Bosch Gen 4 Resistance

[Chris@EDC]

Hi All
Does anyone else out there riding bike with Bosch Gen 4 find that there is resistance in the motor when your pedalling beyond 25km option on motor? As i feel like at times i working against the motor when riding beyond that limit when pedalling.
Thanks in advance

 

[Mteam]

There's very little resistance (or none in fact) from the motor, what you're feeling is the weight of pedalling a 20plus kg bike.

I find with the motor its very easy to be in too high a gear for the speed your going and when the motor finally switches off you feel the full effort of being in too high a gear.

You can show there is very little resistance by putting the bike in a workstand and turning the pedals by hand with the motor switched off, it will feel the same as turning the pedals of a regular bike, assuming they're in the same gear.

 

[Mikerb]

....or another way to test the resistance...or lack of it...beyond the motor cut off point, is to ride on a level tarmac road ( preferably without a stiff headwind) and accelerate up to and then beyond the motor cut off ( which you can hear). Off road it is easy to be fooled by how much the motor is helping push big tyres through uneven terrain such that when it cuts out you get to feel just how much rolling resistance there actually is. As a bove in the right conditions there is very little motor resistance with the motor off.

 

[Chris@EDC]

....or another way to test the resistance...or lack of it...beyond the motor cut off point, is to ride on a level tarmac road ( preferably without a stiff headwind) and accelerate up to and then beyond the motor cut off ( which you can hear). Off road it is easy to be fooled by how much the motor is helping push big tyres through uneven terrain such that when it cuts out you get to feel just how much rolling resistance there actually is. As a bove in the right conditions there is very little motor resistance with the motor off.

I did that and turn the motor off and found going down hill i did not have any resistance, so i do question the motor resistance and the possibility of the clutches holding you back when peddling, i was riding a Foucus Jam2 6.8 and my friend was riding Trek Rail 9 both with the same motors and both of us experienced the same effect.

 

[Mteam]

I did that and turn the motor off and found going down hill i did not have any resistance, so i do question the motor resistance and the possibility of the clutches holding you back when peddling, i was riding a Foucus Jam2 6.8 and my friend was riding Trek Rail 9 both with the same motors and both of us experienced the same effect.

Or try taking the chain off the front ring and try turning the pedals with your feet or hands, there is no resistance from the motor or the various mechanisms in it, what you are feeling is the effort of pedalling a 20+kg bike possibly in too high a gear when you have been used to the motor giving you free Watts.

Eg let's say the motor cuts out at exactly 15.5mph and let's say it takes 200watts to propel you and your bike at 15.49999 mph, you're putting in 100 Watts and the motor is giving 100 Watts, at 15.5mph the motor cuts out meaning you suddenly have to find another 100 Watts from somewhere in order to stay at 15.5mph because the motor is no longer giving any assistance, this is going to feel like a significant extra effort, which will feel like motor drag, but it's not, its just the extra effort of you having to provide all 200 Watts to maintain 15.5mph

 

[MrPeaski]

Eg let's say the motor cuts out at exactly 15.5mph and let's say it takes 200watts to propel you and your bike at 15.49999 mph, you're putting in 100 Watts and the motor is giving 100 Watts, at 15.5mph the motor cuts out meaning you suddenly have to find another 100 Watts from somewhere in order to stay at 15.5mph because the motor is no longer giving any assistance, this is going to feel like a significant extra effort, which will feel like motor drag, but it's not, its just the extra effort of you having to provide all 200 Watts to maintain 15.5mph

This is the best explanation I've seen for this

 

[Chris@EDC]

This is the best explanation I've seen for this

I understand what your saying but as i stated, we turned our motors off on each bike and the resistance stopped, cannot explain it any easier, I'm an engineer and completely understand physics, i understand and my legs feel it what's occurring when peddling on the flats.
On the mountain tracks your not reaching these larger speeds which in many cases it would not be felt.
Anyway thanks for explanation.

 

[GrahamPaul]

I understand what your saying but as i stated, we turned our motors off on each bike and the resistance stopped, cannot explain it any easier, I'm an engineer and completely understand physics, i understand and my legs feel it what's occurring when peddling on the flats.
On the mountain tracks your not reaching these larger speeds which in many cases it would not be felt.
Anyway thanks for explanation.

Sounds odd to me. When on tarmac I spend a lot of time over the 25kph support cut off. I've never noticed any difference between having the motor switched on or off (I've tried both) in terms of resistance. (I've got a Gen 4 in a Jam² 6.7)

 

[Hobo Mikey]

I just pedal and enjoy the ride.

