Pedals with TWO left-hand threads
06-16-22, 12:05 PM
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Pedals with TWO left-hand threads
Just in case anyone else gets caught by this manufacturing stupidity - the left-hand version of this pedal (VP398T, shown below) is completely normal - left-hand threads go in the crank, right-hand-threads on the outer end for the cone.
The right-hand one has right-hand threads to go in the crank, and left-hand threads on the cone end, cone, and locknut.
The right-hand one has right-hand threads to go in the crank, and left-hand threads on the cone end, cone, and locknut.
06-16-22, 01:03 PM
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yeah... I learned the hard way that some Shimano SPD pedals use left hand threads for the cone on the right pedal....
This was on an A520 pedal.
I had another set of A520 pedals that did not have this characteristic. Crazy!
Looking around at some Shimano pedal manuals, there is mention that some models have these left hand threads. There was some sort of color coding of the locknuts. Unfortunately, the color coding was not unique, so it's not going to get the attention of anyone who isn't already looking for it.
Steve in Peoria
This was on an A520 pedal.
I had another set of A520 pedals that did not have this characteristic. Crazy!
Looking around at some Shimano pedal manuals, there is mention that some models have these left hand threads. There was some sort of color coding of the locknuts. Unfortunately, the color coding was not unique, so it's not going to get the attention of anyone who isn't already looking for it.
Steve in Peoria
06-16-22, 02:06 PM
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Left-handed threading on the LEFT pedal actually makes a lot of sense, just as it would on the driveside of either axle, for the same reason.
I've seen both examples self-tighten when RH threading was used, causing bearings to bind fiercely and in one case shatter a rear hub's bearing cup.
Oddly enough, I came across one example of a headset cone that very definitely tightened itself during a long ride, by some mysterious action of asymmetric bearing friction but could have been prevented by heavier tightening of the locknut.
I've seen both examples self-tighten when RH threading was used, causing bearings to bind fiercely and in one case shatter a rear hub's bearing cup.
Oddly enough, I came across one example of a headset cone that very definitely tightened itself during a long ride, by some mysterious action of asymmetric bearing friction but could have been prevented by heavier tightening of the locknut.
06-16-22, 02:57 PM
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Left-handed threading on the LEFT pedal actually makes a lot of sense, just as it would on the driveside of either axle, for the same reason.
I've seen both examples self-tighten when RH threading was used, causing bearings to bind fiercely and in one case shatter a rear hub's bearing cup.
Oddly enough, I came across one example of a headset cone that very definitely tightened itself during a long ride, by some mysterious action of asymmetric bearing friction but could have been prevented by heavier tightening of the locknut.
I've seen both examples self-tighten when RH threading was used, causing bearings to bind fiercely and in one case shatter a rear hub's bearing cup.
Oddly enough, I came across one example of a headset cone that very definitely tightened itself during a long ride, by some mysterious action of asymmetric bearing friction but could have been prevented by heavier tightening of the locknut.
Indeed, if a threaded fastener is large enough to have sufficient torque applied when tightening, you don't even need the locknut (i.e. french and italian BB cups).
[1] The most important locknut on a bicycle is the one outboard of the right-hand rear wheel cone. This should be very VERY tight. And if you have a cheap hub with no locknut immediately adjacent to the cone, just a spacer and a dropout-facing nut outboard that, fix it - get a real locknut, and a shorter spacer - and then the outboard nut.
