"Significant Motor Resistance While Pedalling With Motor Off" Myth Busted: Physical Proof

Nashcruiser

Well-Known Member
Region
USA
City
Nashville Tn
I turn mine off as much as I can. Going down hill and on flat terrain. Something else that reduces drag is down shifting. Mine has ten gears and third, forth, and fifth are all peddleable without juice from the battery. If I can’t keep the cadence up around 50 - 60 rpm then I look for help from the battery. Yesterday I went for 17 miles with 1,200 ft in elevation gain and still have 72% charge.
 

kmccune

Active Member
What's your point?

I made it clear that the quality ebikes that I own don't have issues.

Not entirely sure why you are assuming what I own or do not own.
Trying to agree with you or are you one of those people who will not allow that?( met a few in my timeline)
 

edb

New Member
Region
Europe
Hi all, new e-bike person here,

I've been riding my new e-bike (kalkhoff endeavour 1.b move), for 3 days (probably doing 2-3 hours each day), and yes, I definitely have the same frustrations as described here.

I am happy to admit that motor drag may not be the culprit here (it feels that way cause the motor makes some noise when pedaling in OFF mode), but _something_ on that bike is pulling back. Even on a downward slope, the bike just slows down a lot. There is zero inertia, after every kick, the bike just seems to want to stop. I get that it's heavy (and I am heavy too), but it really doesn't feel right. At the end today, I ran out of battery for about 1 km, on a flatish road. It was excruciatingly painful to pedal that distance in OFF mode.

Do I need to add some grease anywhere? How inflated should me tires be? Is there some kind of dynamo that's slowing stuff down?

Also I think the guys who mounted the bike didn't change the firmware as I ordered larger wheels. There are speed o meters on the roads here, and they consistently show a smaller number than my bike computer. Then the assistance stops at 22kph instead of 25kph, so annoying.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
It's Bosch Performance Line, it says Bosch eBike System 2 on the website, not sure that's what you mean by generation
There were Gen 1, 2, and 3, and the current is Gen 4. The generations before 4 used a very small chainring (such as 16 or 18 teeth). These older Bosch motors were believed to create the motor drag. I don't know. If you can raise the rear wheel, try to rotate the crank with the assistance OFF. Do you feel any resistance? No? Then the reason of your Kalkhoff slowing down is elsewhere.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
but _something_ on that bike is pulling back.
After given it some thought, it is very strange what you are describing. If you ride downhill and don't pedal, there is a freewheel in the rear wheel hub that cuts all the interaction with the drive-train. So, coasting or descending are not dependent on the motor at all!

Again, I say the "pulling the bike back" must be an impression, as unpowered ride is contrasted with the ride with big assistance earlier.
 

kmccune

Active Member
Fat tires are harder to pull, get on a "Specialized' bike of some model,I was frankly amazed at how easy those things pedaled in grass with the motor off. Lube the chain and check the 'chainline" and make sure the bearings are not to tight. Went to site and checked bike out, wow very nice,As best I can ascertain no fat tires( site didn't work for me-Poor English-less Deutsch) Make sure that the battery is working, might be a crazy wire problem. Is that a middrive?
 

edb

New Member
Region
Europe
Yeah no fat tyres. As Stefan noticed, my problem is mainly with the bike slowing down while not pedaling, so can't be the chain or battery. It must be the tyres which are under-inflated (I am pretty heavy) plus the baby seat I have in the back, and maybe the wheel needs some grease... I don't know. I probably bought it from a lousy website that didn't mount it well. I'll have it serviced maybe...
 

kmccune

Active Member
Yeah no fat tyres. As Stefan noticed, my problem is mainly with the bike slowing down while not pedaling, so can't be the chain or battery. It must be the tyres which are under-inflated (I am pretty heavy) plus the baby seat I have in the back, and maybe the wheel needs some grease... I don't know. I probably bought it from a lousy website that didn't mount it well. I'll have it serviced maybe...
Well its worth a try,I got on an unserviced "acoustic bike yesterday and my legs gave out immediately, didnt breathe hard it was like my legs had no strength and I do ride on hills sitting down with low pedal assist, the thing is those heavy ebikes pedal easier. with little or no assist with properly inflated tyres. Get a small tyre pump (Ryobi makes a nice one with built-in digital pressure gauge. And a good BS can tune your bike to its maximum performance
 

