14 ms·

Bike Frame Stiffness

steelframe 4y ago
I feel this HN account had been just waiting for this article. The points the article makes about torsional and lateral tension helped me understand better why I prefer steel over carbon. I've always described it as "feeling more in-sync" with the bike. For example, the subtle instinctive biomechanical action of putting more weight down on the outside pedal to re-align the wheels when you start to understeer just feels great, like you're "one" with the bicycle.
- giuliomagnifico 4y ago
  Yes but are dispersing power. It’s the same (endless) story as the vinyl VS digital… you can “feel” better the vinyl but the digital is technically better.
  - rhn_mk1 4y ago
    Where is the power dispersed? Typically bike frames are made of elastic materials which return the power that was injected through the deformation. If the power isn't returned, then the deformation was plastic and you have a bent frame, so that isn't really an option.
    - giuliomagnifico 4y ago
      Yes but it returns the power when your pedal is at the “death point” and you aren’t making power on the frame, then the power is dispersed through the frame flex when not needed. The frame should be soft vertically on the seat tube.
      - rhn_mk1 4y ago
        I'm not sure if I see it. If you're not putting a force on the frame, then the frame is not twisted, and it doesn't return anything. You have to push in order to recuperate the energy. If you remove the force so fast that the frame doesn't have the time to return the energy back to you, then it will disperse the energy by ringing. But i don't think it's realistic unless you drive your pedals with hammer strikes.
        zardo 4y ago
        You also have the possibility of transferring that energy into tire deformation and heating.
      - zwieback 4y ago
        I would think that most of the energy goes in between 12 and 3 o'clock and then flexes out from 3 to 6. So if the flex pushes back against your leg a good part of the energy should go back on the road.
  - ehnto 4y ago
    Depends on your goals though I think. Since ride quality and feel is a factor, it's not objectively true that carbon is better than steel. Just that it has better stiffness. Do you want better stiffness? Well it depends entirely on what you are doing and what you want to experience. For example, in a touring bike, you might prefer steels robustness and softer feel for long hauls. Some people might prefer carbon for it's lightness. It's all down to choice, neither is objectively better.
    - giuliomagnifico 4y ago
      Yeah absolutely correct but the article was talking about professional cycling. I’m also a cyclist (not touring oriented) and the stuff a bike is, the more I like it. A racing bike should flex vertically but not horizontally.
  - blacksmith_tb 4y ago
    I tend to agree - unless you had the ability to compare the ride of identical frames made of different materials - same angles, same components and tires, I suspect a lot of the 'feel' of the ride comes from having been told steel is more forgiving, aluminum is harsh, etc. We have a lot of very subtle control over the frame, angles, wall thicknesses, and I would expect a skilled builder to be able to produce the desired performance for whatever frame material. That said, there do seem to be some obvious poor choices, I am not going touring on an all-carbon frame that could fail catastrophically in the middle of nowhere, no matter how comfy.
- ehnto 4y ago
  Have you ridden aluminium bikes in a way that lets you compare? I have a steel and an aluminum frame, but they have different applications so I can't compare. I do feel more harshness in the bars on the ALU frames, like sharper peaks in vibrations.
  - baggsie 4y ago
    A good alu frame is more comfortable than a cheap steel or carbon frame IME. I think a lot of the perceived differences comes down to tyres rather than frame material - steel bikes are much more likely to have >35mm tyres than alu with 25 - 28mm.
    - SyzygistSix 4y ago
      And a really good steel frame (or titanium that has been butted to ride like steel) is even more enjoyable still, at least for a lot of folks. A hand built steel frame is luxurious and will ride like a dream.
      - zardo 4y ago
        > A hand built steel frame is luxurious and will ride like a dream. Surely that depends on the hands.
      - deebosong 4y ago
        I've tried the following: • steel, straight-gauge Hi-Ten from the mid 90's • steel, double-butted, Columbus SL from the late 70's/ early 80's • steel, double-butted, Tange 1 from the late 80's • steel, not sure but it was a Kona Rova from 2020 I believe • aluminum, Cannondale R300 from the mid 90's • aluminum, Specialized SmartWeld DSW from 2016 • aluminum, Cannondale Synapse from the late 2010's I personally love Columbus SL. I believe it was 0.1 mm thicker all around than even the Tange 1 bike in numbers (but I'm not sure if both triangles were double-butted or only the main one). But it feels springier, even with the same wheels & tires & components swapped between the two frames. I didn't mind the Cannondale Synapse. It subjectively felt better than the Smartweld aluminum, but the difference could have been in the wider tires on the Synapse (versus the Spesh). The Kona Rove... for some reason was a bit of a letdown. People seem to love that bike, though. And Hi-Ten is as stiff and clunky as everyone says. Pure beater material right there. But the Cannondale R300's mid 90's aluminum was even harsher and wrist-numbing. It'll rattle you to your core! All of this is anecdotal & subjective, though. I've learned to compensate the added road-noise from the Specialized aluminum by hovering off my saddle and bending my elbows a bit while loosening my grip. But man, I love that racing steel bike. It makes me wanna try Tange Prestige of the road variety, and Ti as well. Only other thing I'm super curious about is CAAD 12 Aluminum, but on forums I've read that CAAD 12's are slightly harsher than SuperSix Evo's (all carbon). ––– Edited to include some other bikes & models
