% difference between gears ahhhhhh!!!!
#1
Senior Member
Thread Starter
Join Date: Aug 2010
Location: East Coast, Canada
Posts: 91
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
% difference between gears ahhhhhh!!!!
This is driving me insane.
Sheldon Brown's gear charts say that the difference between 53/11 (128.9") and 53/12 (118.2") is 9.1%.
How does he get that answer?
Math incompetent,
G
Sheldon Brown's gear charts say that the difference between 53/11 (128.9") and 53/12 (118.2") is 9.1%.
How does he get that answer?
Math incompetent,
G
#3
Senior Member
Thread Starter
Join Date: Aug 2010
Location: East Coast, Canada
Posts: 91
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#4
Senior Member
Join Date: Apr 2011
Location: Alpharetta, GA
Posts: 15,280
Bikes: Nashbar Road
Mentioned: 71 Post(s)
Tagged: 0 Thread(s)
Quoted: 2934 Post(s)
Liked 341 Times
in
228 Posts
Converting to gear inches is what confuses things. It's just extraneous when comparing gears, where gear ratios are all that's needed.
(52/11 -52/12) = (52/11)/(52/12) - 1 = (12/11) - 1 = 1.0909 - 1 = .091 = 9.1%
52/12
When you think about it, only the rear cogs matter for the percentage increase when all else is the same so you can write it down at the start:
(12-11)/11 = 1/11 = .091
(52/11 -52/12) = (52/11)/(52/12) - 1 = (12/11) - 1 = 1.0909 - 1 = .091 = 9.1%
52/12
When you think about it, only the rear cogs matter for the percentage increase when all else is the same so you can write it down at the start:
(12-11)/11 = 1/11 = .091