Australian Cycling Forums - Bicycles Network Australia

A year and a half ago I bought a nice light carbon road bike to complement my well-used mountain bike. Everyone said, "Get clipless pedals! They're much more efficient and you'll go faster!" so I duly purchased a pair of decent Shimano SPD pedals and shoes to match.

Soon afterwards I bought myself a Garmin Edge 500 and started recording my thrice-weekly rides, most of which are around familiar loops in the Adelaide Hills. Over the course of the last year I was very happy to see a gradual improvement in my time around one such loop, a 30km trek through undulating terrain with an elevation gain of 400m, from 1h13m to 1h04m.

This week I decided to stick some cheap plastic platform pedals on the bike to see how much slower I would be without being clipped in. Lo and behold - I did the circuit in 1h01m, my fastest time ever.

So what's the story? I've been riding bikes for more than 30 years and on average I cover at least 100km each week. Am I just an idiot who doesn't know how to pedal while clipped in? Or are clipless pedals the unnecessary product of a rather clever marketing campaign?

arkle

Well, the main thing that changed is your effective saddle height got higher by ~5mm. I find going from flats to SPDs I have to raise the saddle by 5mm to compensate. You went the other way without lowering your saddle.

Other than that, it's mainly marketing and perception. I use both and think SPDs may be marginally (< 1%?) faster, only because of a less compressible, less rubbery contact with the axle. This is mainly due to the difference in shoes usually used and the way they contact. Once again though, this is just perception as (like most) I can't prove it conclusively either way.

To me, the main difference I have used to pick which style I use is how technical and/or how fast the terrain is. For me, the more technical favors flats, the faster favors SPDs.

I think SPDs are cheaper to run because flats chew through more shoes.

Clipless pedals help you maintain your form and position relative to your pedals, plus give some stability when standing. They are not some kind of speed advantage. They might give an advantage if your sloppy pedalling hurts your power output or endurance (read: sore joints/muscles/feet).

As for why you saw an increase with platforms? Could have been a bad set up/cleat positioning that created a slight dead spot in your stroke, or it could have been nothing—you could have just been pushing harder. Three minutes over an hour-plus long ride is easily within the margin for error.

Nobody wrote:Well, the main thing that changed is your effective saddle height got higher by ~5mm. I find going from flats to SPDs I have to raise the saddle by 5mm to compensate. You went the other way without lowering your saddle.

Other than that, it's mainly marketing and perception. I use both and think SPDs may be marginally (< 1%?) faster, only because of a less compressible, less rubbery contact with the axle. This is mainly due to the difference in shoes usually used and the way they contact. Once again though, this is just perception as (like most) I can't prove it conclusively either way.

Mmm good thought Nobody but I did raise the saddle to compensate for the the change in contact height.

And the shoes I used with the platforms were great heavy rubber-soled Keen walking pumps (I call them "power pumps").

Three minutes over an hour is significant for me. My performance is normally pretty stable.

arkle

sherlock wrote:Clipless pedals help you maintain your form and position relative to your pedals, plus give some stability when standing. They are not some kind of speed advantage. They might give an advantage if your sloppy pedalling hurts your power output or endurance (read: sore joints/muscles/feet).

As for why you saw an increase with platforms? Could have been a bad set up/cleat positioning that created a slight dead spot in your stroke, or it could have been nothing—you could have just been pushing harder. Three minutes over an hour-plus long ride is easily within the margin for error.

Well... maybe you're right sherlock. The cleat positioning was done for me by the man I originally bought the bike from. I did find that with the platform pedals my right foot naturally shifted slightly further to the right on the pedal than SPDs would usually allow. The problem with clipless pedals is that unless they're set up in the exactly the right position you're locked into a less efficient position and there's nothing you can do about it! And the error may only need to be slight. I'm going to try modifying my cleat positioning to mirror the natural positioning I adopted with the platforms.