- zwieback 4y ago
  Yes, sir, and you had to wait 10 years for it! I've only had steel frames myself but when I try out non-steel frames I can't say I dislike them, just that they feel strange. I'm still trying to understand the talk about over/understeer and how the bottom bracket is involved. Are you saying you put down more weight on the outside pedal on each rotation of the crank as you're going through a turn? Also, isn't there some wasted energy going into flexing the frame that should go into the road?
  - PascLeRasc 4y ago
    There is some wasted energy from flexing during really hard pedaling, but off-road this can actually make you more efficient when the frame keeps the rear wheel attached to uneven ground.
- zwkrt 4y ago
  In bike messenger circles there is a phrase "steel is real". The idea being that when you inevitably eat shit going around a corner you might dent your frame, but the chances that a steel frame will crack or shatter is basically zero. And more importantly dings and scratches don't cause the structural integrity to degrade like happens with aluminum or carbon fiber. Your steel fork is bent? Hit it with a hammer until it's true again!
  - Scoundreller 4y ago
    Also applies to fixing steel wheels. Can slam them against the ground, hammer them, and step on them to bend them back into shape without losing as much strength as one would on aluminum.
    - joe_the_user 4y ago
      Aside from being absurdly heavy, steel wheels are dangerous since they become extremely slippery to brake shoes in rain or wet conditions. I don't think steel rims are common any more - or at least they shouldn't be unless you use disk brakes or something.
      - whalesalad 4y ago
        I'm guessing this person might be referring to steel car/truck wheels? A lot of serious crawlers/off-roaders prefer steel wheels because 1. they are cheap and easy to fix/replace, 2. they are easy to weld on beadlocks, and 3. you can definitely repair them out on the trail with a hammer.
      - Scoundreller 4y ago
        Not common in new builds, but because of their durability and repairability, they’re still around.
  - soulofmischief 4y ago
    Oh, I wish. Unfortunately a nasty accident bent my steel tube beyond repair due to structural integrity concerns, and I still have yet to find a bike I've felt so at one with... This one was an early 80's Schwinn before the Chicago plant shut down and it's hard to find the exact kind I like.
- jackmott 4y ago
deleted 4y ago
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rhn_mk1 4y ago
How is an article about stiffness and deformations lacking a single picture of the forces in play?
- s1mon 4y ago
  There are a bunch of photos showing the test fixtures that they're using to measure frame flex which pretty clearly show what they're constraining and where they're adding force with the cylinder. It's not a free body diagram and it doesn't show the rider, but what exactly are you looking for?
  - rhn_mk1 4y ago
    Well, diagrams. Apply this force, get this displacement, this is how wheels are out of plane (disregarding that turning makes them out of plane already). None of the pictures are labeled, and they only show one setup: pressing the pedal without sitting on the seat, without holding the handlebars, while both wheels remain in plane. I'm not sure if it's even possible to keep both wheels in plane when pedalling on a moving bicycle, if only due to pressing on the handlebars.
soared 4y ago
Bike stiffness is really interesting, especially when compared to skiing. I think its easier to understand with boot and ski stiffness which operate in similar manners, where a stiffer boot allows you to convert more of your movement down to the ski instead of being absorbed by the boot! I recently switched my indoor trainer from my aluminum frame to and old carbon frame and found it much more comfortable, which I think is from the less stiff old carbon allowing more movement. I wasn't aware of bottom bracket stiffness, but seems to make sense that single speeds tend to feel better for me if the bottom bracket can be simpler and stiffer?
- arnejenssen 4y ago
  Yes. Imagine rowing a boat with flexible oars. Then it is easy to understand how much force is lost.
  - fluoridation 4y ago
    Well, not really. It's not like you'd be permanently bending the oars. When you complete each stroke you're going to get back nearly all of the energy that went into the elastic deformation. There's going to inevitably be some energy lost in warming up the oar, but it's not at all obvious that a slightly flexible oar would be perceptively or even effectively worse than a stiff oar.
  - deleted 4y ago
    [deleted]
LesZedCB 4y ago
CyclingAbout has an amazing video on frame stiffness https://www.youtube.com/watch?v=5f8PGpKUKro https://www.youtube.com/watch?v=5f8PGpKUKro i guess it makes sense when this article is talking about road bikes, but in MTB and gravel bikes, where geometry is so much more malleable, the geometry plays such a huge role in stiffness, almost independent of material. you can have a crazy stiff steel bike (e.g. kona honzo esd) or a crazy compliant carbon bike.
- dranudin 4y ago
  This. You can more or less get any kind of stiffness, with any material by changing the geometry. I guess the different feel that people have when using frames of various materials is more due to geometric constraints of the frame. A frame with the same geometry (which includes tube thickness etc) and a different material will behave differently. But in theory you could construct a frame with equal stiffness in all directions from other materials. However, you might run into other problems, like fatigue resistance or tensile strength or sth with a particular geometry. That will then force you to choose another geometry for other materials (e.g. aluminum frames will have a bigger tube diameter than steel frames, due to buckling of the tubes - if you want equal weight)
