Originally Posted by Kommisar89

Ok, so now that I've had some time to look at the info provided above and Sheldon's spacing information, I think a workable combination can be made -

Standard Shimano 9-speed spacing is 4.34 mm C-C divided by a 1.67 derailleur ratio would give cable pull of 2.5988mm for a 9-speed shifter:
4.34 / 1.67 = 2.5988

With the Sachs derailleur ratio of 1.60, 2.5988mm of cable pull would move the derailleur 4.158mm
1.60 * 2.5988mm = 4.158mm

If you fitted a SRAM 9-speed cassette with 1.80mm thick cogs with Shimano 10-speed 2.35mm spacers, you should get 4.15mm C-C spacing.

That should work just fine for a fully indexed 9-speed Sachs-Huret drive train.

Check my math for me if you would. Does that sound right?

Originally Posted by Dave Mayer

Your Sachs New Success front shifter will handle either a double or triple-ring crankset. Since you have an 8-speed cogset in the rear, you will want to run a 7/8 speed chain. The rings on a 10-speed crankset may not be happy with the wide chain. Buying an older triple road crankset off Ebay would be my solution.

The bigger problem could be your rear derailleur; I assume it is a Sachs New Success unit. If it is a short-cage derailleur, it would not have enough chain takeup capability to handle the triple. You would want the long cage version; these show up on Ebay at inflated prices on a regular basis.

BTW: I have 2 sets of stock early 90s New Success Ergopower shifters, obviously made by Campagnolo. They are in no way compatible with Shimano rear derailleurs - not even close. And it has nothing to do with the cassette spacing. However, the Sachs New Success rear derailleurs and shifters are completely compatible with Campagnolo derailleurs from 1992 to 2000. So if you went to a triple crankset, you will be able to substitute a long-cage Campagnolo derailleur from this same vintage.

Finally, only one out of 100 shop mechanics will be able to figure out the deep issues with your drivetrain. Sachs New Success was sold in very small quantities over here, and it has some subtle compatibility issues. Nice stuff though.

And one in 10 shops will be motivated to simply not sell you an entire drivetrain with wheels.

So careful where you take your advice from, and resist any temptation to change a lot of stuff out or to rack up a big bill.

Originally Posted by bikemig

I know that the OP owns a triple but the existing derailleurs should be able to handle a compact without any trouble.

Also this thread might be useful: http://www.bikeforums.net/showthread...riple-Crankset

And this: http://www.bikehugger.com/post/view/...-compact-crank

Also sachs new success can work with shimano: http://www.bikeforums.net/showthread...-compatibility