How do the following Shimano 8-speed cassettes differ?
Ignore differences in appearance.
CS-HG31, CS-HG41, CS-HG51They are phosphate coated, nickel plated & chrome plated respectively.

Which one lasts longer? More rust resistant? Less wear on chain?
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Added
I don't care about appearance, so it is not a factor. Same goes for weight.Available gear ratios are fine.That leaves durability, rust resistance & chain wear. Unless you can think of other factors.
Please do not derail the thread.

Why ignore differences in appearance? I think that's probably the main thing other than possibly weight if you are a weight weenie. Along with the possibility they don't offer some gear combos or ranges in all of them.

Likely they'll all wear about the same. If there are weight differences, then that'll be difference in material used. Lighter usually being the higher tier product. .

All of that is going to depend on factors unique to you.

+1

Differences are more about weight and cosmetics, rather than wear.

Ironically, more expensive cassettes often have shorter lives owing to lighter (softer) materials used.

As for rust resistance, the plating or other surface treatment effectively resists rust except for wear zones which expose the base metal, Here they act like railroad tracks which don't rust al long they are used regularly. So, you'll be good with any of the options as long as you don't leave the bike sitting out in the rain unused.

In prior generations, lower end had clusters were riveted together and others had long allen screws. Don't know if this has changed.

Cassettes on bikes that are used often as long as the chains are well lubricated almost never rust. The lube from the chain coats the cogs of the cassette inhibiting rust. Apart from that, more expensive cassettes may use various dodges to reduce weight, things like alloy carriers with several cassette cogs riveted to them, titanium cogs for the larger sizes, even aluminum alloy cogs for the biggest sizes. Usually, cassettes are designed to last on average about the same time. Lightweight components cost a whole lot more, but they have a reasonable lifespan compared to less expensive heavier components. Nobody would spend twice or 3 times as much for something that wears out in half the time

I use a dry lube, so I generally buy nickel plated cassettes. I like the look and they are easy to clean; personal preference.

I would think that a true chrome plated, or hard chrome plated, cassette might be better, but I'm not sure if that chrome plating is much different than the nickel ones I buy. I tend to stay away from the black cassettes, but if I used a wet lube, I'd probably go that route. Why buy silver when it will be black in a few hundred miles.

I don't think there is enough of a difference in durability or corrosion resistance between them to matter.

John

Cassettes cogs are either steel or Ti, not aluminum alloy. Aluminum alloy would wear out super quickly against a steel chain. The vast majority of cassette cogs are steel. Dura-Ace cassette cogs are Ti and yes, they cost twice as much and wear out in half the time. Personally I think it's pretty silly to buy a DA cassette to save a minuscule amount of weight, but there are plenty of people who think it's worth it.

You are correct, but there have been cassette/ freewheel cogs that have used aluminum alloy big cogs to save weight. The larger the big cog the slower it wears out considering how seldom it is used. Aluminum alloy cassette/ cogs have often been used over the years

Not all steel is the same. Likewise with other alloys.

I haven't been super impressed with Shimano cassette longevity. But, I don't know the solution either.

SRAM RED is supposed to make tough cassettes. But, they aren't available in 8-speed. And they are MUCH MORE EXPENSIVE than the cassettes you have listed above.

As far as the choice between CS-HG31, CS-HG41, CS-HG51. I'd tend towards the higher end, but overall I'd choose the cassette by price, availability and gearing.

Exactly!

CS-HG31 - Black, $17: Shimano Altus CS-HG31 Cassette (Black) (8 Speed) (Shimano/SRAM) (11-30T) - Performance Bicycle (performancebike.com)
CS-HG41 - Matte grey, $23: Shimano CS-HG41 Cassette (Silver) (8 Speed) (Shimano/SRAM) (11-30T) - Performance Bicycle (performancebike.com)
CS-HG51 - Silver, $22: Shimano Alivio CS-HG51 Cassette (Silver) (8 Speed) (Shimano/SRAM) (11-28T) - Performance Bicycle (performancebike.com)

For a $6 difference I would not worry about anything else other than gearing and color. I doubt anyone who rides an 8 speed cassette is a weight weenie, at least not with respect to the bike that cassette is on.

This is one solution: Prestacycle UniBlock Cassette | 11-Speed Shimano / SRAM /Campagnolo for HG 11 Freehub - Prestacycle

But only affordable compared to Dura-Ace.

