Viewing 40 posts - 1 through 40 (of 81 total)
  • Steel frames, climbing and psychology
  • roverpig
    Full Member

    I’ve posted on this before, but it’s still doing my head in 🙂

    I swapped my steel fatbike (ICT) for a carbon fibre one (Dude) last summer. I’m running the same wheels/tyres on the new bike and the seat angle is steeper. It’s also almost 5lb lighter, yet I’m consistently 5-10% slower up climbs and I can’t understand why.

    You can’t cheat physics, so either more of my power is getting to the back wheel on the steel frame, which seems unlikely, or I’m putting out more power for some reason. I’m tending towards the latter, but it’s still a mystery. There is more “spring” to the steel frame, so I wonder if that just eggs me on to try harder for some reason?

    downhillfast
    Free Member

    Gearing? Is it the same on both? Are you in the same gear on the same climb on both

    Tyres? Different Tyres? Pressures? Or the same as before?

    Position? Is your position on the bikes Much different from each other? Sometimes a small change e.g.. seatpost height can have a comparatively large effect on your efficiency.

    ghostlymachine
    Free Member

    Is your position the same on both bikes. And is it right/any good on either bike?

    Seat post angle should make no difference at all. Just gives you a different possible range of positions.

    Reach is far more important.

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    kayak23
    Full Member

    You were younger when you had the steel frame.

    Age gets to us all innit.

    roverpig
    Full Member

    These are all seated climbs (I very rarely stand). Despite the steeper seat angle on the Dude the effective top tube is the 12mm longer.

    I’ve run exactly the same tyres (and wheels) on both and pressure is the same (measured using the same digital gauge).

    Originally I did just put it down to being a year older, but I’m not convinced.

    There is one 20 minute climb where I’ve set a faster time on the Dude. I overtook somebody at the start and although I try not to be silly about these things it’s hard not to give it the beans when you know there is somebody behind. On that climb my fastest time on the Dude is 16% faster than my fastest on the ICT, which does tend to suggest that I can be faster on the Dude I just don’t tend to try as hard for some reason.

    NormalMan
    Full Member

    Stiffer frame losing traction?

    chakaping
    Free Member

    Fitness / fatness an issue?

    I know I’m slower than I was last year after a miserable three or four months of constant illness.

    ghostlymachine
    Free Member

    These are all seated climbs (I very rarely stand). Despite the steeper seat angle on the Dude the effective top tube is the 12mm longer.

    Ignore effective top tube. Whats the change in your position over the bottom bracket?

    If thats changed that could explain a lot of the differences.

    philjunior
    Free Member

    CBA?
    Tired?

    Unless you’re really smashing it and finding a difference, probably just those. I find my speed at a “comfy” pace varies greatly.

    Obviously my flat out speed varies a bit too, considerably more than 5-10%. And the weather/ground conditions make a difference even more than that.

    How long did you have the last bike for? Are you comparing your fastest ride on the old bike to whatever you happen to do on a given day on the new one?

    orangespyderman
    Full Member

    Whats the change in your position over the bottom bracket?

    This.  I spent ages fiddling around on my other bike because I realised that some fairly small changes had a significant impact on my pedaling efficiency.  Seat fore/aft even by small amounts made a helluva difference.

    I suspect if you spend some time getting the position sorted on the new bike you’ll feel a difference, and see a difference on your segments.

    But yeah, also fatter/older/less fit? 🙂

    jameso
    Full Member

    You can’t cheat physics, so either more of my power is getting to the back wheel on the steel frame, which seems unlikely, or I’m putting out more power for some reason. I’m tending towards the latter, but it’s still a mystery. There is more “spring” to the steel frame, so I wonder if that just eggs me on to try harder for some reason?

    Maybe .. Google “Jan Haine planing”.

    I doubt it’s all as one or the other as he suggests but I do think the stiffer BB = faster climbing bike think is b0llocks. A stiff bike simply responds to your input differently and feels more ‘responsive’. That will egg on riders of a certain nature who buy stiff light bikes. But over a longer climb or ride all that matters in that respect is how you and the bike work together, so I can see where Jan is coming from re ‘bikes that plane’. If I go from one of my road bikes to another, one difference in feel is BB stiffness. The softer bike isn’t slower in any way, it just has a different response. I like it on open roads yet I don’t like frames that get too whippy overall.

