Gear Ratio Calculator

[Bravesst]

When shopping around, researching ebikes, less is written about gear ratios than motor options. When I got my bike, pedaling topped out at 15 mph, not very satisfying for me. I've upgraded to a 60 tooth ring up front (while the existing 7 speed 11/28 cog remains in the rear), and can now actually pedal at over 20 mph with a cadence of about 60 (my comfort zone). I wound up getting interested in Rize ebikes for this reason (as well as many others), but they feature a 52 tooth chainring with a 11/28 nickel plated cog. You can look all these numbers up on this website.

Bicycle Gear Inches Table | BikeCalc

Calculate gear inches given chainring, sprocket, tire and wheel sizes.

www.bikecalc.com

 

[Sierratim]

Looks like the Rize gearing is fairly typical. With a max cadence of 60rpm changing out the chainring is the way to go to get your bike speed up.

My class 3 ebike has assistance up to ~28mph. With gearing of 48t x 11t and 700x47 tires I need to hit a cadence of over 76rpm to max out the assist level. I can do this on the flats. Since I'm in my 70's, I would think that conditioning to increase your cadence is also an alternative, baring any medical issues.

As an aside, all ebike motors have an cadence range where they are designed to produce max output power. For my ebike this is at 90rpm and higher. So upping my cadence even further will get more motor power. 90rpm is awfully high for me, but I do increase my cadence to get more power when I need it in short bursts.

 

[Art Deco]

My class 3 ebike has assistance up to ~28mph. With gearing of 48t x 11t and 700x47 tires I need to hit a cadence of over 76rpm to max out the assist level. 90rpm is awfully high for me, but I do increase my cadence to get more power when I need it in short bursts.

90 rpm is spinning right along. Good for you, Sierratim.

 

[Sierratim]

90 rpm is spinning right along. Good for you, Sierratim.

Not sayin' I can do that very long, but it's there if I need it, at least early in a ride...

 

[Dono Be]

You can look all these numbers up on this website.

WOW GREAT table.....I'm keeping that around

 

[smorgasbord]

@Bravesst , thanks for the link to that calculator. That's great to have not only when buying a bike, but when you're thinking about upgrading components like front chainrings or rear cassettes. I particularly like the Speed At Cadence tab.

 

[MentalCC]

My favorite gear calculator is Derailleur, definitely worth checking out!

 

[smorgasbord]

My favorite gear calculator is Derailleur, definitely worth checking out!

Doesn’t handle fat bike tires or large diameter rims.