still not to sure what to make of bosch ebike system

[footpump]

have been trying to get to grips with my bosch powered ktm macinna active line
have now covered 130 miles.
shortish none to steep hills I can do ok in sport.
on a road that rises slightly regardless of going from tour to sport and whatever gear I seemed to be stuck at 11mph?
saterday on my subway one tdz mid drive loaded with panniers and locks went to open air market and returned with bulging panniers this is a 25 mile round trip with 16 very hilly miles sport mode.
not sure I could do the same trip on the bosch which is lighter 20.4kg but 50nm vs 60nm tdz

I tried a local hill yesterday about 1.5 miles which rises fairly steeply near the end in turbo but did not make it to the top,
range however 48 miles 2 bars showing out of 5 average speed a lowly 9.3mph

 

[Deleted member 4366]

How heavy are you?

 

[Danidl]

How heavy are you?

... And wind direction and speed matters a lot also..

 

[KTM Bike Industries UK]

You need to spin more with Bosch... look at the little black bar chart on the side of the display, if this isn't at the top, the Bosch motor isn't helping you at its max potential. Change down a few gears and go at a faster cadence (not more power) just spin and see if it works.

 

[KTM Bike Industries UK]

Here is a useful graph that might help explain what I mean... and some explanation I've just found on the wonderful world wide web.

"nteresting graph here from a German Discussion Forum. Note that this was measured before Brose's latest Motor Update which is said to have increased it's performance a bit.
X = Cadence, Y = Watt. Remember that W = U/Min (Cadence) x Torque (NM).
The performance benefit of the Bosch CX results from it's internal 1:2.5 gearing which allows the Motor to operate in a optimized performance window.
Things that can be seen here:
- Yamaha (old one, not PW-X) is optimized for lower cadence
- Shimano peaks at a cadence of 90!
- Bosch CX peaks around 85...
- Brose did a very bad Job (until their latest update), and this confirms our own findings that as a Levo rider (or similar) you are the slowass in a Bosch CX rider group

Cheers"

Thanks to the facebook group for finding this.

eMTB Electric Mountain Bike Smile

https://www.facebook.com/groups/1744092975911526/?fref=nf

 

[Woosh]

- Shimano peaks at a cadence of 90!
- Bosch CX peaks around 85...

your heart must be in pretty good condition to maintain this sort of cadence for more than a couple of minutes.

 

[KTM Bike Industries UK]

your heart must be in pretty good condition to maintain this sort of cadence for more than a couple of minutes.

Nothing to do with your heart... cadance is about spinning your legs, not about the load / power that is being put through them.

My 70+ year old mum, who's just had hip surgery, can beat me up steep hills in the Cotswolds on a Bosch Active line bike, when I'm on my normal road race bike.

You have to ride them slightly differently to normal bikes, just spin, its not all about power from the rider, the motor does it for you.

 

[KTM Bike Industries UK]

your heart must be in pretty good condition to maintain this sort of cadence for more than a couple of minutes.

and also remember, if you put out that cadance, it'll give you c600 watts of additional support, which is A LOT.

You don't have to put in that cadance to get a lot more power than even professional cyclists can maintain.

 

[Woosh]

you must have inherited her excellent genes!
The user has to put in at least 25%, the bike 75% at most. In order to beat you at climbing hills, I suppose your Mum puts in 200W at 85 rpm, the motor 600W, her heart rate should be what? 110 bpm?

 

[Deleted member 4366]

Those graphs are completely misleading when it comes to hill-climbing. It's torque you need to climb steep hills, not power. Power only affects how fast you can go up the hill if you have enough torque. You can have massive torque for climbing with very low power. That's why my small Xiongda motor can climb steeper hills then any 1500w direct drive motor.

The problem OP has is that he can't get enough torque from the motor, presumably because he can't press the pedals hard enough to get maximum torque when he needs it. If he changes down to first gear and is starting to stall out, how is he supposed to spin the pedals faster? That's his whole problem that he can't spin the pedals fast enough. Telling him to spin them faster is not going to help!

 

[Emo Rider]

Nothing to do with your heart... cadance is about spinning your legs, not about the load / power that is being put through them.

My 70+ year old mum, who's just had hip surgery, can beat me up steep hills in the Cotswolds on a Bosch Active line bike, when I'm on my normal road race bike.

You have to ride them slightly differently to normal bikes, just spin, its not all about power from the rider, the motor does it for you.

It is all about the cadence and I give this advice to all my customers. I use to be in triathelon club and learned about the value of higher cadence on a regular road bike. Maintaining the same speed, cycling at an 80 to 90 rpm cadence in the right gear results in a lower heart rate than cycling slower in a gear too high. I can achieve greater range using a high cadence and use the the rpm display on my Yamaha system to measure my peddaling speed.

