problem is that you didn't go to engineering school and take materials science and statics. Think about the concepts of tension and compression while holding a toilet paper or paper towel tube in your hands. Try to bend it without collapsing it. The tube is extremely light yet not that easy to bend. Holding it in front of you and trying to bend the ends down, the top is in tension and the bottom is in compression. That's a frame tube, hard to bend, i.e. stiff. Materials which are hard to stretch and compress like carbon fiber/epoxy laminate make a very stiff frame tube. Plus you get to vary the stiffness by the thickness of the laminate. Plus it's not carbon cloth like in the photo. It's "tows" of unidirectional fibers running lengthwise, but at some slight angle to the long dimension of the tube. Thus the tube is also stiff rotationally. Plus you can vary the rotational stiffness vs. the longitudinal stiffness just by changing the angle of the carbon tows. Carbon fiber structural design is not a simple thing, not at all. With metal, the builder is limited to what is made commercially, diameter, wall thickness, and alloy. Not so with carbon/epoxy. Pretty easy to see why carbon is such a popular material.

woodcraft

Thanks for the tutorial. I do have a working understanding of this stuff in spite of not having gone to engineering school.

The guy in the video seemed to be talking about the stiffness of CF independent of it being made into a structural composite, so I was commenting on that.

Personally, I think carbon fiber bike frames are good, but my current bike count is 1 CF, 4 aluminum, for whatever that's worth.

tomato coupe

This video seems to be mostly about the host being annoyed that some people are really enamored with carbon fiber as a material, and some now use it in applications where it's cosmetic, not structural. He argues that carbon fiber isn't as stiff as everyone thinks, yet concludes that a carbon frame that's designed to be as stiff as an aluminum frame can be much lighter. Yeah, that's kind of the point dude.

Carbonfiberboy 

I have one carbon, 2 alu, 1 steel. I'm glad I did no harm. I worry I come on too strong sometimes.

Seattle Forrest

Why would anyone go looking for informative on some random dude's youtube?

colnago62

Not much different than coming here.

downhillmaster

Too perfect.

bruce19

What makes the different grades of CF different? And, does it get down to the point where a "lower" level of CF frame is less desirable than say a good AL frame? From a materials science perspective.

Trakhak

Anisotropy

Carbonfiberboy 

Different grades of CF have different yield strengths and other properties. Better costs more. Stronger CF of course means you can use less of it, and more importantly, less resin, thus a part of the same strength and stiffness is lighter, not much, but lighter. There may be other variables with the resin and layup of which I'm unaware. I'm not an expert on carbon frames! I'm just familiar with the technology and have used it a little.

facorsig

I have a degree in materials engineering and a Professional Engineering license in metallurgical engineering. For what it's worth, my road and gravel bikes are titanium frames. There is confusion between stiffness (modulus) and yield or tensile strength. At the end of the day, you ride what you prefer, not something to impress other people.

Fred

WhyFi

Wow, 6 years between registering and your first post - kudos!

bruce19

Just curious....what is it about TI that you like?

edmguirk

I am new to this forum so this is a bit of a hot take but I thought this was all thrashed out back when people were comparing steel, aluminum, and titanium.

I commented on the original video a while ago because he seemed to only be interested in stiffness as if that is the only important thing. Stiffness is irrelevant unless you include strength and weight. A carpet fiber epoxy matrix might not be as stiff as the original fibers but geometry can makeup whatever loss occurred. I can make a bike of any stiffness with any material as long as you don't mind how safe or heavy it is. Sure, CF has directional strength different from steel/alu/tit but all the same arguments still apply. It's always some kind of compromise.

Whatever happened to beryllium?

And, after all, everybody also compromises on style and cost so which one is really best?

facorsig

My road rides are endurance rides of 100km and 200km mostly over chip seal roads. I like the vibration attenuation associated with titanium. I do have an aluminum frame bike which I use on my trainer. I have limited riding experience on carbon frame bikes, mostly rentals.

Fred