javier_e06 4y ago
My impression with stiffness is can be annoying if once is not pushing hard in a criterium or something. I have a carbon/Alu frame and an old steel bike. The steel bike shields me from the imperfections of the road. For long rides that is ideal. Very interesting article.
dboreham 4y ago
This takes me back. My Dad was an amateur road racer and time-trialer, and also an engineer. So of course he designed his own frame geometry and would talk at length about stiffness. Back in the days of Reynolds steel tubing this was. No fancy carbon fiber.
mtmail 4y ago
https://www.cube.eu/bg-en/cube-world/technology/test-lab https://www.cube.eu/bg-en/cube-world/technology/test-lab has more photos of a test lab, split into road vs mountain bike tests. As a mountain biker I don't care much about road conditions but I want the frame and suspension tested going down stairs, jumps and other forces.
cloudc0de 4y ago
I got a Surly steel bike that rides like a dream, I can't go back to the stiffer stuff. I also had an aluminum bike break in half just cause I rode off a curb, I don't worry about that at all with steel frames.
LAC-Tech 4y ago
If I ever get into recreational cycling I need to make a mental note to not read about any performance stuff ever again. I'll get something rigid with relatively wide tires and disk brakes and not give two shits about weight or stiffness. I'm not nor have I ever been someone looking to shave seconds off in a race, I'm just some naturally unfit guy that happens to love riding bikes. Also need to stop talking to other cyclists online. "Oh yeah 100 miles is easy", not for me it isn't.
- mperham 4y ago
  A good amount of “legacy” bike advocates are actively hostile to e-bikes, equating them to “cheating”. It’s gatekeeping bullshit. Anytime someone asks me bike buying advice, my only reply is “go to your local dealer and talk with them”. That relationship and taking a few test rides are far more important than any spec on a sheet.
  - mauvehaus 4y ago
    ... and if the first shop you visit isn't vibing with what your goals and/or personality are, try another. Shops that cater to commuters and transportation cyclists are very different from ones that cater to hardcore road or mountain bike riders.
  - fluoridation 4y ago
    The thing about bikes is that if you want to go fast, you have to put in kilometers on the saddle. That trains not just your body, but also your mind, and teaches you how to behave on the road. An electric bike allows someone with little training to go much faster than they would be able to otherwise. Now imagine that you're an experienced rider going at a cool 35 km/h and as you're about to pass a newbie on an electric bike they swerve into you because they don't yet have the habit of looking back before moving sideways. Yes, it's a mistake of that particular person alone, but it's a mistake they were able to make because e-bikes exist.
    - deleted 4y ago
      [deleted]
Zigurd 4y ago
If you have a quality aluminum frame bike, it probably has a carbon fork. If you find the ride harsh, you'll get most of the benefit of a carbon frame by swapping in a carbon seat post, stem, and bars. There are plenty of good, moderately priced carbon parts available, and changing these parts is very simple. If you are on 23mm tires, change them for 28mm, which will fit in almost all rim brakes. On lo-end carbon frame bikes you will find alloy bars and seat posts, which is silly.
MezzoDelCammin 4y ago
My personal $.02 on frame stiffness is that it's way overrated. The bike I personally spend most time on is a steel frame, but I've never once asked myself a question of "is this stiff / bouncy" enough. When I started having issues with too much road vibration giving me a mild case of cyclists palsy (temporary mild paralysis of ulnar nerve), it was due to the surface I was riding on (gravel) and the distances / times. Solution was adding suspension stem to the handlebar. To me, the "steel is real" argument speaks about the general durability / repairability of the frame. But AFAIK, modern CroMoly steel butted tubes aren't "that" great for welding or cold setting either (to be debated). IMO the famous road repairs of 90's adventurers who had their cracked frames repaired by no matter what farmer with a stick welder in the midle of Kazakhstan are simply long gone now. Personally, the thing I watch for in a bike frame first and foremost is the geometry and the actual personal fit (ideally by a professional fitter). The number one issue I've seen most beginners have related to bike frames is simply being too optimistic on their abilities and spending thousands on frames that they simply don't have the mobility and flexibility for.
- fluoridation 4y ago
  Yeah, pretty much. Bicycle frames are basically completely rigid vertically, as far as the forces that are normally encountered is concerned. The only possible source of vertical compliance are the tires and the suspension, if there is any. Some frames may be more or less laterally or torsionally compliant, but I'm skeptic that either makes much of a difference while riding.
  - wiredfool 4y ago
    I'd add saddle rails/saddles, handlebars, and forks to that list of vertically compliant parts. There's also a bit in the wheels, but only 1mm or so.
- hinkley 4y ago
  Perceptions on stiffness vary greatly with your inseam length, and I feel like it's fruitless to have conversations without stating what frame size you're looking at. If you start with a bike model that is already known to be mushy and try to ride a 60 or 62cm size it's going to be even worse. When I still rode I chose a frame that some other club members characterized as 'harsh' but they were riding something more like a 56. Even a couple inches makes a huge difference in leverage.
markandrewj 4y ago