    5lbs won’t make a huge difference on a climb either. Some, but not at a level that’s easy to measure.

    n0b0dy0ftheg0at
    Free Member

    Just lost a reply, gg STW forum…

    Worn tyres when on Dude?

    More weight over rear wheel on ICT?

    Worse fitness/fatigue/form when on Dude?

    Wind direction?

    I’ve climbed Old Winchester Hill on both my ~9Kg road bike and my ~13Kg Wazoo (29×2.35″ G-one front and 4″ Jumbo Jim rear), yet despite the ~4Kg difference, their best times are 9mins40secs vs 10min37secs. Similar crosswind, both mid summer, within a week of each other. Does not compute! 😆

    https://www.strava.com/activities/1068540608/analysis/1318/1536

    https://www.strava.com/activities/1059909803/analysis/4857/5494

    molgrips
    Free Member

    If you don’t think frame flex is an issue, try this: Grab your frame and pull hard on the bb, see it flex.  Now do this once a second for five minutes, reckon you’ll get tired?  You’ll have used up a noticeable amount of energy, and gone nowhere.

    Now, not saying one way or the other definitively, but it’s worth some thought.

    slowster
    Free Member

    OP, this article  on frame stiffness by Jan Heine of Compass Bicycles might interest you (edit – I think this is what jameso is referring to).

    I don’t know if it’s relevant in your particular case, but I do suspect that (for road frames especially) aluminium, titanium and carbon have supplanted steel as the mainstream before all the advantages and disadvantages of steel’s properties were fully understood and recognised (and I’m not sure that they are even now).

    In other words, although it’s possible to change the performance characteristics of carbon frames by changing the lay up etc., which should result in bikes that perform as well or better than steel and be much lighter/stronger as well, you need to know precisely what those performance characteristics are that you want your carbon frame to possess.

    I think a lot of the desirable properties of steel frames were/are inherent to the material, the smaller diameter tubesets historically used for steel, and some of the construction limitations (e.g. lugged and brazed with horizontal top tubes). Because there was no alternative to those steel frames and design/construction methods, there was never any incentive for those properties to be thoroughly researched and understood. When aluminium and carbon came along, their obvious advantage of lighter weight was so compelling and they were so quickly successful in replacing steel (especially in road racing), that there was no commercial incentive for the industry to seek to replicate some of the less obvious/less well understood desirable properties of steel in its aluminium or carbon frames.

    taxi25
    Free Member

    I’d just take the bike out of the equation. 10% slower is you putting out 10% less power (or howether that works) for whatever reason. The Dude being lighter and stiffer will be faster. If it bothers you try to find out why your powers down.

    fasthaggis
    Full Member

    Did you suddenly put the pie shop on speed dial ?

    Do you get passed more in races?

    Is there someone that used to be slower ,that is now beating you up your fav climbs?

    Can you even remember what gears you were using on the other frame?

    These ^^are all Friday questions,so feel free to ignore all of them ;-p

    Rorschach
    Free Member

    Fatter.

    amedias
    Free Member

    If you don’t think frame flex is an issue, try this: Grab your frame and pull hard on the bb, see it flex.  Now do this once a second for five minutes, reckon you’ll get tired?  You’ll have used up a noticeable amount of energy, and gone nowhere.

    Do the same thing on your super stiff frame and you’ll still get tired, it’s all about how much energy you put in 😉

    Go push as hard as you can against a brick wall, then let go, what happens? you get tired and go nowhere. Repeat procedure on a vertical trampoline, what happens?

    The assumption you’ve made is that none of the energy is returned. It is. If you put 200N into the BB of the flexy frame it’ll deflect Xmm, if you put that same 200N into the BB of the stiff frame it might deflect Ymm (where Y<X), but they both spring back. You still put 200N in both cases, so the question actually becomes how much of your input force would get transmitted to the back wheel?

