Bottom bracket issues :(

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10/21/2015 11:13 PM
Edited Date/Time: 10/21/2015 11:24 PM

Ok so Recently picked up a second hand scavenger bridge frame and having issues with tight and loose spots in chain initially thought it was a stretched chain replaced it issue still there i then realized the sprocket did not have a hat spacer i swapped sprockets as i did not have a spacer that fit my tree sprocket issue still happening i noticed that my sprocket is spinning off axis so i pulled my spindle out to see if it was bent or anything like that and it seems to be all good and straight so do crank arms as i was about to put another spindle in to test i noticed that there was no spacer in between the bb bearings could this cause my spindle to spin off axis ?

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P.S Rear wheel / driver has been ruled out as it is a brand spanking new wheel

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Parkrat is lyf !

10/21/2015 11:48 PM
Edited Date/Time: 10/21/2015 11:49 PM

1 : Your grammar is atrocious .

2 : "no spacer for my BB bearings could this cause my spindle to spin off axis"

3 : I am just as clueless as you are . Worst comes to worst buy a new BB and see what happens . Probably poor chain alignment , bearing issues , maybe a warped sprocket but I doubt it's due to a spacer , yet again I am no mechanic .

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Instagram : braydenbuckingham
My Cult 2 Short

10/21/2015 11:55 PM

In the process of swapping in the bottom bracket from my fit frame and i am not sure why you need to make a point about my grammar i think i did pretty damn well considering i am dyslexic and as long as you can read what i am typing i don't see why it is an issue smile

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Parkrat is lyf !

10/22/2015 12:30 AM

It can still be read, but poor grammar makes it a hell of a lot harder to read and comprehend things since the whole thing's a run on sentence. A lot of people would just stop reading not even halfway through.



So you say the sprocket is spinning off axis? Like when you look at your bike from the side, you'll see it move up and down? Or is it bend side to side when standing over your bike looking down at it?


If it's moving up & down, make sure the top hat/sprocket adapter is the correct size for the sprocket & spindle. It should fit snug in the sprocket, and snug on the spindle. If it doesn't and has room to wobble around, then it's the wrong size.


If it's moving side to side, it could be a number of things.

-Again make sure the sprocket adapter is the correct size.
-Make sure you tighten your sprocket bolt AFTER you tighten your crank bolts. When you take your crank arms off, you need to loosen the sprocket bolt too, then tighten it up only after you tighten your crank bolts up. The reason behind this is if you tighten the sprocket bolt first, it can cause the sprocket to sit unevenly against the crank arm even when tightened up, and cause it to look bent and give you tight/loose spots in your chain
-Double check your spindle to make sure it isn't bent. Pull it out of both crank arms and roll it on a flat surface like hard class or a countertop. If you see it wobbling, it's bent and is likely the problem
-make sure it isn't the sprocket. You said you put a different one on but both sprockets could be bent too.


Also, while the internal spacer that goes in between the bearings might not be causing your problem, you really should get one.

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10/22/2015 12:46 AM

yep the hat is the correct size pulled straight from my other bike its snug on the spindle and in the sprocket when my cranks are all tightened up the sprocket lifts up on one side even when tightening cranks and then tightening sprocket same size bb and same size spindle as my old setup. the only difference is one spindle has a very fine spline the other spindle is the big spline type designed for cranks with pinch bolts

and internal spacer is now in

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Parkrat is lyf !

10/22/2015 12:48 AM

Change it to wumbo

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Instagram : braydenbuckingham
My Cult 2 Short

10/22/2015 6:06 AM

Step 1: Put your cranks back in
Step 2: DO NOT PUT THE CHAIN ON
Step 3: ????
Step 4: Profit


In all seriousness, put your cranks on, tighten everything properly, THEN WITHOUT INSTALLING THE CHAIN, spin the cranks and figure out which way the sprocket moves. If it is ONLY up and down, it is not centered properly, OR damaged/out of round. If it goes SIDE TO SIDE, it is either bent, OR does not sit well on the crank arm, and a spacer or two might be necessary to adjust accordingly.


Also make sure any spacer for the sprocket is set so it is on the INSIDE of the sprocket (IE BB Side) and not between the sprocket and the crank arm.

Also your chain could be stretched unevenly, in which case you would want a new chain.

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"Hey anybody ever make that mistake like right when you wake up in the morning and you believe in yourself?" -Kyle Kinane

"BIKES!" -Tom Segura

10/22/2015 7:36 AM

Almost every time I have had this issue it has been the sprocket not centering perfectly on the spindle, even with the correct size sprocket hole and/or adapter. The center hole in most of the sprockets I have seen is not a clean, drilled or machined hole, looks more like a rough casting or the flash left by a waterjet cutting process. At any rate, this is what I attribute the problem to first, before looking for another cause.
I turn the crank until the chain is at its tightest, mark the forward facing portion of the sprocket, then remove it from the spindle and find some thin metal shim material to put between the sprocket and spindle, or adapter and spindle, to keep it centered. The shim will go opposite where you marked the tight spot. 4 out of 5 times this will solve the problem for me.

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