Cheeto

Well got my new trek 3900, and have noticed some rough shifting from my FD.
It shifts fine, until i hit the 5th or 6th gear in the back, and then it hesitates to go up or down to the second or third chainring.
I spent about 20-30 minutes riding around in circles trying to re adjust the barrel adjusters but havnt any luck.
I've also noticed that when im on the second or third chain ring, my RD doesnt shift as smoothly as it normally does. But i cant notice anything until about 5th or 6th (out of 8)
so i guess im just asking another annoying "help me fix this newb question" but heh, someones got to ask them eh? lol.

rankin116

https://www.parktool.com/repair/byregion.asp?catid=53

Cannondaler

Your deraileur cables have stretched which is normal on a new ride. The shop you bought it from will most likely tune it up for free or the article above in rankin116 post will tell you how to do it. They just need a little adjustment.

Cheeto

yea, but do i realy want to use my 1 free tune up on that? lol

they told me not to turn any screws, just barrels lol.

guess ill have to bring it in, because i dont have luck with FD's.

Im more of a brakes, wheels and chain type.

i hate working on deraileurs lol.

Cannondaler

This is pretty much what the free tune up is for. They know that the cables are going to stretch after a short break in period so they want you to bring it back in for adjustment. Once it is re-adjusted it should stay in good working order for awhile barring any accidents etc.

rankin116

I'm not sure what you mean by the cog numbers above, so are you crossing too much? I' mean, are you trying to use the little ring up front with the smallest cog in the rear, or the largest up front with the largest in the rear?

Cheeto

Oh, lol does that cause problems by doing that?

(sry ive rode a single speed for like 6 years, dont know much about gears.)

i guess i am "crossing" to much.

cryptid01

Public service announcement: cables don't stretch.

Cheeto

according to my LBS owner
cables stretch, chains don't.

Cheeto

something i just thought of.
the braiding just gets tighter I'd imagine, making the cable longer hence it "stetching"

Cannondaler

Yes cables do stretch. And yes it is because the twists or braiding gets tighter and causes the cable to elongate. This is why shops like you to bring the bike in after the first month or 100 miles or so so they can re-tune the gears and brakes. I have assembled several thousand bicycles in my time as a mechanic and have seen it happen on every one.

junkyard

I've been told the same.

To the OP - Based on your description, it sounds to me like you are cross-chaining.

Cannondaler

They both do.

cryptid01

How does it twist if it's fixed at both ends?

Cannondaler

Cables are made of several smaller strands of cable twisted together when tension is placed on a new cable these strands will get tighter against one another causing the cable to elongate. It's like the coiled cable on an old phone only the twists are much shallower so even though the cable is made of steel it will stretch until all the slack space between the strands is removed.

cryptid01

Huh. That's just crazy that these bicycle cable manufacturers don't have the foresight to pre-stress these cables from the factory. Heck, even if you stood on one end of the cable and stretched it overhead, you could put more tension on the cable than anything it would ever see from a derailleur spring, no?

Trimbler

Since you're sinking fast, here's a rescue line Cannondale-type guy: https://groups.google.com/group/rec.b...1a7d?lnk=st&q=

Cannondaler

Thanks but I've already given up on this kid.

mtnbiker66

TGMBG.......represent

Cheeto

Chains dont stretch, they wear out and the rollers get smaller -according to the LBS owner.

Why given up on me? i'm just trying to care for my bike.

Thanks for the help guys, ill look into all those sites and decide if i want to try myself or just let the professionals do so.

Cannondaler

I would never give up on you Cheeto you are like the brother I never had. And you are correct about the chain rollers but mechanics generally refer to it as "Chain stretch"

Cheeto

Oh, lol...
Oh, i was just trying to sound all technical lol!

I can maintain and fix and itstall all kinds of stuff,
just Derail's. aren't my thing LOL.

Cannondaler

Read the articles on Park's website and give it a try before you take it into the shop. It really isn't that hard once you get used to it. If you can do brakes you can do derailluers, give it a shot.

https://www.parktool.com/repair/byreg...mageField2.y=8

cryptid01

If you're referring to me, that's funny.

It's pretty evident that you didn't read the link. Which is also funny.