4

Crankset Shimano FC-S125, 105 Golden Arrow and I know I'm using the right bottom bracket (119mm)

The pedals Shimano Clipless SPD M505

My shoes Broken link, please fix

I've got a problem with my shoe scuffing the crank arm when I turn.

Potential issues

  1. I'm using mtb shoes on a road bike
  2. Old crank (not a smooth molded form)
  3. Pedals
  4. positioning of cleat?

Any ideas or advice appreciated.

The bike (excuse the weird cinelli decals, I bought it like that. I am not sure if it is a real cinelli). enter image description here enter image description here

  • I think it's not the shoes - they look fine. – andy256 Jan 15 '15 at 21:47
  • Where is the scuffing on the shoes and where on the cranks? – andy256 Jan 15 '15 at 21:53
  • This question would be easier to read if you inlined all the things you're using (i.e. which shoes, etc.) – Batman Jan 15 '15 at 22:06
  • Post a picture of the soles of the shoes to show how the clips are positioned. – paparazzo Jan 15 '15 at 23:30
  • Regardless of the "reason", the only fix (short of tossing shoes, pedals, or cranks) is to adjust the plates. Don't simply angle them so that your heels can't twist inward, but move the plates (via the slotted holes) horizontally all the way to the inside edges. – Daniel R Hicks Jan 16 '15 at 2:12
7

The proximate answer is that your shoes at the closest point, are too close to the crank arm, but that hardly solves your problem!

This distance is affected by a large number of factors: your cleat position, pedal axel length, pedal float, bottom bracket length, and crank arm construction.

Pedal float becomes a factor if you heel-in during your pedal stroke (some peoples hips naturally make them "duck-footed." In this case a longer pedal axel or shifting the cleats to a more inboard position can help. However shifting the cleats too far can also cause hot spots in some situations as the pedal platform will not be supporting the shoe as evenly as a more centred position.

Too add to the confusion people may also take a duck footed position to compensate for pedal stance (often referred to as the Q Factor), the distance between the pedal attachment point and the centre of the bicycle. Q Factor is a function of both the bottom bracket width (axle length) and the crank arms construction. Different cranks have a different nominal Q Factor measurements. If your bike has a wide Q Factor and your body prefers a more narrow stance, and your pedals have enough float to accommodate, you may pedal heel-in to reduce the realized stance, which can also cause the shoe/crank rubbing.

Finally, you may be pedalling in a mostly neutral heel position and simply have wide feet and short pedal axels and/or an outboard cleat position. In this case a more neutral cleat position (inboard vs outboard) or longer pedal axel may solve the problem.

Without more information it is impossible to diagnose which factors are applicable to your situation.

2

While adjusting your cleats may be a valid answer if you have room to adjust the width, but not the angle, pedal spacers may also be an option. They essentially lengthen the spindle of your pedal and move you pedal contact point out away from your crank arm. Several different companies make them, those are just an example.

2

Where are your shoes scuffing the crank arm? I had a similar issue. I was scuffing just below and slightly in front of the knob on my ankle joint. I adjusted the cleat on my shoes so that my feet are pointing ever so slightly inwards and this solved it because this moved the contact point away from the crank arm.

Two caveats:

  1. Suddenly adjusting your foot position by too much is a bad thing. It can lead to all kinds of injuries and issues in the various joints and ligaments in your legs. If you need to move your feet by too much do it in small steps or don't do it!
  2. There still is some flex in the cleats on most pedals. That is: you can twist your feet a bit, from pointing inwards to pointing outwards when you are clipped in. You may need to exaggerate the adjustment of your cleats to make sure you account for this movement otherwise you'll still be scuffing the crank arm after you make the adjustment.

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