Bosch climbing speed

[fishingpaul]

I was chatting to somebody with a new bosch cube bike,asking what it was like on our local hills,he said it does 15mph and then cuts out,it still does 15mph up a nearby 20% hill in turbo mode apparently,the best i can manage on a good day is about 13 mph at the steepest point on said hill,this is with a de- restricted ezee motor at 48v and 18a controller,and with a decent amount of pedaling effort, i thought that was pretty good,compared to some of my previous ebikes that have only made 7 or 8 mph up this hill,is the bosch really that good,running at the legal setting as supplied.

 

[Danidl]

I was chatting to somebody with a new bosch cube bike,asking what it was like on our local hills,he said it does 15mph up a nearby 20% hill in turbo mode,the best i can manage on a good day is about 13 mph at the steepest point,on a de- restricted ezee motor at 48v 18a controller,with a decent amount of pedaling effort, i thought that was pretty good,compared to some of my previous ebikes that have only made 7 or 8 mph,is the bosch really that good,running at the legal setting as supplied.

Yes it does . But remember you are also pedelling a good bit also. You get 250% extra for any effort you put in. So compared to an ordinary non electric bike you are getting 350% total effort.

 

[fishingpaul]

Yes it does . But remember you are also pedelling a good bit also. You get 250% extra for any effort you put in. So compared to an ordinary non electric bike you are getting 350% total effort.

 

[KTM Bike Industries UK]

Yes it does . But remember you are also pedelling a good bit also. You get 250% extra for any effort you put in. So compared to an ordinary non electric bike you are getting 350% total effort.

The CX motor is 300% extra

 

[fishingpaul]

On the steepest bits i drop to 13mph,still climbing i can get 19mph at the top of the hill,without assistance i would imagine 4mph at the steepest ,and 8mph at the top,i once managed the hill with a broken chain,but it was very slow going.

 

[fishingpaul]

Ok 300% extra,does that mean 15 mph is effortless up a steep hill,that lycras get out of the saddle to go up,and casual riders often get up and push rather than ride.

 

[soundwave]

under cut off speed the motor can use 7-800w at 18a well the Yamaha one does so will be close to that

its why i can hit speeds of over 30mph on the flat

 

[georgehenry]

On one of the hills I regularly use to get back home from the shops I can hit just shy of 20mph in the standard setting on my yamaha but that does require me to hunker down and add as much effort as I can, sort of team effort.

Even on steep hills in standard it can maintain 12mph with a relaxed rider, and when I want the exercise 12mph in eco, but that requires a lot of effort from the rider.

I have to say that in comparison to my quite aged hub drive bike the crank drive Yamaha really shines when climbing.

I have a local off road hill that I loved to try and climb on my conventional hard tail and which is a complete bugger being as steep as I can manage and with lips, loads of roots and a smattering of rocks as well as narrow and technical. For ages I just could not get up it. Then one day I managed it and knowing it was possible started to get up it more frequently after that but still often with many a fail.

After getting my sDuro Yamaha I rode it over to the hill to see how it would cope and it went up with laughable ease.

 

[IR772]

Ok 300% extra,does that mean 15 mph is effortless up a steep hill,that lycras get out of the saddle to go up,and casual riders often get up and push rather than ride.

No

 

[Danidl]

Ok 300% extra,does that mean 15 mph is effortless up a steep hill,that lycras get out of the saddle to go up,and casual riders often get up and push rather than ride.

.. doable yes , effortless no.

 

[Trevormonty]

The CX drive will get you most hills without breaking a sweat if you take it easy and use low gear. Typically double your manual climbing speed without a sweat, triple if you are willing to put some effort in.

I initially made mistake of going all out in low gear (12km/hr) on very steep off road hills and failed. Drop speed back to around 8km/hr and it just hauls me up if I can keep front wheel on ground.

 

[footpump]

ive looked recently at cube and giant mtbs £2300-£2700 out of my price range but all seem to have powerfull moters 75-80nm
bosch active line 50nm bosch performance 63 bosch performance cx 75nm

I actually came to dead stop trying to go up a short steepish hill (50nm moter activeline)

 

[soundwave]

the active performance and sclass motors are all the same inside and software limited.

the cx motor is also the same just a bit smaller and more nm.

