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Moving from old style pedals years ago, to when I took up cycling again more recently, I noticed a difference when oiling the bike, while doing maintenance.

After oiling an old style pedal, I would always flick it to see that it rotated more freely due to the new oil. It would do several rotations and take a few seconds to slow down. But doing the same with my newer clip-in pedals, they only do a few turns.

Is this due to the one-sided pedal (Shimano LOOK pedal design) having a weighted end? That is, does this pedal slow down more quickly after it is flipped, due to it's asymmetrical pedal weight distribution? Or, do people think there would inherently be more friction in such a pedal?

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Likely two things.

  1. Bearing seals will slow down free spinning. In actual use the added resistance from the seals is minimal and the seals ensure the bearings remained greased and in good working order despite the weather conditions (e.g., from dry and dusty, to wet and gritty).
  2. SPD-SL are weighted so that the single sided pedal platform faces you (i.e., the rear of the pedal settles in the downward position), making engagement after a stop much easier. Without the weighting the pedal would likely present either side (cleat platform or backside) when you start pedalling making consistent and easy cleat engagement a no go. Anything that is not evenly weighted will not spin as freely as something that is balanced (e.g., unbalanced loads in a washing machine). In use the uneven weighting isn't an issue as the pedals orientation remains static in use.

In short, the test you derived for old style pedals worked well for them, but hold less meaning for newer Shimano SPD-SL road pedals.

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  • Actually, the pedals don't rotate during riding. The cranks do.
    – ojs
    Commented Jun 30, 2016 at 18:37
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    @ojs - actually the pedals rotate around the axles, which are fixed to the crank arms which are rotating. The pedal orientation relative to the ground, however remains fixed. Point taken, minor revision made.
    – Rider_X
    Commented Jun 30, 2016 at 18:49
  • Useful and informative answer, thanks @Rider_X
    – MikeRoger
    Commented Jul 1, 2016 at 7:57
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I came here worried about the same thing and after reading answers and comments decided to measure. Measure the friction torque that is. The force required to turn my seemingly tight Look Keo pedal is about 10g at 5cm, that’s a torque of 0.005 Nm. Work per revolution is that times 2π so about 0.03 J. For two pedals together 0.06 J. A good cyclist is making about 1 revolution per second so this pedal will rob her of 0.06 Watts.

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  • Nice, but confirming: this is continuous force, not just the one needed to break from initial binding/viscosity; is that right?
    – Sam7919
    Commented Nov 11 at 10:03
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    Yes, continuous, but other people have made the point that after a while the grease will warm up and resistance will decrease. Although, I dont see how 0.03W of heating power can do that, but maybe.
    – Kphysics
    Commented Nov 12 at 11:06
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    My understanding is that bearing friction increases with total load, probably proportional to the load. The drag from the rubber seals stays similar. You are likely measuring purely seal drag.
    – Weiwen Ng
    Commented Nov 12 at 21:52
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    @WeiwenNg Good point! The bearing friction is far far smaller. Pedaling at full power puts approx 20kg force on the pedal, that's not much for a steel ball bearing. But you are right, I didnt realize the drag we are worried about here is from the rubber/plastic seal. That one will not be affected by warming up the grease at all.
    – Kphysics
    Commented Nov 14 at 10:21

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