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Comment by dgacmu | Hacker News Reader

The gear advantage of a mid-drive rocks but I was quite surprised that I chewed through a rear cassette in under a year / about 1k miles -- a 250W motor + heavy cargo bike + kid passenger + a large and pretty strong rider exert an awful lot of force. And with the assist, I almost never use the larger cogs, so all the wear gets concentrated. (This compares to many, many thousand miles on my road bike.)

Still love the thing, though.

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Maintain your chain! I chewed through a nice cassette on my mtb quickly by not watching my chain and replacing it when worn. A worn chain will dramatically increase cassette wear. I only replaced it yearly and should have probably done twice per year.

Since then, I switched to hot waxing my chains and have now gone a year with the same chain reading as almost new. (Actually use 2 chains but both are barely worn)

There’s a great site called zero friction cycling that details all of this. The key that they opened my eyes to was looking at the total cost of riding including the cassette.

Would an internally geared hub solve for this type of wear?

IGH's are not all that rugged. Most have a published requirement for a minimum ratio between the chainring and cog, that translates into an approximate torque limit. I love my old Sturmey Archer AW hubs, but I'm not sure I'd recommend one for the aforementioned use case.

Shimano E5000 is an IGH rated for e bikes.

Seeing how as I regularly managed to break the drive cross in my 3-speed SA hub just by pushing the thing real hard under pedal power alone - this is 40 years ago - I don't think they're particularly strong. I fixed my bike by myself so all this cost me was a new drive cross but still, it shouldn't break in the first place.

I think material science minute might have advanced over 4 decades.

The cross is made of a fairly hard type of steel. They knew how to make that 40 years ago so I don't think there is any noticeable difference. If anything I suspect the older gear hubs were built stronger than the current ones.

I manage to ruin chain and cassette in under a year on my acoustic bike. The trick is to ride fast in all weather and never clean the chain.

Congratulations, your brief comment has managed to trigger me in 3 different ways.

Why would that surprise you? A semi serious mountain biker will go through a cassette on an analog bike in 2 years. You're driving the thing with a huge motor, cargo and an entire extra human. Your expectations must have been unrealistically high.

The difference between a mid-drive (in which all of the force goes through the rear cassette) and a rear hub drive (in which only the pedal force goes through the rear cassette) is large.

Also, most people online report over 2k miles on a cassette. Pittsburgh's hills and more force are apparently good for some extra wear.

(Also, a 250W motor is fairly small by e-bike standards. They generally start at 250 and go up from there; 750W is not uncommon.)

I have a friend in your same scenario. I’ve never thought to ask how quickly he goes through cassettes on that bike.

I think the follow-on post above about making sure to be better about maintaining the chain is part of it. I'm a little lazy with my road bike chain because I mostly only ride it in good weather, and I carried the same attitude to the e-bike, which gets a lot more stress per mile and I'm more likely to ride in rain.

I'm not hot waxing it, though it's tempting, but I do wipe it down and apply T-9 much more regularly now. We'll see -- I'm 400 miles into the new chain and cassette...

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