Tech Question: will 7spd crankes work with a 9spp rear der.?

[SteveFrench]

Hello,

I'm in the process of building up a Tommasini Sintesi which has a 130mm rear end. I intend to use dura-ace 7700 9sp downtube shifters and 9spd rear derailer. Will my dura-ace 7400 cranks (which came on a 7speed bike) work with a 9speed set up? Or maybe I'll need new chain rings?
Thanks for any help!

[Kontact]

They'll work fine as is.

If you want to "upgrade" to 9 speed spacing, you just replace the inner ring with a 9/10 speed version. The cranks themselves haven't changed. In practice, this is almost never necessary.

[bike22]

they'll be fine.

[SteveFrench]

Thanks Fellas!

[SteveFrench]

One more thing. I have a complete 7speed campy drive train that I would love to use. I assume this isn't compatible with the new(er) 130mm spacing. Is that correct? I'm not interested in cobbling something up with spacers. Thanks again.

[Kontact]

You can use as much or as little of the 7 speed stuff as you like. You can use it on friction with any cassette/freewheel 5 through 10 speed. You can use it indexed with a 7 speed Shimano cassette and 2mm spacer on a Shimano 8/9/10 freehub with perfect shifting and 130 spacing. You can compress your 130 spaced frame down to 126 with the QR and use the old Campy hub, or cold set a modern steel frame to 126.

Or, you can add two 2mm to the original hub between the locknuts and cones on both sides to make a 130 hub. This is not "cobbling", and the original axle is long enough work fine. And you can remove the spacers at any time to switch it back to 126. This would be my first choice as it keeps everything original and makes removing the wheel easy from modern frame.

[SteveFrench]

You can use as much or as little of the 7 speed stuff as you like. You can use it on friction with any cassette/freewheel 5 through 10 speed. You can use it indexed with a 7 speed Shimano cassette and 2mm spacer on a Shimano 8/9/10 freehub with perfect shifting and 130 spacing. You can compress your 130 spaced frame down to 126 with the QR and use the old Campy hub, or cold set a modern steel frame to 126.

Or, you can add two 2mm to the original hub between the locknuts and cones on both sides to make a 130 hub. This is not "cobbling", and the original axle is long enough work fine. And you can remove the spacers at any time to switch it back to 126. This would be my first choice as it keeps everything original and makes removing the wheel easy from modern frame.


Awesome info. Thank you. For the sake of simplicity I think I'll try adding the 2mm spacers to the hub. Thanks again.