TSDZ2 Chainline and Sacrificing Cogs

[XyloSesame]

I (finally) received everything I needed to bolt on the Tongsheng, but have a few questions related to gearing.

It looks like I'll be losing 1-5 of my 11-42 cassette unless I rebuild the cassette or find another alternative. The chainline is perfect through 6th gear (11, 13, 15, 17, 19, 22), but I lose all lower gears (25, 28, 32, 36, 42).

On my previous e-bike, I ran gears similar to a non-pedelec and kept the assist power levels fairly low; I'm not sure if this was simply "the way I ride" or if the previous bike was suited for that more traditional ride. If I keep the TSDZ2 setup as-is, losing the lower gears, will I be placing too much strain on the motor? Is there a practical reason I would need a wider range of gearing on an e-bike? Any thoughts or suggestions?

 

[ilu]

Which chainring are you using? It looks red so perhaps the custom made narrow-wide with offset?

Is there a reason why chainline angle inwards is worse than outwards? To me it seems that 2nd cog wouldn't be worse than 11th. To be on the safe side you could tune the derailleur to leave out the two biggest cogs, and unless you're riding in difficult terrain the 11-32 range should be plenty enough.

I use a larger 130 bcd spider on the TSDZ2 and mounted a 38t chainring on the inside of the spider. This allows me to use the whole 11s range, and only on the largest cog there's rubbing sound and thus significant extra wear on the drivetrain.

 

[ilu]

Check also this thread:

https://electricbike.com/forum/forum/knowledge-base/motors-and-kits/bbshd/39170-how-to-rework-rear-sprockets-for-mid-drive-systems

 

[Platypus]

If I keep the TSDZ2 setup as-is, losing the lower gears, will I be placing too much strain on the motor?

Hard to tell, but my gut instinct is "you'll be fine". Installing a temperature sensor is a sure way to prevent any problems. I advise keeping a low enough gear you can cycle home on a flat battery.

Is there a practical reason I would need a wider range of gearing on an e-bike?

Apart from needing a get-me-home gear, no. Having a motor should mean you need a smaller gear range. For example, Pinion market their 6 speed gearbox for ebikes, but sell 12 & 18 speed for normal bikes.

Any thoughts or suggestions?

Yes. In addition to here, ask a bicycle mechanic. Gears are the sort of thing which is best worked on in person by someone with a bit of experience. A short chat with a mechanic could save you days of frustration (depending on your skill).

Sort out clean shifting first with the gears that you have. Sacrifice lower gears if you need to. Only then would I investigate whether you have the right cassette size.