Gearing

I am the first to admit that the technical stuff “floats my boat.” This is true with the mechanics of the bicycle as well as the training and physiology of the cyclist. This page provides “drivetrain” information on Scooter.

I’m planning to ride Scooter who has Shimano’s compact double  Dura Ace components. The rear cogs go from 11 to 28 (11,12,13,14,15,17,19,21,24,28) and the front crankset is  34/50. This gearing has served me well here in Colorado. I’ve done several serious mountain rides (Triple Bypass, Loveland to the top of  Trail Ridge road and back which is 7,000 ft in just shy of 90 miles) and I hope to climb Mt Evans this spring before the tour begins. Although I must admit I am a little nervous about doing the tour with the compact double as opposed to a triple crank, I’m committed at this point and will design my training to give myself the best chance of being successful.

From Sheldon Brown’s webiste, this works out to the following Gear Chart (Gain Ratios using 170 mm cranks — which is probably longer than what I actually have, but the relative data is still interesting).

            11        12       13        14        15        17        19        21        24        28

34      6.1      5.6      5.1      4.8       4.5      3.9       3.5       3.2       2.8      2.4

50      8.9      8.2     7.6      7.0      6.5      5.8       5.2       4.7      4.1       3.5

 

Also from Sheldon Brown’s webiste, here are the Gear Inches for Scooter:

            11            12            13          14         15          17          19          21        24         28

34      81.2      74.5       68.7      63.8     59.6     52.6      47.0      42.5     37.2    31.9

50     119.5    109.5    101.1     93.9     87.6      77.3      69.2      62.6     54.8    46.9

Again, from Sheldon Brown’s webiste, here’s the MPH for each gear assuming 80 rpm (which is probably pretty close to my “cruising”  pedaling rate):

            11          12         13          14            15          17        19       21         24        28

34      19.3     17.7     16.4      15.2      14.2        12.5     11.2    10.1      8.9      7.6

50     28.4     26.1      24.1      22.3      20.86     18.4     16.5    14.9    13.0     11.2

And lastly,  from Sheldon Brown’s webiste, here’s the MPH for each gear assuming 60 rpm (which may be my cadence on a long, tough climb — so only the “granny” gears really matter from this table):

            11           12         13          14           15        17      19       21       24       28

34      14.5     13.3      12.3      11.4      10.6      9.4     8.4     7.6      6.6      5.7

50     21.3     19.5       18.0      16.8      15.6    13.8    12.3     11.2    9.8      8.4