I sent the following email to Specialized Care today. Perhaps, your answer will prove more informative?

I own a 2015 Specialized Diverge (mechanical bike). I live in Denver. I am a strong rider. I generally

ride about 5,000 miles per year. I weigh 225 pounds. I have generated over

800 watts on a stationary bike. I do not have a power meter, so I do not

know how much power I can sustain over 70 miles. I am a software engineer,

so precise calculations are important to me.

The main reason for considering a Creo Expert is to ride 70 miles from

Denver to Fort Collins as fast as possible.

I have a mechanical mountain bike with a single chainring. I start to spin out of

gears on my mountain bike at higher speeds. I do not like the single chain

ring efficiency at speeds over 25mph.

I always use the big chainring on my Specialized Diverge for 25mph speeds. I would like

the Creo Expert chain to be as straight as possible at 25mph. I expect to

ride for miles, on country roads, in the same gear at 25mph. My typical

cadence is 95 RPM.

1. Which chainring/cassette combination is optimal for 25mph battery

consumption?

2. How much aerodynamic overhead does the Creo frame incur over the

Diverge?

- The bottom bracket is wider. I suppose the downtube is wider to

accommodate the battery?

3. How much power is consumed by the eBike to overcome it's weight,

aerodynamics, motor resistance, etc...?

- I suppose the Eco setting (30%) is needed to offset the overhead?

4. If I rode the bike with and without electric power, how would I

calculate the minimum motor power and battery capacity I would need to ride

70 miles at 25mph?

5. Is the Di2 shifter synchronized with the motor to suspend power when

shifting gears?

I understand 170 watts are generally required to reach 20mph speeds. 300

watts are generally required to reach 25mph speeds. The SL 1.1 is rated at

240 watts. The maximum sustained speed of the motor should be between 20 to

25mph. 28mph only makes sense to me, when I supply the underlying speed.

1. What speed do I need to pedal the Creo Expert at without power, for

the bike to achieve 28mph with power?

Attached please see the ride I am most concerned about optimizing battery power at 25mph. The section from Westminster to Boyd Lake State Park.

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