Three minutes over an hour is significant for me. My times are usually very stable. And to beat my fastest ever clipless time by 5% was a big surprise when I was expecting my time to increase. This theory about being able to pull up on clipless pedals doesn't help much when your cardiovascular system is already maxed out from all the pushing down. It seems to me that if you're limited to a continuous power output of, say, 250W, any power you want to use in pulling up is necessarily taken away from pushing down.

arkle

arkle wrote:Mmm good thought Nobody but I did raise the saddle to compensate for the the change in contact height.

I should have said, "If you didn't". Sorry.

arkle wrote:And the shoes I used with the platforms were great heavy rubber-soled Keen walking pumps (I call them "power pumps").

Another factor influencing this is cadence or how much you stand up. I find with MTBs that the more I stand or the lower the cadence, the more sapping the squishy tires and/or shocks are. Maybe you have a high average cadence so limiting the effective loss?

arkle wrote:This theory about being able to pull up on clipless pedals doesn't help much when your cardiovascular system is already maxed out from all the pushing down. It seems to me that if you're limited to a continuous power output of, say, 250W, any power you want to use in pulling up is necessarily taken away from pushing down.

Yeah this has been discussed many times here. The experts say pulling up lowers your overall long term efficiency. At least one study shows that faster cyclists just push down harder.

http://www.ncbi.nlm.nih.gov/pubmed/1997818


http://isbweb.org/data/kautz/index.html

I find with clipless pedals that I feel more secure connected to my bike, especially over technical terrain that is rough: they stop my feet rattling off the pedals. Dabbing and reconnecting is just slightly less easy with cleats, but not to the point of making me nervous any more. And as you'd expect, getting air off water bars, jumps and drop-offs is much less nerve-wracking if you are securely clipped in.

IWith clipless I pedal in a smoother, more circular motion which becomes more helpful on steep climbs when the surface is loose. Pulses from mashing the pedals or standing and grinding just result in wheelspin and lost forward momentum from the suspension bobbing.

Another plus from being clipped in is that once you have set your pedal position up to your liking, it is exactly the same each and every time. I've also seen some nasty injuries from the pin-spikes on flats getting intimate with their riders' shins. Off-road, I'd be wanting shin pads. That makes riding much less comfortable in the warmer seasons, which would adversely impact sustainable power output.

I don't have a power meter to tell either way which is more efficient, but you can probalby tell I have a firm preference for being clipped in.

Regarding your time for the set course, this can be impacted by temperature and wind strength, how well you've slept and eaten and by how much work you've done on the bike in the week leading up to the ride. I am always significantly faster if I've had a taper week leading up to the session compared to a normal training week. For the comparison to have any meaning you need to control for all these variables.

trailgumby wrote:I don't have a power meter to tell either way which is more efficient, but you can probalby tell I have a firm preference for being clipped in.

Ya think? Tell us what you really think. I still say most people who are critical of flats never mastered them IMO (not that I have). Techniques like heal dropping for grip and scooping with toe dropping for bunny hopping etc make a difference to their usefulness.

You'll be happy to know I'm going to be brave/cheap and try some SPDs on the MTB again (already have them on the road bike). For now I'm tired of wearing out shoes quickly and thought I might try enjoying reduced wear while gaining a higher risk of fractured bones on technical sections.

arkle wrote: Three minutes over an hour is significant for me. My times are usually very stable. And to beat my fastest ever clipless time by 5% was a big surprise when I was expecting my time to increase. This theory about being able to pull up on clipless pedals doesn't help much when your cardiovascular system is already maxed out from all the pushing down. It seems to me that if you're limited to a continuous power output of, say, 250W, any power you want to use in pulling up is necessarily taken away from pushing down.

Nobody already linked to one of the studies, but yes: pulling up is not efficient. Some of the best TT'ers even generate some negative torque at the top of their stroke, but pulling up only worsens the overall torque generated.

Anyway, I really just don't count 5% as an effective measurement, especially from the first time back on platforms. I can make 5% on a long enough ride by tucking in more against a headwind on a good flat.