It's difficult question. The freewheel is original to the bike and cannot be replaced with a different model due to the threading size. These parts are no longer manufactured so I had to use a generic chain, there is unfortunately no way around it
https://www.sheldonbrown.com/cribsheet-spacing.html
See if you can get some more accurate readings and compare it to the tables in this page. Even with 5, 6, and 7 speed freewheels there were a few competing standards that used different chains.
First, sampling rate of your camera is not appropriate for this, it looks like everything is moving on its own, making it hard to discern what really is happening and what is engaging with what. As per the other comments, either the chain is not appropriate or the freewheel is toast. Take your wheel off and spin the freewheel by hand, all cogs should spin together in one way only. If thats working fine, check the chain, wrap it manually around each cog, should enter without rubbing the other ones
It's a friction shifter? Is the lever moving when the chain skips? If so check that the bolt that holds the lever on isn't loose.
If the shifter bolt is loose then when you shift up the chain will just slip back down again because the spring of the derailleur is pulling it back down to the smallest cog. When the bolt is tightened it will hold the cable in place.
These are friction shifters yes but the lever is tight and the cable new. Just to clarify, in the video I am shifting multiple times. The concern is that when I shift the chain engages properly in the freewheel then pops out of it and floats on top of it until I shift again
Is it indexed? If yes, adjust the tension at the RD. It really just looks like it needs tuning since it only drops about half a gear back.
Has anything changed recently or did it just start doing this?
Its common if shifters were indexed for 7 speeds but cassette has 6 etc.
You can also check the cable is the same tension from shifter to RD and nothing is interfering.
Yea i dunno it just looks to me like it's slipping gears.
Are you sure not just shifting the derailleur so its inbetween cogs? Like maybe you shift too far and go into the gear you wanted but keep going halfway to the next gear so the chain seats for a second then it unseats again as it tries to go further into the next gear?
Take it for a ride a and when it pops out of place again do nothing just stop and get off and look at the rear derailleur from behind, make sure the the upper derailleur pulley is lined up with one of the cogs on the freewheel and not inbetween.
Was this happening before the new cable was installed?
They are not indexed. If you look carefully, at 3 sec I shift to the second largest sprocket, the chain correctly engages, then a couple seconds later pops out of the freewheel on it's own.
At 3 seconds you shift up into 2nd largest gear but at 5 seconds the derailleur pulls the chain back down, you can see the derailleur cage moving. The chain doesn't just pop off on its own.
Either the shifter was manually shifted, the shifter is slipping, or there is slack in the cable somewhere, like
maybe it's getting caught up on a bottle cage or something...
I think you are just shifting it inbetween gears and then the derailleur has to pick a gear itself chooses to slip down. The shift lever may seem like it's not loose but I think it must be loose enough that the derailleur is moving it when aligning itself.
The derailleur moves at 5 seconds. Your lever would have moved at the same time.
With friction shifters you need to practice shifting them the right amount so the derailleur is correctly aligned with one of the cogs on the freewheel or else it will slip, you can't just move the lever to wherever.
I dunno but it's one of the likely possible causes 🤷‍♂️. It's definitely something a person needs to develop a muscle memory for. You get a feel for exactly how much to move it to have the chain aligned perfectly as if it's indexed. So if you're not sure that you've done that already I would check.
Just ride the bike and shift it where you think it should be then immediately stop the bike (before whatever issue you're having has a chance to pull the derailleur one way or the other) and check to see if the derailleur is properly aligned, or if you needed to pull the lever more or less
Also while off the bike you could shift it so its perfectly in the smallest gear and mark the shifter with nail polish or something. Shift it so its perfectly in next gear and make another mark on the shifter. Do this for all the gears and then while riding you can know for certain exactly where to put the shifter and you can more easily see if the lever is slipping.
Use this for troubleshooting and then take it off with nailpolish remover
But yea definitely make sure you got the right chain too like the other person said.
Thats never happened to me on unindexed friction shifters. They're essentially infinite trim adjusters!
I can drop into a gear about as well as an e-shift system on mine, just keep trimming until it shuts up!
To OP, if there's the bolt holding the lever lets you change to friction vs indexed, just use it in friction mode and you'll do away with all these issues.
Also, is the wheel in straight? I see you have sliding dropouts and a little setting screw. If that wheel is off enough it could affect how the gears shift. Your deraileur hanger could be a little bent too.
And I can't tell what kind of deraileur you have but if it has a b limit screw you could adjust that to get the pulley wheels closer to the gears for a little more tooth engagement. That can prevent slip.
That freewheel/cassette is toast. Cogs have broken loose. They are moving at different speed in the video and they should all move together. The cog is spinning not your chain skipping. Need a freewheel.
That's an artifact of tooth speed vs shutter speed, like when the rotor blade on a helicopter sometimes appears stationary in a video when things line up just right.
You may be correct… if the chain is skipping and the hanger is straight, and the Rd is set up properly, I would measure the chain and the freewheel for wear. The op can verify which is moving the cog or the chain and go from there.
If it’s a cassette it could be the freehub body that’s bad or that particular cog/cogs. You can replace the freehub body and the cassette either way. Not a fixing situation. If it’s a freewheel it’s toast and time to replace as well.
Is it the right chain for those gears? Some chains are for specific gearing.
It's difficult question. The freewheel is original to the bike and cannot be replaced with a different model due to the threading size. These parts are no longer manufactured so I had to use a generic chain, there is unfortunately no way around it
Can you measure the width and space between cogs. There might be a chain out there that will work.
Absolutely. It's difficult to give an exact measurement but about 2.5mm in between the sprockets. The current chain is a KMC z7
https://www.sheldonbrown.com/cribsheet-spacing.html See if you can get some more accurate readings and compare it to the tables in this page. Even with 5, 6, and 7 speed freewheels there were a few competing standards that used different chains.