 

[Danidl]

ive looked recently at cube and giant mtbs £2300-£2700 out of my price range but all seem to have powerfull moters 75-80nm
bosch active line 50nm bosch performance 63 bosch performance cx 75nm

I actually came to dead stop trying to go up a short steepish hill (50nm moter activeline)

What gear were you in ?

 

[Trevormonty]

Active with 15t chainring and 9 spd 11-34(34) should climb almost any sealed hill without any problem.

Part reason my CX is such great climber is low gearing 15t 11spd 11-42.

 

[fishingpaul]

Sorry to put it another way,but would a 16 stone at a guess fairly unfit rider,be able to do 15mph on a 20% hill on a cube bosch motor,i do not doubt that they would climb almost any hill,but are they so good that the 15mph top speed,is easier to maintain than on a bafang bpm or ezee hub motor,i thought crank drive motors were better for climbing very steep hills but at lower speeds.

 

[Danidl]

Sorry to put it another way,but would a 16 stone at a guess fairly unfit rider,be able to do 15mph on a 20% hill on a cube bosch motor,i do not doubt that they would climb almost any hill,but are they so good that the 15mph top speed,is easier to maintain than on a bafang bpm or ezee hub motor,i thought crank drive motors were better for climbing very steep hills but at lower speeds.

The attached reference gives a calculator for bike power consumption , and takes into account the normal power losses of wind resistance, tyre rolling resistance and also gradient. A human being can generate 50 watts indefinitely... Well for hours on end, 100 watts for shorter times and upwards of 500 watts for very short explosive exertions. A trained cyclist with well developed muscles and lungs can double some of these these.. maybe.

https://www.gribble.org/cycling/power_v_speed.html.
According to this calculator a 100 kg person on a 25kg bike and travelling at 25km.hr will need 110 watts of power , whether from a battery or by their own muscle or both. . This assumes still air, so the person is travelling relative to the air at 25jm.hr.
If the slope of the road is 1% rise the power rises to 200w
If the slope is 5% rise the power is 500w
If the slope is 10% rise the power is 1000w.
If the slope is 20% rise the power is 2000w.

On turbo assist mode the peak power is 3.5times the human input. , If the person puts in 100w then the total power is 350w or 25km on a 3% slope.
If the person were to put in 200 watts, then a total of 700 watt could result... This would be in my opinion at or beyond the limit of the Bosch engine.and were it done, the battery would be fully depleted in 20 minutes.

 

[anotherkiwi]

Nice calculator! 45 km/h for an unrestricted GSM on the flat at 500W spot on the numbers!

 

[Danidl]

I was chatting to somebody with a new bosch cube bike,asking what it was like on our local hills,he said it does 15mph and then cuts out,it still does 15mph up a nearby 20% hill in turbo mode apparently,the best i can manage on a good day is about 13 mph at the steepest point on said hill,this is with a de- restricted ezee motor at 48v and 18a controller,and with a decent amount of pedaling effort, i thought that was pretty good,compared to some of my previous ebikes that have only made 7 or 8 mph up this hill,is the bosch really that good,running at the legal setting as supplied.

... The term cut out is misleading... The bosch motor gives full power assistance up to 15 then it progressively gives less and less so that it is giving nothing at about 16 .., once you drop below 15 the power comes back on.
A key point is that any of the motors need to be close to their sweet spot speed for max power . With the multiple gears on a cd motor that is easier to achieve. On a hub motor, unless it can get up to that speed,. It wastes energy into heat. If it can get there then it will be just as effective.

 

[footpump]

hi all if indeed moters are all the same but software limited is there a (chip) in the moter or the software in the lcd?
there does not seem to be any bosch/dealer options to go from active to performance .
yesterday tried same hill Carrera with tdz cd drive I am not sure if mines 60nm or 80nm 250 watt though, sport mode 44front 3rd largest on rear bit of a run at it got up ok bit off an effort.
I believe my bosch bike has 18t front which I think equals 36t used rear 23 then 26 got up it but some effort rear is 11-34