I am just getting into working on my own bikes and recently moved the 10 speed cassette from one wheel to another which got be to thinking. It appears to me that most of my wear is in the middle of cassette where the rings are individual and it seems such a waste to through the perfectly good rings away. So, my question is can I rebuild my cassette by buying individual rings? If so, where can I buy the rings? Finally, is there a tool that I can use to measure the wear on the cassette rings so I know which ones to replace?

This was so much easier to do back about 40 years ago , it was the way we kept freewheels going . Today it not so easy , because single cogs are not sold to do so . The best you can do is get another cassette with the cogs you want or need that are not wore as other are . As with most people yes the middle ones are the use one . Other than that yes I do agree with you it is a waste . If anybody have any for sale these guy do , Loose Screws Bicycle Small Parts Hard to find bicycle parts, made easy! For both the classic and modern cyclist. .

In the past and when freewheels were universal what you propose was easy. Every bike shop had "cog boards" with every cog available from Sun Tour or Shimano or Campy or all three. You could mix and match to replace worn cogs or alter the gearing to meet your needs. However, the individual cogs were fairly expensive and replacing more than one or two approached the cost of buying a new complete freewheel.

Modern cassettes generally don't make this possible. First, many cassettes have groups of two or three cogs mounted permanently on a "spider" so they have to be used (or replaced) as a unit. Second, modern cogs have shifting ramps and shaped teeth that have to be aligned properly relative to each other to shift well so you can't just buy a cog and add it to the mix and keep the performance. So, individual replacement cogs are no longer available except by buying more than one cassette and doing a mix-and-match where they fit.

They're out there you have to look around.

https://www.universalcycles.com/shop...53&category=40

They have part numbers so I suspect they can be ordered.

file:///home/chronos/u-71c0988f1649b1a49d367c58f9d512f2c860aba7/Downloads/EV-CS-6700-2924B.pdf

yes, hyperglide cogs are sold individually, some tooth counts are more widely available than others. but if you are satisfied with 7-8 speed cogs the simplest and most economical thing to do is buy a couple of shimano's least expensive cassettes (sometimes less than 15 dollars, and they often are designed without multiple cogs combined on a spider) and break them apart. i've now got a box of them, and the spacers, and if i want a custom cassette of any kind, whether it be three, four, five, six, seven or eight cogs and tooth counta, i just build one up.

Yes, but very few sizes and types are available through the source you linked to and the individual cog costs will make buying a complete cassette an attractive alternative pretty quick.

It's possible to buy some loose cogs if one or two are bad. But any more than that and you might as well replace the whole cassette. An alternative solution is to change your chain sooner so you don't ruin your cassette.

I do this too. I especially like taking off the last cog and adding one to the back. For example, transforming a 12-26 cassette into a 13-30.

Just now predominantly, most of the cogs of cassettes, are all combined in a subassembly, there are no screws to remove to make loose cogs.

that was back in the 8 speed era.

Shimano's 105 and Campy's Veloce 10-speed cassettes are all loose cogs and spacers with no subassemblies or groups. They are possibilities for customizing if you can find the desired replacement cogs or are willing to mix-and-match between two cassettes.

+1. And most new cassettes are reasonably priced. So I don't think I would look too far into rebuilding even if the cassette could be disassembled and the cogs were available.

Miche makes individual cogs for 8/9/10 speed cassettes, Universal Cycles sells 'em:
https://www.universalcycles.com/shop...&category=1569
https://www.universalcycles.com/shop...&category=1569
https://www.universalcycles.com/shop...&category=1569
https://www.universalcycles.com/shop...&category=1569
https://www.universalcycles.com/shop...&category=1569