The Search for a Carbon Bike that Feels like a Metal Bike

[Mike Lopez]

Originally Posted by weisan

Hi Mike pal, so nice to hear from you!

Can you elaborate a bit more about your doubt?

I don't doubt that the static stiffness characteristics of the two frames could be duplicated and it might even ride the same from the springy standpoint but I don't think it would feel the same feedback wise at the contact points.

Many have commented on the various factors. Mass, material resonance differences etc. As said...some ring and some dampen. The two materials in question are polar opposites.

I guess it depends on which "feel" you're looking for. The springy or the resonance.

[Mike Lopez]

Originally Posted by NHAero

The aluminum frame I built for my undergrad thesis had 1.5" OD tubes that were externally butted in a lathe, and the tube size and wall thickness was designed based on reproducing the stiffness of a steel track frame.

The photo shows a close-up of the ST/TT/CS junction with the seatmast continuing up. The butts are visible.

Gary figured out that he should copy me

Very nice! I like it. How did it ride?

[Mike Lopez]

Originally Posted by NHAero

The aluminum frame I built for my undergrad thesis had 1.5" OD tubes that were externally butted in a lathe, and the tube size and wall thickness was designed based on reproducing the stiffness of a steel track frame.

Mike - As someone who's studied both statics and mechanics, your description makes me smile because I've (tried?) used similar when describing some stuff to friends who aren't super technical when discussing shaped steel tubing from the 80s and 90s. Very cool hearing the story about your time at Sp'ed, I can imagine that's how a lot of those early bikes were done. The Bruce ti-carbon Rando bikes are amazing works of rolling art.

Also, living in the area, I'd love to see what goes into the process of the composites side of things some day once things become a bit better with the way things are right now. Not sure that's something you do or have entertained in the past; I assume there's lots of proprietary stuff that goes on, so I understand if that's not in the cards.

My favorite way to describe/demonstrate the section props is to use a 6" machinists scale or business card. Easy to bend in one plane but not the other. Cross sectional area and material props are the same but the moment is massively different.

Regarding a visit. We could perhaps set up a time that would work out. We're just a small development / short run shop and visits aren't a generally a problem. We do however serve as contractors to customers that consider their projects sensitive so the doors are closed on those days.

[NHAero]

I'm not sure I can claim the levels of discernment that many commenters on this thread and others have. It was made to be short and quick handling and stiff in the sense that the rider was 135 pounds and not a trained racer.

It's fun to look at people's weight weenie builds today with carbon fiber. My bike as a fixed gear was 12 lb 5 oz. No carbon. Steel fork. Besides the frame, I made the pedals and hubs, all else was off-the-shelf components. Way lighter and less stiff than Klein's commercial frames.

It was robust enough to ride in the Mt. Washington (NH) Hillclimb in 1975 and 1976. In '75 they wouldn't let me ride a fixed gear, so I left 1/2 hour before the race and rode alone to the top, geared 1:1. Never had to stand on the pedals, and ended up with a time that would have been top ten. There are some rides where light weight helps and back then it was true of both bike and rider

Originally Posted by Mike Lopez

Very nice! I like it. How did it ride?

[eddief]

I ride Conti 5000 x 32 on my Roubaix and Panaracer GK Slicks x 35 on my Creo. Granted the bikes are quite different but feel is feel. Not racing but I prefer the Panaracers with less air and lovely ride.

[flying]

Originally Posted by mhespenheide

Steve points out, above, that "Aluminum doesn't flex", but as understandable as that statement is in the context of a CAAD10 or Specialized Allez Sprint, what about the Vitus 979 or the Trek 1400? Those certainly flexed. Most modern carbon doesn't flex, but what about the Look 585 or an early 90's Specialized Epic or similar Trek (bonded to aluminum lugs, I think)? Or a classic Calfee?

I always thought that was the "lugs" difference or having joints that did somehow allow some flex/spring to be felt in frames like the Look 585 or Vitus 979

Compared to Monocoque carbon bike frames or Large diameter Alum Tubes welded together without lugs

[mhespenheide]

Originally Posted by flying

I always thought that was the "lugs" difference or having joints that did somehow allow some flex/spring to be felt in frames like the Look 585 or Vitus 979

Compared to Monocoque carbon bike frames or Large diameter Alum Tubes welded together without lugs

I am not an engineer, but while the lugged construction might dampen some vibration as the energy passes from one material to another (I'm thinking of waves partially reflecting and partially transmitting as they pass from one medium to another), the flex seems much more likely to be related to the diameter of the tubing.

