Timeline for Square taper crankset develops play after changing bottom bracket
Current License: CC BY-SA 3.0
16 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 26, 2017 at 11:08 | vote | accept | Christian Lindig | ||
| Jun 26, 2017 at 3:43 | history | tweeted | twitter.com/StackBicycles/status/879183347947380738 | ||
| Jun 25, 2017 at 23:00 | comment | added | whatsisname | @ChristianLindig: the problem really isn't usually that the crank goes 'too deep' but that the square cutout becomes a sort of pincushion shape. | |
| Jun 25, 2017 at 20:51 | comment | added | Christian Lindig | Thanks for all the comments that in combination give a good picture what to check and provide options what to do. I'm fairly certain that the crank arms are not yet sliding too deep onto the spindle but will check that. | |
| Jun 25, 2017 at 20:27 | answer | added | whatsisname | timeline score: 2 | |
| Jun 25, 2017 at 19:28 | comment | added | Chris H | @DanielRHicks I've never fancied using thread locker on cranks, or felt the need, as it would require undoing a good join just to apply it. Retightening after a few hundred metres and a good bounce on the pedals, then again after a few tens of km has always done the trick for me. | |
| Jun 25, 2017 at 19:22 | comment | added | Chris H | @Carel I certainly wouldn't recommend riding with it wobbly, even though that's not the failure mode I'd expect. But shimano should be JIS whatever the age. Sheldon as usual is instructive: sheldonbrown.com/bbtaper.html | |
| Jun 25, 2017 at 18:09 | comment | added | Carel | @Chris H: The standard for square tapers has also changed. It may be possible that this is an incompatible mix of old and new. But anyway, it's not recommended to ride with a wobbly square taper crank. I have experienced a broken spindle due to that and I can tell you that the edge is (more than) razor-sharp. It will cut through the calf without you noticing. | |
| Jun 25, 2017 at 12:32 | comment | added | Daniel R Hicks | It's not unusual to put a dab of (removable) thread lock compound on the screws. But you should generally do this only after a "break in" period, giving the cranks a chance to seat fully on the spindle. And, as others have said, the crank's "socket" can get deformed to the point that nothing's going to fix it. | |
| Jun 25, 2017 at 10:42 | comment | added | Chris H | @Carel that's a good point but only if you keep taking them off. Most square taper cranks these days are riveted to the chain rings so the cranks get replaced and hardly ever refitted. One of my bikes with square taper is on its third BB and second crankset, for example. | |
| Jun 25, 2017 at 10:39 | comment | added | Chris H | I wouldn't worry too much about the threads if both the screws and the spindle are steel. But I wonder if the wrong thing is bottoming out so it never does up tight. What happens if you screw a screw in without the crank arm on that side? It should go all the way home just turning it with your fingers. | |
| Jun 25, 2017 at 10:36 | comment | added | Carel | The problem with square taper cranks is that the holes widen over time. Up to the day where they go to 'deep' over the spindle and the bolt can't push them in because the head sits on the spindle.That's when the time has come to replace the cranks. | |
| Jun 25, 2017 at 9:38 | history | edited | Christian Lindig | CC BY-SA 3.0 |
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| Jun 25, 2017 at 9:37 | comment | added | Christian Lindig | I had originally greased the spindle surfaces but since the problem started removed the grease both on the spindle and the screws. I believe it reduced the problem. I am surprised that the screws would loosen at all. | |
| Jun 25, 2017 at 9:16 | comment | added | Criggie♦ | Could be your crankset is getting old too? And the change of BB is showing up wear in the square interface? Did you over-grease the spindle surfaces before fitting the cranks? | |
| Jun 25, 2017 at 8:20 | history | asked | Christian Lindig | CC BY-SA 3.0 |