Crank Slop
 

Hi Group,

I have a question about the slop I have in my crank. I’m not sure if this is common or if something is wrong with it.

When I peddle it seems like it’s not engaged and then all of a sudden it engages and no more slop.

Thanks in advance for any advise.

Welcome. The crankarm lives in the bottom bracket. If the BB is too loose, you'll get side to side play, or slop, whatever you want to call it.

How to test: Grab each pedal or crankarm and try pulling sideways. You shouldn't be able to.

If you can, chances are your bottom bracket is too loose.

You'll need to remove the non-drive-side lockring with a lockring tool and crankarm with a crank puller tool to get at the bottom bracket.

There's a fixed cup on the driveside and an adjustable cup on the non-drive-side. When you pull the non-drive-side crankarm off, it allows access to the adjustable cup. To adjust the BB only, you always start with the adjustable cup.

Using a bottom bracket tool if necessary - sometimes an adjustable wrench will work - you can tighten the adjustable cup to the point where there is no play, but the spindle still spins freely - no binding when the pedals turn.

Then reassemble in the same order, making sure there is no play and binding simultaneously. If there is, go back and adjust again.

If you haven't done an overhaul in awhile, now would be a good time as long as everything is apart. Take the ball bearings in each cup out, clean them with solvent (iso alcohol is good), and repack with fresh grease.

Lots of videos around if you prefer visual instructions. You can also ask questions here if you get stuck.

Side to side or forward?

Forward not side to side

Freehub or freewheel (whichever you have) is the issue. It could be gummed up or it could be broken. Some strategically placed penetrating oil is the test for the gummed up condition. If the freehub or freewheel is shot, then a replacement is in order.

Left crank, correct?

If so, and if it's aluminum and uses a single bolt or nut to secure it to the bottom bracket spindle, there's a pretty good chance the bike was ridden while the nut or bolt was loose and that you'll need to replace the crank, which will have deformed where the crank has been wiggling on the spindle.

For more detailed help, you should upload photos to your Gallery here and then add a post in this thread saying that you have done so. Someone will retrieve the photos and add them to the thread.

I can’t post pictures yet!
they say you need 10 posts before you’re able to do so

Reread my post. You are not yet allowed to add pictures to a post in a thread like this, but you can upload pictures in your Gallery (see the links at the top of the page).

You didn't answer my question. Correct that the loose crank is the left one?

I’m not sure which side is the issue.
i will take pictures tomorrow and upload them as you suggested

The problem is described as "crank slop", but the symptoms of not being "engaged" and then being "engaged", seems more like an issue of forward drive and not a loose crank. That would be an issue with the rear wheel, either freehub or freewheel.

Checking for slop in the left crank is the first test i'd do. Hold the right crank stationary and try to wiggle the left crank forward and backward.

If the crank is sloppy on the spindle, the OP can try torquing the bolt, but chances are a new crank is needed. Generic replacement cranks are pretty cheap if the original is a common type.

If there's no slop, then go on to checking for drive train issues. If the problem is that the chain skips forward under pedaling pressure, chances are that the bike needs a new chain and cassette.

This seems like the answer, based on the brief description.

In reply to my question regarding which crank seemed loose, the OP said "I’m not sure which side is the issue," which implies that the slop is felt on one side or the other but not both. If the problem is indeed that a crank has deformed at the interface with the spindle, then it'll be the left crank.

But drive train issues are common, too. Hope the OP sorts out the problem.

Couldn’t it also just be completely normal since free hub/freewheel engagement isn’t instantaneous. Also starting to pedal in too low of a gear after coasting causes the same symptoms that OP describes.

I will be surprised if it is crank arm related. If the arm's interface with the spindle is damaged enough to cause engagement issues then I would think it would be very obvious to the OP since the arm would be loosey-goosey to the point of flopping around. That said, anything is possible I reckon.
https://cimg0.ibsrv.net/gimg/bikefor...21207db82e.jpg

Not with THAT attitude!

It's either the one or the other, or something else.

I posted some pictures of my bike in my gallery as suggested and one of my bruised big toe :-) LOL

Okay silly me it seems this is the case and nothing is wrong with my crank as I have checked it as suggested and nothing seems loose. It would only happen once in a while like stated in quote. Just seemed like something was wrong since it would take a bit of time for it to engage.

Thanks to everyone for replying and trying to help me!

In another thread the headline was of giving birth to a frame. Didn't open it. Sounds painful and of details I don't need to know.

I like to cover me bases!
John