Mid drive

[EddiePJ]

I have fully explained my reasons above, look at the bullet points. You don't appear to be offering any reasons why a hub drive is better in a proper off road technical situation.

As I stated both motor systems have their place, but crank drive is always going to be better off road on tough technical terrain and climbs. For the bulk of users who want to ride bridleways and highways, a hub drive makes a lot of sense. That I can't even begin to dispute, and would even state that they are more fun, and pleasurable to ride.

Funny that you now also refer to torque as the important factor, when just yesterday you stated that torque was of no importance, and that it was gearing that counted.

Torque doesn't mean anything. It only depends on the gearing, which can be easily changed.

So which is it?





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[Wisper Bikes]

Happily another great thread!

I think what in essence is being said is there are a multitude of uses for an e-bicycle which is compounded by the fitness of the rider and the terrain the bike will be used on. There is enough choice now and market forces will make certain the perfect ebike will be available, one to fit any set of criteria. A bike does not exist that is all things to all people so don't try and find it.

I think we all agree, the best way to choose is to go to a good ebike shop, listen to the advice from the professionals. Test ride all the bikes they offer, when you find the correct bike you will know. It isn't necessarily the most expensive in the shop!

Regards, David

 

[Deleted member 4366]

I have fully explained my reasons above, look at the bullet points. You don't appear to be offering any reasons why a hub drive is better in a proper off road technical situation.

As I stated both motor systems have their place, but crank drive is always going to be better off road on tough technical terrain and climbs. For the bulk of users who want to ride bridleways and highways, a hub drive makes a lot of sense. That I can't even begin to dispute, and would even state that they are more fun, and pleasurable to ride.

Funny that you now also refer to torque as the important factor, when just yesterday you stated that torque was of no importance, and that it was gearing that counted.



So which is it?

The problem is that you've taken that quote out of context. I used it when talking about the torque figures that manufacturers state for their CD bikes, like Bosch is 60 Nm and Yamaha is 70Nm makes it sound like the Yamaha is more powerful; however, the Yamaha might have lower power, but it gets it's torque with lower gearing and lower speed.

The only thing that makes a difference is the actual torque at the back wheel whatever gear you're in. The Xiongda motor has an internal low gear, so it makes very high torque directly in the wheel no matter which gear you're in. It can change to a higher internal gear, which roughly doubles the speed and halves the torque, so it can give you speed and torque like a CD motor, but it runs at higher power than a Bosch or Yamaha, so it makes more torque at the same speed as them.





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[EddiePJ]

Just out of interest Dave, what is the opinion about the motor on this set up. Ignoring the bikes design with it's very scary looking shock position, the hub design appears to look very robustly built?

The drop out design caught my eye in relation to your latest build project.

Full suspension. http://www.cheetah.de/e-bike/e-bike-mountainspirit.html

Hardtail. http://www.cheetah.de/e-bike/e-bike-forpleasure.html

I really love the look of the hardtail, and those clean lines are what I'm aiming at for the Orange Zero project. For that though I'll be looking at the smallest possible motor and battery combination that I can get away with.


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[chris_n]

Does the Xiongda motor fail if you push the bike backwards? Are there any reliability based concerns? Does it take a cassette or freewheel? How is it for building a strong rear wheel that is properly aligned. All questions I have seen directed at rear hub motors.

 

[Deleted member 4366]

Just out of interest Dave, what is the opinion about the motor on this set up. Ignoring the bikes design with it's very scary looking shock position, the hub design appears to look very robustly built?

The drop out design caught my eye in relation to your latest build project.

Full suspension. http://www.cheetah.de/e-bike/e-bike-mountainspirit.html

Hardtail. http://www.cheetah.de/e-bike/e-bike-forpleasure.html

I really love the look of the hardtail, and those clean lines are what I'm aiming at for the Orange Zero project. For that though I'll be looking at the smallest possible motor and battery combination that I can get away with.


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It's difficult to know without knowing the speed of the motor winding (KV). I would guess that it can be reprogrammed for 45 km/h, so might be a bit weak on low speed torque and efficiency. It doesn't say the voltage. If only 36v, it'll probably not be as good as a KTM Panasonic, which has 48v. That's all just a guess, though.

One other thing. Rear suspension doesn't work very well with a heavy motor in it because the ratio of unsprung to sprung mass is too low. That's one area where crank-drives do get an advantage.

 

[Deleted member 4366]

Does the Xiongda motor fail if you push the bike backwards? Are there any reliability based concerns? Does it take a cassette or freewheel? How is it for building a strong rear wheel that is properly aligned. All questions I have seen directed at rear hub motors.

I push mine backwards every day and it's still going strong, so no. The only failures I know have been on recumbents or similar, where people paddle them backwards with a lot of force and weight on the motor. It's not a problem on a bicycle because there's not enough weight on the wheel, which would skid if the motor locked.

Mine has done 4000 miles and isn't showing any signs of wear, even with my weight on it. I guess it will run on to over 20,000 miles. Time will tell. I guess that there's not a lot of people that would do 4000 miles on an electric bike.

The hub has 36 holes in it. You can build it as straight or strong as you want. Mine's straight, strong and completely maintenance free. I don't really understand your question.

It's a freewheel motor. I got round the low top gear problem by using a DNP freewheel, which is showing no signs of wear after 4000 miles.

 

[chris_n]

"The hub has 36 holes in it. You can build it as straight or strong as you want. Mine's straight, strong and completely maintenance free. I don't really understand your question."
It was more a question of can you get sufficient dish on the drive side in particular and still have the rim centred in the frame.

 

[Deleted member 4366]

Bikes with Bosch, Panasonic, Kalkhoff and Brose motors all have special frames to mount the motor. If an OEM wanted to use a Xiongda motor, or any similar motor, they should also have a special frame with a suitable offset. I modified my rear subframe so that the rim sits centrally without a dish. Self-builders don't normally have access to frame modifications, which means they have to compromise by dishing wheels. Unfortunately many people involved in the supply chain of ebikes haven't got a clue, so I'm not surprised to see dished wheels on OEM bikes, which are completely unnecessary.