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SPD's power advantage....Myth?

ceecee Posts: 4,553
edited August 2010 in MTB general
From the roadie based article on the front page..... Technique: Uphill battle
Dr Auriel Forrester of Scientific Coaching: “Pulling up on the pedals decreases power output as it interferes with the all-important downstroke on the other side – specifically, you can’t pull up against gravity at the same rate or same force as you can push down with gravity!”

Now, I have often thought that the connection might help you to keep a good pedalling technique, although this is possible with flats too.

That only leaves a feeling of connectedness to the bike as an advantage of SPD's....

Are there any other advantages?
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  • AnonymousAnonymous Posts: 79,667
    when i had a go on spds for a few rides i figured that the pushing and pullng effect of spds made a difference in accelerating but at a constant speed the pull counteracts the push. just my observation based on my experience, i have no science to support it but no matter hwat advantages are offerred by spds, all i know is they made me lose confidence and for that reason, i dont like 'em.
  • stumpyjonstumpyjon Posts: 4,069
    I find mine more efficient off road as I don't have to concentrate on keeping my feet on the pedal. SPD's also ensure your foot stays in the optimum position on the pedal. As you say you can do all that with flats but it takes more practice. I for one am not about to remove my SPDs.
    It's easier to ask for forgiveness than for permission.

    I've bought a new bike....ouch - result
    Can I buy a new bike?...No - no result
  • AnonymousAnonymous Posts: 79,667
    stumpyjon wrote:
    I find mine more efficient off road as I don't have to concentrate on keeping my feet on the pedal. SPD's also ensure your foot stays in the optimum position on the pedal. As you say you can do all that with flats but it takes more practice. I for one am not about to remove my SPDs.

    thing about the optimum position is that regardless of the science or whatever, i find i am more comfortable and more efficient with the pedal in the middle of my foot as opposed to under the ball, another negative for spds for me.
  • stumpyjonstumpyjon Posts: 4,069
    Here goes another helmet thread :lol:

    Just need someone to start a HT / FS thread, at least we're firmly on the same side there Sheeps.
    It's easier to ask for forgiveness than for permission.

    I've bought a new bike....ouch - result
    Can I buy a new bike?...No - no result
  • AnonymousAnonymous Posts: 79,667
    stumpyjon wrote:
    Here goes another helmet thread :lol:

    Just need someone to start a HT / FS thread, at least we're firmly on the same side there Sheeps.

    sorry, i wasnt trying to be argumentative (honest) just adding my tuppence worth.

    i was thinking this thread needs balancing with a ht vs fs thread, we havent had one since wednesday!!
  • AnonymousAnonymous Posts: 79,667
    i remember the last spd efficiency thread, there was lots of iscussion but i was suprised that with all of the science nerds, sorry, experts* on here i thought someone would have applied some kind of sciencey type reasoning to give an actual evidence based response, how hard could it be


    *im certain there are som efolk studying/teaching science on BR
  • anto164anto164 Posts: 3,500
    There's a reason why the professional XC racers use clips not flats...

    SPDs are better for power transfer anywy..

    Normally flat pedals use trainers that are soft soled, so you waste a lot of energy through the flexy shoes..
  • AnonymousAnonymous Posts: 79,667
    anto164 wrote:
    There's a reason why the professional XC racers use clips not flats...

    SPDs are better for power transfer anywy..

    Normally flat pedals use trainers that are soft soled, so you waste a lot of energy through the flexy shoes..

    doesnt that energy pushed into the sole get returned to you as the materil of the sole returns back to shape?
  • Chunkers1980Chunkers1980 Posts: 8,035
    I'd think so - it's just efficiency - you'll lose some.
  • AnonymousAnonymous Posts: 79,667
    I'd think so - it's just efficiency - you'll lose some.

    either way, i thk the tiny loss of power through my soles wont have to big an effect on my general bike riding rubbishness!! :lol:
  • unixnerdunixnerd Posts: 2,864
    I put SPDs on my mtb because my feet were slipping on the pedals in wet weather.

    But the big advantage on or off road is the ability to pull up on the back stroke. If I come to a big hill and I'm tired I can use my underused muscles to pull up on the backstoke and it makes a big difference.

    I'm slowly learning to always pull up on the road bike which has done wonders for my top speed. Why have a set of muscles you're not using?
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  • meanredspidermeanredspider Posts: 12,337
    doesnt that energy pushed into the sole get returned to you as the materil of the sole returns back to shape?

    Not completely - it absorbs energy (hence the shock absorbing features of trainers) and turns it into heat. A spring would reasonably efficiently return the energy but not a trainer sole.
    ROAD < Scott Foil HMX Di2, Volagi Liscio Di2, Jamis Renegade Elite Di2, Cube Reaction Race > ROUGH
  • stumpyjonstumpyjon Posts: 4,069
    either way, i thk the tiny loss of power through my soles wont have to big an effect on my general bike riding rubbishness!! :lol:

    Same for me but I'll take any advantage that allows me stay on the bike for longer even if it means being physically attached.
    sorry, i wasnt trying to be argumentative (honest) just adding my tuppence worth.

