[Erion929]

Ok, I'm a relative newb, having only ridden for short periods of time over the years...though this time is for real! :blush2:


So yesterday, I'm 1/3 of the way through my 3 hr. ride plan and the first thing I notice is the chain jamming, then releasing through a backpedal, when I switched from the big ring to the small ring. No other issue, and kept riding.

Soon after, I noticed I could not shift back to the big ring. Also, while still on the small ring I could only use the biggest 4 cogs, as the rest of the smaller cogs produced horrible derailleur rub. Figured my ride plan was derailed and detoured over to the LBS where, after 2 minutes and $15, it was fixed.

Questions:
-- Is it common to have these derailleur adjustments needed mid-ride? I thought they would be more subtle, not immediate, and wouldn't ruin a ride...leaving time to get them adjusted.

-- The LBS tech wouldn't tell me what he did, I guess harboring his job security....only told me the cable was "too tight". So what kind of adjustment was the most likely thing he did? I will go read the Park Tool site, but have a feeling I will still be in a fog with the terminology and adjustment spots.

Thanks for any info!

**

 

[Amfoto1]

Hi,

New bike?

It sounds as if either the derailleur wasn't tightly mounted and slipped....

Or, new cables (new bike or replacments on an older bike) often go through a break in period... sometimes referred to as "cable stretch", although it's not actually the cable stretching... it's the cable housing more fully seating in the various mounting points, but the results are the same... Time for a tune up.

Because it happened so suddenly and there was such severe cross chaining, I suspect the first situation... which would sort of point toward whoever assembled the bike initially.

Often with a new bike the shop will offer a "500 mile tune up" to correct for the second situation.

In neither situation will the cable end up too tight... just the opposite in fact, it would loosen. Maybe the repair tech was just saying so out of job security, as you suggested.

Once set and so long as nothing slips, the front derailleur isn't likely to go out of adjustment too easily. It will eventually wear out, but only after many happy miles. The cables will wear out many times and need replacement and subsequent adjustment many times before the FD actually needs replacement.

 

[Peanya]

Sounds like the derailleur was dirty, and he simply cleaned it. The cable could have been loose too for all I know.
Derailleur adjustments are very simple, and once you learn how to do it, you'll never go to a LBS for that again. Go to the park tool website for instructions on adjusting and maintaining the derailleurs. Also look into cleaning and lubing your chain regularly as well.

Oh, it's not common for that to happen. And the tech probably just didn't care to take the time to tell you, maybe thinking that if you don't know regular cleaning/maintenance, that it'd be over your head.

 

[Erion929]

Yes, the bike is relatively new, as I bought it used with ~300-400 miles on it. In general, the bike has been great, but the front has always been a little slow to step up to the big ring. With the adjustment it is a lot better. So maybe it wasn't set up right to begin with. I just don't know what looks correct and what doesn't.

I do clean the drivetrain regularly, so I don't think it was unusually dirty...probably only 100 miles since last cleaned/lubed.

I guess I need to read thru the Park Tools site and study a little. I was just perplexed as to why it went south so fast in the middle of a ride...

**

 

[cs1]

Well, it's fixed and you're riding so that's all that counts. It's hard, actually almost impossible to tell what happened. So, chalk it up to experience.

 

[cxwrench]

Hi,


Or, new cables (new bike or replacments on an older bike) often go through a break in period... sometimes referred to as "cable stretch", although it's not actually the cable stretching... it's the cable housing more fully seating in the various mounting points, but the results are the same... Time for a tune up.

while i agree w/ the basic idea of this post (cables don't really stretch, housing compresses and ferrules 'seat')...i don't think it should be the expected norm. a competent mechanic should be able to make sure that all this happens in the shop, while either building a new bike or performing a cable/housing replacement. a customer should be able to take a new or tuned up bike on the road and not have to worry about a 'mandatory' cable adjustment in the first few day/weeks of riding.
if the shifting goes out of adjustment like this, the mechanic didn't do his/her job correctly.

 

[Mike Prince]

The front derailleur is one of the more basic mechanisms on the bike so there really should be no mystery about it. If it was always sluggish to shift to the big ring, that's a sign of a too loose cable, not a too tight one - this doesn't sound like a cable adjustment issue but a friction issue. If the derailleur slipped (either rotated or moved down the tube) the chance of the derailleur being damaged by the chainwheels are pretty high. If I had to guess he didn't tell you what he did because he didn't replace any parts and didn't want to justify charging you the shop minimum for a basic adjustment. No offense but he probably figured that if you couldn't fix this on the road you probably wouldn't understand his explanation of the adjustment he did.

I remember a few years back a guy on a group ride had a similar problem, he asked me to look at it when the group stopped. His under-BB cable guide was crusted up with dried energy drink and dirt. A few squirts of a water bottle and to his surprise the shifting was instantly fixed

 

[2cflyr]

-- The LBS tech wouldn't tell me what he did, I guess harboring his job security....only told me the cable was "too tight".
**

you need to find a new LBS then. I am a wrench at a med/high end shop and I'm glad to tell you what i did and how you can fix it.

the Park website is a great resource.