still not to sure what to make of bosch ebike system

[Trevormonty]

With 15t on front should still have 1-2 extra gears for going >15mph assist cutoff ie going down hill.

The bosch like all mid drives uses gears to help it climb hills, just same as cars. If you select a to high gear it and you are going to struggle. A hub drive motor is already geared for moderate hills and will deliver its max performance regardless of which gear you are in or how much effort you put in, as long as you turn pedals to activity cadence sensing.



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[Woosh]

It could be worth you changing to either a 16t (40t equiv) or even 15t (37t equiv)

I am not sure that changing the front cog would make the OP spin the cranks any faster.
I don't know the physical condition of the OP but judging from the average customer coming into my shop, spinning the cranks at 85 RPM is OK for Darrana but out of the question for most of them.
Most of them can manage 60 RPM though. It's not so much that they lack of leg strength, it's just that they are not used to spinning fast.

This is a guy starting at 100 RPM, a tad more than necessary to get the best out of the CX, then slowing down a bit. If the OP can compare himself with the guy in the video and post his finding, we may figure out how to help him.

 

[EddiePJ]

I am not sure that changing the front cog would make the OP spin the cranks any faster.

But it would significantly lower the gearing, which would help make life easier.

Without a gear chart for reference, by how much would simply be guess work.

 

[Woosh]

I used to ride my little 20" folding Zephyr CDN but gave it up and ride my Compact CD, going from 20" wheels to 24" wheels because my cadence has dropped with time. It's not so much the legs power because both have cadence sensors, just that spinning fast builds up lactic acid faster than it can be removed. Aging in other words.

 

[KTM Bike Industries UK]

Cadence has nothing to do with power, its just how fast the cranks are spinning. If you drop the chain off you can spin at 100-150rpm with ease, so the bigger you make the gear the harder achieving any cadence becomes. So if you're trying to achieve 80ish RPM cadence, you make the front cog smaller, or the rear ones larger to make it easier to achieve the target cadence and therefore get the motor to do the most work. Its not about power really, its about learning to get the best from the motor.

 

[Woosh]

Cadence has nothing to do with power,

The OP said in his first post:

on a road that rises slightly regardless of going from tour to sport and whatever gear I seemed to be stuck at 11mph?

The OP can hit 15.5mph on flat roads but stuck at 11mph on that particular hill regardless of gear. That means that his legs can only provide so much power.
A steeper hill will slow him down below 11mph.

 

[Artstu]

I used to ride my little 20" folding Zephyr CDN but gave it up and ride my Compact CD, going from 20" wheels to 24" wheels because my cadence has dropped with time. It's not so much the legs power because both have cadence sensors, just that spinning fast builds up lactic acid faster than it can be removed. Aging in other words.

I'm genuinely shocked by the lack of understanding in this post. Who are you?

 

[Woosh]

I'm genuinely shocked by the lack of understanding in this post. Who are you?

there is nothing special. Both bikes are crank driven with the same Bewo motor on the same rotational sensor system, same 46T chainring, you pedal as much or as little as you like, power wise. My 20" bike has Nexus 3 IGH, 18T cog. My 24" compact has 8-speed 11T-34T freehub. Both have roughly the same weight.
The speed is of course tied to the selected gear. I still have both bikes, both are compact and light but I now prefer the 24" although it only half folds, because the 24" bike has more gear inches than the 20" bike, I prefer it because the cadence is more leisurely.

 

[Deleted member 4366]

I'm genuinely shocked by the lack of understanding in this post. Who are you?

I'm not convinced by what you're saying. It's programmed to respond in a certain way based on cadence and pressure, so learning to get the best from it is about watching that power scale and giving it what it wants for the best results power wise.

I'm not shocked by what's written in this thread, but there's certainly a lack of understanding about how motors work. As I keep saying, you need torque to climb hills, not power. All our ebike motors make maximum torque at low speed. It doesn't matter if you have a Bafang hub-motor or a Bosch mid-drive. They make maximum power at about 75% of maximum rpm but if you don't have enough torque, you can't reach that speed.

What most people are saying is that if you find that a hill is too steep to walk up, try running up it because you make more power when you run.

 

[nemesis]

I have a Bafang BBSHD 1500w mid motor MTB and a Bosch CX hybrid and the Bosch is not far behind the Bafang in performance,both great motors.The Bafang has no torque sensor so gives full power with just crank movement sensing.

 

[footpump]

hi all max cadence would be about 70 on flat but not for very long.
the intuvia display shows a down arrow, which suggests dropping to a lower gear if it senses the gear your in might be too high.
the hill in question 1.5 miles ramps up a fair bit in the last few hundred yards.
not sure if I would do it on my vita uno speed sensor as its 3 years since I tried the same route.
whilst stationary I hear (good morning) as lycra lad on racing bike goes past but not as fast as I would have thought managed to catch up with him in turbo.
the other thing is trying to find reviews of bosch bikes from owners, seems few and far between, plenty of stuff from bosch showing Heinz and Helga pootling along on the flat at 10mph.
the active line described by bosch as (harmonius) performance line as sporty.

lots of you tube stuff most in german though.

have fitted cadence computer to my subway,

 

[Artstu]

My Bosch Classic goes up hills like this

 

[Emo Rider]

I'm not shocked by what's written in this thread, but there's certainly a lack of understanding about how motors work. As I keep saying, you need torque to climb hills, not power. All our ebike motors make maximum torque at low speed. It doesn't matter if you have a Bafang hub-motor or a Bosch mid-drive. They make maximum power at about 75% of maximum rpm but if you don't have enough torque, you can't reach that speed.

