How much more effecient are SPD's compared to flats?

as above really,not expecting exact percentages by the way…?

17.3% – if dry

interesting i heard 17.4%

0%
for a start, you have to say efficiency of what
but for most of us, the limit to the power we can output is cardiovascular, not muscle power, so the pedals make no difference

SFB is absolutely correct. That's why no professional cyclists use SPDs.

Oh…..

Depends on what lifts your skirt 😉

Marginal for the downward stuff, although this is directly linked to your confidence and ability to not end up in a mangled mess of tubes and what was you.

XC race whippets benefit due to the upward pull available from being clipped in. This can have a energy sapping effect if you are not of this stereotype and prone to this type of punishment.

I found that sticky flats suited my riding better and gave me confidence through the knowledge that i can bin the bike if i get 'comprimised'.

the limit to the power we can output

Power output isn't the same as efficiency.

That's why no professional cyclists use SPDs.

I said "most of us" – who aren't professionals. If, and it's a big if, you have enough lung and heart power to drive your muscles to their limits then you may be able to get some marginal extra from pulling up too

DruidH

I assume you can't read, as he said for most of us.
Can't exactly say professional cyclists are like most of us on here

Hard to say. I feel that they make me pedal better. Although my flat pedal pedalling seems to have improved too, probably from using SPDs, paradoxically.

Effect of a novel pedal design on maximal power output and mechanical efficiency in well-trained cyclists

Authors: Erwin Koninckxa; Marc van Leemputtea; Peter Hespela
Journal of Sports Sciences, Volume 26, Issue 10 August 2008 , pages 1015 -1023

Abstract

In this study, we evaluated the effects of a novel pedal design, characterized by a downward and forward shift of the cleat fixing platform relative to the pedal axle, on maximal power output and mechanical efficiency in 22 well-trained cyclists. Maximal power output was measured during a series of short (5-s) intermittent sprints on an isokinetic cycle ergometer at cadences from 40 to 120 rev · min-1. Mechanical efficiency was evaluated during a submaximal incremental exercise test on a bicycle ergometer using continuous O2 and CO2 measurement. Similar tests with conventional pedals and the novel pedals, which were mounted on the individual racing bike of the participant, were randomized. Maximal power was greater with novel pedals than with conventional pedals (between 6.0%, sx = 1.5 at 40 rev · min-1 and 1.8%, sx = 0.7 at 120 rev · min-1; P = 0.01). Torque production between crank angles of 60° and 150° was higher with novel pedals than with conventional pedals (P = 0.004). The novel pedal design did not affect whole-body O2 or CO2. Mechanical efficiency was greater with novel pedals than with conventional pedals (27.2%, sx = 0.9 and 25.1%, sx = 0.9% respectively; P = 0.047; effect size = 0.9). In conclusion, the novel pedals can increase maximal power output and mechanical efficiency in well-trained cyclists.

12.43336%

Rosby?

youd be surprised how much quicker they can make you on the downs once you get your head round the fact that you are NOT stuck to the bike …. and you can use not getting bounced off to your advantage

trail_rat – in that case, how much quicker would sam hill be if he ran spds. 😀

Efficiency is probably the wrong way to look at it, but roadies? all clipped in, XC racers? all clipped in, Cyclocrossers? all clipped in, Downhillers? Some clipped in although new ruling suggests that they won't be allowed to for the same bullshit reasons that banned skinsuits.. 😉

I rode flats last week, first time in a year or so. It felt dangerous my feet were all over the place, wont do that again, never mind efficient there more control with spd's.

They're going to ban SPDs from DH?

WHAT THE ****. SPDs are like taking your stabilisers off, it's when you become a proper cyclist.

Haven't ridden flats for years and don't want to – I feel faster, more efficient and more comfortable with my pads properly secured. I am a spinner though so that possibly makes a difference.

They're going to ban SPDs from DH?

WHAT THE ****. SPDs are like taking your stabilisers off, it's when you become a proper cyclist.

It was an April Fool a while ago on
http://www.pinkbike.com/news/spd-ban-2009.html.

As for the 'proper cyclist' bit I think you may find that you are wrong…
It's not about what pedals you use…

On a regular mountain bike, it doesn't make as much difference as you might imagine. Good pedaling doesn't rely on being clipped in.

Hmmm I think clips allow you to maximize the use of all your leg muscle groups. This would spread the effort across more muscles thus you would thinly makes them more efficient than flats.

