Road Cycling - Compatibility

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siklikemadrid
07-24-04, 07:09 AM
Hopefully somebody can help me out...

I was wondering if my downtube shifters (Shimano 105) will be compatible with a new cassette. I currently have a 7 speed in the back and would like to upgrade to a 9 speed. I've already taken into account the freewheel hub/body, so I'm simply looking around for another wheel that is for a 8/9 speed. The rear derailleur I'm not too sure about... All components on the bike are shimano 105 but are 10 years old. So if anybody can provide some insight, that'd be very much appreciated. Thanks

annonymous
(not really)

nutbag
07-24-04, 03:25 PM
I assume it's index shifting? How old are the levers?

I'm pretty sure they won't index with 9 speed, but they should with eight. I suppose they would shift on 9 speed if you just used friction shifting. Older Shimano 7, and 8 speed had the same spacing, but when they went to 9, they chose to narrow the chain, and therefore the spacing.
Retro Grouch
07-24-04, 06:56 PM
Actually, the spacing for 7 and 8 speed isn't exactly the same, but it's close enough for a grade "b" fit. If you aren't too particular, you can mix parts and they'll work together most of the time.

9-speed cassettes have nine cogs in the same amount of space that 8-speed cassettes use for only eight cogs. Obviously, that's not going to index very well with a 7-speed shifter. Needs a narrower chain too.

On non-index mode, you can get your shifter to pretty well work with anything.