I've found for my riding an 11-17-28 "cassette" with 8-speed spacing works well with a 30 tooth front ring to keep my speed at 20 mph or so. The limited chain deflection (17 is "straight" so only shift one gear to either side) seems to wear well and the 8-speed components are cheap and strong. Can't wait for the new SRAM 8-speed chain since it's supposed to be stronger.
To answer your question (always forget about that), this system should wear well, but I have limited experience with Sunrace.
Within a few years the best system may be an IGH so the chain (or belt) can stay straight (Rolhoff-type, but not $1500 for the hub alone). Who knows, maybe a pinion geared motorized BB system; this may not be feasible, but I'm not an engineer so please be gentle.
This may be premature for Ebikers here in the US, most us just got our mid drive eMTB recently.
Time will tell, I also see a huge market for eMTB accessories (not hacks/mods), in a form of better clamps to reposition the computers. Or to simplify the Ebike cockpit. I like simplicity, my hats off to the Turbo Levo designers.
As power increases to 750w, the rational for this increases as well. IGH with Rolhoff being the gold standard are popular with the Kit guys if you have the budget. Others go with smaller freewheels (yes freewheels) with fewer cogs to reduce cross chaining. With more power, there's less need for the gear range we run on mtbs, since you're doing a lot less work. There's lots of discussions regarding drivetrain wear and durability on the ebike forums.
Thanks Harryman, I chose KMC because of their reputation and my personal experience with their products.
Their Ebike specific chain is not available here in the US yet. So hopefully the X10 (not the lightweight version) can hold up well to the 250watt motor and my current weight. Unfortunately Im not as light as I used to be. But Im finally working that too
On my hard tail fatbike with either the Nexus3 or the C-50, I use the KMC singlespeed ebike chain. I have well over 500 off-road miles with no wear according to Park Tool..... I'm using the Luna Mighty-Mini 30t chainwheel on this bike and steel 34t rear sprockets that I make from BMX chainwheels and so far only the alloy chainwheel is showing any wear.
RaceFace NW 32T Chainring, Shimano SLX rear mech, SunRace CSMS3 11-42T 10s Cassette, and KMC X10 Ti chain. It shifts really smooth, quiet and precise! Even under torque. Way better than the stock 2X drivetrain that came with my rig. We'll see how they hold up with long term use.
Getting a power link at "the perch", one of our busiest bike shops, I was talking with the guy about e bikes in general. They have sold at least 20 so far this year, which is pretty outstanding for a LBS in a town with not all that many people.
But the real lesson for me: all the chains in town are too short for my bike. So if you get a e-bike it may be worth it to order an extra right off the bat.
I broke mine in low gear (exceptionally low due to the 2x front) at low speed pretty steep. Now, the LBS guys say they have not seen any other broken e-bike chains, and they are renting the bikes like mad.
It may be bad maintenance tactics by me, as my emphasis has been more on cleaning than lubrication. I'm going to be more careful on that
My drivetrain problems started when I broke my rear deraillure on my recent ride. Since I still had a lot of miles to cover. I converted it to a single speed. Really expensive error on my part, single speed and full sus frames dont mix!
That chewed up my chain and cassette. Good thing the freehub was still OK.