    I know, just got trigger happy, should've waited for few more posts but we all know where this is headed - singlespeed, fixie or 29". - which is the most niche?
    It's easier to ask for forgiveness than for permission.

    I've bought a new bike....ouch - result
    Can I buy a new bike?...No - no result
  • mea00csfmea00csf Posts: 558
    the big advantage i feel is the smooth transfer of power. i find technical uphills easier because instead of mashing at the pedals as i did with flats, i'm turning smooth circles with a constant power meaning no problems with grip. I'm sure that's all prossible with flats but not for me!
  • SalsaSalsa Posts: 753
    unixnerd wrote:
    But the big advantage on or off road is the ability to pull up on the back stroke. If I come to a big hill and I'm tired I can use my underused muscles to pull up on the backstoke and it makes a big difference.
    This^
  • The RookieThe Rookie Posts: 27,804
    Dr Auriel Forrester of Scientific Coaching: “Pulling up on the pedals decreases power output as it interferes with the all-important downstroke on the other side – specifically, you can’t pull up against gravity at the same rate or same force as you can push down with gravity!”
    Which sounds like rubbish to me......

    If I'm out the saddle then the pedals have to support my weight (less weight on bars) so I can either put 100% on one pedal, or lift at 5% on one side and have 105% on the other, net force increase of 10% on the pedals, of course I can't pull up with the same force I push down as the net force has to support my weight, he may be great at 'scientific coaching' Newtons laws of physics are clearly an anachronism to him though!

    Even if not out the saddle you unweight your buttocks by pushing down on the pedal, he's trying to suggest you won't by that on SPD's you would try and get a perfect match on up/down pulls with full weight on the saddle - only an idiot would try and do that!

    Simon
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • richg1979richg1979 Posts: 1,087
    push/pull technique will offer a little more torque but at the cost of a lot more energy as its pretty obvious that the more muscles you use the more energy is used so you will burn out a lot faster by pushing and pulling,

    its good to use use the push/pull when you need that bit extra to over come a tough bit in the climb like a short very steep part but you should not be pushing and pulling often.
  • NorthwindNorthwind Posts: 14,675
    richg1979 wrote:
    push/pull technique will offer a little more torque but at the cost of a lot more energy as its pretty obvious that the more muscles you use the more energy is used so you will burn out a lot faster by pushing and pulling,

    its good to use use the push/pull when you need that bit extra to over come a tough bit in the climb like a short very steep part but you should not be pushing and pulling often.

    Yup, exactly, unless you're the bionic man anyway. That's my main recollection of SPDs, I definately could put down more power in bursts but it drained me incredibly fast. Definately NOT more efficient for me. It did ensure a nice smooth spin though which takes a lot of effort on flats, and that's beneficial for sure, but once you've learned that skill you can do it on flats too if you put the effort in.

    There's some studies that suggest that the "uplift" actually is no such thing, in fact it doesn't add power, it just eliminates powerloss by unweighting the rear pedal. Effectively if you don't unweight it, your downstroke is partly wasted by pushing your other leg up the upstroke, so lifting that leg wins back the downstroke power. Seems plausible, I have no clue at all if it's true.
    Uncompromising extremist
  • furbyfurby Posts: 200
    I find one advantage of SPD's is on loose or slippy ground, it can help in smoothing out the power, esp on a steep climb and make it easier to find grip.

    And I ride, currently, with flats.....
  • paul.skibumpaul.skibum Posts: 4,068
    Er sorry push pull is bollocks - you are trying to pedal in circles - spds' help you push each pedal through the top of the stroke, down, back under the bottom of the stroke and pull back up, as one leg supports on the down and back the other is doing the up and top - anyone who has been to a spinning class can tell you how to power through a given resistance - it definitely works over flats where half of the move is lost.

    This does nto imply flats are better or worse for riding a mountain bike only different for what you want to achieve. Note - Dirt magazine are rabidly pro flats but their dirt Norco sponsored rider Ben Cathro (I think) is a spd rider. as are about 60-70% of the world cup downhill and all the xc team. So just the freeriders on flats primarily then.....
    Closet jockey wheel pimp censored .
  • NorthwindNorthwind Posts: 14,675
    edited July 2010
    This does nto imply flats are better or worse for riding a mountain bike only different for what you want to achieve. Note - Dirt magazine are rabidly pro flats but their dirt Norco sponsored rider Ben Cathro (I think) is a spd rider. as are about 60-70% of the world cup downhill and all the xc team. So just the freeriders on flats primarily then.....

    When we're all WC standard rider this might have more relevance to us :wink: Not trying to be funny, I just can't see why it would apply, those guys have enormous power and fitness so chasing after last percents makes sense. I doubt many of us do. What works for XC racers doesn't always work for us, that's why we don't have 20lb hardtails with near-slicks, and lycra that lets bystanders see every vein.
    Uncompromising extremist
  • AnonymousAnonymous Posts: 79,667
    edited July 2010
    cee wrote:
    From the roadie based article on the front page..... Technique: Uphill battle
    Dr Auriel Forrester of Scientific Coaching: “Pulling up on the pedals decreases power output as it interferes with the all-important downstroke on the other side – specifically, you can’t pull up against gravity at the same rate or same force as you can push down with gravity!”

