Bosch mid drive

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sendler2112

100 kW
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Dec 7, 2012
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Seems there is very little written (little interest in turn key mid drive bikes due to cost) about the Bosch mid drive. I'm looking for a good torque sensing trail bike for my son to help him keep up with me on my regular mountain bike. For tight single track. From what I have read on EBR the Bosch has the most transparent torque sensing assist. So no need for a throttle to complicate things in the woods over muddy roots. Do these work well in low speed, tight trails. My other concern, is the top overall gearing of the Bosch long enough with an 11 tooth rear. The front sprocket is only 18 but I do know that there is an internal multiplier on the crank. Can this system pedal as fast downhill as a normal 44x13 bike? What do you think about the IZIP at $3,000. I don't have time to mess with a kit.
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https://electricbikereview.com/izip/e3-peak-plus/
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Or just go with something cheaper like the Magnum with cadence and a trigger.
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https://electricbikereview.com/magnum/peak-ebike/
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I would have to say the Yamaha has slightly quicker engagement on the PAS and uses regular chainrings also, so replacement is easier. The Bosch drivers get hooked teeth pretty quickly that suck a new chain up so every few chain swaps you need to do the driver too.

Both systems though totally lock you into their proprietary chargers, batteries, replacement displays after a crash etc, so there is a lot to be said for a simpler system like the Magnum where if (when) it fails, you could get generic charger, or a replacement motor cheap, and maybe that your kid could learn to keep running, which isn't going to happen with a Bosch unless he's a computer genius that can build his own dongle and software hack to talk to the Bosch system.

Re fast downhills... unless you get a speed model (28mph) or aftermarket speed unlocker, the Bosch has a real hard cutout at about 19.5 miles an hour. So any trail faster than that, it will just feel like a heavy bike as the power won't come on. I find for a good pedaler on say a fire road where you can go fast, it can be annoying sometimes where you're rolling into a low spot, and want to build speed for a short climb ahead... right as you're getting on it to build momentum the motor cuts out, and really disrupts the feeling of the sprinting towards a hill to momentum your way up it roller coaster style and then rolling right into the next one. But if you're never going that fast to where you're crossing that 19.5 barrier a lot, its not a problem.
 
Voltron said:
I would have to say the Yamaha has slightly quicker engagement on the PAS and uses regular chainrings also, so replacement is easier. The Bosch drivers get hooked teeth pretty quickly that suck a new chain up so every few chain swaps you need to do the driver too.

Both systems though totally lock you into their proprietary chargers, batteries, replacement displays after a crash etc, so there is a lot to be said for a simpler system like the Magnum where if (when) it fails, you could get generic charger, or a replacement motor cheap, and maybe that your kid could learn to keep running, which isn't going to happen with a Bosch unless he's a computer genius that can build his own dongle and software hack to talk to the Bosch system.

Re fast downhills... unless you get a speed model (28mph) or aftermarket speed unlocker, the Bosch has a real hard cutout at about 19.5 miles an hour. So any trail faster than that, it will just feel like a heavy bike as the power won't come on. I find for a good pedaler on say a fire road where you can go fast, it can be annoying sometimes where you're rolling into a low spot, and want to build speed for a short climb ahead... right as you're getting on it to build momentum the motor cuts out, and really disrupts the feeling of the sprinting towards a hill to momentum your way up it roller coaster style and then rolling right into the next one. But if you're never going that fast to where you're crossing that 19.5 barrier a lot, its not a problem.
Click to expand...

Have you had a chance to ride an eMTb with the Shimano system? I am curious how it compares to the other OEMs.
 
The reviewer seemed to like the Bosch better than the Yamaha saying that the Yamaha was programmed to a low cadence, or had a low kv, so he couldn't spin up hills. And except for not having zero start below 20 rpm, he felt that the Bosch had quicker response.
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https://electricbikereview.com/guides/ebike-mid-drive-motor-comparison/
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I'm still wondering about the over gearing with the Bosch. I understand the power will drop out at 20 mph, but does it have enough gearing with an 11 in the back to pedal faster on your own for down hills. Or are your legs also spun out around 20 mph since it has an 18 in the front?
 
sendler2112 said:
Now that I found this torque sensing mid drive kit I might go with that.
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https://endless-sphere.com/forums/viewtopic.php?f=28&t=79788
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Click to expand...

They seem to have the most quality issues so far. I own one but its coming off soon to be replaced with a better system for our needs. Its not for sale.

The Bafang BBS02 would be a better option IMO.
 
Triketech said:
sendler2112 said:
Now that I found this torque sensing mid drive kit I might go with that.
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https://endless-sphere.com/forums/viewtopic.php?f=28&t=79788
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Click to expand...

They seem to have the most quality issues so far. I own one but its coming off soon to be replaced with a better system for our needs. Its not for sale.

The Bafang BBS02 would be a better option IMO.
Click to expand...
Agreed, having had all the BBSxx series and now the TSDZ, I'm disappointed in the Tongsheng. MAC from here on out. Nuff PIA mid drives. Unless I were a power fan and went with one of the custom mid drives. I'm so done with China's mids.
 
sendler2112 said:
I'm looking for a good torque sensing trail bike for my son to help him keep up with me on my regular mountain bike.
Click to expand...

From following the largest German language forums for eMTB at https://www.pedelecforum.de/forum/index.php?forums/fertig-pedelecs.14/ it would appear that the Bosch CX system is the most powerful one (in terms of output), the Brose system would seem to be the most driveable one (best human-machine-integration), and the Shimano E8000 system somewhere in between.

All of these are tightly integrated mid-drive solutions.

Note that all of this is within the rules defined in the EU for electric bikes - but given that people ride serious alpine trails uphill with that, it would seem as if the machinery is not the limit, there. Ignore these 250 Watts labels - these are present to satisfy EU directives; in reality "peaks" are much higher.

A nice online magazine can be found at http://ebike-mtb.com/en/ - this will give you an idea of the market place in, let's say, continental Europe at the moment, target demographic being people killing it in the Alps.

If I was ready to spend now, I'd go for some 2018 Specialized Turbo Levo kit (https://www.specialized.com/ch/de/men/bikes/mountain/turbo-levo/turbo-levo-fsr); the Specialized R&D center for eMTB is located sufficiently close to the Swiss Alps (in Cham, Switzerland) to allow for efficient testing :p
 
I am friends with the local bike shop owner who is the number 1 Specialized ebike seller in NY. He has offered to give demos for an entire trail ride. But the pricing of all high end mid drive bikes is so high,
 
sendler2112 said:
But the pricing of all high end mid drive bikes is so high,
Click to expand...

You pay ("bleed out of the nose"?) for the R&D that goes into human-machine-integration (HMI); suffer from the fact that the market is all but saturated; are crowded out by plenty of people who have plenty of disposable income they like to spend on new toys.

Yeah, 6-7k Euro (list price, new) on such a bike is nothing to sneeze at.
 
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