Crank drive or otherwise?

[royH]

Hi all, can anyone explain the pros and cons of crank drive bikes as opposed to alternatives? Looking through the reviews I see good and bad so any guidance would be most appreciated.

Many thanks.

 

[Deleted member 4366]

The advantage of crank-drive is that you get a large speed range, trading torque for speed and vice-versa as you change the gears. Disadvantage is more difficult gear-changing and wear on the transmission, and you generally have to pedal more on a crank-drive. You have to keep changing gear as you go up and down hills.

Hub motors give their power regardless of which gear your in, so much more relaxing. No wear on the transmission. The disadvantage is the limited speed range. If you want hill-climbing torque, you can't have speed as well, or if you want a fast one, you can't have good hill-climbing.

There's now the two-speed hub-motor from Xiongda, which behaves more like a crank-drive than a hub-motor apart from the transmission wear. It has immense hill-climbing torque, but you have to go very slowly, but in the high gear it has a fair turn of speed. You have to use the gears much more than a single-speed hub motor.

As an opinion, crank-drive is better for sporty riding. Hub-motor is better for commuting and touring.

 

[KTM Bike Industries UK]

d8veh, have you tired a new Panasonic hub drive bike??.... honestly they blow the Bosch crank drives out of the water for even sport offroad riding.

Having ridden both extensively in the hills on and offroad around our offices in the Peak District, all the staff here chose the hub drive for their personal bikes and for their partners, whether it be for leisure, commuting or annoying people on Strava.

we sell loads more crank drive than hub drive.... but I know which I'd choose if it was my money.

Personally I think there are good crank drives, and good hub drives. But there isn't a simple crank is better than hub, or hub is better than crank option, as different people have different needs.

And as a competitive cyclist, I personally prefer the hub drive in our range... but we do both for a reason.

Col.

 

[Kudoscycles]

Colin,I tried the KTM Panasonic Cross hub drive yesterday,it's a very attractive and well specified bike and very powerful hill climber,priced competively at just over £2k..really liked the bike.
KudosDave

 

[RobF]

Leaving brands aside, the two systems give a different riding experience.

Hub drives either push or pull you along, but crank drives are more like traditional cycling because all the power goes through the chain.

How important the difference is will depend on the rider's preferences.

I prefer crank drives, but could happily live with either as regards riding feel.

Crank drive is the safer option if you want to all but avoid the possibility of broken spokes.

 

[amigafan2003]

As an opinion, crank-drive is better for sporty riding. Hub-motor is better for commuting and touring.

Exactly my experience with both sstems as well.

If I was commuting or racking up the miles, hub drive every time. Offroad, crank drive wins.

Hub drives are also better for inexperienced riders or those who don't have any mechanical sympathy.

 

[Artstu]

Crank drive lets you beat the Pro riders too

 

[Geebee]

As I live in very hilly terrain I prefer the crank drives for their climbing ability.

There is one factor to take into account that I never hear mentioned, on a PAS (non torque) operated hub when you pedal the motor will accelerate upto its max speed if left in its top PAS setting which means you basically do zero or 25 kph short of tapping the brakes or consantly changing the PAS setting.
On a Crank drive with the same PAS, low may get a 8 kph top speed and that will step up with the gears, this is very handy in traffic as when I come up behind a slow car I just shift down to mattch speed and the same as they accelerate, so with a crank drive you dont have to alter PAS at all, I ride in highest assist at all times and adjust speed and power use with the gears.

Obviously IF you have a throttle you can over ride the PAS.

Basically having ridden both I find the crank drive more like riding an unassisted bike.

 

[Deleted member 4366]

As I live in very hilly terrain I prefer the crank drives for their climbing ability.

There is one factor to take into account that I never hear mentioned, on a PAS (non torque) operated hub when you pedal the motor will accelerate upto its max speed if left in its top PAS setting which means you basically do zero or 25 kph short of tapping the brakes or consantly changing the PAS setting.
On a Crank drive with the same PAS, low may get a 8 kph top speed and that will step up with the gears, this is very handy in traffic as when I come up behind a slow car I just shift down to mattch speed and the same as they accelerate, so with a crank drive you dont have to alter PAS at all, I ride in highest assist at all times and adjust speed and power use with the gears.

