# Excellent gear/speed calculator!! (sticky?)



## lazzer408 (May 18, 2008)

I found this tonight. This thing is beyond helpfull for calculating gear ratios and speed for a motorcycle or any EV really.

http://www.gearingcommander.com/

It's a little tricky if you don't understand motorcycle gearing so here's some tips.

-Make your primary ratio 1:1 (this was an internal reduction in the stock engine only).
-Set any (or all) of the 6 gear ratios to 1:1 and read the calculated values for that gear only.
-Set the Final Drive Ratio to the sprocket ratios you'll be using. 15:60 for example.
-Other values can be left at their defaults or adjusted to suit tire changes ect.

You can enter maximum RPM (MP RPM) to your motor's limit and find out your top speed.


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## lazzer408 (May 18, 2008)

Here is an example of my Yamaha. I set the max RPM to 5k and the sprockets are 15-front 60-rear. Notice the Primary Ratio is 1 and the other ratios are 1:1.

I can see that 47mph is 2500rpm and that's very close to where I'd like to be. 76mph is 4000rpm so highway speeds seem reasonable but RPM is a touch high imo.


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## Little Rhody (Jun 17, 2008)

Great find, simple to use, fast and accurate. 

LR


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## frodus (Apr 12, 2008)

I found this a while back, its a great little tool. I ended up setting up a spreadsheet, and forgot about this... thanks for reminding me  I definately need it now, I need to get a new rear sprocket (gearing is a little off  )


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## mattW (Sep 14, 2007)

I moved the computer stuff to the Chit Chat section as a new thread...
Thats a decent resource, also take a look at the excel calculations at www.electricmotion.org, it is freakishly useful and very customisable to your bike, it not only gives you the speed with certain gear ratios, it tells you the amp draw too. Very clever.


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## Little Rhody (Jun 17, 2008)

mattW said:


> I moved the computer stuff to the Chit Chat section as a new thread...
> Thats a decent resource, also take a look at the excel calculations at www.electricmotion.org, it is freakishly useful and very customisable to your bike, it not only gives you the speed with certain gear ratios, it tells you the amp draw too. Very clever.



Humph..............

I will have to check that out. Thanks mattw. 

LR


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## lazzer408 (May 18, 2008)

mattW said:


> take a look at the excel calculations at www.electricmotion.org


Couldn't find it. Got a direct link?


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## mattW (Sep 14, 2007)

I can't direct link because the site is all one address but its under specifications and is called Excel spreadsheet, actually I just copied the link so you should be able to download it from here


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## lazzer408 (May 18, 2008)

Oh it's just a spreadsheet? I don't even use Excel.


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