Bicycle gear calculator
04-25-21, 10:52 AM
#1
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Bicycle gear calculator
Perhaps it is just my system, but I no longer can access the bicycle gear calculator that is popular here. Are others able to get it? I really enjoy the visualization it provides with different combos of rings and rear gears. Help!!
04-25-21, 11:01 AM
#2
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I always use the Sheldon Brown one. https://www.sheldonbrown.com/gear-calc.html
i just tried it and it’s working fine. Hope this helps.
i just tried it and it’s working fine. Hope this helps.
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04-25-21, 01:35 PM
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Thanks for the info. I will look into my settings.
04-25-21, 08:15 PM
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I like putting the numbers in Excel and graphing the ratios. This gets me in full geek mode.
For most of the gear charts, it would be your cassette or freewheel number of teeth in rows and Chainring number of teeth in columns. Where the cells intersect you will use the following to calculate the gear inches to fill in the cells.
Take the Chainring number and divide it by the cassette number, then multiply by the wheel size in inches. I use 27" for 700C. I'm more interested in the jumps and overlaps than the precise gear inches. If you have a 52t chainring and a 14t cassette cog that would be a ratio of 3.714. Multiply that by 27" and you get 100 gear inches. Equivalent to a Penny Farthing with about a 100" diameter wheel.
On the other end of the spectrum you may have a '90's mountain bike with a 22t bailout chainring and a 28t rear cog with a 26" wheel. This would work out to 32"
You can also do this with Sturmey-Archers or other internally geared hubs as well by getting the straight gear ratio and multiplying it by the internal percent overdrive and then underdrive.
Some people look at only the ratios, however, by using gear inches we can compare bikes with different wheel sizes.
If you were setting up a miniVelo, Moulton or BikeFriday to be a speedy roadbike and you are looking for an equivalent 100 gear inches for your top gear, you can do the math and compare a 20" wheel (or 17" wheel in the case of the Moulton) to a 27" wheel bike.
Just for my geeky self amusement if we were limited to a 13t cog in the rear, we would need a 65t chainring to get 100 gear inches on a 20" wheel.
For most of the gear charts, it would be your cassette or freewheel number of teeth in rows and Chainring number of teeth in columns. Where the cells intersect you will use the following to calculate the gear inches to fill in the cells.
Take the Chainring number and divide it by the cassette number, then multiply by the wheel size in inches. I use 27" for 700C. I'm more interested in the jumps and overlaps than the precise gear inches. If you have a 52t chainring and a 14t cassette cog that would be a ratio of 3.714. Multiply that by 27" and you get 100 gear inches. Equivalent to a Penny Farthing with about a 100" diameter wheel.
On the other end of the spectrum you may have a '90's mountain bike with a 22t bailout chainring and a 28t rear cog with a 26" wheel. This would work out to 32"
You can also do this with Sturmey-Archers or other internally geared hubs as well by getting the straight gear ratio and multiplying it by the internal percent overdrive and then underdrive.
Some people look at only the ratios, however, by using gear inches we can compare bikes with different wheel sizes.
If you were setting up a miniVelo, Moulton or BikeFriday to be a speedy roadbike and you are looking for an equivalent 100 gear inches for your top gear, you can do the math and compare a 20" wheel (or 17" wheel in the case of the Moulton) to a 27" wheel bike.
Just for my geeky self amusement if we were limited to a 13t cog in the rear, we would need a 65t chainring to get 100 gear inches on a 20" wheel.
05-05-21, 01:19 PM
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Calling Mac/Apple experts
So I went into Firefox on my Mac mini desktop and can get the gear calculator but not on safari on my iPad or Mac mini. Only one update behind on iOS 13.6 On iPad . Any pointers from others?
05-05-21, 01:24 PM
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05-05-21, 02:08 PM
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Nope, just a blank screen for me
05-05-21, 02:27 PM
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05-05-21, 03:05 PM
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Just checked, my pencil and paper method still works.
The calculator is a bit slower, however.
The calculator is a bit slower, however.
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
05-05-21, 04:46 PM
#12
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Fixed
I just updated my iPad to 14.5.1 and all is fine now. I love that gear calculator, so glad it works now. I am always afraid of latest updates crashing everything, but all well now. I guess I may have to do it on the Mac mini system too.
