Campagnolo record 2017 (Non Ho) Rear Deral Strange Behaviour

Discuss light weight issues concerning road bikes & parts.
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Posts: 1257
Joined: Wed Mar 09, 2016 7:13 pm

by 3Pio

I have kinda strange Behaviour of my 2017 Campagnolo Record (Short Cage) Rear Deral (and non HO version).

On this deral i have around 4000-4500 km since i install it in January, and on all my wheelset i use 12-29 cassette

While i go i bought a new 12-29 cassette and install it on one pair of my wheelset.. When i installed i realized in the middle of ride that i have to add some tension to cable ussing barrel on the back..

So far so good...

I switched back to other wheelset, and while everythig was fine, i realize some jumping in 26 cog (all others worked perfectly), and under some more torque.. Fix the problem, loosing a bit of tension...

Just to mention that cassette have about 9000 km on it..

Next rides i was switching between that two wheelset and no adjustment needed until last ride..

Just to mention just a day or two before that ride everything was perfect, and i did not left bike anywhere to consider that someone readjusted something...

On last ride, i was totaly suprised realizing riding 29 cog the chain went in the spokes (i stopped imediately nothing is damaged).. And that happened twice on same ride (so decide to get back from the climbing any further and to get back home)

When i put bike on the stand i realize that limit screw was totaly readjusted, and cant realize how that happened.. I removed the screw to check if loctite is missing, but it was not missing.. Anyway i added few more drops and tried to adjusted...

Working perfectly on any combination except 36/26, that jumping again.. If i loose cable tension no more jumping, but dont work properly shifting from 12 to bigger next two-three cogs in the rear and 52 in the front.. Adding tension fix this, but again jumping JUST in 26 cog and 36 in front...

I started thiking that maybe something about cassette spacers.. So tried again with wheelset which have brand new cassette (again all cassettes are 12-29)

What can be? How it's possible liit screws to be radjusted them self? Vibrations? Never ever happened this to me .. Until now, when i set deral it's like that for years and no need to touch anything (except barrell in the rear sometimes)...

And that strange jumping just in 26 cog.. Maybe deral hanger bent? Internal routing cable problem?

Posts: 803
Joined: Sat Feb 07, 2009 5:52 am

by spud

didn't have this exact behavior. But on a 3 year old bike with 5-6K miles on it, during a stretch of 5-6 months, I was periodically unwinding tension a half a turn on the rear cable to get the shifting correct. Never before in my life have I had to continue unwinding tension on a derailluer. Checked the lever end to see if there was fraying near the head, and the cable guide at the BB, no, all was fine. Just recently, I had to start winding some tension back on to get perfect shifting. Never figured out why.

In your case, I'd check for fraying, and that the cable guide and rear housing is clean.

by Weenie

Posts: 43
Joined: Tue Aug 13, 2019 1:15 pm

by CrankyCarbon

maybe something is compressing/stretching. Are you using the Campy Cables or another brand?
also check to make sure the cable is moving freely. unbolt it in the rear der, and hold it and shift at the same time (yes, long arms needed or get someone to help you). Try to feel if it's smooth or catching on something.

make sure the shifting mechanism's first shift is in sync with the derailleur.
Also, is the rear cable located in the groove. I had shifting oddities when I didn't make sure the cable was exactly in the groove when I tightened the locking bolt.

I'm also a bit confused by your mileage: cassette (which cogs are heavier worn), chain, crankset. Are the der jockey wheels & cage okay and straight when you look at it through the entire range (look from the back to make sure it's not angled)?

Posts: 384
Joined: Sun Jan 05, 2014 11:04 pm
Location: Denmark

by Attermann

i had a record derrallieur behave strangely, that was a short cage non HO too, then it went into the spokes, and i don't know why, now i have bought a Medium HO instead, and that works loads better, there have been a problem with the carbon cage on some derrailleurs.

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