    At some point the reaction force from the frame will be such that your input wont deflect it any further, and so the ‘excess’* input then has to go somewhere, hopefully to the back wheel. On the face of it the common sense answer is ‘more’ will be transferred on the stiffer frame, and in general that’s true but it’s not quite as simple as you think, the interesting bit is that at some point the frame will spring back and, the biomechanics of pedalling means that how your output is delivered, and for how long over the pedal cycle is not straightforward, that springing back can work with your pedal stroke as much as it can against it.

    Frames are springy** yes and not ALL of the energy you put into deflecting them is returned, but a very very large percentage is. The interesting questions start when you ask if the way in which it is returned, and the timing WRT to pedalling, has any impact on how your leg power actually gets transmitted, and whether or not that impact is greater than the tiny amount of work actually ‘lost’ in deflecting the frame.

    Too stiff can be just as bad as too flexy, there’s a sweet spot, well a sweet range anyway, in the middle, but it’s dependant on the rider, their power output and way in which it’s delivered too. It’s also relevant whether you’re talking about an immediate response like in a sprint or short burst of power, versus a longer output and getting into a rhythm, it can be very fatiguing pushing against a very stiff thing over and over, and in some cases less so than pushing against something with a little give if it works better with your particular output.

    I’m not saying that’s what’s going on here OP, if could just as easily be position change, or pure dumb luck, but the whole stiffer=faster thing doesn’t always hold water in the real world.

    * TBC ‘excess’ not because you can’t deflect any further if you pushed in that direction, but because the component of your input force acting in that direction is the limit, which illustrates even more why it’s related to the pedal stroke.

    ** regardless of material, its the amount of flex that’s important.

    Sanny
    Free Member

    The Ice Cream Truck is the better bike…..there, I said it. Somebody had to! I have a Truck and a significantly lighter, soon to be returned sadly,  cannondale fat caad. I love the Cannondale but the Truck wins every time when I am going out for a ride. I think the added weight means I just go at a steady pace and feel no need to sprint like a dafty. Oh and it definitely climbs better too. My suspicion is that it has just that bit more traction and is less easily deflected on rocky climbs than the fat caad.

    jameso
    Full Member

    If you don’t think frame flex is an issue, try this: Grab your frame and pull hard on the bb, see it flex. Now do this once a second for five minutes, reckon you’ll get tired? You’ll have used up a noticeable amount of energy, and gone nowhere.

    Now, not saying one way or the other definitively, but it’s worth some thought.

    Same here, I don’t think it’s either-or. But if I put the same amount of muscle force into an immoveable bar I’ll be equally tired (edit, as said above – slow typing here). The flex is irrelevant in that example. In a bike drivetrain the frame flex is linked to pedalling motion, both are cyclic and linked. I can’t add it all up or model it but I can see and feel how it works and I don’t see it as a loss of power overall, only a change in delivery that I can work with.

    Assuming the chain stays tight, the BB sway is working with my pedal motion and if the frame isn’t getting hot there’s nothing being lost in that flex. We don’t put out power in a square wave manner so we don’t need absolute stiffness either. Some just prefer how it feels. Oval rings change how power is delivered in a different way and they have fans and detractors.

    I’d say it’s simply easier for a brand to sell you Lighter and Stiffer and it’s easier to manufacture as much stiffness as possible, compared to getting frame flex levels right for frame size, rider weight and pedal style. But when all those flex and power aspects balance up I can believe that it works as well and perhaps better than a very stiff frame, for some riders.

    matt_outandabout
    Full Member

    It isn’t something as simple as a dragging disc or hub is it…?

    If not, I am going with steel being narrower tubing, so lest wind resistance…

    molgrips
    Free Member

    Do the same thing on your super stiff frame and you’ll still get tired

    But then build it into a bike and see what happens.  When you pedal you are adding force which is resisted by two things – the frame, and the wheel.  The stiffness of the frame provides a reaction to your pedalling force.

    Imagine a frame made of rubber.  What would happen when you tried to pedal?  The frame would boing and you’d go nowhere.

    f the frame isn’t getting hot there’s nothing being lost in that flex

    It is getting warmer, just not enough to feel cos it’s being lost to the environment.  Your energy is going into potential energy stored in the springy metal, but it’s not being returned to the drive train.  It’s the energy spent wiggling the BB from side to side which doesn’t make you go anywhere.

