NotGonnaLie Posted August 26, 2011 Report Share Posted August 26, 2011 So, i've had my phase 1.2 for about 2 months now... and recently a crank fell off, because it appears not to have been tightened properly... So i tightened it up, and it loosened again... I repeated this and it started to get loose again... Now i've tightened it again, and this time i've done it really tight, and it doesn't seem to be coming loose.. yet, Basically the question is, what's most likely to be causing this problem? As the thread in the BB and on the crank bolt both seem to be fine. Thanks Quote Link to comment Share on other sites More sharing options...
bike_dummie Posted August 26, 2011 Report Share Posted August 26, 2011 This usually happens when the splines have worn in a certain way then you take them off and dont put them back on the same splines. Also try a a bit of loctite on the crank bolts and make sure you tighten the cranks avery 10 mins or so when riding. Quote Link to comment Share on other sites More sharing options...
NotGonnaLie Posted August 26, 2011 Author Report Share Posted August 26, 2011 Feel like a noob... splines? Quote Link to comment Share on other sites More sharing options...
Pete.M Posted August 26, 2011 Report Share Posted August 26, 2011 Exact same thing happened to my phase, kept coming loose for a couple weeks then stopped. Been fine for a month or so now. Hopefully yours will stop too. 1 Quote Link to comment Share on other sites More sharing options...
bike_dummie Posted August 26, 2011 Report Share Posted August 26, 2011 i presume its isis not a taper. A taper is where your cranks attach to your bb is a square. As seen in the linked picture, link A spline is the same principle as the square but it has splines the spiky bit on the outside instead of the taper, link theres also a tarty video guide on this here. Quote Link to comment Share on other sites More sharing options...
NotGonnaLie Posted August 26, 2011 Author Report Share Posted August 26, 2011 Ahhh, i see! Yeah it is isis, thanks for that Quote Link to comment Share on other sites More sharing options...
number1spark Posted August 26, 2011 Report Share Posted August 26, 2011 you could always try locktight thread lock. its used on cars to stop nuts and bolts undoing under vibration. around £4 from halfords. i use it on my bikes. Quote Link to comment Share on other sites More sharing options...
Silferme Posted August 27, 2011 Report Share Posted August 27, 2011 If you go for Locktite just remember to use the blue version. The red is used for "permanent" hold. (not entirely permanent as it can be easily loosened by heating the bolt) 1 Quote Link to comment Share on other sites More sharing options...
isitafox Posted August 27, 2011 Report Share Posted August 27, 2011 If the bike's brand new I'd put it down to the cranks bedding in on the bottom bracket splines. When you get a new BB and set of cranks they tend to not go on all the way so need tightening up every 40 mins or so for the first few weeks till they've properly bedded in. That may be the cause of the problem. Quote Link to comment Share on other sites More sharing options...
NotGonnaLie Posted August 27, 2011 Author Report Share Posted August 27, 2011 They do seem to have started behaving themselves now So i guess that's what it is, thanks everyone! If it does happen again, i'll try blue loctite Quote Link to comment Share on other sites More sharing options...
wozz Posted August 28, 2011 Report Share Posted August 28, 2011 i got a second hand bike and the crank is lose its taper. i thought to tighten the bolt it was supposed to go the same way as the pedal goes to prevent it being undone when you pedal but mine tightens the opposite way to the pedal? has someone been a numpty? Quote Link to comment Share on other sites More sharing options...
trials owns Posted August 28, 2011 Report Share Posted August 28, 2011 (edited) i got a second hand bike and the crank is lose its taper. i thought to tighten the bolt it was supposed to go the same way as the pedal goes to prevent it being undone when you pedal but mine tightens the opposite way to the pedal? has someone been a numpty? On both of the crank bolts, They should turn right and tighten on both sides. If the crank starts wobbling and the bolt undos fairly quickly your cranks/bb might be warn due to it being second hand. Your thinking of the pedals in the sense the thread goes the way the pedal rotates. Edited August 28, 2011 by trials owns Quote Link to comment Share on other sites More sharing options...
wozz Posted August 28, 2011 Report Share Posted August 28, 2011 yeah it does look a bit worn to be honest. any recommendation for a new crank set? (i.e make?) Quote Link to comment Share on other sites More sharing options...
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