Cassette Replacement, Or You Can Teach An Old Dog New Tricks :)

[Stefan Mikes]

When I was replacing the chain in my 2017 Vado 5.0 when the chain got stretched past the 0.5% mark, I could enjoy the cassette for a pretty long time. When I was forgetting to replace the chain for, say, 3200 km (2000 miles), typically the four smallest sprockets on the Shimano CS-M7000-11 (11-46T) cassette were getting worn and needed replacement, which was always done by my brother Jacek.

Following the severe breakdown of my Vado that resulted in the warranty rebuild of the Vado 5.0 to the current Vado 6.0, I lost the count of kilometres ridden on the two incarnations of that e-bike. As the outcome, as many as five smallest sprockets on the cassette wore out. I thought to myself you needed to replace the entire cassette once in a while With the new cassette in my hands, I discovered both my brother and the local bike mechanic had no time to do the cassette swap for me fast. So I pedalled my Vado SL to a good bicycle store in Warsaw and bought a cassette wrench and the cassette whip (at last having these tools in my collection!)

First of all, I had to watch a Park Tool video on YouTube to understand how you actually apply the whip to the cassette sprocket!

Removing the old cassette from the freehub body was actually very easy...

Yes, yes, I know the old cassette was not only worn but also dirty That cassette has survived since August 2020, only the 4 smallest sprockets were replaced three times (I think).

Now, I had to learn new tricks. I could observe how my brother was working on the old cassette in the past, so I knew it consisted of four big sprockets pinned together, and a big number of smaller cogs, and importantly, the spacers. What made me very surprised was the new cassette set was bound with a plastic "hub" for transportation purposes. Once I removed the "hub" from the sprocket cluster, I naively thought I could just slide the whole assembly onto the freehub body! Oh no no no no! The way you are putting the sprockets and spacers onto the freehub body is a highly organized procedure. I had to dismantle the cassette, putting each sprocket and related spacer aside in the proper orientation and order. Then I started re-assembling the cassette on the freehub body.

When the process was done, I placed the lockring in the socket, did several turns with my fingers to secure it, and then applied the newly bought cassette wrench. Rattle! and the thing was done! I have never thought the cassette replacement could be that easy! Ya, but I knew I should be very careful during the process.

Now, I start thinking to replace the chainring (the chain itself is brand new). Should I replace the chainring after 7500 km ridden?

 

[TrevorB]

I work on replacing first chain about 3000km ie 0.75 stretch and maybe one or two of small cogs on cassette. Run 2nd chain and complete drivetrain into ground until it gives trouble ie >4000kms. Then replace everything, cassette, chain, chainring, idlers.
If you spend lot of time on flat in small cogs could wait until 3rd chain before running it into ground.

 

[bobf]

Barging in with some comments after the fact. Feel free to ignore me!

The recommended tightening torque on the lock ring is usually pretty high, 40 NM or so. Can you tell if you got near to that? I have a beam-style torque wrench for that purpose. Looks like the head of your cassette wrench has a square cutout that could engage with one.

Not sure if it matters, but during tightening I use the chain whip to hold the cassette so that I don't strain the freehub mechanism.

People claim you can check for worn cogs or chainwheel by seeing whether a new chain sets into the teeth properly. I haven't tried it enough to say whether it works.

 

[Stefan Mikes]

The recommended tightening torque on the lock ring is usually pretty high, 40 NM or so. Can you tell if you got near to that? I have a beam-style torque wrench for that purpose. Looks like the head of your cassette wrench has a square cutout that could engage with one.

I watched the Park Tool video prior to the cassette replacement, and used these tools:

The handle length of the cassette wrench is designed as to deliver the proper amount of torque for an average person. The indication of the cassette properly tightened is the noise from the serrations on the lockring and the first cog. Once you have heard that and the wrench handle stops moving, the cassette has been properly tightened.

Not sure if it matters, but during tightening I use the chain whip to hold the cassette so that I don't strain the freehub mechanism.

The Park Tool video specifically instructs you not to use the whip during the cassette tightening. During the normal e-bike operation, the chain acts on the cassette with torque of (say) 35 to 90 Nm (depending on the motor), and the freehub mechanism is designed to handle that stress.

People claim you can check for worn cogs or chainwheel by seeing whether a new chain sets into the teeth properly. I haven't tried it enough to say whether it works.

Cannot say for the other people but for me the indication of worn cassette cogs post the chain removal is the chain skipping on the cog while riding. Last time, it was pertaining to as many as five sprockets!

 

[fooferdoggie]

The recommended tightening torque on the lock ring is usually pretty high, 40 NM or so. Can you tell if you got near to that? I have a beam-style torque wrench for that purpose. Looks like the head of your cassette wrench has a square cutout that could engage with one.

Not sure if it matters, but during tightening I use the chain whip to hold the cassette so that I don't strain the freehub mechanism.

40nm is not much at all when your talking what the thing takes while peddling. on a really good day I can put out 700 thats about 80-nm then add in what my mid drive is adding it maxes out at 85nm.