Question concerning gear ratios
stigma
Posts: 51
Is the difference "mathematical" between a cassette of say, gear ratios 11-23 and 12-25 in terms of performance?
In reality, Does 12 /11 = 10 per cent difference equal 10% heavier gear ratios when going downhill?
and, does 25/23 = 8 per cent equal 8 % lighter gear ratios when going upnhill?
In reality, Does 12 /11 = 10 per cent difference equal 10% heavier gear ratios when going downhill?
and, does 25/23 = 8 per cent equal 8 % lighter gear ratios when going upnhill?
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Comments
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The difference between an 11 tooth sprocket and a 12 tooth sprocket is entirely dependant on the size of the front chainring. If you were running a 53 tooth chainring up front, then there would be only a very slight change between an 11t sprocket and a 12t. However, when running on a 36t chainring, the difference between an 11t and a 12t sprocket will be quite noticeable.0
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50 / 12 = 123"
50 / 11 = 113"
91.87% difference
34 / 25 = 37"
34 / 23 = 40"
92.5% difference0 -
AndyOgy wrote:The difference between an 11 tooth sprocket and a 12 tooth sprocket is entirely dependant on the size of the front chainring. If you were running a 53 tooth chainring up front, then there would be only a very slight change between an 11t sprocket and a 12t. However, when running on a 36t chainring, the difference between an 11t and a 12t sprocket will be quite noticeable.
Not so, in percentage terms anyway. The difference between the 11 cog and 12 cog is 1 tooth regardless of the front ring size, so the percentage difference is always the same for all front chain ring sizes (9.1% increase in gear ratio going from 12 to 11, or a 8.3% decrease coming the other way).
Likewise for 25 to 23, it is always 2 teeth, giving an increase of 8.7% in gear ratio going from 25 up to 23, and 8.0% decrease going the other way.0 -
dgstewart wrote:AndyOgy wrote:The difference between an 11 tooth sprocket and a 12 tooth sprocket is entirely dependant on the size of the front chainring. If you were running a 53 tooth chainring up front, then there would be only a very slight change between an 11t sprocket and a 12t. However, when running on a 36t chainring, the difference between an 11t and a 12t sprocket will be quite noticeable.
Not so, in percentage terms anyway. The difference between the 11 cog and 12 cog is 1 tooth regardless of the front ring size, so the percentage difference is always the same for all front chain ring sizes (9.1% increase in gear ratio going from 12 to 11, or a 8.3% decrease coming the other way).
Likewise for 25 to 23, it is always 2 teeth, giving an increase of 8.7% in gear ratio going from 25 up to 23, and 8.0% decrease going the other way.
How does that disprove what I said? I was referring to the overall gear that you end up with, rather than just counting teeth and working out the % difference between 11 and 12.0 -
AndyOgy wrote:The difference between an 11 tooth sprocket and a 12 tooth sprocket is entirely dependant on the size of the front chainring. If you were running a 53 tooth chainring up front, then there would be only a very slight change between an 11t sprocket and a 12t. However, when running on a 36t chainring, the difference between an 11t and a 12t sprocket will be quite noticeable.
Because you say that the change will be more signficant with the 36t chainring than the 53t. It won't it will be exactly the same % change, and in terms of actual gears (ratios or inches) the differences will be larger with the 53t, not the 36t.0 -
36x12 to 36x11 is 108.64%
53x12 to 53x11 is 109.24%
Not the difference between 'very slight' and 'quite noticable' me thinks.0
