Crank arm goes loose
#1
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Thread Starter
Crank arm goes loose
hi all installed new bb on my road bike recently
i put on the non drive side cranks arm
properly
however arm keeps.going loose on ride
i even torque it properly
but still goes loose on long ride
bb is gxp
should i use thread locker?
suggestions?
i put on the non drive side cranks arm
properly
however arm keeps.going loose on ride
i even torque it properly
but still goes loose on long ride
bb is gxp
should i use thread locker?
suggestions?
#2
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The usual cause is the arm's fit to the axle has been damaged by the auger action of being ridden with a too loose retaining bolt. Andy
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AndrewRStewart
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Is the bolt actually loosening or does the arm just wobble? Do you have the splined washer/dust cover installed on the non drive side of the spindle before installing the crank arm? If that washer is not installed, the arm will never tighten fully against the bearing and the crankset will have some side to side movement. Is that a real GXP bottom bracket or one of the Shimano style 24mm bottom brackets with a reducer on the non drive side to make it work with GXP?
#7
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Thread Starter
hi there that pic is of my old BB which was a GXP. i do have a New GXP installed which is working well.
The crank arm does not wobble at all, i was able to install it properly. I will check to make sure the dust cover/washer is on, it is on though. so it seems.
yet crank arm after riding like over 3 hours does get loose i have to tighten still. i will take new pics of the crankset though, just in case and post here,.
everything seems to fit properly though
The crank arm does not wobble at all, i was able to install it properly. I will check to make sure the dust cover/washer is on, it is on though. so it seems.
yet crank arm after riding like over 3 hours does get loose i have to tighten still. i will take new pics of the crankset though, just in case and post here,.
everything seems to fit properly though
#9
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Thread Starter
those are new pics above of the crank it is and BB also pic of the dust cap /space to show i do have one there
#10
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The best way but to actually "test in the field" to determine if a splined crank fitting will stand up to use, unless the spline wear is so great that it's obvious. A tapered square design is easier to observe this wear at an earlier stage, although many still won't see what an experienced eye can. So the OP has done this test and the results are in. Andy
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AndrewRStewart
AndrewRStewart
#11
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Thread Starter
yes i tested it riding and still gets loose, what else can i do?
#12
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Sounds to me that it is just not tight enough. Just because it is torqued to the specifications doesn't necessarily mean that it is tightened enough. Make sure that it is very tight.
#13
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It looks like you still have part of the old destroyed bearing stuck on the drive side of the spindle. There is not supposed to be anything on the spindle. That could be preventing the crank from seating correctly on the drive side and it won't allow the non drive arm to seat fully. It will never tighten properly, unless the step on the spindle can seat against the back side of the non drive bearing.
#15
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Thread Starter
oh really!!! so should be totally clean, yes what happened before, i put in the NEW BB my old one while riding, self destructed. i got all this metal grinding noise etc. I never realized that other part was not supposed to be on crank still as its really on there, so should i try to take it off then? i am sure your referring to the small metal ring as the large one is the spacer?
thanks for your help i will try that and see if i can remove it all
thanks for your help i will try that and see if i can remove it all
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That metal ring should not be there. I'm not sure about this spacer you are referring to, there are no spacers on a GXP road install.. I suspact that the thing you are calling a spacer is also part of the old bearing. The only thing that could be on the drive side of the spindle is the plastic bushing/dust shield from the drive side bearing. Sometimes they get stuck on the spindle and pull out of the bearing.
If the spindle is installed correctly, you should be able to tighten the non-drive arm as hard as you can without affecting its ability to spin. If the bearings start to bind when you tighten the crank arm, something is wrong. GXP cranksets prevent side to side movement by trapping the non drive bearing between the step on the spindle and the crank arm. They should be tightened hard against one another. The drive side of the spindle always has space between the bearing and the spider, with some spindle showing. This is normal and no spacers should be used to try to take up that free space.
I'm a little troubled by the amount of grease in the stepped down area of the spindle on the non-drive side. If this was just pulled out of the bottom bracket, that grease should have been squeezed out of that space by the non drive bearing. It's possible that the grease is still there because the old bearing was preventing the spindle from being fully inserted. However, I'm going to ask again if this is a GXP bottom bracket that has a 24mm ID bearing on the drive side and a 22mm ID bearing on the non drive side. I suggest trying to insert the spindle from the non-drive side and see how far it goes in. If the bottom bracket is correct, the spindle will only go in as far as the step on the spindle.
If the spindle is installed correctly, you should be able to tighten the non-drive arm as hard as you can without affecting its ability to spin. If the bearings start to bind when you tighten the crank arm, something is wrong. GXP cranksets prevent side to side movement by trapping the non drive bearing between the step on the spindle and the crank arm. They should be tightened hard against one another. The drive side of the spindle always has space between the bearing and the spider, with some spindle showing. This is normal and no spacers should be used to try to take up that free space.
I'm a little troubled by the amount of grease in the stepped down area of the spindle on the non-drive side. If this was just pulled out of the bottom bracket, that grease should have been squeezed out of that space by the non drive bearing. It's possible that the grease is still there because the old bearing was preventing the spindle from being fully inserted. However, I'm going to ask again if this is a GXP bottom bracket that has a 24mm ID bearing on the drive side and a 22mm ID bearing on the non drive side. I suggest trying to insert the spindle from the non-drive side and see how far it goes in. If the bottom bracket is correct, the spindle will only go in as far as the step on the spindle.
Last edited by dsaul; 06-06-20 at 03:21 PM.
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#17
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Thread Starter
yes i tried to put it in the non drive and it barely went in, so i do have BB on right side for sure.
#18
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Thread Starter
i was able to get old part off crankset. reinstall nand went in well. i was able.to tight non drive side very vulcan forced tight
seems ok except some play still
i did not use spacers
i used one but found there was play so install with out. which crank seems tighter yet still play
i did bang drive side to secure crank too
what should i do?
seems ok except some play still
i did not use spacers
i used one but found there was play so install with out. which crank seems tighter yet still play
i did bang drive side to secure crank too
what should i do?
#19
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Thread Starter
tried again with spacers still get play
up and down. side to side
more grease as well
cranks was tighten strong
what am i doing wrong?
up and down. side to side
more grease as well
cranks was tighten strong
what am i doing wrong?
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The only things that could cause play is you forgot to install the splined washer under the non drive arm or the black plastic bushing/dust shield is missing from the drive side bearing. If those are there and you still have play, then something is wrong with the bottom bracket or the spindle could be damaged.
I'm not sure where you are putting these spacers or what type of spacers they are, but the only spacers that could possibly be used on a threaded GXP bottom bracket are installed between the cups and the frame when installing an MTB crankset on a 68mm bottom bracket. There are never any spacers on the spindle, except the splined washer under the non drive arm.
I'm not sure where you are putting these spacers or what type of spacers they are, but the only spacers that could possibly be used on a threaded GXP bottom bracket are installed between the cups and the frame when installing an MTB crankset on a 68mm bottom bracket. There are never any spacers on the spindle, except the splined washer under the non drive arm.
#22
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Thread Starter
update. the dust cover on drive side i took off accidentally
install now with it
success!!
install now with it
success!!
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