I wonder what a smaller-diameter modern aluminum or carbon would ride like, if stiffness weren't the primary driving intent of the designers. But then, it sounds like that was part of the idea behind the Aethos...!

[fredd]

Originally Posted by mhespenheide

I am not an engineer, but while the lugged construction might dampen some vibration as the energy passes from one material to another (I'm thinking of waves partially reflecting and partially transmitting as they pass from one medium to another), the flex seems much more likely to be related to the diameter of the tubing.

I wonder what a smaller-diameter modern aluminum or carbon would ride like, if stiffness weren't the primary driving intent of the designers. But then, it sounds like that was part of the idea behind the Aethos...!

I used to ride a 1999 Kona Kapu made of (by modern standards) small diameter aluminum tubes and that thing was so so smooth. A wet noodle under power, but more comfy than my current Max ride.

[mhespenheide]

Originally Posted by fredd

I used to ride a 1999 Kona Kapu made of (by modern standards) small diameter aluminum tubes and that thing was so so smooth. A wet noodle under power, but more comfy than my current Max ride.

And therefore, there should be some middle diameter out there that's not a Vitus 979 but also not a CAAD9. Right?

If only I had the time and money to go buy a bunch of Al and CF bikes from the early to late 90's and see what the best results are.

[flying]

Originally Posted by mhespenheide

I am not an engineer, but while the lugged construction might dampen some vibration as the energy passes from one material to another (I'm thinking of waves partially reflecting and partially transmitting as they pass from one medium to another), the flex seems much more likely to be related to the diameter of the tubing.

I wonder what a smaller-diameter modern aluminum or carbon would ride like, if stiffness weren't the primary driving intent of the designers. But then, it sounds like that was part of the idea behind the Aethos...!

Yes for sure & goes without saying but...
What is always a surprise to me is folks compare "Carbon" never realizing that a Tube & Lug Carbon frame feels nothing like a monocoque carbon frame

[avalonracing]

Originally Posted by mhespenheide

And therefore, there should be some middle diameter out there that's not a Vitus 979 but also not a CAAD9. Right?

=

As someone who had a Vitus 979 and a Klein Quantum Race, I know what you mean. That Vitus was such a nice riding bike in a way the Klein never could be but the Klein felt like a rocket in criteriums.

[fredd]

Originally Posted by mhespenheide

And therefore, there should be some middle diameter out there that's not a Vitus 979 but also not a CAAD9. Right?

If only I had the time and money to go buy a bunch of Al and CF bikes from the early to late 90's and see what the best results are.

To complicate it further. My old Rossin Synthesis had similar diameters to the Kona, but probably thicker tubes as it weighed a lot more, and it was super harsh.

[Zackus]

So any update here? Is the Aethos everything you wanted it to be and more? The grail bike with quality of steel and the weight of carbon?

[rain dogs]

Originally Posted by RyanH

My question to you all that ride metal bikes, do you know what I'm talking about and have you ridden any carbon bikes that do have that smoothness?

For those curious why I'm asking or even trying to go away from Ti if I like it so much, the short answer is that I want a new bike that descends like the Crux, is disc and sub 6.8kg. It'll be a tall task getting a metal disc bike light whereas an Aethos is literally half the weight of a Ti disc frame and could possibly check all those boxes.

Late to the party here, must have missed this thread. My 2 cents...

I'd describe myself as much of a weight weenie as anyone (but maybe not?) but my philosophy is "if all is equal, get the lightest component you can"

I think more people are weight weenies than they think. Why Super Record over Chorus? Performance isn't better (if you ask quickstep mechanics who fitted Chorus derailleurs for years cause record is "too damn flexy"... it's worse.

Cutting to the chase. The lightest, lightest carbon frame will make a bike that's 300g-700g lighter than an ultralight steel/ti bike. And they're NOT the same. Why stress that little weight? That's 10-14 seconds at threshold up a 10km climb @ 5% .... 10 seconds! For hours, days, months, years of a worse ride.

And I'm not dismissing getting an ultralight bike... but it comes with all the other bows and ribbons. Sometimes super stiff rocketships are fun too! But this "the best of both" for an nearly insignificant weight difference.... meh.

It's like saying I want a carbon saddle for weight with the comfort of a couch. Makes no sense to me. Carbon bikes have an identity crisis - people always want them to be a bike of another material. Buy carbon? Ride it and own it, I say... but then I don't ride carbon frames.

[flying]

Originally Posted by rain dogs

Carbon bikes have an identity crisis - people always want them to be a bike of another material. Buy carbon? Ride it and own it, I say... but then I don't ride carbon frames.

^^True ^^

& I dont ride carbon either