What most people are saying is that if you find that a hill is too steep to walk up, try running up it because you make more power when you run.

On my Yamaha system, going up a hill, there are times I upshift to increase resistance thus tricking the system to cut in. This helps me pick up speed and get back up to the cadence I perfer. Otherwise, I would still be plodding along at a slower speed. Having said that I do agree with what you are saying about torque. It is still no more work at the correct power setting. I never use high btw.

 

[soundwave]

hi all max cadence would be about 70 on flat but not for very long.
the intuvia display shows a down arrow, which suggests dropping to a lower gear if it senses the gear your in might be too high.
the hill in question 1.5 miles ramps up a fair bit in the last few hundred yards.
not sure if I would do it on my vita uno speed sensor as its 3 years since I tried the same route.
whilst stationary I hear (good morning) as lycra lad on racing bike goes past but not as fast as I would have thought managed to catch up with him in turbo.
the other thing is trying to find reviews of bosch bikes from owners, seems few and far between, plenty of stuff from bosch showing Heinz and Helga pootling along on the flat at 10mph.
the active line described by bosch as (harmonius) performance line as sporty.

lots of you tube stuff most in german though.

have fitted cadence computer to my subway,

you not seen my vids then lol

 

[chris_n]

I'm not shocked by what's written in this thread, but there's certainly a lack of understanding about how motors work. As I keep saying, you need torque to climb hills, not power. All our ebike motors make maximum torque at low speed. It doesn't matter if you have a Bafang hub-motor or a Bosch mid-drive. They make maximum power at about 75% of maximum rpm but if you don't have enough torque, you can't reach that speed.

What most people are saying is that if you find that a hill is too steep to walk up, try running up it because you make more power when you run.

As I said earlier he is still two gears above his lowest, why worry about 11mph it's irrelevant. As d8veh says it's all about torque, lower the gearing and sit there spinningyour pedals in bottom gear and torque multiplication will get you there.
I was spinning up an Alpine climb this morning at 7Kmh overtaking regular MTBs on my Yamaha motor even in eco power setting (looking to increase range and up my work rate), if I upped it to std or max I could either go faster in a higher gear or keep the same speed in a lower gear with considerably less effort.

 

[footpump]

2 weeks ago saw someone I spoke two before on a reise and muller ebike,
he was going up a steep hill, not sure of speed but certainly did not seem to be spinning the pedals at any great speed or cadence, not a young guy neither.
I have just spotted that reise and muller have bosch moters so have perused a bit more.
the r+s bike is a nevo touring hs the moter is the performance vertion so 63nm vs 50nm but I believe this is a s class pedelec so assists up to 28mph
if its torque rather than power for hills as stated
or have I missed something as regards the nevo
https://www.r-m.de/en-gb/e-bike/nevo/nevo-touring-hs/#17N06_040206

 

[soundwave]

if you want gearing to go up steep hills then you want a smaller sprocket 14-16t if you are wanting speed then a 18-20t sprocket is what you want. how fast you want to spin the pedals just depends on what size sprocket you like i have 18t on my bike and a 15t for climbing if i need it.

tho if you stick this on it it will not even climb hardly anything was a fkn mission just to get going even on the flat tbh

 

[Danidl]

I'm not shocked by what's written in this thread, but there's certainly a lack of understanding about how motors work. As I keep saying, you need torque to climb hills, not power. All our ebike motors make maximum torque at low speed. It doesn't matter if you have a Bafang hub-motor or a Bosch mid-drive. They make maximum power at about 75% of maximum rpm but if you don't have enough torque, you can't reach that speed.

What most people are saying is that if you find that a hill is too steep to walk up, try running up it because you make more power when you run.

... d8veh, as you well know, but others might not, power is torque x revs . In a hub motor the designer decided on an optimum road speed and selected the motor accordingly. In a crank drive, the designer did not have to make that decision, as the gears allow the user to select between cadence , roadspeed and torque.

 

[Woosh]

In a hub motor the designer decided on an optimum road speed and selected the motor accordingly.

and the target weight of the rider because acceleration is an important design goal.
I use several motors for different rider weights; Bafang SWXH for up to 14st, SWX02 for up to 16st and BPM for over 16st. The Bafang G06 motor on the Rio fat bike has same pulling power of the BPM.

 

[anotherkiwi]

Thanks for the video Woosh my cadence is effectively between 80 and 90 just by eye. You also know you are at the right cadence by motor noise, if you are in the wrong gear and at the wrong cadence the motor will tell you.