Bicycle Mechanics - Derailleru shifts perfectly in all but one gear

Hi all. I mainly frequent the roadie forum, but this problem has got me stumped. On my 2001 Cannondale R3000Si (less than 750 miles), the rear derailleur skips 4th gear. It shifts quite perfectly to the others, but 4th from the largest/easiest gear, it clanks, strips and bounces between 4th and 5th gears. I've screwed with the barrel adjuster and cable tension to no end, and the darn thing just won't fix. I even replaced the cassette. Still the same problem. I wonder if maybe the dropout is bent, but everything else works perfectly.
It's 9 speed Dura Ace, BTW.

Thanks in advance for any help!!

Cole

Hi all. I mainly frequent the roadie forum, but this problem has got me stumped. On my 2001 Cannondale R3000Si (less than 750 miles), the rear derailleur skips 4th gear. It shifts quite perfectly to the others, but 4th from the largest/easiest gear, it clanks, strips and bounces between 4th and 5th gears. I've screwed with the barrel adjuster and cable tension to no end, and the darn thing just won't fix. I even replaced the cassette. Still the same problem. I wonder if maybe the dropout is bent, but everything else works perfectly.
It's 9 speed Dura Ace, BTW.

Thanks in advance for any help!!

ColeA bent hanger usually affects more than one cog,but LBS can check it easy enough.

Rusty cables and/or dirt in the rear housing can cause shifting problems like that.

if all else is normal, the limit screws aren't adjusted correctly. refer to the park tools website and follow the instructions to the letter...

sd

if all else is normal, the limit screws aren't adjusted correctly.

The limit screws have nothing to do with his skipping a gear in the middle of his cassette.

I would look into the cables/housings first, than maybe derraileur needs some cleaning/lubrication, or the shifter itself either needs cleaning/lube or either derraileur or the shifter maybe damaged.

if all else is normal, the limit screws aren't adjusted correctly. refer to the park tools website and follow the instructions to the letter...

sd

As Trek Biker said, "The limit screws have nothing to do with his skipping a gear in the middle of his cassette." Please don't give bad/wrong advice if you don't know, it just create more confusion for the person asking the question.

fujiacerider, I had a similar problem with my Ultegra setup. I'd go for a ride and the chain would jump gear on me at about the same place yours does. I put it on the stand when I got home home and trimmed it with the barrel adjuster until it shifted fine. Would take it out the next day and had the same problem. The problem I had making adjustments on the stand was that the frame flexes as you ride/pedal. Although I was able to "fix" on the stand, it was different when I took it out on the road.

What I had to do was make adjustments to the rear der. barrel while I was riding. I simply reached down at the rear barrel adjuster and turned it left or right, while I was riding, until the chain stopped jumping. Once I did this, it never jumped again.

***DISCLAIMER***: I don't know how your bike handling skill is, so I'll leave this to your discretion to try this. Please, only do this if you if you're a good bike handler.

Hi all. I mainly frequent the roadie forum, but this problem has got me stumped. On my 2001 Cannondale R3000Si (less than 750 miles), the rear derailleur skips 4th gear. It shifts quite perfectly to the others, but 4th from the largest/easiest gear, it clanks, strips and bounces between 4th and 5th gears. I've screwed with the barrel adjuster and cable tension to no end, and the darn thing just won't fix. I even replaced the cassette. Still the same problem. I wonder if maybe the dropout is bent, but everything else works perfectly.
It's 9 speed Dura Ace, BTW.

Thanks in advance for any help!!

Cole
I had a similar problem... on my new campy. not sure if it is exactly the same problem as yours.. read my post here: http://www.bikeforums.net/showpost.php?p=592407&postcount=1

Thanks much for the replies all.
EagleEye, I'd read elsewhere about that frame flex, but I just couldn't bring myself to belive that my CAAD5 was flexing under the pathetic amount of watts I stick to it. On top of that, it would shift gears even when I had it in the "stand" (hung by some shoelaces from the ceiling).
As it turns out, I had clamped the rear derailleur cable on the OUTSIDE of the clamp bolt, rather than the inside. I switched it around, and sure enough, it shifted perfectly. Did some adjusting, took it out for a ride today, and sure enough, problem-o sloved.
Man, do I feel like an idiot!

Thanks again,
Cole

---snip---
As it turns out, I had clamped the rear derailleur cable on the OUTSIDE of the clamp bolt, rather than the inside. I switched it around, and sure enough, it shifted perfectly. Did some adjusting, took it out for a ride today, and sure enough, problem-o sloved.
Man, do I feel like an idiot!

Thanks again,
Cole

tee he he he... join the club! :)