There are still cassettes made today that use alloy large cogs:

https://www.microshift.com/models/cs-h113-11-46t/

https://www.jensonusa.com/Sunrace-CS...Speed-Cassette

For that price, I wouldn't worry about it wearing out, LOL! Compare any of these with an 11-speed cassette.

Well, for the first time since the COVID endemic began, 11-speed Ultegra cassettes are now < $70.

Well, OK. A 50T cog will take longer to wear out, but not just because it is seldom used. It makes sense that a 50T cog might be alloy for the same reason a 50T large ring would be. The more teeth on a gear, the more the load is spread out vs. say the 11T cog on a cassette.

I doubt you will find a road cassette with an alloy large cog.

Miche makes them for Shimano and Campagnolo, and I'm looking at the 30-tooth alu cog right now. This cog is very slick and very light. All things being equal, a 30 tooth cog should wear at 1/3 the rate of a 10.

If you replace your chains at no more than 0.75%, or 3-4 chains for every cassette, the alu cogs should last a long time.

That one is listed as Chromoly. That would be either 4130 or 4140 steel. It should be a solid alloy, but it isn't as hard as can be. I'd hope most cassettes would be a version of chromoly, but I rarely see it specified, so perhaps not.

The SRAM Red
https://www.sram.com/en/sram/models/cs-xg-1190-a2

Is listed as being made out of heat-treated high grade tool steel. I don't see it listed on the 12 speed, but I assume it is similar. That is a big class of metals, but it has about twice the carbon content of the chromoly, and would be what would be used to cut chromoly. Heat treating is critical with a fine line between toughness and brittleness.

Ahem:

https://www.ebay.com/itm/403097074486

https://www.cycletaiwan.com/oarsm-ha...ette-road.html

Not something I'd be interested in buying. But they do seem to exist.

Thanks guys.
I don't care about appearance, so it is not a factor. Same goes for weight.
Available gear ratios are fine.
That leaves durability, rust resistance & chain wear. Unless you can think of other factors.
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What can I say? A fool and their money are soon parted?

FWIW EDCO cassettes last a long time, are very reasonably light in their price class & won't bite into the freehub body...And given the proper lock ring you can run 11 speed road on the standard Shimano compatible 8,9,10 speed freehub. Potentially saving you the cost of a wheel build should you find yourself with 11 speed shifters, derailleurs but no budget for wheels. The upgrade path is a no-brainer.

The smaller the front chainring, the higher the chain tension is. Aluminum freehub bodies just don't stand much of a chance against the individual skinny cogs of modern cassettes. Especially against strong riders. If you can't have a Titanium or steel HG freehub body a monoblock cassette really is a smart way to go unless you have a ready supply of replacement freehubs kicking around.

Shimano's failure to bundle cogs on the smaller half of the cassette is reprehensible.

High end hubs cost many, many, hundreds of dollars. Why waste a perfectly good wheel build or expensive hub with a self destructive, poorly designed, failure causing cassette?

Cassettes of monoblock design from any manufacturer beat the poorly crafted, pizza cutter design of ShimaNO any time, anywhere. It's a shame most people just accept aluminum freehub bodies are disposable. They don't have to be.

To put it plainly: If you have a nice hub, why waste money on anything other than a monoblock?

That being said: You've got 8 speed. None of what I typed is relevant here. 8 speed hubs are held together with pins/rivets, etc...to spread the load evenly over a large area. You won't have freehub bite problems. Get what's most readily available & the range you like.

I like HG51 or HG50 11-28, it does not have 3t jump in the middle, only 2t. Remove 11 and 13, add a top position 13 and 34 in the end and you get a nice 8s touring cassette: 13-15-17-19-21-24-28-34.

Where are these Miche cogs available? Out-of-stock everywhere I checked.
Prefer steel though.

I have never been a fan of boutique hubs with alloy freehubs. The only hubs I have built wheels with are Shimano, White Industries and Bitex. Yes, Bitex hubs have an alloy freehub, however they have anti-bite splines. That being said, my preference are Shimano hubs as I don't like the noise level of the WI or Bitex freehubs. The trouble with Shimano is that if you want to build with a spoke count other than 32 or 36, you will have to go with Dura-Ace. Not to mention it doesn't appear Shimano makes any rim brake hubs anymore, so you have to look for new/old stock.

There are fully alloy cassettes out there. Very weight weenieish though
https://www.recon-harry.com.tw/products_detail/2/3/7