Just some general thoughts, so please understand I am not prescribing one over the other. The ride quality of a bike is largely dependent on frame geometry and manufacturing process. With a good layup, and geometry, carbon can be more stiff then steel. This is actually the promise of carbon, to be stiffer then steel while being lighter. However a good quality aluminum bike can also be lighter, and more stiff, then a carbon bike with a low quality layup. Steel tubing also comes in a variety of different qualities. https://gravelcycling.wordpress.com/2016/07/07/steel-the-different-types-of-steel-in-bike-frames/ https://gravelcycling.wordpress.com/2016/07/07/steel-the-dif.... The obvious benefit to steel for me is the reliability and repairability. Ride quality can also be different depending on surface, steel is better at dampening vibrations then aluminum on gravel surfaces. Although carbon can obviously be quite nice, and you are seeing it used in tough ultra distance rides like the GDMBR. That said your wheel choice, and seatpost, will have a bigger impact on ride quality then frame material as far as vibration. Generally speaking the weight of your bike is going to be most noticable on climbs. How noticable will also depend on your gear range. This video about titanium bike myths discusses some of the points I outlined above in further detail. https://youtu.be/1CTjg1TFHDc https://youtu.be/1CTjg1TFHDc
- hinkley 4y ago
  It's easy with steel to go outside of the realm of easy repairability. In the last days of steel before aluminum became affordable and even before carbon fiber did, it was common to for fancier bikes to have tubing that changed thickness (interior of course) once or twice, as stiffness at the ends of the tubs tends to matter more, and it's easier to weld thicker pieces of metal. And then you had Serotta, who before they switched to titanium, made steel frames that were not just double-butted, but they also spirally ground the butting to maintain most of the torsional stiffness but lose a couple more ounces of weight.
  - markandrewj 4y ago
    Yeah, but try getting carbon repaired after a crash. It's not impossible, but it's also not as easy to work with as a material. That said a lot of new high end carbon bikes will come with crash replacement on the frame.
litoE 4y ago
I don't get the whole stiffness argument. If the frame is not stiff then some of my energy goes into flexing the frame back and forth as I pedal, and eventually gets wasted as heat. This is bad if I'm into some sort of competitive riding. But if I ride the bike just for the exercise, then I'm interested in wasting energy and I don't care too much about how it was wasted.
- abrookewood 4y ago
  A stiff bike is an efficient bike, but not a comfortable one. I once rode in the Gong Ride (Sydney to Wollongong) and, determined to set my bike up as efficiently as possible, pumped my tyres up to 120 PSI. The bike felt incredibly fast ... but my testicles went numb.
  - fluoridation 4y ago
    Tips: 1. Wear cycling shorts and pull your boys up so that you're not sitting on them when you ride. 2. Don't put so much weight on the saddle. The saddle is not a seat, it's meant as an extra point of control to lean the frame. Put your weight on the pedals. Also, is the saddle at the correct height? I ride tires at 115 PSI daily and have never had issues with numbness anywhere on my body.
  - nl 4y ago
    > but my testicles went numb This is about the seat you are using and the time you are spending on it, not the stiffness of the frame or ride. There is a reason why male seats have cut-outs. You just need to find one that works for you.
  - jlarcombe 4y ago
    Didn't feel much stiffness for a while after that then
- ak217 4y ago
  Not only that but a frame that's not stiff is going to result in more play in the chain and cables that lever against the frame. That means uncommanded or skipped shifts, uneven brake feel, sloppy braking and cornering feel as the frame gets loaded/unloaded in different directions. The real reason a frame should not be optimized entirely for stiffness at the expense of everything else is material fatigue. A frame that maximizes stiffness is a frame that puts its materials under more stress. So if you dial up the stiffness all the way, you'll get less longevity and eventual stress fractures or worse. What most riders think of as stiffness/springiness/feel in their bike comes from the flex (or lack thereof) in their tires, seat, seatpost, spokes, and the harmonic response of their frame to vibrations from the ride. That response is actually a key part of subjective rider satisfaction, I think because we subconsciously feel more in control (because we can feel what the bike is doing better) when the vibrations are more pronounced.
virgulino 4y ago
Obligatory reference to Jan Heine, the "heretic" who has been talking about this for many years: Frame stiffness double blind test: https://www.renehersecycles.com/what-is-planing/ https://www.renehersecycles.com/what-is-planing/ https://www.renehersecycles.com/the-biomechanics-of-planing/ https://www.renehersecycles.com/the-biomechanics-of-planing/ https://www.renehersecycles.com/expert-discussion-on-frame-stiffness/ https://www.renehersecycles.com/expert-discussion-on-frame-s... https://www.renehersecycles.com/myth-4-stiffer-frames-are-faster/ https://www.renehersecycles.com/myth-4-stiffer-frames-are-fa...
oakmad 4y ago
I can't wait for the Hambini analysis of this one.
- james_woods 4y ago
  HELLO HAMBINI FANS AND WELCOME
kazinator 4y ago
> But when it comes to pedalling, we know that higher is not automatically better. Sure, if you like weird rubbing to show up under load (e.g. steep climbing) that isn't there normally.
martyvis 4y ago
Funny. The YouTube algorithm just recommended this review of 1990s mountain bike that has a cable in place of the downtube. https://youtu.be/0ekXSqE4gNQ https://youtu.be/0ekXSqE4gNQ
1letterunixname 4y ago
I had an aluminum frame Cannondale racing road bike that was exhausting to ride because it had a short wheelbase, compact frame (small triangle), and was very stiff.

