[Stanceslao]

I can hear grinding and sometimes bike does not shift on my daughter's walmart bike. I figured out it was the loose sprocket. Now I am not sure if it is supposed to have play, or supposed to be tight, but I think it's the latter.

Can you please guide me which tool I need to tighten/remove the sprocket so I won't buy the wrong one. I have attached a picture and a video..
Thank you.

 

[sgltrak]

That is a freewheel and not a cassette. It likely needs to be replaced, in which case you would use a splined freewheel remover that fits Shimano freewheels. You might be able to tighten the outer bearing race on this freewheel using a pin tool.
Freewheel remover:

FR-1.3 Freewheel Remover — Shimano®, Etc.

Designed for the removal of most freewheels with a 12-spline tool fitting, including Shimano®, Sachs Aris®, SunRace®, and others.

www.parktool.com

Pin Tool:

SPA-2 Pin Spanner

Our classic pin spanner design, sized for retaining rings on self-extracting cranksets including Shimano®, Campagnolo®, SRAM®, and FSA®.

www.parktool.com

 

[Stanceslao]

That is a freewheel and not a cassette. It likely needs to be replaced, in which case you would use a splined freewheel remover that fits Shimano freewheels. You might be able to tighten the outer bearing race on this freewheel using a pin tool.
Freewheel remover:

FR-1.3 Freewheel Remover — Shimano®, Etc.

Designed for the removal of most freewheels with a 12-spline tool fitting, including Shimano®, Sachs Aris®, SunRace®, and others.

www.parktool.com

Pin Tool:

SPA-2 Pin Spanner

Our classic pin spanner design, sized for retaining rings on self-extracting cranksets including Shimano®, Campagnolo®, SRAM®, and FSA®.

www.parktool.com

Thanks, this bike is new, just bought it today... anyway, i am ordering the tools now. Thanks

 

[Taroroot]

Thanks, this bike is new, just bought it today... anyway, i am ordering the tools now. Thanks

If this brand new, the shop really should fix this. You could try fixing, but its really the shop’s obligation to fix it or replace the wheel witg a good one.

 

[wschruba]

That is a freewheel and not a cassette. It likely needs to be replaced, in which case you would use a splined freewheel remover that fits Shimano freewheels. You might be able to tighten the outer bearing race on this freewheel using a pin tool.
Freewheel remover:

FR-1.3 Freewheel Remover — Shimano®, Etc.

Designed for the removal of most freewheels with a 12-spline tool fitting, including Shimano®, Sachs Aris®, SunRace®, and others.

www.parktool.com

Pin Tool:

SPA-2 Pin Spanner

Our classic pin spanner design, sized for retaining rings on self-extracting cranksets including Shimano®, Campagnolo®, SRAM®, and FSA®.

www.parktool.com

At the risk of making a blanket statement, the bearing race probably isn't loose. Cheap freewheels have a ton of internal clearance; if one was inclined, and had access to either an identical new freewheel/an equivalent model (same size bearing cone/core), you could harvest the shims for adjusting the preload on the assembly, and drop one or two into the mounted freewheel. This would reduce/remove the rocking of the freewheel--though they all do rock to some degree, unless they are old, adjustable Suntour models/you have access to shim stock to get it perfect.


The bearing race (the bit with the pin holes in it) is a left-hand [reverse] thread, by the way... It unscrews to the right. Without a freewheel vise, you are better served by leaving the freewheel mounted on the wheel, but again, unless you have shims on hand/donor freewheel to get them from, just throw the pin spanner on the cone, tighten it, and let it ride for now. A whole new freewheel unit from Shimano is a whopping $14-15, so it's not worth driving into unless you have a desire to do it.

 

[Stanceslao]

If this brand new, the shop really should fix this. You could try fixing, but its really the shop’s obligation to fix it or replace the wheel witg a good one.

This is a walmart bike, they don't replace parts. I am willing to work on it.

=====================

At the risk of making a blanket statement, the bearing race probably isn't loose. Cheap freewheels have a ton of internal clearance; if one was inclined, and had access to either an identical new freewheel/an equivalent model (same size bearing cone/core), you could harvest the shims for adjusting the preload on the assembly, and drop one or two into the mounted freewheel. This would reduce/remove the rocking of the freewheel--though they all do rock to some degree, unless they are old, adjustable Suntour models/you have access to shim stock to get it perfect.


The bearing race (the bit with the pin holes in it) is a left-hand [reverse] thread, by the way... It unscrews to the right. Without a freewheel vise, you are better served by leaving the freewheel mounted on the wheel, but again, unless you have shims on hand/donor freewheel to get them from, just throw the pin spanner on the cone, tighten it, and let it ride for now. A whole new freewheel unit from Shimano is a whopping $14-15, so it's not worth driving into unless you have a desire to do it.

