# Smaller and more powerful, the evolution of motors continues



## Harryman (Jun 14, 2011)

"The result is a bit like a chip tuning for your car: the software should now enable more torque and a superior performance over a broader cadence range, which essentially makes the motor more attractive for those riders looking for speed and performance."

Too bad it's only the old and disabled riders interested in emtbs. 

First Ride: Giant Full-E+ 0 SX Pro with the all new SyncDrive Pro Motor | E-MOUNTAINBIKE Magazine


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## jsalas2 (Nov 29, 2008)

Good read, thanks.


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## eBikesmith (Jan 31, 2017)

I'm glad to see Giant putting out a nice product with a solid EX1 drivetrain. Interesting choice with the Yamaha over Bosch. I'm also glad to see Yamaha stepping up their game. To the OP, the title feels misleading. I was under the impression that this wouldn't just be a class 2 eMTB. 

80Nm of torque is not exactly evolutionary. With a 500Wh battery, an avg rider will hit 6-10mph on most uphill grades at most, and will definitely be slower than pretty much any decent AM or DH bike on the descent. Again, thanks for the read, but title is a bit misleading.


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## Harryman (Jun 14, 2011)

eBikesmith said:


> I was under the impression that this wouldn't just be a class 2 eMTB.


It's not, it's a Pedelec, they are limited to 250w continuous and no throttle. It would be sold as a Class 1 here.


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## Gutch (Dec 17, 2010)

Hmmm, may give my anticipated Moustache ebike a run for the money.


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## Moe Ped (Aug 24, 2009)

Not sure if I did the math correctly but if this system delivers 80Nm torque at a cadence of 120 rpm that's a 1000 watt motor output.


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## JRT_in_WMass (Jul 22, 2013)

Moe Ped said:


> Not sure if I did the math correctly but if this system delivers 80Nm torque at a cadence of 120 rpm that's a 1000 watt motor output.


 You seem to have wrongly attributed total power output to the motor and have not subtracted out the rider's contribution to the total.

I have no direct experience with the drive assy under consideration, so my comment in this is based on the description provided by the article linked by the OP. The article claims output torque of 80 Nm at 360% of rider input at 120 rpm pedal cadence. The article does not indicate that the drive assy output rpm is the same as rider cadence input rpm, and that perhaps false assumption is included in the calculations below.

Max power output from drive assy, motor and e-bicyclist combined: 
(80 Nm * 120 rpm ) / 9.549 = 1005 W

360.0% = 3.600

Rider contribution to drive assy output 
torque: 80.00 Nm / 3.600 = 22.22 Nm 
power: 1005 W / 3.600 = 279.2 W

Motor contribution to drive assy output 
torque: 80.00 Nm - 22.22 Nm = 57.78 Nm 
power: 1005 W - 279.2 W = 725.8 W

If the motor considered separately is limited to 750 W, then...
725.8 W / 750.0 W = .9678 = 96.78% efficiency, which seems optimistic but might be plausible at optimum design operating conditions.


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