LimboJim

Well-Known Member
Yeah no fat tyres. As Stefan noticed, my problem is mainly with the bike slowing down while not pedaling, so can't be the chain or battery. It must be the tyres which are under-inflated (I am pretty heavy) plus the baby seat I have in the back, and maybe the wheel needs some grease... I don't know. I probably bought it from a lousy website that didn't mount it well. I'll have it serviced maybe...
Maybe check for brake misalignment/drag, too.
 

matdarecki

New Member
Region
Europe
I have Bulls Lacuba Evo 2017 or 2018 with Brose T motor. With motor off, I can't go even 5 km/h - it's so (extremely) hard. Maybe my motor it's piece of junk :), and you have newer versions of motors - because producers now advertise "no motor drag" and there is a reason they do it. I've red a few discussions, generaly with conclusion that it's a e-bike's weight. I do NOT agree. When I go, lets say 20 km/h, and turn off the motor (whole electric system), my bike goes well without pedalling, with very little resistance, slowing very slowly, I can feel that wheels work smoothly. But when I try to pedal, it's impossible to keep that speed, and it's very havy resistance, coming definitly from the turned-off motor. It's not a problem with turning the pedals, but it's problem when you push the pedals - that force you have to fight against comes not from fat weels, but from the motor. More force you put in, more resistant force you're facing.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
I have Bulls Lacuba Evo 2017 or 2018 with Brose T motor. With motor off, I can't go even 5 km/h - it's so (extremely) hard. Maybe my motor it's piece of junk :), and you have newer versions of motors - because producers now advertise "no motor drag" and there is a reason they do it. I've red a few discussions, generaly with conclusion that it's a e-bike's weight. I do NOT agree. When I go, lets say 20 km/h, and turn off the motor (whole electric system), my bike goes well without pedalling, with very little resistance, slowing very slowly, I can feel that wheels work smoothly. But when I try to pedal, it's impossible to keep that speed, and it's very havy resistance, coming definitly from the turned-off motor. It's not a problem with turning the pedals, but it's problem when you push the pedals - that force you have to fight against comes not from fat weels, but from the motor. More force you put in, more resistant force you're facing.
Have you tried taking the chain off your chainring and rotating the crank by hand?

2017 Brose T is basically the same as 2017 Specialized 1.2 motor that is equipped with double freewheel.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
I can guarantee Mat the 2017 and newer motors have no drag.
Again: Did you take the chain off the chainring, turned the motor on, and spun the crank with your hand?
 

matdarecki

New Member
Region
Europe
I can guarantee Mat the 2017 and newer motors have no drag.
Again: Did you take the chain off the chainring, turned the motor on, and spun the crank with your hand?

Stefan, probably I was wrong. [I deleted my last post to cut the confusion.]
Today I've tried without chain and it seems ok - no drag. Truly, I don't understand why it's so extremely hard to drive this e-bike with motor off. Sometimes I go with hevy load on the back of my normal bike, and even though it's simalr weight, it's not even close so hard to move. [Off course, I checked the brakes - everything is ok.]

Yesterday I wrote an e-mail to Brose USA, where I asked a few questions. I wrote that I have Bulls Lacuba Evo from 2016 and I experience strong resistance while trying to drive with motor off. Motor seems ok, no cracking etc. They replied today:

"You most likely have a C16162 drive and definitely not a Brose Drive C E22243. The drive has two freewheels so there should be no noticeable resistance when the support is switched off.
Replacement drive for the C16162 (produced until the end of 2016) is the current Brose Drive T C91143.
Bulls also does not use a Brose e-bike system but the BMZ Drive System, where only one component is from Brose, the drive unit.
Best regards"

So... even older C16162 does not have a drag issue.



 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
Mat,
Trust me: pedalling a heavy e-bike (and especially accelerating it) without assistance is just a pain because you need to deliver a lot of kinetic energy to it. Your traditional bike must be more lightweight. The power delivered by the full power motor is so high (at the level of a racing professional) that we simply are confused when losing that kind of assistance.
 

Rider51

Member
Region
USA
I'm with Stefan. I've ridden a few e-bikes, including ones where the motor completely disengages (I own one). It's the weight that's the issue. Until you get to the level of something like a Specialized Creo, or Obrea Gain, etc. you're going to notice the weight being the drag more than anything.