Can it work? 7 speed sis with 8 speed cassette

I'm talking Dura-Ace-clickety-click-swift-shifting:

is it possible to shift into all 8 gears by adjusting the hi/lo ? surely if there are only seven clicks on the shifter this can't work.

At the moment it only skips past one gear [3rd sprocket whilst downshifting, 4th on the upshift]

It's not a Dura Ace shifter as far as i can make out - has 7sis written on the side and can be switched to friction shifting. - checked velobase but the shifters i have aren't there!

if it's not possible, using friction on the reg is fine, then switch into SIS when it's time for drag races at the lights...

this may all be totally silly, however.

Is the cassette 8 and everything else 7speed such as the derailleur

8 sprockets 8sis Derailler 7sis shifter

How about the original wheel? Looking at the frame spacing and if the wheel was a freehub or a cassette with a spacer

No. 7 speed and 8 speed are so called as they have a different number of speeds.

And different spacings on the cassettes/freewheels.

You may have enough travel non-index for the derail to move cog-to-cog across the whole range; there is no way to tell other than to try it. You may be lucky and it's worn/slack enough to do it. Or, for about £5 or less you can get the correct shift lever.

hmmm i thought it was gonna be a 7 ≠ 8 situation,

the friction shifting works across the range, so its no real problem - sis just feels soo damn good.

also - and this is real nerdy - the levers are exage 500 [comme ça] and yes there are a couple of dura ace 7402 shifters on the bay but they're not as nice as the pure metal sculpted 500's!

• the grey and white paint is an acquired taste ...
  
  

so naaow i'm wondering if the actual levers themselves can be switched with the sis mechanisms - so exage levers on a 8sis mechanism??

i know its mad -

WAIT

just spotted this :

not a bad idea! hmm very tempting...

Cassette spacing is also critical, especially on pre 96 DA stuff which is different to Shimano's other groups of the time. See Lord Sheldon for further info: http://www.sheldonbrown.com/dura-ace.html

the lord hath spoken

And don't let the finish put you off if you find the correct levers. They're easy to strip and polish to a finish like those in that pic.