freewheel loose bearing

[chrisclaydon48]

Hello I have a problem i am hoping someone can help me with.
The problem is this my chain seems to jump occasionally, I can ride for 5 or six miles with no issue then all of a sudden the chain jumps or it sounds like it or something else is making the noise, and it will then happen frequently this happens without any gear changes .
When the bike is on the stand and i hand pedal while going up and down through the gears it is perfect, the derailleur is hanging inline with sprockets, the only thing that i can see is the freewheel has some slight play on its bearings so sprockets can be wobbled a little, I am not sure if this is normal.
Any advise would be appreciated
My chain is quite new KMC Z7
Freewheel quite new DRIFT MANIAC 7 Speed Freewheel
Derailleu quite new RASHION RD-M390 A-cera Rear
shifter Meghna Right Thumb Gear Shifter

[hamster]

I bet it only ever happens in one gear - in which case it's a worn sprocket.

[chrisclaydon48]

Hi thanks for your reply in mainly happens on the smallest sprocket (11 teeth) but it dos occur in next gear as well but less, the sprocket and the chain ring are both quite new only done 150 miles on them

[DevonDamo]

Without seeing the play in your freewheel, it's not possible to categorically state that that's the cause, but I can definitely say that it's possible. I recently solved a similar problem on my hybrid bike by sorting out the wobbly cassette. I did this by cleaning the teeth/spline things which engage the freehub into the wheel hub, cleaning the splines where the cassette slides onto the freehub and tightening it all back up. Obviously, this is a different system to your screw-in freewheel, and mine had seen a lot of use and was full of hard-packed crud, but doing this fully resolved the issue, so it shows that a bit of wobble on your rear sprockets can cause this sort of problem.

If I were you, I'd first see if I could fix it the easy way, i.e. unscrew the freewheel, clean up the threads and re-tighten it back onto the wheel. If that doesn't work, you could either have a crack at greasing/replacing the internal bearings, if that's possible, or look at getting a new one. If you take the wheel into a local bike shop, they could have a look at the play before ordering you a replacement.

[hamster]

I bet it's wear. Try fitting a part-worn chain and see if it improves. 11T sprockets don't last long with a badly worn chain as the load is over so few teeth. Your freewheel is a brand I've never heard of and may be poorly toleranced, leading to the problem.

[chrisclaydon48]

I have inspected everything and found the smallest sprocket is not allowing the chain to full engage as the side plates on the chain are rubbing on the spacer between sprockets also some of the teeth on the sprockets are in poor condition , this has only done miles so it will be going back hopefully that will solve the problem . See photo attached

[cycle tramp]

I have inspected everything and found ....also some of the teeth on the sprockets are in poor condition , this has only done miles so it will be going back hopefully that will solve the problem . See photo attached Sprocket.jpg

When checking the condition of teeth on freewheels, bare in mind that some of the teeth may be shaped differently to aid gear shifting -
I think those teeth in the photo may have been designed to look like that, the give away sign are the little ramps underneath those teeth.

[chrisclaydon48]

Thanks for that I had noticed the ramps and had wondered about them, but the wear marks on the spacer between the sprockets where definitely not there when it was new, and the chain is running on the side plates not on the rollers on the smallest sprocket.
I am being sent a new freewheel hopefully the will solve the issue.

[colin54]

Did you re-adjust the high (h) and low (l) gear limit screws when you fitted the new Freewheel/Derailleur, possibly the chain is not quite making it down onto the smallest cog correctly ? If you haven't already, do an adjustment set-up from scratch when you get the new freewheel, you particularly don't want the chain going over the top into the wheel due to an incorrect low (l) screw setting . From your description it sound to me like the chain outer plates may be sitting on top of the smallest cog and just need the h screw letting out a bit.
There are plenty of youtube videos describing this procedure , apologies if you are already aware and have tried this.
https://www.youtube.com/watch?v=OV1AVcdNjMM
One by RJ the bike guy.
Or study this article on Sheldon Brown's site, if you haven't read it already.
https://www.sheldonbrown.com/derailer-adjustment.html
Good Luck.

[Slowtwitch]

Worn sprockets. Pound on it

[cycle tramp]

Worn sprockets. Pound on it

Having had a look at the photo again, I see your pound and raise you ten I can't see anything in the photo attached that indicates the sprockets are worn, just that there appears to be some indentation to the spacer of the smallest sprocket.

[Steve O'C]

I can't see anything in the photo attached that indicates the sprockets are worn,

This looks odd to me. but not sure how that could have happened in 150 miles.

Capture.PNG (226.68 KiB) Viewed 607 times

[Steve O'C]

Oops, I take it back. Just found a picture of a new one online
Presumably shaped like that to help shifting up.

Capture.PNG (140.22 KiB) Viewed 600 times

[cycle tramp]

Oops, I take it back. Just found a picture of a new one online
Presumably shaped like that to help shifting up.
Capture.PNG

Yes, I've got the same sort of shark tooth on my freewheel which starts with a 13 tooth cog - whilst it may help gearing shifting, it does nothing for the service life of the freewheel. This a is a photo of a freewheel from the 1980's

As you can see the teeth are fuller with no ramps. The service life for this freewheel is going to be miles longer than the one i'm currently using. However shifting would have been a bit more clunky- which would have been an issue for today's gear shifters, but back then shifting would have been operated by friction shifters which would have been able to cope with the task.

[chrisclaydon48]

Today I fitted new freewheel and went for 15 mile ride mainly of road with no issues, so for mee that confirms that the issue was with the freewheel.
I found the article recommended by colin54 on Sheldon Brown's site very informative.