Re: Fixing loose pedal

<[email hidden]> wrote in message
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Quoted message said:

Leo Lichtman said:

It's likely that over time, you may have been riding with a loose
pedal, which would cause the threads to wear. Now, when you tighten
it, the thread still has clearance, and can wiggle. Super glue is
fairly brittle, so it probably breaks up when you start to ride. As
an alternative, I suggest you try Loctite. There are different
grades for different applications, but they are all more tenacious
and pliable than C/A glue.

http://www.loctite.com

I think that is a reasonable assessment and because pedals naturally
move in crank threads even when in best condition. A pedal ridden
until it falls out has probably ruined the threads to the point that
there is no practical repair possible.

No means other than a new crank can secure this interface now. The
reason for left hand threads on left cranks is that the pedal spindle
is always moving, no matter how much it is tightened and in that mode,
it will unscrew from precession without a left hand thread (or a right
hand thread for right cranks).

This design problem deserves to be fixed because thread motion also
causes crank failures in which the pedal suddenly breaks out of the
crank throwing the rider to the ground if standing at that moment.
When the left crank does this, the rider falls under any adjacent
vehicle (in right hand traffic). This is a design flaw that can be
fixed easily but because bicycles have always had this problem, no one
wants to fix it.

I have implemented the fix and I have tested it over a period during
which I would most likely have had five or so crank failures, judging
from failure rates prior to the design change. The change was made on
cranks identical to ones that previously failed and from the same
production of which I had reserves because they failed so often.

Jobst Brandt
[email hidden]

Another thing that may work OK is to clean the pedal threads and the crank
arm threads thoroughly.
Then use JB Weld epoxy or an equivalent metalized epoxy adhesive to glue the
pedal back in.
Another way is to clean the crank arm threads after you remove it from the
bike, and using a Propane torch, heat it up real good
and use a good quality aluminum soldering rod or two or three to fill in the
hole, then drill and retap the hole with the appropriate left or right hand
tap.
Most bikes use 9/16x20 threads, but the cheaper bikes with 1 peice cranks
typically use 1/2"x20' threads left or right hand.
But I suppose if you are careful, you could do this without removing the
crank arm, but drilling and tapping a straight hole may be difficult.

"Earl Bollinger" wrote: (clip) But I suppose if you are careful, you could
do this without removing the crank arm, but drilling and tapping a straight
hole may be difficult.
^^^^^^^^^^^^^^
I would say, "Next to impossible." The threaded hole has to be parallel to
the bottom bracket axis, which is not easily to get by eye. It almost HAS
to be done on a drill press or mill, with proper measuring and clamping. If
the angle is off, you will feel the pedal "orbiting" on every revolution.