Large-platform SPDs vs. small ones

Hi Lee,

I’ve been riding large platform clipless pedals (DX resin cage etc) since I started riding clipless way back when. I quite like them, however push is coming to shove and I’ve had enough sand kicked in my face etc etc, to cut a long story short, I have found myself needing to shed some weight from my bike. The weight difference between DX clip ins and say XT pedals is pretty enormous in the scheme of things.

Pedals must be rotating weight. Should this be as noticeable as lighter wheels and tyres?

With stiff soled race shoes, do you think I’ll miss the extra platform? From memory running regular spd size pedals doesn’t make you any less aggressive on the trail.

Thanks,

Chris Q.

Chris is a strong, skilled rider who will actually benefit from optimizing his equipment. We he visited from Australiea this year, we did a few clinics together, then he stomped me on an XC ride — on my heavy bike, at altitude.

Hey Chris!

What an awesomely nerdy question. I’d love to rock some diagrams, but it’s late, and I want to get some dinner.

Benefit of smaller pedals #1 – Less rotating weight
Pedals do rotate, and rotating weight has a much greater impact than non-rotating weight.

Simplified, but fun:

– Pedal radius = 175 millimeters = 7 inches

– Wheel radius = 330 millimeters = 13 inches

So … reducing wheel weight has almost twice (1.85x) the benefit of reducing pedal weight.

– DX platform pedals = 568 grams per pair

– Deore XT pedals = 350 grams per pair

Taking 218 grams off your pedals is like taking 118 grams off your wheels. That’s four ounces, or 1/4 pound, for you Americans. Not earth shattering, but noticeable.

But! This 1:1.85 ratio only applies when your cranks and wheels are rotating at the same rate, say when you’re buzzing your 34×34 up a long climb. If you’re in a lower gear, light pedals make more of a difference. If you’re in a higher gear, lighter pedals make less of a difference.

Braaap! is still spelled Braaap! in Australia.

Benefit of smaller pedals #2 – More clearance
Missing a rock by a millimeter is still a miss!

I used to drive a forklift in a warehouse that was laid out with one inch of extra room for the forklift and a pallette. Talk about stress for a 17-year-old. My boss used to say, “An inch is as good as a mile.”

Benefit of larger pedals #1 – More support
If your shoes are soft or worn out, small pedals will make your feet sore. Good shoes nullify this.

Benefit of larger pedals #2 – Easier to get your feet back on
Good skills nullify this.

The bottom line
If you want relatively high-impact weight savings at a relatively low cost, try the smaller pedals.

Chris, since I know you’re a strong, skilled XC racer, I say rock the XTs.

Get some!

— Lee

PS: A few years ago I wrote and illustrated an article for VeloNews about the effect of heavier, grippier tires over the course of a trail ride. This piece was way over the top, even for that magazine, and it never got published. I’ll dig it up for you guys.