Obviously IF you have a throttle you can over ride the PAS.

Basically having ridden both I find the crank drive more like riding an unassisted bike.

You could set a lower PAS setting. That's like saying, "There's a problem with throttles. If you leave it fully on, you'll go maximum speed everywhere".

Anyway, these things are nothing to do with motor characteristics. They're the control system that can apply to either type of drive system

Crank drive lets you beat the Pro riders too

That's a great effort, but I think there's a few hub-motored bikes around that would annihilate that time:

http://www.pedelecs.co.uk/forum/threads/custom-build-4080-18-fet-56mph.16989/#post-209187

 

[Artstu]

As I was typing it I did think about the more powerful hub motored bikes, wondering just how quickly they'd do it.
That ride did get through the battery very quickly last night, that's the thing isn't it, it's all a compromise, I think my bike gets closest to being reasonably fast, with reasonable range. Excluding bikes with bigger batteries of course.

 

[Deleted member 4366]

There's also some pretty powerful crank-drives. You can have either as powerful or fast as you want. For a bike from a shop, yours is a pretty good result. A hub-motor with a speed of at least 270 rpm would be needed. I think the only shop one which would give your Bosch a run for its money would be the Ezee Torque. it has a 250 rpm motor, but a 700c wheel, which would give more power up to about 18mph, but would then max out at about 21mph. It could be a close race.

We have the Bristol hill-climb race for legal bikes in a few weeks. No crank-drive has won yet. My money is on the Oxygen Emate winning this year. It was first two years ago and second last year, so it has to be the favourite. why don't you come and give it a run for its money. I'll bet you the pint that Cyclezee owes me.

 

[Artstu]

I'd better start training on my sprinting ability then me and the bike don't sprint very well, what with my lack of power and the soft start of my Hub gear compatible Bosch motor.

My segment time above of 12.58 drops to a truly pedestrian 30.19 on my light ish unpowered bike !

 

[Geebee]

You could set a lower PAS setting. That's like saying, "There's a problem with throttles. If you leave it fully on, you'll go maximum speed everywhere".

Anyway, these things are nothing to do with motor characteristics. They're the control system that can apply to either type of drive system


That's a great effort, but I think there's a few hub-motored bikes around that would annihilate that time:

http://www.pedelecs.co.uk/forum/threads/custom-build-4080-18-fet-56mph.16989/#post-209187

It applies to the most common PAS type at the moment, adjusting PAS constantly is at best arkward and requires taking your eyes of the road and with some bikes one hand off the handle bar, not ideal in traffic.
It is directly linked to the motor type they respond differently with the the most common control method, and I am guessing (havent tried for myself) that the new torque simulation controllers will make speed control by PAS not usable.

 

[Deleted member 4366]

It applies to the most common PAS type at the moment, adjusting PAS constantly is at best arkward and requires taking your eyes of the road and with some bikes one hand off the handle bar, not ideal in traffic.

I've not heard that one before.I thought most bikes crank-drive or hub motors have a panel where you adjust the power.

 

[Geebee]

If you are talking about taking the hand off the bars, the Ezee I tested recently had the PAS panel in the center of the handle bars

 

[amigafan2003]

That's a great effort, but I think there's a few hub-motored bikes around that would annihilate that time

http://www.strava.com/segments/4109724?filter=overall

And that was taking it easy ;-)

 

[Artstu]

http://www.strava.com/segments/4109724?filter=overall

And that was taking it easy ;-)

Dan ?

 

[amigafan2003]

Dan ?

Yes?

;-)

 

[Deleted member 4366]

If you are talking about taking the hand off the bars, the Ezee I tested recently had the PAS panel in the center of the handle bars

The same with this Bosch one:
http://www.bosch.com/media/com/innovation/insidebosch/powertrains_of_tomorrow/ebike_4_w734.jpg