If you are riding fire road and bridleways then it don't much matter, but I'm putting my foot down on some of the bad the rooty stuff at least once most days out. And at speed I reckon I would probably crash if clipped in.

I haven’t actually 'fallen' off in years, but I always use flats. – Except on the road.

hmmmmmmmmmm the old debate 🙂

Flats encourage you to learn technique better as you can't cheat by pulling up on the pedals.

Only have SPD's on roadbike (SL) and singlespeed, proper mountainbike(s) on flats. SPD's on SS is only cos my feet kept slipping of pedals stomping on tricky uphills.

000000000000000000.1 x .888888888888888888 = have go

There is no debate, clipless pedals are more efficent and allow you go apply more power throughout the pedal stroke. Assuming correct muscle recruitment and pedaling technique though.

Ahhh, but being clipped in isn't cheating and your better technique is just compensation for crap pedals. It's not actually a better technique, just different.

I love how people fixate on efficiency, I can't imagine a less efficient bunch of riders than mountain bikers. We wear unaerodynamic kit and ride unaerodynamic bikes, we like huge fat tyres even though most of the time we don't need the grip, we mash excessively high gears because it feels all GRRRR, we ride with the seats at the wrong height, we carry around tons of deadweight in rucksacks, and we stop every 15 seconds to eat haribos. So obviously it's important that we should have the most efficient pedals available.

jedi, weird eh?

bob, yeah very 🙂 🙂

How much more efficient? Enough for me!

I switch back and forth now and again (riding flats enough to be happy with them). There are climbs I can make on my SS with SPDs that I can't make with flats. Same legs, same trail conditions, less ability to climb with flats. I don't know how that translates to gears, though, I suppose.

FWIW, I find I have marginally more control with flats. Any twisting that goes through my feet has an immediate effect on the bike instead of being translated into float. But when you're used to it, which is better for riding down hills is a matter of style. As others have said, look at top-level DH: some flats, some SPDs.

Well yes that is entirely true Northwind and I completely agree, but the fact remains that technically spds offer the potential for greater efficiency, Brian Lopes says so in his mountain biking technique book so it must be true! 😉

We wear unaerodynamic kit and ride unaerodynamic bikes,

Lycra all the way

we like huge fat tyres even though most of the time we don't need the grip,

I've got a Furious Fred on the back of my bike, weighs less and rolls quicker than some road tyres

we mash excessively high gears because it feels all GRRRR

Works for Ullrich!

We ride with the seats at the wrong height,

Nope, saddle's at the right height thanks, and never moves!

we carry around tons of deadweight in rucksacks,

Very rarely use a Camelbak, and it's never full of crap!

and we stop every 15 seconds to eat haribos.

I've never eaten Haribo on a ride in my life!

Am I qualified to use SPDs!?

I'd actually have thought the shoes make a similar difference, stiffer soles, better power transfer and what not. Whenever I've ridden flats (only for commuting, and occasional messing around probably five times in my life!) they feel absolutely atrocious!

I think SPDs are more efficient, for me its most noticible on short steep climbs where you can pull up as well as push down and I do think it feels more natural being clipped in……….but I still prefer riding flats, I like being able to jump off the bike easily

Edit: agree with njee about stiffer shoes prob making more difference

With efficiency being a ratio of output/input they are both exactly as efficient as each other. If you start pulling up on the pedals with spds then you are putting more in so will obviously get more out. One turn of the pedals done at the same speed in the same gear on the same gradient still takes the same effort and gives you the same forward propulsion.

On the road I think it is very noticeable, as people have said you can pull up as well as pull down. But I only really do this when I'm seated and trying to accelerate rapidly. Whenever I stand to sprint I only push down (don't know if that's my own personal lack of technique?).

On mountain bikes I find that there are too many other variable so cadence is interupted by positioning pedal to avoid obsticles or find a stable stance for technical bit. I notice very little difference unless it's smooth.

I spin fine in flats (ss 32:16 so it happens a lot) I can also power up the hills too.

Crampons w/thin shoes are more efficient than SPDs.
Your foot is closer to the axle.

People rarely 'pull up' with SPDs – they're just good at keeping the chain tight. Quads are much stronger than hamstrings.

Its all about control

Are you a pussy who lets the bike control you

OR

Do you control the bike ?