Is 40Nm enough? What is power? We must torque!

fatblokish

Guru
Location
In bath
Ok, for a simpleton, what's the difference betwixt power and torque?

I really like the look etc of the Ribble Hybrid Al e but am concerned that the torque will be insufficient to shift my significant mass up challenging inclines.

I've ridden a great number of e-bikes over many miles (mostly Bosch type mid drives but also Brompton electric, urban arrow etc) and am concerned that the modest 40Nm will not leave me smiling at the end of the ride.

I'm too far away to give one a test drive so your thoughts please.
 

Sharky

Guru
Location
Kent
Still a long way for you, but Ribble have just opened a new store in the Bluewater shopping centre. Just off the east side of the M25. They are offering test rides in the car parks somewhere.
 

Smudge

Über Member
Location
Somerset
With 40nm of torque i would say definitely get a test ride to see if its enough for you. I suspect it will struggle on hills, especially if you're quite a heavy rider.
My first ebike was an Ekit fitted to a hybrid, this kit had 35nm of torque in its hub motor and tbh it was gutless on hills, even just slight inclines you could feel it labouring. I've since removed this kit altogether as i've had enough of its poor torque.
On my Pioneer E, it has a TranzX hub motor with 45nm of torque and this is much better, but i don't think i would want any less torque than this with a hub motor.
 
Power is simply the product of torque and cadence ( Cadence x Torque =Powwwwer) Power meters are simply a load cell, and an inertial cadence sensor. If you know what your power is, and at which cadence your pedalling, you can work out the Torque.
 

Ananda

Active Member
Location
Athens, Greece
Simply put, torque relates to the magnitude of the force moving you forward and power relates to how fast this force can move.
 
Last edited:

CXRAndy

Guru
Location
Lincs
Torque is the 'ummph' that pushes in your seat when accelerating in a car, same for electric motors- the pick up punch from low speeds.

Power is related to how fast you accelerate.

40nm is on the low side. I have built a crank driven ebike- motor rated at 80nm 750W peak.

I would get a test ride, find a steep slope. Ride up slowly in a big gear and then accelerate by pushing hard on the pedals, the bike should pickup quickly in pace. If its slow to increase then the motor isnt strong enough for you.
 

KneesUp

Guru
I've had two cars that happen to have the same power output - 140bhp - and weigh pretty much the same (1285kg vs 1385kg) The diesel one had 224 lb-ft torque, and the petrol one has 128 lb-ft.

In practice this means they are both as fast as each other, but the diesel felt faster - you need to rev the 'nads of the petrol one because all the power is at the top end, and you need to be in the right gear. With the diesel it didn't seem to matter what gear you were in, or how lazily it was revving, you just put your foot down, and their was a brief moment whilst it span up the turbo (I loved that little pause) and then it would fling you up the road. (It's such a shame diesel is so bad for the world - I loved driving them)
 

Smudge

Über Member
Location
Somerset
I used to have a Suzuki 1800cc v twin cruiser, for this big motorcycle engine, it only had around 120bhp. Many sports bikes of far lesser cc will have more bhp than this. But this cruiser had around 120 ft/lbs of torque, you could be in top gear doing 30mph at less than 2,000 rpm. To accelerate you wouldn't need to drop a cog, just twist that throttle and it would pull like a freight train.
That is torque.
 

TyrannosaurusTreks

Formerly known as Giantbadge
Location
Somerset
I used to have a Suzuki 1800cc v twin cruiser, for this big motorcycle engine, it only had around 120bhp. Many sports bikes of far lesser cc will have more bhp than this. But this cruiser had around 120 ft/lbs of torque, you could be in top gear doing 30mph at less than 2,000 rpm. To accelerate you wouldn't need to drop a cog, just twist that throttle and it would pull like a freight train.
That is torque.
Yes smudge I had the triumph thunderbird, loved the torque.
Fat bloke i had the giant with 80nw which would climb any hill no problem, I’m on a trek now with 63nm & that’s very good as well but I wouldn’t want to go down to 40nm I’m 14st-10lb.
 

adoli

Member
Location
Switzerland
No. 40NM is marginal if you want a grin on your face.^_^
I have an e-bike Mountain Bike from Canyon with Shimano Steps 8000 and it has 70NM peak power.
Put that on boost and you have a lot of fun (up to 25kmh). Can do 25% inclines to the point where I struggle to keep the front wheel down.

If you're looking at Bosch motors, go for the Bosch Performance Line (not the Active line) - IF you want a grin.
 

jowwy

Guru
No. 40NM is marginal if you want a grin on your face.^_^
I have an e-bike Mountain Bike from Canyon with Shimano Steps 8000 and it has 70NM peak power.
Put that on boost and you have a lot of fun (up to 25kmh). Can do 25% inclines to the point where I struggle to keep the front wheel down.

If you're looking at Bosch motors, go for the Bosch Performance Line (not the Active line) - IF you want a grin.
i have the bosch active line Plus and at 18st 4lbs it has no problem propelling me up 20% climbs, with 50nm...........as long as you have the right gears available to you
 

Scaleyback

Senior Member
Location
North Yorkshire
I have the Orbea Gain road e-bike. This has a 40nm of power. It is not a heavy bike (as e-bikes go) and I am a 70kg rider. It is brilliant for me but I seriously doubt it would be sufficient for a ‘heavy’ rider especially when paired with the average 20+ kg e-bike.
 

NickWi

Über Member
...........but I seriously doubt it would be sufficient for a ‘heavy’ rider especially when paired with the average 20+ kg e-bike.
Actually it still works well. At 100kg I'm no lightweight, but as long as you accept what a Gain is designed to do, i.e. power assisted rather than powered, then it gives you that subtle, feels like it's riding with the wind behind you feeling that makes the Gain such a pleasure to ride. Hills, yes it's never going to haul you up like a Giant eroad that has 80nm of torque, but it still gives more than enough assistance to help me up hills I'd previously got off and walked.
 
Top Bottom