I feel this HN account had been just waiting for this article. The points the article makes about torsional and lateral tension helped me understand better why I prefer steel over carbon. I've always described it as "feeling more in-sync" with the bike. For example, the subtle instinctive biomechanical action of putting more weight down on the outside pedal to re-align the wheels when you start to understeer just feels great, like you're "one" with the bicycle.

giuliomagnifico 4y ago
Yes but are dispersing power. It’s the same (endless) story as the vinyl VS digital… you can “feel” better the vinyl but the digital is technically better.
- rhn_mk1 4y ago
  Where is the power dispersed? Typically bike frames are made of elastic materials which return the power that was injected through the deformation. If the power isn't returned, then the deformation was plastic and you have a bent frame, so that isn't really an option.
  - giuliomagnifico 4y ago
    Yes but it returns the power when your pedal is at the “death point” and you aren’t making power on the frame, then the power is dispersed through the frame flex when not needed. The frame should be soft vertically on the seat tube.
    - rhn_mk1 4y ago
      I'm not sure if I see it. If you're not putting a force on the frame, then the frame is not twisted, and it doesn't return anything. You have to push in order to recuperate the energy. If you remove the force so fast that the frame doesn't have the time to return the energy back to you, then it will disperse the energy by ringing. But i don't think it's realistic unless you drive your pedals with hammer strikes.
      - zardo 4y ago
        You also have the possibility of transferring that energy into tire deformation and heating.
    - zwieback 4y ago
      I would think that most of the energy goes in between 12 and 3 o'clock and then flexes out from 3 to 6. So if the flex pushes back against your leg a good part of the energy should go back on the road.
- ehnto 4y ago
  Depends on your goals though I think. Since ride quality and feel is a factor, it's not objectively true that carbon is better than steel. Just that it has better stiffness. Do you want better stiffness? Well it depends entirely on what you are doing and what you want to experience. For example, in a touring bike, you might prefer steels robustness and softer feel for long hauls. Some people might prefer carbon for it's lightness. It's all down to choice, neither is objectively better.
  - giuliomagnifico 4y ago
    Yeah absolutely correct but the article was talking about professional cycling. I’m also a cyclist (not touring oriented) and the stuff a bike is, the more I like it. A racing bike should flex vertically but not horizontally.
- blacksmith_tb 4y ago
  I tend to agree - unless you had the ability to compare the ride of identical frames made of different materials - same angles, same components and tires, I suspect a lot of the 'feel' of the ride comes from having been told steel is more forgiving, aluminum is harsh, etc. We have a lot of very subtle control over the frame, angles, wall thicknesses, and I would expect a skilled builder to be able to produce the desired performance for whatever frame material. That said, there do seem to be some obvious poor choices, I am not going touring on an all-carbon frame that could fail catastrophically in the middle of nowhere, no matter how comfy.
ehnto 4y ago
Have you ridden aluminium bikes in a way that lets you compare? I have a steel and an aluminum frame, but they have different applications so I can't compare. I do feel more harshness in the bars on the ALU frames, like sharper peaks in vibrations.
- baggsie 4y ago
  A good alu frame is more comfortable than a cheap steel or carbon frame IME. I think a lot of the perceived differences comes down to tyres rather than frame material - steel bikes are much more likely to have >35mm tyres than alu with 25 - 28mm.
  - SyzygistSix 4y ago
    And a really good steel frame (or titanium that has been butted to ride like steel) is even more enjoyable still, at least for a lot of folks. A hand built steel frame is luxurious and will ride like a dream.
    - zardo 4y ago
      > A hand built steel frame is luxurious and will ride like a dream. Surely that depends on the hands.
    - deebosong 4y ago
      I've tried the following: • steel, straight-gauge Hi-Ten from the mid 90's • steel, double-butted, Columbus SL from the late 70's/ early 80's • steel, double-butted, Tange 1 from the late 80's • steel, not sure but it was a Kona Rova from 2020 I believe • aluminum, Cannondale R300 from the mid 90's • aluminum, Specialized SmartWeld DSW from 2016 • aluminum, Cannondale Synapse from the late 2010's I personally love Columbus SL. I believe it was 0.1 mm thicker all around than even the Tange 1 bike in numbers (but I'm not sure if both triangles were double-butted or only the main one). But it feels springier, even with the same wheels & tires & components swapped between the two frames. I didn't mind the Cannondale Synapse. It subjectively felt better than the Smartweld aluminum, but the difference could have been in the wider tires on the Synapse (versus the Spesh). The Kona Rove... for some reason was a bit of a letdown. People seem to love that bike, though. And Hi-Ten is as stiff and clunky as everyone says. Pure beater material right there. But the Cannondale R300's mid 90's aluminum was even harsher and wrist-numbing. It'll rattle you to your core! All of this is anecdotal & subjective, though. I've learned to compensate the added road-noise from the Specialized aluminum by hovering off my saddle and bending my elbows a bit while loosening my grip. But man, I love that racing steel bike. It makes me wanna try Tange Prestige of the road variety, and Ti as well. Only other thing I'm super curious about is CAAD 12 Aluminum, but on forums I've read that CAAD 12's are slightly harsher than SuperSix Evo's (all carbon). ––– Edited to include some other bikes & models
zwieback 4y ago
Yes, sir, and you had to wait 10 years for it! I've only had steel frames myself but when I try out non-steel frames I can't say I dislike them, just that they feel strange. I'm still trying to understand the talk about over/understeer and how the bottom bracket is involved. Are you saying you put down more weight on the outside pedal on each rotation of the crank as you're going through a turn? Also, isn't there some wasted energy going into flexing the frame that should go into the road?
- PascLeRasc 4y ago
  There is some wasted energy from flexing during really hard pedaling, but off-road this can actually make you more efficient when the frame keeps the rear wheel attached to uneven ground.
zwkrt 4y ago
In bike messenger circles there is a phrase "steel is real". The idea being that when you inevitably eat shit going around a corner you might dent your frame, but the chances that a steel frame will crack or shatter is basically zero. And more importantly dings and scratches don't cause the structural integrity to degrade like happens with aluminum or carbon fiber. Your steel fork is bent? Hit it with a hammer until it's true again!
- Scoundreller 4y ago
  Also applies to fixing steel wheels. Can slam them against the ground, hammer them, and step on them to bend them back into shape without losing as much strength as one would on aluminum.
  - joe_the_user 4y ago
    Aside from being absurdly heavy, steel wheels are dangerous since they become extremely slippery to brake shoes in rain or wet conditions. I don't think steel rims are common any more - or at least they shouldn't be unless you use disk brakes or something.
    - whalesalad 4y ago
      I'm guessing this person might be referring to steel car/truck wheels? A lot of serious crawlers/off-roaders prefer steel wheels because 1. they are cheap and easy to fix/replace, 2. they are easy to weld on beadlocks, and 3. you can definitely repair them out on the trail with a hammer.
    - Scoundreller 4y ago
      Not common in new builds, but because of their durability and repairability, they’re still around.
- soulofmischief 4y ago
  Oh, I wish. Unfortunately a nasty accident bent my steel tube beyond repair due to structural integrity concerns, and I still have yet to find a bike I've felt so at one with... This one was an early 80's Schwinn before the Chicago plant shut down and it's hard to find the exact kind I like.
jackmott 4y ago

