Donor bike for rear hub motor

[ruffruff]

I want to build my own this time around.
I bought a Giant Rincon off Fleabay but I didn't notice it was 24 gears until I hit the BUY button.

I'm looking at an Ebikling kit and they come with the 21 speed cassette. Am I going to have an issue dropping the kit wheel with 7 gears on the cassette into the dropouts on the Rincon that has the 8 gear cassette on it originally? OR can I take the 8 gear off and put it on the kit hub?

Any help is appreciated.

 

[rich c]

Does the motor really accept a cassette, or is it a freewheel? I thought motors that accept cassettes were rare.

 

[ruffruff]

Good question, I need to get my terminology down and do some more research.

The kit is clearly a freewheel, but i don't have the bike in hand yet to determine if its a cassette or freewheel.

 

[ruffruff]

I guess my real question is, will I have any issues with dropouts, etc using the kit with 7 gear freewheel if they bike is setup with 8 gears?

Spacing, chain line, etc????

 

[BigMatt]

I guess my real question is, will I have any issues with dropouts, etc using the kit with 7 gear freewheel if they bike is setup with 8 gears?

Spacing, chain line, etc????

Having done something similar to this on several Ebikeling conversions, I do not think you’ll have any major problem. Your 8 gear shifter ought to work reasonably well with your 7 gear cassette if you adjust your derailer range to not go beyond a certain range. You’ll just top out at 7 gears (right rear) and 8 won’t move out further.

If you have an issue, you can also cheaply and rather easily replace the original gear shifter on the bike to something like this (3x7 = 21 gears). I like the grip shifters with the thumb throttles. You need a thumb gear shifter if using a twist throttle though (see bottom link).

SRAM MRX 21 Speed (3 x 7) Grip Shift Set https://www.amazon.com/dp/B003EQCKJG/ref=cm_sw_r_cp_api_i_PXe-Db24NKT0H

Paraout Tourney SL-TX30 3x7 Speed Thumb Gear Shifter Levers for MTB Combo with Inner Shift Cables https://www.amazon.com/dp/B07GNM33CK/ref=cm_sw_r_cp_api_i_j3e-DbZ9V91SK

Personally, I converted one 21 gear bike to a 7 by doing away with the middle derailer and left shifter altogether. (I changed the chain ring from 3 to 1 and got a bigger ring, but you don’t have to.) If you use an EBike correctly (motor does the heavy work of low gearing), you don’t really need the 21 gear range. I kept all 21 gears on another EBike conversion because it didn’t get in the way, but I have yet to actually use the middle derailer (or left side 3 ring middle derailer) since converting...

 

[BigMatt]

Good question, I need to get my terminology down and do some more research.

The kit is clearly a freewheel, but i don't have the bike in hand yet to determine if its a cassette or freewheel.

Also, my (1,200/1,500 Watt, 700c, 26 inch and 26 inch fat bike kits) Ebikeling kits all came with a separate cassette that had to be screwed on to the provided wheel/hub.

You could likely just screw something like this (8 gear cassette) on instead if you can’t the cassette off the rear wheel of the bike you ordered. The tools required to take off these cassettes are tricky and hard to find (and come in multiple non-standard configurations). They’re easy to get on though... Just hand tighten then ride around the block letting the chain tension do the full tightening.

SunRace 8 Speed Road Bike Cassette 11-23 Compatible with (Shimano or Sram) https://www.amazon.com/dp/B00BW4TPQ8/ref=cm_sw_r_cp_api_i_mhf-DbZ5N45X9

 

[tomjasz]

Does the motor really accept a cassette, or is it a freewheel? I thought motors that accept cassettes were rare.

No, pretty common these days. Liking cassettes these days since There is more flexibility in using fewer gears and being able to adjust with spacers. To reduce gear on a freewheel hub can need a thread on adapter. Kinda hard to find. So hard that I keep a spare in my parts box.

 

[tomjasz]

Good question, I need to get my terminology down and do some more research.

The kit is clearly a freewheel, but i don't have the bike in hand yet to determine if its a cassette or freewheel.

Won’t really matter which it is. Just get the correct set Of gears. If you have a cassette on the bike buy a new freewheel. I like the wide range 11T x 34T With a single 42T chainwheel. I just have no need for all those gears once electrified. My one speed MAC is incredibly simple. But I have no hills to climb. Or none that I can’t run up long before overheating.

BTW a cassette slides on and a freewheel threads on.

 

[tomjasz]

I guess my real question is, will I have any issues with dropouts, etc using the kit with 7 gear freewheel if they bike is setup with 8 gears?

Spacing, chain line, etc????

The width will be with a mm or two. 135mm standard rear. Just get some decent torque arms. I hate those sloppy punched out versions. Nice stainless Grin are the best fitting typically. If it aluminum I use two. Not cheap but neither is a trashed frame. Those inexpensive kits are gaining popularity, upgrading to better known brands rather than the clones is a good move, in my experience. Same with controllers. I’m liking multi-range controllers. I can run 36, 48, or 52v with no drama. BetterControllers also mean quieter running. And having regen braking is pretty cool to.

See eBikes.ca motor simulator. They have 9-Continent hub motors. The original, that others clone. MAC from Cutler MAC, or the newer Bafang gear drives from eBikes.ca are a good deal too. Very small and stealthy. These days I’m liking stealthy builds.