1-piece crank problem

[UncleKudzu]

i put a crank with a small chainring on my latest find. it's great for hitting the hills around here, but the bearing on the chainring side keeps getting crushed. i changed back to an adult sized chainring and crank, but the bearing on that side failed again. i'm sure i'm putting everything together in the right order, so is this maybe an adjustment problem? also, can chainrings be changed on a one-piece crank?

i enjoy riding this bike, so any help will be appreciated.

 

[CCR]

just go slow when putting the last bearing cone on (on the non chain gear side) if the crank wiggles before it gets tight it could be moving the chain gear side bearing out of alignment without you noticing, ive waste several bearings myself slow and steady is the way to go

 

[SkidMark]

Sometimes they aren't seated right, and they will crank down, but will feel kinda scrapey. You won't realize something is wrong until it all goes south. Long ago I was told to always use the cups that come with the bottom bracket you are using, to never mix brands, i.e. use Schwinn bearings and races with Schwinn BB cups, Use Tange bearings with Tange cups, etc.

You can remove the chainwheel by unscrewing the bearing race, it's right -hand thread. I usually clamp the crank in a vise to spin it off.

 

[UncleKudzu]

thanks, guys. i wonder if i'm over-tightening, since i thought it was loose when the bearing retainer failed the first time. it works fine for a while after reassembly, then, under stress, it makes a sound that must be a bearing popping out and of course it's downhill from there.

i'll try matching cups and retainers and maybe not tightening so much. it looks so simple and straightforward, but somehow i'm getting it wrong. i wanted to try going back to the original crank with a smaller chainring, but can't get the chainring to loosen. who knew bike mechanicing could be so involved :wink:

 

[Anonymous]

Unc,Are ya sure youre not putting the bearing(s) in upside down?

The open face of the bearings should face each other in the bottom bracket.

 

[UncleKudzu]

The open face of the bearings should face each other in the bottom bracket.

thanks, MagicRat. i wondered about that earlier on, so i made sure i was putting them in correctly. whatever is going wrong is a mystery to me, but it's a beautiful autumn day out there and i'm gonna gather my wrenches, go forth and try it again.

thanks again for the responses.

 

[roadmaster]

i have rebuilt so, so, soooooo many 1piece cranks, that i can do it in my sleep. they are a little tricky to tighten down, as the left side bearing cone will tend to tighten as you torqu down the main nut, despite the washer in between to prevent that. so when i tighten mine, i leave the cone slightly loose and anticipate and compensate for the slight cone tightening as i tighten the main nut. id cheack my bearings and races and maybe even find another beater with a doner 1 pc cranks.

hear is the beautiful part, cuz you can swap out chainrings on a 1pc. you will see the retaining cone nut holding the chainring on and it can be loosenen via a good table vise to put it in or a reliable creasent or pipe wrench will usually do the trick. regular threads i believe. id get a doner 1pc crank arm with the same arm length, put on my chainring and use the doner hardware. and i am willing to bet that that bike is a murray (headbadge) and i own two, a westport and a monterey. take it from me, the spin on bearing cone on the left side has difficult ability to tighten by hand as per its design and i have replaced mine with the fatter styled cones with the two notches to help tighten them.

sorry to ramble on, but this is something that can be fixed, and doner bb hardware and bearings is the way id go. don't over tighten the bearings either, cuz they will bind if not seated right and your bb will start puking up bearings as it grinds itself into oblivion.

 

[UncleKudzu]

roadmaster, that's good information! thanks!

and yes, it's a Murray Monterey, so your specific information will likely apply. i do thinkk that i've been over-tightening, for one thing.

again, i appreciate all the responses.

 

[vanilla_gorilla]

use lots of grease to "glue" it in place

 

[roadmaster]

good lookin out. lots of grease too, and parts shouldn't be that hard to find. i also own a black huffy good vibrations cruiser similar to the others. small world. good luck and if you ever have any more questions, pm me.

 

[mastershake916]

Just do it loose ball, pack it with grease and then just put in the proper size bearing (same size as the 1 piece retainered ones, you can just pop them out), and leave room for one extra bearing, so that there's enough room for grease to move about inside. even though it's a little hard to keep the bearings in place when you're re-assembling it, it will COMPLETELY solve your problem. Also, use some heavy grease, like disk brake grease or marine grease.

 

[Markm]

Just do it loose ball, pack it with grease and then just put in the proper size bearing (same size as the 1 piece retainered ones, you can just pop them out), and leave room for one extra bearing, so that there's enough room for grease to move about inside. even though it's a little hard to keep the bearings in place when you're re-assembling it, it will COMPLETELY solve your problem. Also, use some heavy grease, like disk brake grease or marine grease.

good idea!! :mrgreen: :mrgreen: