Hello BikeForums! This will be my first post...
I just purchased a lightly-used 2003 Vortex frame that has been built up with a mostly-matching Dura Ace set. The price was good, and I'm very excited about the bike, but there is a compatibility issue or two to sort out.
The rear derailleur (Shimano RD-7800) doesn't hang quite low enough below the cassette, so on the largest three cogs, the upper jockey wheel hits and bumps against the teeth. Usually I believe you would adjust the b-screw to control this, but the b-screw has already been fully tightened and there still isn't enough clearance.
The cassette has 9 cogs from 12-27 teeth. Looking around online, (see Bikepedia and BicycleBlueBook) I see this bike is usually built with a 12-23t cassette... so could it be that the frame geometry doesn't allow for anything larger?
I know my rear derailleur should be compatible with up to a 27t cog, according to Shimano's docs. But also, it is a 10-speed derailleur, whereas everything else in the setup is for 9-speed. So could that be part of the issue?
I would love to hear from other Litespeed/Vortex owners about what cassettes you use.
Also... what about finding and installing a *longer* b-screw? Is that ever an OK solution to a problem like this?
Thank you in advance for any help! It is much appreciated!