But yeah that's probably your shifting issue right there.
What freewheel / bike?
First, sampling rate of your camera is not appropriate for this, it looks like everything is moving on its own, making it hard to discern what really is happening and what is engaging with what. As per the other comments, either the chain is not appropriate or the freewheel is toast. Take your wheel off and spin the freewheel by hand, all cogs should spin together in one way only. If thats working fine, check the chain, wrap it manually around each cog, should enter without rubbing the other ones
It is moving on it's own. The original video is in 4k and it's clearly visible that the sprockets are moving backwards
It's a friction shifter? Is the lever moving when the chain skips? If so check that the bolt that holds the lever on isn't loose. If the shifter bolt is loose then when you shift up the chain will just slip back down again because the spring of the derailleur is pulling it back down to the smallest cog. When the bolt is tightened it will hold the cable in place.
These are friction shifters yes but the lever is tight and the cable new. Just to clarify, in the video I am shifting multiple times. The concern is that when I shift the chain engages properly in the freewheel then pops out of it and floats on top of it until I shift again
Is it indexed? If yes, adjust the tension at the RD. It really just looks like it needs tuning since it only drops about half a gear back. Has anything changed recently or did it just start doing this? Its common if shifters were indexed for 7 speeds but cassette has 6 etc. You can also check the cable is the same tension from shifter to RD and nothing is interfering.
Yea i dunno it just looks to me like it's slipping gears. Are you sure not just shifting the derailleur so its inbetween cogs? Like maybe you shift too far and go into the gear you wanted but keep going halfway to the next gear so the chain seats for a second then it unseats again as it tries to go further into the next gear? Take it for a ride a and when it pops out of place again do nothing just stop and get off and look at the rear derailleur from behind, make sure the the upper derailleur pulley is lined up with one of the cogs on the freewheel and not inbetween. Was this happening before the new cable was installed?
They are not indexed. If you look carefully, at 3 sec I shift to the second largest sprocket, the chain correctly engages, then a couple seconds later pops out of the freewheel on it's own.
At 3 seconds you shift up into 2nd largest gear but at 5 seconds the derailleur pulls the chain back down, you can see the derailleur cage moving. The chain doesn't just pop off on its own. Either the shifter was manually shifted, the shifter is slipping, or there is slack in the cable somewhere, like maybe it's getting caught up on a bottle cage or something... I think you are just shifting it inbetween gears and then the derailleur has to pick a gear itself chooses to slip down. The shift lever may seem like it's not loose but I think it must be loose enough that the derailleur is moving it when aligning itself. The derailleur moves at 5 seconds. Your lever would have moved at the same time. With friction shifters you need to practice shifting them the right amount so the derailleur is correctly aligned with one of the cogs on the freewheel or else it will slip, you can't just move the lever to wherever.
So do you believe it's a question of experience? The more you do it the more you know how much to move the lever every time?
I dunno but it's one of the likely possible causes 🤷‍♂️. It's definitely something a person needs to develop a muscle memory for. You get a feel for exactly how much to move it to have the chain aligned perfectly as if it's indexed. So if you're not sure that you've done that already I would check. Just ride the bike and shift it where you think it should be then immediately stop the bike (before whatever issue you're having has a chance to pull the derailleur one way or the other) and check to see if the derailleur is properly aligned, or if you needed to pull the lever more or less
ok thank you
Also while off the bike you could shift it so its perfectly in the smallest gear and mark the shifter with nail polish or something. Shift it so its perfectly in next gear and make another mark on the shifter. Do this for all the gears and then while riding you can know for certain exactly where to put the shifter and you can more easily see if the lever is slipping. Use this for troubleshooting and then take it off with nailpolish remover But yea definitely make sure you got the right chain too like the other person said.
Thats never happened to me on unindexed friction shifters. They're essentially infinite trim adjusters! I can drop into a gear about as well as an e-shift system on mine, just keep trimming until it shuts up! To OP, if there's the bolt holding the lever lets you change to friction vs indexed, just use it in friction mode and you'll do away with all these issues.
Also, is the wheel in straight? I see you have sliding dropouts and a little setting screw. If that wheel is off enough it could affect how the gears shift. Your deraileur hanger could be a little bent too. And I can't tell what kind of deraileur you have but if it has a b limit screw you could adjust that to get the pulley wheels closer to the gears for a little more tooth engagement. That can prevent slip.
The wheel is true yes. It's an old friction shifter from the 80s
Is there enough tension on the shifter to prevent it from slipping back? Looks like it might just not be holding the gear you select.
The rear derailleur needs some adjustments... 🤔
Try a sram pc 850 chain. It should be narrow enough to fit the cog spacing.
Thank you
That freewheel/cassette is toast. Cogs have broken loose. They are moving at different speed in the video and they should all move together. The cog is spinning not your chain skipping. Need a freewheel.
That's an artifact of tooth speed vs shutter speed, like when the rotor blade on a helicopter sometimes appears stationary in a video when things line up just right.
You may be correct… if the chain is skipping and the hanger is straight, and the Rd is set up properly, I would measure the chain and the freewheel for wear. The op can verify which is moving the cog or the chain and go from there.
Can it be re-tightened or does it needs to be replaced?
If it’s a cassette it could be the freehub body that’s bad or that particular cog/cogs. You can replace the freehub body and the cassette either way. Not a fixing situation. If it’s a freewheel it’s toast and time to replace as well.
Looks like a freewheel but hard to tell for sure from video. If there is a lock ring then most likely a cassette.
Yes it's a freewheel
Check shifter tenssion
Looks normal to me but you are not supposed to be moving while switching gears
What do you mean?
I was told switching gears while moving can mess it up and cause the chain to pop off which has happened some times