Originally Posted by
Sidney Porter
On an 8 speed I am shifting the front and rear deraileurs for the most part at the same time. It becomes a perdictable pattern. For example the bike in question has a 52/42 with an 11-28 (11,12,14,16,18,21,24,28)
Thinking in gear inches you can see the progress red indicates that it would be on the 52 while green is on the 42, black is a cross chain gear that should not be used.
39.6, 46.2, 49, 57.2, 61.6, 65.3, 69.2, 76.2, 79.1, 85.7, 92.3, 98, 100.7, 114.3, 124.3
The jumps are not bad where I would typically ride 57-85. The 2 cross chained gears cause a big jump. When you are in the middle of the cassette (57-98) the pattern is the same: when you move to the large chainring you also need to move up to one larger sproket, to go to the next gear you would move to the 42 and move the rear down 2 sprokets smaller, the next gear would be back to the 52 and move the next larger sproket. You reverse it going the other way.
Obviously this is harder than a 10 or 11 speed. But once you understand the concept and the pattern is is managable.
I think where people fail with 8 speeds is that the expect to be able to stay in the same chainring that makes the jumps ugly. Using my example
39.6, 46.2, 61.6, 69.2, 79.1, 92.3, 100.7
49, 57.2, 65.3, 76.2, 85.7, 98, 114.3, 124.3
I in no way need that 124.