replacement pedal dust caps

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alexnharvey
Posts: 903
Joined: 10 Jan 2014, 8:39am

Re: replacement pedal dust caps

Postby alexnharvey » 12 Jan 2020, 8:28am

My grandfather, a keen racing and touring cyclist, found what was either a starting pistol or a deactivated revolver (the bore was solid) on the road and gave it to me, a 9-10 year old child at the time, and for full context, growing up in Northern Ireland in the 1980s.

Absolute madness and as you can imagine the greatest gift a boy could've wished for. The item swiftly disappeared and to this day my parents deny any knowledge of these events having occurred.

Road bounty remains a great interest of mine.

On another note, one could scarcely wish for a safer drug than nitrous oxide although I imagine the vast majority are using it as an adjunct to cannabis and other drugs rather than on its own. Shame about the littering though, and the 'whippits' are not a nice thing to hit with a bike tyre.

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Mick F
Spambuster
Posts: 47792
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: replacement pedal dust caps

Postby Mick F » 12 Jan 2020, 8:40am

My grandfather gave me a bayonet sometime in the early 1960s.
I still have it.

One like this one, but mine is dated 1877.
https://www.youtube.com/watch?v=I3Lkz20iHWE
Mick F. Cornwall

Brucey
Posts: 36763
Joined: 4 Jan 2012, 6:25pm

Re: replacement pedal dust caps

Postby Brucey » 12 Jan 2020, 2:36pm

I've measured a DMR V8 (original type) pedal and dustcap.

The bore into which the dustcap pushes into is ~20.1mm ID. There is a shallow counterbore about 0.8mm deep, ~20.8mm dia.

Accordingly the dustcap has a thin (~0.5mm thickness) flange of about 20.8mm dia and the rest of the cap is a (not super-tight) push-fit into the pedal bore. I reckon the dustcap is usually retained by the inevitable burr on the pedal body (from the usual knocks and nudges) as much as anything else.

My collection of dustcaps does not include an identical version. not quite; I have one which is a snug push-fit into the pedal, but the top of it is the wrong size and sticks out. I reckon it would soon be knocked and lost.

Note that whatever dustcap is fitted, if it goes more than a few mm into the pedal then it needs to have a recess which is about 14mm dia so that the bearing locknut clears the inside of the dustcap. Obviously if the pedal bearings develop free play, the locknut will contact a close-fitting dustcap and this will soon dislodge it.

As others have suggested, it may well be possible to find a cap from a bottle (or similar) that can be made to fit. However as a temporary measure I'd suggest a strip of gaffer tape about 1" wide and 3" long. Further turns of tape can be used to secure the ends of this strip to the centre barrel of the pedal. This arrangement won't last for ever but it will probably keep the weather out long enough to sort out a better repair.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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SimonCelsa
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Joined: 6 Apr 2011, 10:19pm

Re: replacement pedal dust caps

Postby SimonCelsa » 12 Jan 2020, 5:02pm

I did think about a strip of gaffer tape or similar as a temporary stopgap, however this morning I found a couple of drop handlebar endcaps which, after slicing off the penetrative ends have provided a nice slightly domed cover. I superglued these into position and they will be good for a while.

As you pointed out, I don't want to use anything which penetrates the hollow too far as it may interfere with the lock nut and possibly over tighten or loosen the pedal cones.

All fairly trivial stuff on the grand scale of things but it's good to keep gear going if at all possible.

Brucey
Posts: 36763
Joined: 4 Jan 2012, 6:25pm

Re: replacement pedal dust caps

Postby Brucey » 12 Jan 2020, 5:29pm

I just had a thought; something about the measurements seemed familiar, and I just realised what it is. I've not checked this to be 100% sure but a 1p coin ought to fit the counterbore but not enter the pedal wholesale; the diameter of a 1p coin is between the two sizes I measured earlier. Glue, tape, or a clip of some kind could hold it in place, and if it drops out, it'll cost, er 1p to replace it with another one.... :wink:

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~