 

[Johnevo]

Have performance line cx and gen 4. Nil resistance in gen 4

 

[7869hodgy]

It’s getting used to the difference between motor assisted and normal riding.

I hated my ebike on the first long ride.

The tip is to be gear or two lower than you would normally be and it’s fine. However the extra weight does impact smoothness

 

[sunstoner]

Or try taking the chain off the front ring and try turning the pedals with your feet or hands, there is no resistance from the motor or the various mechanisms in it, what you are feeling is the effort of pedalling a 20+kg bike possibly in too high a gear when you have been used to the motor giving you free Watts.

Eg let's say the motor cuts out at exactly 15.5mph and let's say it takes 200watts to propel you and your bike at 15.49999 mph, you're putting in 100 Watts and the motor is giving 100 Watts, at 15.5mph the motor cuts out meaning you suddenly have to find another 100 Watts from somewhere in order to stay at 15.5mph because the motor is no longer giving any assistance, this is going to feel like a significant extra effort, which will feel like motor drag, but it's not, its just the extra effort of you having to provide all 200 Watts to maintain 15.5mph

Yep agree with the above.

Well put btw @Mteam

It is a strange feeling when you get past the limit. You can even feel the extra needed while bombing downhill at 15.5mph+ with no motor assistance. Granted its less, given assistance by the gradient but you can still feel it.

 

[Mikerb]

run higher tyre pressures and/or change to tyres with much lower rolling resistance and the chances are the apparent motor drag will be a lot less.

 

[Waynemarlow]

The tip is to be gear or two lower than you would normally be and it’s fine.

That sort of depends on the engine type, some of them have a poor high cadence response to input from the peddles ( thats just the nature of electric engines ), the later engines are getting better though with better elctronic control to get higher RPM of the motor.

But if you fool the brain into lowering your cadence by changing gear earlier than normal as the poster states, you can get a happy compromise on these early designs. Interestingly the brain understands better if you have a wider gap between each gear as in run a 9spd or 10 spd cassette, Suntour does now some really good solidly built wide ratio 10 spd cassettes, I've had them for years on our Ebike conversions, tad notchy when new, but after a couple of 100 miles, they bed in and at that point you change chains, not cassettes. Good kit if you can get over the brain brand issue.

 

[AF1]

I agree with Chris@EDC , but judging by the opposition on here to his notion, this motor resistance must be confined to only a few bikes. If so, then for both he and his ride buddy to experience it together is surprising. I too found that when pedaling above 15 mph on the flat or downhill, I definitely felt and heard the motor braking effect. Is there a clutch that might be malfunctioning?

 

[Stihldog]

In the past week my motor loses power momentarily,(Bosch gen4), I quickly shift down and power thru it until a reset occurs and then I’m able to continue on under peddle assist. On occasions I completely lose power to the motor and computer. This is when I need to stop and turn on the Kiox again.
I’m scheduled in to get this repaired at the LBS. Losing peddle assist has shown me that I must shift down quickly in order to maintain momentum. I don’t mean to hijack this thread but I have experienced analog peddling on a emtb.

 

[MarkoT]

I agree with Chris@EDC , but judging by the opposition on here to his notion, this motor resistance must be confined to only a few bikes. If so, then for both he and his ride buddy to experience it together is surprising. I too found that when pedaling above 15 mph on the flat or downhill, I definitely felt and heard the motor braking effect. Is there a clutch that might be malfunctioning?

Same here,
brand new bosch gen 4, it is weird feeling, when you pedaling above 15 mph, more you put power from your legs, more motor kinda lose somewhere it, if you pedal more lightly, motor drag is also lower.. it’s like offline speedlimiter, and it does it even you shut down the motor..

 

[flash]

Same here,
brand new bosch gen 4, it is weird feeling, when you pedaling above 15 mph, more you put power from your legs, more motor kinda lose somewhere it, if you pedal more lightly, motor drag is also lower.. it’s like offline speedlimiter, and it does it even you shut down the motor..

As stated above. Take the chain off and then pedal the bike (motor on or off or whatever). Removing all other factors is the only way to see what the motor is doing. Once the chain is on you also have bike weight, tyre choice, tyre pressure, *road* surface, gradient and a few other factors to take into account.

Not saying you don't have an issue but that's the way to find out.

Gordon

 

[Ricky_1973]

I've got 2 set of wheels on my cube stero hybrid 160, 1 with the Maxxis (minion back and assegai front) and 1 with schwalbe hurricanes - you will not believe the difference in rolling resitance - yes it is that staggering - with the maxxis is like you're on a constant brake while the schwalbes just keep on rolling forward. Just don't try to go downhill on those hurricanes...