Eco-friendly Cassette reusability?

[BikeGremlin]

I got this question via email:

I used to ride 30 km. to work, each way, 5 sometimes 6 days a week.
With that much riding I decided it would be more economical to buy tools and do my own work.
One thing bothered me. My riding style meant 90% of the time I would use the 4 high gears on my cassette. Despite this, I had to replace the entire cassette.
What if someone, maybe me, had the idea to custom build cassettes so that half the time only the 4 high gears (less teeth) could be replaced.
This would lower the "carbon footprint" of cassette replacement. The custom cassettes would allow for the gears to slide into slots, one on top of another; much like the highest gear (11 teeth) slides onto the freehub before 40 Nm fixes the cassette to the freehub.
Please let me know if this is a good idea as I think it would save money on cassette replacement as well as cut down on waste (carbon footprint.)

 

[BikeGremlin]

Hi,

A good question.

Many modern cassettes come with a spider that holds the largest few sprockets in place. However, there are still models with whole sprockets separated by spacers, that can be disassembled. Decades ago, cassettes were held together with hex (allen) bolts so you could easily disassemble them. Nowadays, they are held by rivets that you need to file/drill and punch out. This is how to do it (the video is in my native, Serbocroatian, but the entire procedure is shown):

Again, decades ago, cassettes had symmetrical mounts. Those were called Shimano "Uniglide" cassettes. They allowed you to flip any sprocket once it is worn, and get a practically new sprocket (doubling its lifetime). Later, Shimano found a way to "improve" shifting by making sure the sprockets are always mounted only one way. That also means you can no longer make the sprockets last double their lifetime. This is a hack that still lets you do that:

Relja

P.S.
Please use the forum for any questions.