Bicycle Mechanics - Dura-Ace 8 spd indexing question

Hi,

I just picked up indexed Dura-Ace shifters - 8 speed with matching RD. I was wondering if it would work with the Mega 7 11-28 freewheel Harris Cyclery sells. I was going to put a Cyclone 7000 6spd set on my Raleigh but would like to keep the Dura-Ace.

Thanks

7 speed spacing is 5.0mm, 8 speed is 4.8mm. Some have tried mating these with varying degrees of success. If you set your RD over the 4th cog, then your max error will be 0.6mm overshifting in both the first and seventh cog.

Or if it doesn't work to your liking and your shifters are DT you can run friction.

Nope. 8-speed Dura Ace is it's own animal. I don't think that it works with anything else.

Nope. 8-speed Dura Ace is it's own animal. I don't think that it works with anything else.

RD and shifter have to work together and only together, but it doesn't affect the cog spacing.

RD and shifter have to work together and only together, but it doesn't affect the cog spacing.

But the cog spacing has to match the shifter. In this case, I think that I've read someplace that 8-speed Dura Ace is spaced like the other 9-speed Shimano groups.

As an interesting aside, QBP doesn't have any 8-speed Dura Ace cassettes listed in it's current catalogue. Do you suppose that might be why the OP was able to acquire the Dura Ace stuff for a reasonable price?

Maybe if I mention Sheldon Brown in my post it will cause his computer to nudge him and he'll give us the definative answer.

But the cog spacing has to match the shifter. In this case, I think that I've read someplace that 8-speed Dura Ace is spaced like the other 9-speed Shimano groups.

As an interesting aside, QBP doesn't have any 8-speed Dura Ace cassettes listed in it's current catalogue. Do you suppose that might be why the OP was able to acquire the Dura Ace stuff for a reasonable price?

Maybe if I mention Sheldon Brown in my post it will cause his computer to nudge him and he'll give us the definative answer.

The O.P. also asked me this question by email this afternoon, and I replied:

>I bought a nice Mega 7 11-28 freewheel from Harris Cyclery and would like to pair it up with
>some components I recently acquired.
>I'm wondering if it would work with either
>Dura-Ace downtube shifters, indexed 8 speed with matching Dura-Ace RD

This will probably work. 8-speed spacing is slightly different from 7, but close enough.

>Suntour Accushift downtube shifters, indexed 6 speed with matching Cyclone 7000 RD

No, but those shifters will work with any Shimano rear derailer (EXCEPT an old (pre-9-speed) Dura-Ace) for 7-speed use.

All the best,

Sheldon

See also my article on Dura-Ace interchangeability: http://sheldonbrown.com/dura-ace