deleted 4y ago

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rhn_mk1 4y ago

How is an article about stiffness and deformations lacking a single picture of the forces in play?

s1mon 4y ago
There are a bunch of photos showing the test fixtures that they're using to measure frame flex which pretty clearly show what they're constraining and where they're adding force with the cylinder. It's not a free body diagram and it doesn't show the rider, but what exactly are you looking for?
- rhn_mk1 4y ago
  Well, diagrams. Apply this force, get this displacement, this is how wheels are out of plane (disregarding that turning makes them out of plane already). None of the pictures are labeled, and they only show one setup: pressing the pedal without sitting on the seat, without holding the handlebars, while both wheels remain in plane. I'm not sure if it's even possible to keep both wheels in plane when pedalling on a moving bicycle, if only due to pressing on the handlebars.

soared 4y ago

Bike stiffness is really interesting, especially when compared to skiing. I think its easier to understand with boot and ski stiffness which operate in similar manners, where a stiffer boot allows you to convert more of your movement down to the ski instead of being absorbed by the boot! I recently switched my indoor trainer from my aluminum frame to and old carbon frame and found it much more comfortable, which I think is from the less stiff old carbon allowing more movement. I wasn't aware of bottom bracket stiffness, but seems to make sense that single speeds tend to feel better for me if the bottom bracket can be simpler and stiffer?

arnejenssen 4y ago
Yes. Imagine rowing a boat with flexible oars. Then it is easy to understand how much force is lost.
- fluoridation 4y ago
  Well, not really. It's not like you'd be permanently bending the oars. When you complete each stroke you're going to get back nearly all of the energy that went into the elastic deformation. There's going to inevitably be some energy lost in warming up the oar, but it's not at all obvious that a slightly flexible oar would be perceptively or even effectively worse than a stiff oar.
- deleted 4y ago
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LesZedCB 4y ago

CyclingAbout has an amazing video on frame stiffness https://www.youtube.com/watch?v=5f8PGpKUKro https://www.youtube.com/watch?v=5f8PGpKUKro i guess it makes sense when this article is talking about road bikes, but in MTB and gravel bikes, where geometry is so much more malleable, the geometry plays such a huge role in stiffness, almost independent of material. you can have a crazy stiff steel bike (e.g. kona honzo esd) or a crazy compliant carbon bike.

dranudin 4y ago
This. You can more or less get any kind of stiffness, with any material by changing the geometry. I guess the different feel that people have when using frames of various materials is more due to geometric constraints of the frame. A frame with the same geometry (which includes tube thickness etc) and a different material will behave differently. But in theory you could construct a frame with equal stiffness in all directions from other materials. However, you might run into other problems, like fatigue resistance or tensile strength or sth with a particular geometry. That will then force you to choose another geometry for other materials (e.g. aluminum frames will have a bigger tube diameter than steel frames, due to buckling of the tubes - if you want equal weight)

javier_e06 4y ago

My impression with stiffness is can be annoying if once is not pushing hard in a criterium or something. I have a carbon/Alu frame and an old steel bike. The steel bike shields me from the imperfections of the road. For long rides that is ideal. Very interesting article.

