About a month ago I ordered a pair of Fizik R4 shoes, they recently came in and I was ecstatic that that looked so good IRL. So ecstatic that when I saw the 12 on the side of the box I didn't realize it was for the UK. I normally wear size 12 or 11 1/2 depending on the brand. Will wearing a complete size larger make a difference in terms of how many watts I can put out or put me at a higher chance of injury?

  • This could possibly be a good question, if you're asking about how the cross-sectional area will affect transmission, but the trouble is, by talking about your feet, you make it difficult to distinguish between that and seeking medical advice. If you are looking for medical advice, you should consult a professional.
    – PeteH
    Jun 21, 2016 at 11:48
  • yes and no. the width is perfect. but the ball of my feet is even with the last 2 mounting holes on the sole of the shoe. would that affect how much power I can put out?
    – Perry Bunn
    Jun 21, 2016 at 12:28
  • But medical advice is, by definition, off-topic here.
    – PeteH
    Jun 21, 2016 at 13:06
  • Just wear thicker socks.
    – Criggie
    Jun 21, 2016 at 19:47
  • Can you get the cleats properly positioned? If the cleats can't be placed properly in relation to your foot, you'll be compensating with increased ankle effort and stress.
    – mpez0
    Jun 24, 2016 at 14:18

1 Answer 1


Everyone will agree that it is best to have shoes that fit properly.

If the shoes don't fit perfectly, it's better to have shoes that are a bit too big, rather than shoes that are a bit too small. As we warm up our feet swell slightly, and if the shoes are too small then the blood circulation can be restricted. That can lead to cramps or numbness.

The issue with shoes that are too large is that the foot could move inside the shoe, causing blisters or other injuries, and reducing power transfer.

If wearing an extra pair of sox and cinching the shoes tightly stops any movement, then you'll be fine.

One concern you may have is cleat position. With shoes that are only one size different, I don't think that will be an issue; you should be able to position the cleats as usual. And research has shown that our preferred cleat position is largely a matter of tradition, and make extremely little difference for power transfer.

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