Thanks for the info.. also can you point me in the right direction, I am looking at amazon and not sure what freewheel to buy. I might just order one, in case I bust this one on the bike while trying to fix it .

 

[wschruba]

The TZ510 is the current model--works fine. You'll want to replace it with the same gear range, 7 speed, 14-28 teeth.

 

[CrozCountry]

This is one of those cases where a real bike shop can really help. Replacing a freewheel on a new bike is cheap and quick and should cost little. Just make sure you get a shimano replacement or something else, no amazon junk.

 

[Stanceslao]

Oh well, that didn't take long, I managed to remove the race with a hammer and a nail, then it looks like there is an extra bearing... then I tried lifting the whole thing... lots of bearings fell form the other side LOL.. looks like I have a looong night...

 

[Sparticus]

The plot thickens...

 

[Stanceslao]

Inner side done.... wish me luck..

 

[Stanceslao]

Hi guys, everything is back, same slack, and same sound... can you please listen and tell me what could be causing the sound, and I swear I have properly indexed it. When i stop pedaling, the sound disappears.

 

[Grinchy8]

Tire rubbing on the kickstand?

 

[Stanceslao]

Tire rubbing on the kickstand?

I thought so too, but it isn't.

 

[wschruba]

I hear nothing but a slight 'shushing' sound. There are two broad causes for that: chordal action (happens when a tensioned drive system momentarily goes through an oscillation of high/low tension. Typically happens in the highest gear, and usually not with stuff bigger than 11 teeth; it is most prevalent at high power/low cadence), or something rubbing.

Assuming #2 is not happening (and frankly, there's so much going on in the drive line of a bicycle that it's difficult to diagnose in a video), the fact that the sound stops when you stop pedalling seems to point to #1. Does it make the sound when you shift to an easier gear?

Typically, when rebuilding a freewheel, you would fill the race, and remove 1-2 bearings. Having the race completely filled doesn't do much when you have that many bearings, and doubly so when you consider that a freewheel's bearings don't actually carry any load. If you'll note in your first picture of the opened freewheel, there is an area just under the threaded area of the core where the cone screws on. There are a number (typically 0-3) thin metal shims on the ledge, which provide internal clearance for the freewheel. You can attempt to remove one or more of the shims, but my experience with modern (cheap) freewheels says that the freewheel will probably bind. You can try it out, though.

 

[Stanceslao]

I hear nothing but a slight 'shushing' sound. There are two broad causes for that: chordal action (happens when a tensioned drive system momentarily goes through an oscillation of high/low tension. Typically happens in the highest gear, and usually not with stuff bigger than 11 teeth; it is most prevalent at high power/low cadence), or something rubbing.

Assuming #2 is not happening (and frankly, there's so much going on in the drive line of a bicycle that it's difficult to diagnose in a video), the fact that the sound stops when you stop pedalling seems to point to #1. Does it make the sound when you shift to an easier gear?

Typically, when rebuilding a freewheel, you would fill the race, and remove 1-2 bearings. Having the race completely filled doesn't do much when you have that many bearings, and doubly so when you consider that a freewheel's bearings don't actually carry any load. If you'll note in your first picture of the opened freewheel, there is an area just under the threaded area of the core where the cone screws on. There are a number (typically 0-3) thin metal shims on the ledge, which provide internal clearance for the freewheel. You can attempt to remove one or more of the shims, but my experience with modern (cheap) freewheels says that the freewheel will probably bind. You can try it out, though.

Thanks for the feedback. I can hear the shushing sound you mention, but the tiktok sound is louder, especially on the latter half part of the video. The sound is either present on all gears, or sometimes disappears. There are 5 shims and a wave washer that I counted.

I went to a local bike shop this afternoon to see if they have the suggested TZ510 above, but they only had the older model TZ500 6 speed instead of 7, and I tried to feel if it was loose as with mine above, but no, it was tight and there was no "play".

I am waiting for a sprocket from amazon, hopefully will be here tomorrow so I can try it on and see if the problem goes away.

 

[Stanceslao]

Update:

While waiting for my deliveries, I tinkered with the bike and removed a few shims as suggested by wschruba above. Removed 3 shims in total, just enough so there is no slack and it doesn't bind...now the bike shifts smooth and no tiktok/knocking sound.... seems I didn't need the new sprocket, but I will keep it in case.

Thank you all for your input and suggestions !!!