dboreham 4y ago

This takes me back. My Dad was an amateur road racer and time-trialer, and also an engineer. So of course he designed his own frame geometry and would talk at length about stiffness. Back in the days of Reynolds steel tubing this was. No fancy carbon fiber.

mtmail 4y ago

https://www.cube.eu/bg-en/cube-world/technology/test-lab https://www.cube.eu/bg-en/cube-world/technology/test-lab has more photos of a test lab, split into road vs mountain bike tests. As a mountain biker I don't care much about road conditions but I want the frame and suspension tested going down stairs, jumps and other forces.

cloudc0de 4y ago

I got a Surly steel bike that rides like a dream, I can't go back to the stiffer stuff. I also had an aluminum bike break in half just cause I rode off a curb, I don't worry about that at all with steel frames.

LAC-Tech 4y ago

If I ever get into recreational cycling I need to make a mental note to not read about any performance stuff ever again. I'll get something rigid with relatively wide tires and disk brakes and not give two shits about weight or stiffness. I'm not nor have I ever been someone looking to shave seconds off in a race, I'm just some naturally unfit guy that happens to love riding bikes. Also need to stop talking to other cyclists online. "Oh yeah 100 miles is easy", not for me it isn't.

mperham 4y ago
A good amount of “legacy” bike advocates are actively hostile to e-bikes, equating them to “cheating”. It’s gatekeeping bullshit. Anytime someone asks me bike buying advice, my only reply is “go to your local dealer and talk with them”. That relationship and taking a few test rides are far more important than any spec on a sheet.
- mauvehaus 4y ago
  ... and if the first shop you visit isn't vibing with what your goals and/or personality are, try another. Shops that cater to commuters and transportation cyclists are very different from ones that cater to hardcore road or mountain bike riders.
- fluoridation 4y ago
  The thing about bikes is that if you want to go fast, you have to put in kilometers on the saddle. That trains not just your body, but also your mind, and teaches you how to behave on the road. An electric bike allows someone with little training to go much faster than they would be able to otherwise. Now imagine that you're an experienced rider going at a cool 35 km/h and as you're about to pass a newbie on an electric bike they swerve into you because they don't yet have the habit of looking back before moving sideways. Yes, it's a mistake of that particular person alone, but it's a mistake they were able to make because e-bikes exist.
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Zigurd 4y ago

If you have a quality aluminum frame bike, it probably has a carbon fork. If you find the ride harsh, you'll get most of the benefit of a carbon frame by swapping in a carbon seat post, stem, and bars. There are plenty of good, moderately priced carbon parts available, and changing these parts is very simple. If you are on 23mm tires, change them for 28mm, which will fit in almost all rim brakes. On lo-end carbon frame bikes you will find alloy bars and seat posts, which is silly.

MezzoDelCammin 4y ago

My personal $.02 on frame stiffness is that it's way overrated. The bike I personally spend most time on is a steel frame, but I've never once asked myself a question of "is this stiff / bouncy" enough. When I started having issues with too much road vibration giving me a mild case of cyclists palsy (temporary mild paralysis of ulnar nerve), it was due to the surface I was riding on (gravel) and the distances / times. Solution was adding suspension stem to the handlebar. To me, the "steel is real" argument speaks about the general durability / repairability of the frame. But AFAIK, modern CroMoly steel butted tubes aren't "that" great for welding or cold setting either (to be debated). IMO the famous road repairs of 90's adventurers who had their cracked frames repaired by no matter what farmer with a stick welder in the midle of Kazakhstan are simply long gone now. Personally, the thing I watch for in a bike frame first and foremost is the geometry and the actual personal fit (ideally by a professional fitter). The number one issue I've seen most beginners have related to bike frames is simply being too optimistic on their abilities and spending thousands on frames that they simply don't have the mobility and flexibility for.

fluoridation 4y ago
Yeah, pretty much. Bicycle frames are basically completely rigid vertically, as far as the forces that are normally encountered is concerned. The only possible source of vertical compliance are the tires and the suspension, if there is any. Some frames may be more or less laterally or torsionally compliant, but I'm skeptic that either makes much of a difference while riding.
- wiredfool 4y ago
  I'd add saddle rails/saddles, handlebars, and forks to that list of vertically compliant parts. There's also a bit in the wheels, but only 1mm or so.
hinkley 4y ago
Perceptions on stiffness vary greatly with your inseam length, and I feel like it's fruitless to have conversations without stating what frame size you're looking at. If you start with a bike model that is already known to be mushy and try to ride a 60 or 62cm size it's going to be even worse. When I still rode I chose a frame that some other club members characterized as 'harsh' but they were riding something more like a 56. Even a couple inches makes a huge difference in leverage.

