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What does "nine-speed spacing" mean? It seems that the shifters do not match the cog set, because you're using nine-speed shifters with only eight cogs. Is this a mistake?
This arrangement is intentional.
Bike Fridays require some special adjustments during production. Bike Friday has learned many tricks, and this is one that works very well.
The SRAM Spectro 3x7 three-speed hub is built to accomadate a seven-speed cassette. Many of our customers want eight-speed cassettes, and the industry is moving away from seven-speed cogs, making them less available.
The solution to this problem is to take a nine-speed cassette, and remove one cog. This makes it an eight-speed cassette, with nine-speed spacing. It also makes it the same overall width as a seven-speed cassette, so it fits on the SRAM Spectro 3x7 hub.
The bottom line is that it is not a mistake, and it works well.