Pedal Spacers

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  • Pedal Spacers
  • shedfull

    I’ve got two mountain bikes and a road bike and I have almost identical road and mountain bike shoes (Specialized BG Comp). When I ride the road bike, I seem to claw my toes up inside the shoe, so that my foot is canted outwards. I do it subconsciously and, when I realise I’ve done it, flatten my feet on the insoles. But it takes a few minutes and they’re clawed up again. This never happens on the mountain bikes, even when I rode long, flat miles on the Canal du Midi in September.

    As mountain bike chainlines are 50mm and the road bike’s is 43.5mm, I’m thinking the whole crankset is probably 10 to 15mm narrower and thus my feet are too close together, which makes me compensate by clawing my toes in the shoe. I heard that Lance Armstrong runs spacers on his pedals and I’m wondering if anyone’s tried this. Are there special spacers you can buy or is just a pack of big washers OK?


    I am not sure 3mm each side on the chainline would make that difference surely? Maybe I’m a sceptic 😉 Have you measured the crank to crank horiz distance on your bikes to see if its different?

    This is defined as the crank’s Q’ factor IIRC 🙂

    Hmm – looked up google and found this:

    Making it Narrow
    Mostly what I’d like to talk about are methods of narrowing the Q-factor, because that’s what many of us need to do when building a streamliner, or when wanting to keep ourselves in a nice aerodynamic package. The two things you can change to narrow the Q-factor are the cranks and the BB. Cranks are not typically rated by Q-factor, but MTB cranks are typically about 20mm wider than road cranks. BBs commonly come in widths between 107mm and 118mm.

    They suggest pedal extenders as well for knee problems at any rate 🙂


    Oh BTW Highpath in the UK do them:

    Think you can get spacers, but of course there is less thread in the crank arm so could be an issue. Certainly putting 7mm of washers per side as you imply would be pushing what I’d think was safe.

    I imagine if Lance decided he needed wider q-factor they’d just build him a set of pedals with longer axles and not faff about with spacers. The holy grail of road cyclists is narrow q-factor for aerodynamics so I’d be surprised LA spent so much time honing his bike/clothing/position only to ruin it all by ‘opening’ his legs out.

    Could you not push the road cleats as inboard as possible? Or are you using MB shoes/pedals on the road bike?


    Quality! Thanks everyone.

    You know, it hadn’t occurred to me to move the cleats around a bit. 3mm there and 3mm in washers might make all the difference.

    Armstrong, IIRC, was found by his physio to be crooked on the bike, which a small spacer on one side was meant to fix. Presumably the gains outweighed the drag from messing up the Q factor, or he didn’t use it on the time trial bike where Q factor makes more difference.

    Thanks for the links – I’ll go buying bigger spacers if I can’t sort it otherwise. It’s annoying because my feet hurt if I don’t uncurl my toes and my knees start to twinge if I do.

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    I was contemplating this on my commute in this morning but vice versa
    i.e. do mtb doubles have a narrower Q dimension than mtb triples.


    Strangely, after having to change my shoes, I felt that my feet were also canted outwards, and tried wedges in various combinations, unsuccessfully, to sort it.A last ditch attempt saw me move the cleats much further forward than I felt the old ones were, may not sort your problem, but has certainly made a hell of a difference to mine though i’m still not exactly sure why.

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