markandrewj 4y ago

Just some general thoughts, so please understand I am not prescribing one over the other. The ride quality of a bike is largely dependent on frame geometry and manufacturing process. With a good layup, and geometry, carbon can be more stiff then steel. This is actually the promise of carbon, to be stiffer then steel while being lighter. However a good quality aluminum bike can also be lighter, and more stiff, then a carbon bike with a low quality layup. Steel tubing also comes in a variety of different qualities. https://gravelcycling.wordpress.com/2016/07/07/steel-the-different-types-of-steel-in-bike-frames/ https://gravelcycling.wordpress.com/2016/07/07/steel-the-dif.... The obvious benefit to steel for me is the reliability and repairability. Ride quality can also be different depending on surface, steel is better at dampening vibrations then aluminum on gravel surfaces. Although carbon can obviously be quite nice, and you are seeing it used in tough ultra distance rides like the GDMBR. That said your wheel choice, and seatpost, will have a bigger impact on ride quality then frame material as far as vibration. Generally speaking the weight of your bike is going to be most noticable on climbs. How noticable will also depend on your gear range. This video about titanium bike myths discusses some of the points I outlined above in further detail. https://youtu.be/1CTjg1TFHDc https://youtu.be/1CTjg1TFHDc

hinkley 4y ago
It's easy with steel to go outside of the realm of easy repairability. In the last days of steel before aluminum became affordable and even before carbon fiber did, it was common to for fancier bikes to have tubing that changed thickness (interior of course) once or twice, as stiffness at the ends of the tubs tends to matter more, and it's easier to weld thicker pieces of metal. And then you had Serotta, who before they switched to titanium, made steel frames that were not just double-butted, but they also spirally ground the butting to maintain most of the torsional stiffness but lose a couple more ounces of weight.
- markandrewj 4y ago
  Yeah, but try getting carbon repaired after a crash. It's not impossible, but it's also not as easy to work with as a material. That said a lot of new high end carbon bikes will come with crash replacement on the frame.

litoE 4y ago

I don't get the whole stiffness argument. If the frame is not stiff then some of my energy goes into flexing the frame back and forth as I pedal, and eventually gets wasted as heat. This is bad if I'm into some sort of competitive riding. But if I ride the bike just for the exercise, then I'm interested in wasting energy and I don't care too much about how it was wasted.

abrookewood 4y ago
A stiff bike is an efficient bike, but not a comfortable one. I once rode in the Gong Ride (Sydney to Wollongong) and, determined to set my bike up as efficiently as possible, pumped my tyres up to 120 PSI. The bike felt incredibly fast ... but my testicles went numb.
- fluoridation 4y ago
  Tips: 1. Wear cycling shorts and pull your boys up so that you're not sitting on them when you ride. 2. Don't put so much weight on the saddle. The saddle is not a seat, it's meant as an extra point of control to lean the frame. Put your weight on the pedals. Also, is the saddle at the correct height? I ride tires at 115 PSI daily and have never had issues with numbness anywhere on my body.
- nl 4y ago
  > but my testicles went numb This is about the seat you are using and the time you are spending on it, not the stiffness of the frame or ride. There is a reason why male seats have cut-outs. You just need to find one that works for you.
- jlarcombe 4y ago
  Didn't feel much stiffness for a while after that then
ak217 4y ago
Not only that but a frame that's not stiff is going to result in more play in the chain and cables that lever against the frame. That means uncommanded or skipped shifts, uneven brake feel, sloppy braking and cornering feel as the frame gets loaded/unloaded in different directions. The real reason a frame should not be optimized entirely for stiffness at the expense of everything else is material fatigue. A frame that maximizes stiffness is a frame that puts its materials under more stress. So if you dial up the stiffness all the way, you'll get less longevity and eventual stress fractures or worse. What most riders think of as stiffness/springiness/feel in their bike comes from the flex (or lack thereof) in their tires, seat, seatpost, spokes, and the harmonic response of their frame to vibrations from the ride. That response is actually a key part of subjective rider satisfaction, I think because we subconsciously feel more in control (because we can feel what the bike is doing better) when the vibrations are more pronounced.

virgulino 4y ago

Obligatory reference to Jan Heine, the "heretic" who has been talking about this for many years: Frame stiffness double blind test: https://www.renehersecycles.com/what-is-planing/ https://www.renehersecycles.com/what-is-planing/ https://www.renehersecycles.com/the-biomechanics-of-planing/ https://www.renehersecycles.com/the-biomechanics-of-planing/ https://www.renehersecycles.com/expert-discussion-on-frame-stiffness/ https://www.renehersecycles.com/expert-discussion-on-frame-s... https://www.renehersecycles.com/myth-4-stiffer-frames-are-faster/ https://www.renehersecycles.com/myth-4-stiffer-frames-are-fa...

oakmad 4y ago

I can't wait for the Hambini analysis of this one.

james_woods 4y ago
HELLO HAMBINI FANS AND WELCOME

kazinator 4y ago

> But when it comes to pedalling, we know that higher is not automatically better. Sure, if you like weird rubbing to show up under load (e.g. steep climbing) that isn't there normally.

martyvis 4y ago

Funny. The YouTube algorithm just recommended this review of 1990s mountain bike that has a cable in place of the downtube. https://youtu.be/0ekXSqE4gNQ https://youtu.be/0ekXSqE4gNQ

1letterunixname 4y ago

I had an aluminum frame Cannondale racing road bike that was exhausting to ride because it had a short wheelbase, compact frame (small triangle), and was very stiff.