    Malvern Rider
    Free Member

    Steel is magic?

    Xmas/N Year  kills fitness for at least 2 months following?

    ymmv

    jameso
    Full Member

    Imagine a frame made of rubber. What would happen when you tried to pedal? The frame would boing and you’d go nowhere.

    That doesn’t mean that a steel frame that flexes a little side to side is losing power though. Steel (carbon, Al, Ti also) flexes and returns with very little loss. Loss would be generating heat – there isn’t anything significant happening there.

    The BB springs back around the dead spot of the pedal cycle and your natural pedal motion has a side to side element to it, it’s all linked. And the BB doesn’t move side to side only, it moves up and down / rotates as the ST flexes in a sway type of motion and that’s where the ‘past the dead spot’ return flex balances out. The power phase of a pedal stroke is only about 90 degrees or so of the 180 from top to bottom anyway. A bit of wind-up then spring-back there is more sympathetic to early and end stages of repeated muscle action than something 100% fixed. It’s why we don’t run with solid soled trainers, the sudden spike is less efficient to the body than a more gradual loading. Not too gradual though – so not too flexy a frame.

    A track or TdF sprinter’s bike might justify that stiffness while a bike for long distances doesn’t, it’d detract overall.  The rest are somewhere in between and it’s more about reaction to input type or load timing than measureable losses.

    amedias
    Free Member

    Imagine a frame made of rubber.  What would happen when you tried to pedal?  The frame would boing and you’d go nowhere.

    I believe this particular bit of reductio ad absurdum was covered by:

    “Too stiff can be just as bad as too flexy, there’s a sweet spot, well a sweet range anyway, in the middle”

    And the rest of the post…matching flex to rider power and style is the important bit, not simply stifferer = betterer.

    The actual % of energy lost in warming up the frame, making noise etc. is tiny. It really really is. The potential energy (most of anyway) stored in the frame is returned, not directly into the drivetrain no, but how and when it is returned as the frame springs back can have a significant impact on you physiologically, and when matched appropriately to the rider/power source it can be dwarf the impact of the tiny losses.

    Again, if you read my post in it’s entirety you’ll see I was also saying it’s important whether you’re talking about a single short bust attack style power delivery, vs a 20-30minute steady output at rhythm, the former scenario can favour a stiffer frame, the latter can favour something with an appropriate amount of give, the way that give works with your power delivery isn’t a trivial matter. (as it seems Jameso is also highlighting while I was typing this post)

    My point isn’t that flexier is always better, it’s that stiffer isn’t always better.

    Appropriate amount of flex, matched to the rider and situation/use is important.

    molgrips
    Free Member

    I believe this particular bit of reductio ad absurdum was covered by:

    It’s not reductio ad absurdum – that’s for debating, this is science.  One can discover the nature of a problem in a thought experiment by extrapolation of variables.

    The actual % of energy lost in warming up the frame, making noise etc. is tiny. It really really is.

    Can you show your working?

    I’ve not done any calculations so I cannot offer a specific solution, I’m only mulling it over for the purposes of group discussion.

    Appropriate amount of flex, matched to the rider and situation/use is important.

    Of course, there are loads of variables overall. I’m more interested in considering the specifics of bb flex vs efficiency at this point.

    A track or TdF sprinter’s bike might justify that stiffness

    You make a good point arguing why bb stiffness doens’t matter, and then you say that it might after all..

    roverpig
    Full Member

    Thanks folks. Some great ideas and interesting further reading in there. Just to try and deal with a few of them:

    You are just putting out more power on the ICT? Yes, that’s my conclusion too. Although I’m still open to it being down to differences in the bike I suspect it’s really me. The question then is why I’d regularly put out more power on one bike than another?

