Graphical Gear Calculator

[ReneHerse]

I've created a graphical gear calculator to play around with different gear combinations and to compare different setups (derailleurs and internal gear hubs) and use corresponding links in (endless /img/vbsmilies/smilies/smile.gif) gearing discussions.

www.gear-calculator.com

Just move the chainrings and cogs around!

 

[jpr95]

That is GREAT!

I only have one small suggestion for an improvement. If you could display the exact gear inches when you mouse over one of the little gear/triangle indicators near the top, I think it would be about as close to perfect as it gets.

Very cool tool. Thanks for sharing.

Jason

 

[rparedes]

Originally Posted by ReneHerse .

I've created a graphical gear calculator to play around with different gear combinations and to compare different setups (derailleurs and internal gear hubs) and use corresponding links in (endless /img/vbsmilies/smilies/smile.gif) gearing discussions.

www.gear-calculator.com

Just move the chainrings and cogs around!

This is great. It's nice to actually SEE it
thank you!!!!

 

[ReneHerse]

Originally Posted by jpr95 .

...If you could display the exact gear inches ...

Thanks for the feedback. I've included the possibility to display the values of the development, ratio and speed for all given combinations, all at once. If somebody is interested in the values, it might be a bit inconvenient to move the mouse over all symbols.
http://www.gear-calculator.com

Dirk

 

[jpr95]

That's an even better idea. Thanks again!

Jason

 

[daviddb]

Super neat tool. Thanks a mil for this!!

David

 

[Desertrider 119]

Here is a gearing question hopefully one of you can answer. Does it require more or less energy from a rider to go from a small chain ring to a large cog, or from a large ring to a small cog. A therodical example would a 34 ring 18 cog be easier, harder or no difference than a 18 ring 34 cog?

 

[tafi]

Energy output depends on how far you travel and over what kind of terrain speed (Energy output = mechanical work done). Your power output depends on the rate at which the work is done (force x speed = rate of energy output). Neither of these depends on gearing.

In short, as long as you are travelling at the same speed on the same road, your power output will be the same no matter what gear you use.

 

[jpr95]

That's if you ignore efficiencies. Every person will have a range of cadence that will be roughly peak efficiency. Getting outside that range would mean that the same speed over the same path may take more energy in a certain gear. For instance, if you shift to your smallest ring in front and largest cog in back, then try to do 25 MPH on flat road, you'll probably be spinning around 200 RPM and bouncing all over the place in your saddle (wasting lots of energy), but you would be much more efficient doing that same 25 MPH on that same road in a large ring and small cog.

Jason

 

[Scott2468]

Originally Posted by Desertrider 119 .

Here is a gearing question hopefully one of you can answer. Does it require more or less energy from a rider to go from a small chain ring to a large cog, or from a large ring to a small cog. A therodical example would a 34 ring 18 cog be easier, harder or no difference than a 18 ring 34 cog?

Good question.

I swear I'm faster & more powerful in 53x19 than 39x14.

I know they're the same and should be the same except the miniscule difference in efficiency. Surely this is not enough to make a noticeable difference.

Do others agree?

What is your theory on this? All in the mind?

 

[AlanG]

Originally Posted by Scott2468 .




Good question.

I swear I'm faster & more powerful in 53x19 than 39x14.

I know they're the same and should be the same except the miniscule difference in efficiency. Surely this is not enough to make a noticeable difference.

Do others agree?

What is your theory on this? All in the mind?

If both methods have the same ratio between one pedal revolution and the distance the wheel travels, what could be different?

 

[tafi]

Originally Posted by jpr95 .

That's if you ignore efficiencies. Every person will have a range of cadence that will be roughly peak efficiency. Getting outside that range would mean that the same speed over the same path may take more energy in a certain gear. For instance, if you shift to your smallest ring in front and largest cog in back, then try to do 25 MPH on flat road, you'll probably be spinning around 200 RPM and bouncing all over the place in your saddle (wasting lots of energy), but you would be much more efficient doing that same 25 MPH on that same road in a large ring and small cog.

Jason

If you are talking about the "energy required from the rider" (output) as Desertrider asked then you don't need to know the rider's efficiency. You do technically need the efficiency of the drive train but that remains pretty constant (between 95-99%) for a broad range of speed. Only when you want to consider energy transfers earlier in the chain do you need the "efficiency" of the rider.

 

[tafi]

Originally Posted by AlanG .



If both methods have the same ratio between one pedal revolution and the distance the wheel travels, what could be different?

Actually they don't, but that isn't the point. Power = force x speed or Power = torque x angular frequency.

Notice that gear ratio doesn't enter the equation.

 

[AlanG]

Originally Posted by tafi .




Actually they don't, but that isn't the point. Power = force x speed or Power = torque x angular frequency.

Notice that gear ratio doesn't enter the equation.

I thought the question was if both gear combinations (53/19 and 39/14) would produce the same result. (Pedal length remains the same.) Since either method will turn the wheel the same amount for a given amount of pedal travel, I don't see how it can matter which you use. What does power have to do with the question?