#### Cybersnow

##### Active Member

- Region
- USA

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- Thread starter Cybersnow
- Start date

- Region
- USA

- Region
- USA

- City
- Carlsbad, CA

In another thread, I wrote,

Not so easy to find, but I eventually dug up this technical page on their E-14 Speedhub.

The internal ratios for gears 1 and 14 are 0.279 and 1.467, resp. With the Ultra's external ratio of 2.5 and an assumed 27.5 inch wheel diameter, that gives 19 and 101 gear-inches, resp.

With that information and answers to the questions below, you could figure out your ideal external ratio and see how close you can get with available front and rear belt sprockets.

Happy to help with the math.

In principle, you could use the same belt if the

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- Region
- USA

Great questions, thanks!

Ideally I would like to be cruising in Rohloff gear 11 @ a cadence of about 70 and going about 16 mph. My legs are relatively strong but not so fast. I can maintain a 60-70 cadence without much trouble. My previous e bike was very light Salsa touring bike with a 750watt bafang motor and battery kit and we did a number of long trips where we averaged about 50 miles a day.

Sorry, not so smart on gear inches. By my simple math of 27.5x3.14x3,05=263.4 which is the distance traveled in inches for 1 pedal rotation. 263.4/12=21.9 is the distance in feet. 21.9x60x60/5280= mph 14.9 at a cadence of 60 and about 17.4 mph at a cadence of 70. This is in gear 11 which I understand is 1 to 1. I compare that to current speed of 12.3 with the same cadence of 60. Not sure what the speed would be in gear 14.

Not sure I did this right but totally open to your input. Also Ravi was asking if I could hit a speed of 20 on a flat but I managed to get to about 18.x in gear 14.

I was very surprised at the overall performance of the bike, not at all that I expected.

Ideally I would like to be cruising in Rohloff gear 11 @ a cadence of about 70 and going about 16 mph. My legs are relatively strong but not so fast. I can maintain a 60-70 cadence without much trouble. My previous e bike was very light Salsa touring bike with a 750watt bafang motor and battery kit and we did a number of long trips where we averaged about 50 miles a day.

Sorry, not so smart on gear inches. By my simple math of 27.5x3.14x3,05=263.4 which is the distance traveled in inches for 1 pedal rotation. 263.4/12=21.9 is the distance in feet. 21.9x60x60/5280= mph 14.9 at a cadence of 60 and about 17.4 mph at a cadence of 70. This is in gear 11 which I understand is 1 to 1. I compare that to current speed of 12.3 with the same cadence of 60. Not sure what the speed would be in gear 14.

Not sure I did this right but totally open to your input. Also Ravi was asking if I could hit a speed of 20 on a flat but I managed to get to about 18.x in gear 14.

I was very surprised at the overall performance of the bike, not at all that I expected.

Last edited:

- Region
- USA

- City
- Bay Area, CA

Speed and gear ratio.xlsx

You may have to download to change the variables

- Region
- USA

I am not sure how to download the file to my ipad. I will try later to download to a Windows laptop

Speed and gear ratio.xlsx

You may have to download to change the variables

- Region
- USA

- City
- Carlsbad, CA

Made a quick online spreadsheet in Google Sheets to explore the problem.Great questions, thanks!

Ideally I would like to be cruising in Rohloff gear 11 @ a cadence of about 70 and going about 16 mph. My legs are relatively strong but not so fast. I can maintain a 60-70 cadence without much trouble. My previous e bike was very light Salsa touring bike with a 750watt bafang motor and battery kit and we did a number of long trips where we averaged about 50 miles a day.

Sorry, not so smart on gear inches. By my simple math of 27.5x3.14x3,05=263.4 which is the distance traveled in inches for 1 pedal rotation. 263.4/12=21.9 is the distance in feet. 21.9x60x60/5280= mph 14.9 at a cadence of 60 and about 17.4 mph at a cadence of 70. This is in gear 11 which I understand is 1 to 1. I compare that to current speed of 12.3 with the same cadence of 60. Not sure what the speed would be in gear 14.

Not sure I did this right but totally open to your input. Also Ravi was asking if I could hit a speed of 20 on a flat but I managed to get to about 18.x in gear 14.

I was very surprised at the overall performance of the bike

Rohloff E14 Rohloff E14 14-speed IGH wheel diam,27.5,in External gearing (stock is 55/22 with 55+22=77 external teeth) front,rear,ratio,sum sprockets,57,20,2.85,77 Internal gearing speeds,14 range,5.265 mean step ,13.6% cadence,70,RPM gear no.,ratio,step,final,gear-inches,mph 1,0.279,—,0.795,21....

docs.google.com

At 70 RPM cadence with the stock external ratio of 55/22 = 2.50, gear #12 gives 16.2 mph, #1 gives 4.0 mph, and #14 gives 21.0 mph.

No idea what external sprockets and belts are available or workable on your bike. But suppose you could go to 57/20. The external ratio would rise to 2.85, but total external teeth would still be 77. At 70 RPM cadence, gear #11 would give 16.3 mph, #1 would give 4.6 mph, and #14 would give 24.0 mph.

Sounds like what you're after — provided the top and bottom gears are acceptable.

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- Region
- USA

- City
- Bay Area, CA

Can you measure the outside diameter or circumference of the rear wheel. a 584mm rim with a 2.4" tire should be about 27.8" diameter or 87.31 circumference

a 70rpm cadence with a 55 front and 22 rear give a rear sprocket rpm of 70 x 55 / 22 = 175rpm

In gear 14 the gear ratio of the hub is 1.467 so the wheel rotation is 175 x 1.467 = 257 rpm

This mean 87.31" x 257 = 22438.7 inch per minute, or 21.2 mile per hour

This does not seem to be what you say you are experiencing, so we need more precision on your circumstances.

But in all cases, you can definitely explore changing the front rear ratio to increase your top speed within the belt size constraints.....

It would be interesting to know if there is any horizontal adjustment available for the rear axle position

- Region
- USA

- City
- Bay Area, CA

Depending on the type of mount for the front sprocket, you can find below the available sizes

- Region
- USA

- City
- Loudoun County, VA.

I am running a ratio of 3.075 (

- Region
- USA

- City
- Loudoun County, VA.

Nice spreadsheet!

Speed and gear ratio.xlsx

You may have to download to change the variables

- Region
- USA

- City
- Carlsbad, CA

Hope she comes back.Just checked the bike it is a 55/22 set up like Jeremy suggested. Oh and my wife‘s Aventon bike with a 750watt rear hub motor and only 50Nm of torque flat ran away from me.

- Region
- USA

- City
- Carlsbad, CA

Thanks!

- Region
- USA

- Region
- USA

She did and rubbed it in!Hope she comes back.

- Region
- USA

- City
- Carlsbad, CA

If we change the cadence to 60, where do we end up?

CORRECTION:

At 60 RPM cadence with the stock 55/22 external ratio, gear #11 gives 12.3 mph, #13 gives 15.9 mph, #1 gives 3.4 mph, and #14 gives 18.0 mph.

This agrees with the result @scrambler posted. (Sorry, above was with 57/20 gearing.)

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