    Just less fit? Yes unless I can prove otherwise that has to be the logical answer. It doesn’t feel right to me i.e. I don’t feel any less fit, I did as many miles (slightly more) last year as the year before, don’t weigh any more etc. But since I don’t race I don’t have an external measure of fitness that I can use. However, I did take the Truck out for a ride on Thursday night (cold and dark). There is only one climb of note on that loop but despite a dusting of snow on the lower section I set the fastest time in my last 15 attempts (most of which were on the Dude). I have to go back to May (in the sunshine) to find a faster time, which doesn’t suggest that I’ve lost fitness. I wasn’t targeting that climb or anything. It’s just in the middle of a loop and I wasn’t thinking about it.

    Just having a good day? If it were one ride I’d dismiss it as that, but I’m comparing my best time (from multiple attempts) on both bikes. Again, if it were just one climb I’d dismiss it, but it seems to hold true for pretty much every climb of longer than 10 minutes or so.

    Body position? They are never going to be exactly the same, but I’ve set them up to be pretty similar. The Dude has the steeper seat angle and conventional wisdom says that should make it climb better, but it doesn’t.

    ICT/Steel is magic? I’m refusing to contemplate that until I’ve ruled out more logical explanations, but it does make me wonder.

    dumbbot
    Free Member

    Steel is betterer

    nedrapier
    Full Member

    So why are you selling the ICT then? Faster uphill, eggs you on, faster downhill, got that “thing”…

    what gives, roverpig?

    I’d love to take it off your hands, but I Don’t Need Another Bike.

    I Don’t Need Another Bike,
    I Don’t Need Another Bike,
    I Don’t Need Another Bike,
    I Don’t Need Another Bike,
    I Don’t Need Another Bike…

    jameso
    Full Member

    You make a good point arguing why bb stiffness doens’t matter, and then you say that it might after all..

    I didn’t say it doesn’t matter, I said it’s not the ultimate aim that most bike brands present in marketing stuff or the ideal for all riders. Well, actually I started by saying ‘stiffer BB = faster climbing bike is bollocks” : )

    Then I’m just saying why I believe one or the other may be better for you. Or Roverpig.

    The Dude has the steeper seat angle and conventional wisdom says that should make it climb better, but it doesn’t.

    Similar thing there – steeper is only better if it’s steeper than a bike that was too slack : )

    roverpig
    Full Member

    So why are you selling the ICT then? Faster uphill, eggs you on, faster downhill, got that “thing”…

    what gives, roverpig?

    Don’t ask me 🙂

    Because I’m a logical sort of person I guess and logic tells me that the Dude is the better bike. It’s lighter, stiffer and has a steeper seat angle. It’s just annoying that the actual evidence points in the opposite direction 🙁 Actually that’s not fair. I do prefer the longer reach on the Dude when descending, although it’s not a big improvement and it still annoys me that it doesn’t destroy the ICT on the climbs when everything I’ve read suggests that it should. Well, everything I’d read until this thread anyway 🙂

    Actually, I’ve just agreed to sell the wheels from the ICT on their own, so I’ll be stripping it down over the weekend. Hopefully somebody will snap up the fame. Otherwise I fear I may be tempted into more experiments which will no doubt just lead to more confusion.

    bigblackshed
    Full Member

    Did you have fun on the ICT?

    If yes, then why are you selling it?

    Riding bikes should be FUN!

    BadlyWiredDog
    Full Member

    I can’t believe no-one’s sad this already, but you need to back to back the two frames in identical conditions, same climb,  with same fitness level before obsessing about BB flex or seatpost angles.

    amedias
    Free Member

    You make a good point arguing why bb stiffness doens’t matter

    Stop being so binary! neither of us have said it doesn’t matter, we’ve said that it’s a complex system with a window of acceptable values, and that within that window the impact overall isn’t that great, and that in some circumstances a bit of flex can work with the rider in a way that overshadows any small losses.

    It’s also worth noting that cadence also has a part to play, flex charateristics at low cadence/high force are different to high cadence/low force, and that’s why rider and use/matching is relevant too.

    One can discover the nature of a problem in a thought experiment by extrapolation of variables.

    No one can’t, it’s a false assumption that extrapolation of a limited data set will lead to a complete expression of a solution. You can make a hypothesis and attempt to test it empirically, but this isn’t simple maths of force in/out and static vectors. The way in which a human being applies force, the magnitude of that force, direction of it from one moment to the next and how interacts with the dynamic system of bike and rest of rider is very complex and extremely hard to model, at lest in terms of what you can post in a thread like this.

