Originally Posted by
Moisture
I have a Trek E bike with the Bosch mid motor system. Almost 2500km now.
So far all I've replaced mechanically was the rear cassette and chain.
You used up a cassette in 1553 miles? The only way to do that is by running a seriously worn chain. If you clean and lubricate your chain properly and measure chain wear as it is happening, replacing the chain as soon as it hits the first wear mark on the chain and well before you reach the second, your cassette should easily last for at least three changes of chains. This is a pretty big deal, when you consider how much cassettes for e-bikes cost. The Deore XT M8000 cassette on my e-bike is typically just over $100, while chains usually are about $40. I suggest you get yourself a good chain wear tool, like the Park CC3.2. It's around $12
Replace the chain when it reaches 0.5 (that is, when the 0.5 pin fits into the chain) and before it reaches 0.75 and you not only won't be replacing chains before it's necessary, you also will be able to reduce the number of cassettes you replace. Basically, this tool pays for itself the first time you use it.