Thanks for all the replies, everyone.
Here's some more info since some questions have been raised. I'm intrigued
by the theory about the derailleur not clearing the large chainring. On the
TT bike, I did install a larger chainring and I may not have reset the the
front derailleur quite high enough. It may look good when the chain isn't
on the ring. It may be another matter when the chain is trying to hop off
that ring and move left. Maybe a little more clearance will make a
difference.
As for goop under the BB where the cable guides are, I learned about that
trick some time ago. I always check that area, clean it and keep it lubed.
Someone brought up temperature. We've just begun having our first cool
evenings. I'm in South Carolina ... so it's a relative thing. Last night
we got into the 40s. That shouldn't cause things to seize up.
I have disconnected the cables completely and determined that the
derailleurs are moving and the springs are working properly. This, of
course, leads me to conclude that it's a cable or cable guide issue. The
wierd part is that the cables are run quite differently between the two
bikes. We're talking about an STI shifter with housing only up by the
handlebars on the road bike ... compared to internal cable routing with a
cable running through housing from the shifters at the end of the aerobars,
all the way to within inches of the derailleur on the TT bike.
On the TT bike, when you shift to the small ring, it will go about once
every 3 tries and, when it does, the end of the cable at the shifter sticks
up a little bit out of the shifter. You can push it down and the derailleur
cage will finish moving over to the stop. From all these things I'm
concluding that it's just time to replace the cables and housings. I'm not
looking forward to that job given the internal cable routing on the TT
frame.
Thanks all,
-
Bob C.
"Of course it hurts. The trick is not minding that it hurts."
T. E. Lawrence (of Arabia)
"psycholist" <[email hidden]> wrote in message
news:[email hidden]...
Quoted message said:HELP!
I took out my time trial bike the other day and, at the foot of a steep
hill, I shifted to the small ring. Nothing happened except that the cable
went slack. I tried a number of shifts. No luck. So I finished the ride
in the big ring. The next day, I took out my road bike. Unbelieveably,
the exact same thing happened. These are bikes I ride all the time ...
several times a week, each. Cable routing is a bit different and I
identified a couple of different possible issues on the two bikes. I
completely removed the one on the TT bike and checked to make sure the
sprint was working properly. I cleaned the cable, put some lube in the
end of the housing, etc. When I put it all back together and adjusted it,
it all worked beautifully on the work stand and also on a quick test ride.
Then yesterday I had a race (TT) with a steep finishing hill. I went to
shift to the small ring and it wouldn't go. I had to shift back, lost all
momentum and had to grind my way to the finish line.
I worked on the road bike similarly. Had it working great on the
workstand. Got out this morning to ride it and it wouldn't shift to the
small ring. When I'd try, the cable would just go slack but the derailleur
wouldn't move.
Anybody know what to suggest? I'm really baffled why this has started
happening all the sudden and why nothing I've tried seems to fix it.
Thanks,
--
Bob C.
"Of course it hurts. The trick is not minding that it hurts."
T. E. Lawrence (of Arabia)