    I’m curious what you make of Jan Heines writings on the subject of frame flex? He’s far from the only one to have written, but is one of the easiest to find online. Have you read about the results from his double blind studies? There is actually an awful lot of dicussion about this very topic already out there on the internet fromt he last 20 years or more, and it makes for very interesting reading. Some of it is pure anecdote, some of it is demonstrably false, and some of it is well backed up by both theoretical and experimental science, none of it is conclusive though, because it’s complex 😉

    Have you done any experiments of your own testing things back to back while trying to keep other factors the same?

    I’ve tried, far from rigorous for sure, but I have spent a fair amount of time experimenting as well as reading and thinking.

    amedias
    Free Member

    Body position? They are never going to be exactly the same, but I’ve set them up to be pretty similar. The Dude has the steeper seat angle and conventional wisdom says that should make it climb better, but it doesn’t.

    Ah, ‘conventional wisdom’ don’t get me started on that 😉

    The steeper SA might make a person climb better on a bike, but it depends on you more than anything, if the steeper SA has put you in a position that is sub-optimal for your body then you might be putting out less power.

    For example, if I sit more upright I can’t pedal as hard or put out as much power, there’s an optimal hip angle for my body, and it works in tandem with reaction forces of my arms on bars, the result being that simply changing SA by itself, unless paired with a corresponding change in bar height or reach might have a negative effect if it moves your body into a less than optimal position. Even if the bars are adjusted to maintain the actual same relationship between contact points it might now put me in a sub-optimal position in terms of weight distribution/traction etc. which means again I might not be able to best make use of my output. And this can depend on terrain as well, so body even body position alone isn’t it, as always, it’s complex 😉

    avdave2
    Full Member

    You are expecting one bike to be faster than the other, if you didn’t you wouldn’t have posted this. It doesn’t matter how much you try to put that belief out of your mind when riding you can’t know how that’s affecting the result.

    You are psychologically driven to put more power out on the steel bike and less on the carbon, the issue is that your inner belief in the difference in power required is wrong and you aren’t putting out enough power on the carbon bike. I’m not suggesting that is the only reason but I’m sure it’s a contributory factor.

    molgrips
    Free Member

    Have you done any experiments of your own testing things back to back while trying to keep other factors the same?

    No, because I evaluate my bikes based on feel 🙂  I have discovered that I really enjoy bigger tyres with a very stiff frame – but I have no idea if it’s faster than the alternative. I spent quite a few years riding a bike that was so flexy that if I stood up and pedalled hard it would shift the front chainring!  I didn’t feel it held me back though except for the fact it stopped me standing up and pedalling hard.

    I think my Patriot needs a steeper seat angle – it’s old fashioned and hence slack – but because I want the rear wheel moved back without extending the reach too much.

    shermer75
    Free Member

    >Maybe .. Google “Jan Haine planing”.

    I just did, it’s fascinating!! 🙂

    https://janheine.wordpress.com/2014/11/23/what-is-planing/

    amedias
    Free Member

    No, because I evaluate my bikes based on feel

    As we all should, it would stop a lot of arguments! 😉

    I do find the occasional experiment interesting though, and even when not trying to prove one thing or another it can be very rewarding to actually try stuff out and it provides a way to quantify things in terms of both numbers and feel.

    Still curious to hear your thoughts on Jan Heine’s ideas* on frame flex? FWIW I don’t necessarily agree with everything he says… but it’s always interesting to hear other peoples thoughts and you seem genuinely interested in the topic so would love to discuss.

    * as I said earlier, they’re not really ‘his ideas’ as there’s been similar discussions and thoughts in various circles for over a century, but his writings on that topic, and his ‘discovery’ of those ideas if you know what I mean…

    PJay
    Free Member

    The time of year perhaps? I built up a new bike last November (although the difference in build is fair greater than yours) and I’m struggling to tell which is/was faster.

    I’ve yet to have a ride on the new bike that wasn’t affected by rain, cold or wind (often all 3). I can’t wait for better weather.

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