Last Autumn I picked up a pair of 2nd hand Shimano 600 (predecessor to ultegra?) STI shifters at the Lars bike show/swap. They were a sweet deal at $10 for the pair and they work perfectly, provided the temp is above 35 F.

Lately, though I've been having trouble getting them to drop down from a larger cog to a smaller one any time the temp outside is below freezing (which is all the fricken time theses days >). It began showing up only on the left shifter but has now migrated over to the right one. They still move from small cogs to larger ones perfectly, but going in the other direction just isn't happening.

When I move the smaller lever that controls the large-to-small shift, there is a noticeable click or catch that happens when its warm out that is totally lacking in the freezing temps. It's as if there is some sort of clutch that won't engage in the cold.

Anybody ever notice something like this? 2 shop guys gave me radically different answers (one said the shifters are done for, the other that I probly need new cables and housing, but they're only 4-5 months old). The bike is still rideable but there are several good hills on my 15 mile commute, so by the time I get here to the brewery I find myself with the chain crossed up in the rookie gear, spinning my brains out.

SS'ing is cool, more so when you meant to do it!

jaime