 

[Deleted member 4366]

It is all about the cadence and I give this advice to all my customers. I use to be in triathelon club and learned about the value of higher cadence on a regular road bike. Maintaining the same speed, cycling at an 80 to 90 rpm cadence in the right gear results in a lower heart rate than cycling slower in a gear too high. I can achieve greater range using a high cadence and use the the rpm display on my Yamaha system to measure my peddaling speed.

You're stating the obvious. What you're saying is that if you make more power, you can go faster. If it were that easy, we'd all be pedalling unassisted bikes with our feet going like a blur. The problem is when you can't make enough power.

As I said before, it's torque you need for climbing, not cadence. Generally, you can make more torque at a lower cadence

 

[KTM Bike Industries UK]

you must have inherited her excellent genes!
The user has to put in at least 25%, the bike 75% at most. In order to beat you at climbing hills, I suppose your Mum puts in 200W at 85 rpm, the motor 600W, her heart rate should be what? 110 bpm?

Sounds like you need to a) try some Bosch bikes, because it does sound like you don't understand your competition. Bosch are doing very very well in the UK, and its for a number of good reasons.

also b), my mother, and her side of the family has zero sporting back ground, I got my cycling legs from my Dad who's raced bikes since the early 60s. There is no way on this earth my mum is putting out 200w, no way. To get up hills I put out 300-400w on my road bike (I have a power meter), so to beat me, my Mum just needs to put out more than that with the help of the motor, and she can easily.

 

[Woosh]

it does sound like you don't understand your competition.

can't say I do, because most of my customers would rather have a throttle just in case.

 

[KTM Bike Industries UK]

can't say I do, because most of my customers would rather have a throttle just in case.

Ok, so maybe this thread isn't for you... or are you just commenting to try to put people off something you don't understand?

 

[Woosh]

or are you just commenting to try to put people off something you don't understand?

no, it's not that. I made a torque sensor bike before and sales were disappointing because we don't have the right profile to sell bikes to the younger ones.
Quite a lot of my customers suffer type 2 diabetes. Their energy level can suddenly drops, making torque sensor bike unsuitable.

 

[KTM Bike Industries UK]

no, it's not that. I made a torque sensor bike before and sales were disappointing because we don't have the right profile to sell bikes to the younger ones.
Quite a lot of my customers suffer type 2 diabetes. Their energy level can suddenly drops, making torque sensor bike unsuitable.

Still not sure why you're commentating on a Bosch thread then, when you have no experience of it. Its clear you're just trying to push your product, not support this or other customers on how to get the most out of their drive.

 

[Emo Rider]

You're stating the obvious. What you're saying is that if you make more power, you can go faster. If it were that easy, we'd all be pedalling unassisted bikes with our feet going like a blur. The problem is when you can't make enough power.

As I said before, it's torque you need for climbing, not cadence. Generally, you can make more torque at a lower cadence

Right you are. And I am guilty of not taking my own advice when on the flats I turn up the power and use a higher gear so the bike does most of the work. I can also do this on hills but like the op said, I will not be able to hit 15mph unless I downshift and pedal faster. It is not as tiring as one might think.

You're stating the obvious. What you're saying is that if you make more power, you can go faster. If it were that easy, we'd all be pedalling unassisted bikes with our feet going like a blur. The problem is when you can't make enough power.

As I said before, it's torque you need for climbing, not cadence. Generally, you can make more torque at a lower cadence

 

[Woosh]

Still not sure why you're commentating on a Bosch thread then, when you have no experience of it. Its clear you're just trying to push your product, not support this or other customers on how to get the most out of their drive.

the physics is simple: the work that the user must input into a Bosch system is 25%. Work = power * time.
Where:
Power = torque * rotational speed, (power in Watts, torque in NM and rotational speed in radian/s).

So the faster you rotate, the lower the torque (less effort on the pedals) you have to input in order to produce the work.

 

[Emo Rider]

the physics is simple: the work that the user must input into a Bosch system is 25%. Work = power * time.
Where:
Power = torque * rotational speed, (power in Watts, torque in NM and rotational speed in radian/s).

So the faster you rotate, the lower the torque (less effort on the pedals) you have to input in order to produce the work.

You are basically correct. If you are in first gear on the low power setting on a torque bike, you will not be able to hit 15mph on a flat or hill. Your formula proves that. But tucking into a hill at full power creates the chain tension that causes the system to respond as and when the incline increases. At first there is no feeling of greater resistance at the pedals through your legs. But as resistance increases, as you climb the hill, downshifting will make this go away. It is all about understanding your bike and how it works. And yes, there are some people that a torque bike is not the best for them. This is all about helping the customer make an informed choice on what's best for them.