    Now, I have often thought that the connection might help you to keep a good pedalling technique, although this is possible with flats too.

    That only leaves a feeling of connectedness to the bike as an advantage of SPD's....

    Are there any other advantages?
    I'm pretty sure you were in on the epic thread where the whole SPD myth was discussed in some detail, yet people still clung to it like a safety blanket?
    Why bother bringing it up again. most SPD claims are bollorks, but enough people with a fundamentally flawed understanding of physics, perpetuate these myths, which means that tons of pedals and shoes are still sold for the wrong reasons
  • paul.skibumpaul.skibum Posts: 4,068
    I agree but if your technique is good for pedalling with spds you do get a benefit. I dont ever get the benefit of flats though - I can do a foot down drift corner - yeah I dont really do that - I can do a no footer on a jump - still not really my thing, I can put my foot down when I feel a bit gay on a section of trail - ok I do that but spds encourage me not to and when I last did it on flats I sprained my ankle.

    spds save lives.
    Closet jockey wheel pimp censored .
  • supersonicsupersonic Posts: 82,708 Lives Here
    This thread is also in the commuting section.My post there was:

    At very low cadence, you can increase power output with SPDs by pulling as you are working against a high gear and causing very high chain tension. The effect is much less at higher cadences,where you cannot pull up as fast as you can push down with the other leg. While power maybe increased at some revs, efficiency may be less when actively pulling up, as the extensor muscles are usually much better developed than the flexor muscles.

    As usually it depends on the cyclist - some find gains ,others don't, and for the off road cyclist are other things to consider.
  • paul.skibumpaul.skibum Posts: 4,068
    There is also the point that spd's work better if you have a strong active core that give the legs a solid base to pedal against - if you end up ehaving hips and body weight around it loses the efficiency. I agree though it tends to depend upon terrain for a mtber - I find spds work well on my lame south east england terrain as its a lot of spinning up to speed on gentle terrain - not sure it is so effective on the western climb to jacobs ladder summit where technique over raw power is a bit more important.
    Closet jockey wheel pimp censored .
  • NorthwindNorthwind Posts: 14,675
    I agree but if your technique is good for pedalling with spds you do get a benefit. I dont ever get the benefit of flats though - I can do a foot down drift corner - yeah I dont really do that - I can do a no footer on a jump - still not really my thing, I can put my foot down when I feel a bit gay on a section of trail - ok I do that but spds encourage me not to and when I last did it on flats I sprained my ankle.

    Hmm. I'd say SPDs give the greatest benefit to people with bad technique- it enforces a good spin and a good foot placement and prevents you being bounced off. Whereas flats will allow you to pedal badly, put your feet in the wrong place, or jump off the bike, unless you have good tecnique. flats were mostly a disadvantage to me when I was re-learning how to ride because I just didn't have the skills to ride well with them, I really wished I could use SPDs. As I got better on flats I stopped wishing I could use SPDs so much. Now I'm ambivalent to the whole thing.

    I do think there's real world riding advantages, the big one is being that little bit more able to get yourself out of trouble. Pushing yourself into things you're unsure of riding, sure you're less likely to put a foot down with SPDs because it's not so easy, but the flipside of that is that most people will be less likely to even make the attempt if they're worried about the price of failure. (yes I know unclipping is no hardship, it becomes such a reflex action but it's still that little bit slower, and if things have got out of control it can complicate things just enough)

    i've ridden down things I know fine I'll probably not reach the bottom of, on the basis that I can get off the bike pretty much instantly regardless of what stupid thing I do. I think I'd never have attempted crack attack at laggan frinstance, or the scarier bits of the fort bill downhill. Or all sorts of other bits.

    But that's not to say everyone else feels the same of course.
    Uncompromising extremist
  • AnonymousAnonymous Posts: 79,667
    richg1979 wrote:
    push/pull technique will offer a little more torque but at the cost of a lot more energy as its pretty obvious that the more muscles you use the more energy is used so you will burn out a lot faster by pushing and pulling,

    its good to use use the push/pull when you need that bit extra to over come a tough bit in the climb like a short very steep part but you should not be pushing and pulling often.

    my limited scientific knowledge allows me to believe this might be the bestest answer to this issue ever. if you love fs and hate titanium single speeds, you might be the best forumite ever.
  • AnonymousAnonymous Posts: 79,667
    push pull is nonsense. It has nothing to do with core strength or moving your hips, it has everythig to do with the point you're applying force from (your other foot) moving.

    The advantages are that your feet are (arguably, i personally don't like any float) more connected to the pedals, that you can pedal better over the top and bottom of the pedal stroke, and that the shoe/pedal interface is markedly stiffer.
  • AnonymousAnonymous Posts: 79,667
    spd pedals are gay

    i know.
  • One thing I notice at trails centres is that I'm beating/keeping up with all but the very fittest of riders, even though I've only been riding just coming up to 18 months.

    I'm often pondering the advantages of Spd's while using flats myself and passing several people clipped in on long climbs. :)
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