Chalo wrote: ↑
Aug 19, 2018 11:51 am
wturber wrote: ↑
Aug 18, 2018 10:05 pm
Many people may find imperfect index shifting unacceptable. But I've spent about 99% of my riding time using friction shifters, so the imperfect operation doesn't bug me at all.
Noisy chain and sprocket operation, stuttering, and skipping are more serious than a mind it/don't mind it issue. It greatly accelerates wear and tear on the components when the derailleur is constantly guiding the chain to an in-between position that doesn't correspond with a sprocket. Lightly engaging the shift-assisting features on the chain and sprockets without actually shifting gradually wears those features away. In a worst case, the chain can skip or drop off when you're standing on the pedals to get up to speed, and a crash results.
Friction shifting allows you to make minor trim adjustments for quiet, smooth operation. Incorrect index shifting doesn't. That's why early index shifters came with a friction mode that could be enabled in case of system damage that misaligned the index positions from the sprockets.
Here's the problem. My system wasn't noisy, didn't stutter, and only skipped in two middle to low gears - which was the "imperfection" that I was dealing with. And that skipping had always gone away with one click up or down. After that, no noise, stutter or skip. The system ran as quietly as I could have ever managed to make it run with a manual friction shifter. I switched to a new 7 speed chain way back when I changed chainring and added the motor.
I'm posting at this later time because I wanted to observe for a few days to make sure I wasn't the "frog in the pot" and hadn't just tuned a noisy and problematic drive train out over time after having gotten used to it. Nope. I could shift so that the system was quiet and reliable in six of the seven gears (I had locked out the lowest gear). That begs the question of how things could run quietly given the spacing differences. My best guess is that there's enough slop in my old derailer and its jockey wheels to allow the chain to shift side to side a bit and fine a smooth "slot" in which to run.
Nonetheless, I had intended to replace the shifter way back when and this got me looking at shifter options again. I found that for less than $20 I could buy a 7 speed Shimano Rapid Fire shifter from Performance Bike in Scottsdale. So that's what I did a couple days ago. I installed it this morning and have eliminated the middle shift sequence ambiguity. And as a minor bonus it turns out, the little gear indication window is placed differently (low side rather than high side)and I can now actually see it and confirm the gear I'm in. That might be handy now and then at stops.
Anyway, for the OP, the shifter was the Shimano Acera SL-M310 Rapid Fire Shifter that you can pick up at probably any local bike shop (not sure about Cambodia - maybe you'd need to order it?), and the freewheel I'm using is the 7 speed DNP Epoch with 11 tooth high gear that I got from Grin. While that may not be a great freewheel, it is head and shoulders better than the piece of garbage that came with my kit. It has the guide ramps that make shifting smoother and more accurate.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
8 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats