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74 Main Street Middlebury
Vermont (802) 388-6666
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Compact Cranks Compact cranks
use a 110mm spider to accommodate a smaller inner
chainring. This allows you to gear almost as low as you would using a
triple with a 30-tooth inside chainring. The 34-28 combination allowed by
SRAM's 11-12-13-14-15-17-19-22-25-28 cassette is very close to a 30-25 with a
triple crankset. The
compact crank typically comes in a 50-36 or 50-34 combination. Compare
high and low gears with your typical double or triple in the following chart:
|
Gear Roll-Out (inches) |
|
|
50 |
|
36 |
|
34 |
|
53 |
|
52 |
|
39 |
|
30 |
|
|
| 11 |
|
119.5 |
|
86.0 |
|
81.2 |
|
126.6 |
|
124.2 |
|
93.2 |
|
71.7 |
|
11 |
| 12 |
|
109.5 |
|
78.8 |
|
74.5 |
|
116.1 |
|
113.9 |
|
85.4 |
|
65.7 |
|
12 |
| 13 |
|
101.1 |
|
72.8 |
|
68.7 |
|
107.1 |
|
105.1 |
|
78.8 |
|
60.6 |
|
13 |
| 14 |
|
93.9 |
|
67.6 |
|
63.8 |
|
99.5 |
|
97.6 |
|
73.2 |
|
56.3 |
|
14 |
| 15 |
|
87.6 |
|
63.1 |
|
59.6 |
|
92.9 |
|
91.1 |
|
68.3 |
|
52.6 |
|
15 |
| 16 |
|
82.1 |
|
59.1 |
|
55.8 |
|
87.1 |
|
85.4 |
|
64.1 |
|
49.3 |
|
16 |
| 17 |
|
77.3 |
|
55.7 |
|
52.6 |
|
81.9 |
|
80.4 |
|
60.3 |
|
46.4 |
|
17 |
| 19 |
|
69.2 |
|
49.8 |
|
47.0 |
|
73.3 |
|
71.9 |
|
53.9 |
|
41.1 |
|
19 |
| 21 |
|
62.5 |
|
45.1 |
|
42.5 |
|
66.3 |
|
65.1 |
|
48.8 |
|
37.5 |
|
21 |
| 23 |
|
57.1 |
|
41.1 |
|
38.8 |
|
60.6 |
|
59.4 |
|
44.6 |
|
34.3 |
|
23 |
| 25 |
|
53.5 |
|
38.5 |
|
36.4 |
|
56.8 |
|
55.7 |
|
41.8 |
|
32.2 |
|
25 |
| 27 |
|
50.0 |
|
36.0 |
|
34.0 |
|
53.0 |
|
52.0 |
|
39.0 |
|
30.0 |
|
27 |
The Bike Center can:
 | Upgrade your current system to a
compact crankset |
 | Order you a complete bike that comes stock with compact
cranks |
 | Build you a custom Lynskey with compact
cranks |
FAQs about compact:
 | How well will a 50-34 work? The
newer cranks with this chainring combination seem to have worked the kinks out
of earlier 50-34s, which didn't always function well with 10spd drive
trains. Campy has a compact-specific front derailleur
specifically designed to handle more than a 14-tooth difference in chainring
sizes. FSA makes a compact-specific front derailleur that works well
with Shimano and SRAM drive trains. |
 | Is the compact viable for racing?
Division I pros are using compact cranks in the mountains in major stage
races in Europe. If the pros can successfully
use a compact for racing, so can you. If you feel undergeared with a 50-34, try a
52-36 or 52-38. |
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