Originally Posted by Kimmo

I paid $10 for my Ultegra 9spd STIs because they had this issue, in addition to the worst case of gummy grease I've seen. It's a separate problem, although lubing helped it a bit - it was evident after I'd stripped, cleaned and lubed the levers; I had to take each of them apart like three or four more times to tweak the springs enough...

I sorted it by making the flippers' springs softer and making the big gear levers' springs stiffer. I used long-nosed visegrips to hold one end of the spring and some stubby long-nosed pliers to hold the other end of the spring to coil or uncoil it enough to sit at least about 5-10 degrees away from where it was. Reassembly is likely to be a little trickier as a result, particularly if the flippers' springs don't have a little groove in the pins they rest against, but at least you don't have to disassemble the whole mechanism to perform this fix. Getting the guts of an STI back together can be a hair-tearing exercise... oh, and if working on one of these, take all steps you can think of to guard against flying, never-to-be-retrieved springs... work on a rag on the floor, for a start. You need a special tool, but you can carve one out of an 8mm socket with a cutting disk on a dremel. With a bit of care, the socket can still work on nuts as thin as you'll find. If you look at the thread in my sig, that should give you a rough idea... the 8spd levers were quite different, but all the same principles apply... 9spd is a little trickier to reassemble.