Ok...for all the nitpicking rabbits of this world - first let me say "I HAVE USED GOOGLE".
For everyone else, I've been putting numbers in Sheldon's Gear Calculator and I can't get any results that I like.
I'm putting together a lightweight 700C tourer and I have:
Chainset = Ultegra C/set 52/42/30 FC6503 9spd
Cassette = LX M580 11,12,14,16,18,21,24,28,32
Results:
52 42 30
11 126.5 102.2 73.0
12 116.0 93.7 66.9
14 99.4 80.3 57.3
16 87.0 70.2 50.2
18 77.3 62.4 44.6
21 66.3 53.5 38.2
24 58.0 46.8 33.5
28 49.7 40.1 28.7
32 43.5 35.1 25.1
This gives me the following useful gears:
1) 25.1
2) 28.7
3) 33.5
4) 38.2
5) 46.8
6) 53.5
7) 62.4
8) 70.2
9) 87.0
10) 99.4 and possibly 116
While I don't want to seem ungrateful for having 10 unique gears to choose from, there seems to be a lot of dead wood and no clear and simple gear change pattern, other than perhaps hogging the middle ring for as long as possible and chain line be damned (at 35" to 102" I could probably nearly live there).
As such, the outer ring is nearly redundant and the inner doesn't fare much better.
I've tried other combinations of chainsets and cassettes, but I can't find anything that is a measurable improvement.
A smaller outer ring simply pushes the two ranges closer together.
When I started touring I had a 14 - 34 5 speed freewheel and a 52/36 chainset.
This gave a clear and easy change pattern, reasonable chainline and well spaced gears.
1) 28.7"
2) 34.8"
3) 44.3" - change to outer ring
8) 64"
9) 82.8"
10) 100.6"
Ok, some of the steps are a little on the large side, but why can't I find cassettes or chainsets that will combine to give a modern equivalent ?
Ideally I'd like to use the cassette I've got and/or the chainset - however for the right results I'd start over.
Is there any way to get a range of about 20/25" to 100/105" with a reasonable number of even steps and - most importantly - a simple gear change pattern ?
I don't want to have to play gear lever gymnastics just to get to the next gear
Any ideas anyone ?
(please stick to inches)
