Which rear-geared-drive for bike that has 8 rear speeds?

[d8veh]

The torque is approximately the same between the two motors. The downside to running the motor at higher speed (voltage) is that you lose efficiency at low rpm, so the risk of overheating on long hills is increased and you use more battery when running at low speed. A lower speed motor will always be more efficient, but that's no use if it doesn't go fast enough.

What you need is a motor that's designed to give enough power to maintain your modal speed of tavelling. That modal speed should be about 60% to 75% of the motor's maximum rpm at the voltage you have chosen.

 

[chvidgov.bc.ca]

There is also a Sunrace 13T freewheel out there which is decent.

Also a Shimano 13T http://www.amazon.com/Shimano-7-Speed-Tourney-Bicycle-Freewheel/dp/B00OJZPRVO


btw I use a 7 speed freewheel in general - the 8 speed shifters typically work fine with 7 speed freewheels with one of the gears dialed out with the derailleur.

 

[rsilvers]

I have not been riding my eBike since I discovered Strava. Now any eBike ride is a wasted opportunity to log a ride.

 

[slowhands]

I have a 48v battery pack, and looking for motors that will work with a Shimano 8-speed cassette.

I am not sure which ones can do that. I have about 139mm space to play with.

If you want to keep your cassette, use any hub motor with a freehub. Freehub motors are not as common as freewheel motors, and they cost a lot more.

Alternatively, you can use an 8 speed freewheel and the more common freewheel hubs. You find them on Amazon or eBay for about $35. Because you have a much wider choice of hub motors, and they cost less, this approach saves money on the total cost.

http://www.ebay.com/sch/i.html?_odk..._nkw=(sunlite,dnp)+8+speed+freewheel&_sacat=0

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias=sporting&field-keywords=dnp+8+speed

 

[slowhands]

Don't waste your time with the Shimano freewheel. 14T top gear will be too slow. Get a DNP one with 11T top gear.

My buddy put an 11-34 DNP freewheel on his pedicab trailer tow bike. It broke on its first night out. He put on a second one he had laid in as a spare. It broke on its first night out.

That's all I need to know about DNP freewheels.

We know they are not as tough as Shimano, that's understood. But a great many folks use them on their bikes with adequate results. It's a compromise, because Shimano does not make 8 or 9 speed freewheels, nor 11T cogs, which we would rather have but can't. For a high powered bike, I would of course prefer the Shimano, knowing it has a better chance of lasting a while longer. Both will wear out quickly in heavy duty use because they are for light duty bicycles, not our hot rods.

In fairness, a pedicab tricycle with trailer is a much higher load than the typical bicycle. You're comparing apples to watermelons.

 

[Chalo]

In fairness, a pedicab tricycle with trailer is a much higher load than the typical bicycle. You're comparing apples to watermelons.

No, I'm comparing a muscle-powered pedicab tow bike to a muscle and motor powered e-bike. They're both applications in excess of the intended design loads for the freewheel. The forces on the pedicab's freewheel are limited by gear ratio and the rider's pedal force. An e-bike's freewheel can potentially see much higher loads, depending on the nature of its motor drive.