Bicycle thread

[yater]

Originally Posted by wxwax

Wow, a lot of you think cables stretch.

And yet I have a hard time believing a guy with his much experience could be wrong about something so basic.

One of our team mechanics is a wrench at rei. He also teaches the basic maintenance classes. He always stretches my cables by hand when I change cables/housing. The other works for our sponsoring bike shop. He also stretches them by hand. It doesn't stretch the cables as much as it beds them into and pulls them through the housing. It also seats the housing in the frame stops.

[ImaPoser]

Originally Posted by wxwax

Interesting. Last night I went to my second REI derailleur class, and both times the guy (25 years working on bikes) said that cables do not stretch, they come pre-stretched.

Sure. Engineering tells us our elevator ropes come out pre-stretched as well and not to figure any in to the equation when roping. We still have to shorten them before they are turned over to the customer.

Originally Posted by Bimble

Yup. Hopefully the set-up guy left enough adjustment in the barrel-adjusters so the cables can be tightened up on the fly.

what barrel adjusters? are they hidden under the hoods on sram or something?

[vfr700]

Originally Posted by wxwax

Wow, a lot of you think cables stretch.

And yet I have a hard time believing a guy with his much experience could be wrong about something so basic.

My 501's come pre shrunk, but they still seem to shrink.

[DoctorIt]

Originally Posted by yater

It also seats the housing in the frame stops.

...and the retaining bolt, and in the shifter housing, etc.

Waxy - everyone's right, to a degree. It's true, over the fairly short distance, and even with the heaviest load a juiced roadie could inflice, the modern cable will not stretch enough to throw a derailleur out of adjustment - we're talking micrometers that a cable would stretch in pure tension (if you put it on a test rig).

However, all of us who work at shops will still setup a bike and then go out in the parking lot for a few laps and really pull on the shifters because, see above, we're talking a cable, with an aluminum ferrule, in a plastic guide, going through another aluminum ferrule, that isn't exactly press fit into the frame stop, and so on and so forth. It adds up, things settle, and the pull of cable changes enough to need a quick tightening.

Clearer now?

[Zodiac]

Originally Posted by wxwax

Wow, a lot of you think cables stretch.

And yet I have a hard time believing a guy with his much experience could be wrong about something so basic.

-ever buy a brand new bike?

If you squeeze the piss out of the brakes and brifters you'll notice it within one day.

Even the top of line D/A cables will do it (just not as much as the cheap chinese stuff).

[wxwax]

Originally Posted by DoctorIt

...and the retaining bolt, and in the shifter housing, etc.

Waxy - everyone's right, to a degree. It's true, over the fairly short distance, and even with the heaviest load a juiced roadie could inflice, the modern cable will not stretch enough to throw a derailleur out of adjustment - we're talking micrometers that a cable would stretch in pure tension (if you put it on a test rig).

However, all of us who work at shops will still setup a bike and then go out in the parking lot for a few laps and really pull on the shifters because, see above, we're talking a cable, with an aluminum ferrule, in a plastic guide, going through another aluminum ferrule, that isn't exactly press fit into the frame stop, and so on and so forth. It adds up, things settle, and the pull of cable changes enough to need a quick tightening.

Clearer now?

Yes, thanks. That's kinda what I'd figured. Tomorrow I do my first back to front derailleur adjustments. Should be entertaining.

[rajflyboy]

Exactly Why you should buy one of these:

http://www.trixter.net/

Originally Posted by PackMule

Hey Merc,


I wanna see a youtube of the first attempt...

[Mercury264]

Originally Posted by rajflyboy

Exactly Why you should buy one of these:

http://www.trixter.net/

First few times that was indeed just like me...but now I can ride them one handed pretty easy. I don't think it's that hard, you just need to be really smooth and not jerk around too much - if that happens, don't try to ride it out, just stop peddling and hang on to something. I do still hang onto a window sill to start but once I'm going, I am good now.

[Bimble]

Originally Posted by ImaPoser

...

what barrel adjusters? are they hidden under the hoods on sram or something?

[wxwax]

I cannot believe that the guy in the first video is right in front of glass doors.

That's insanely dangerous. He's lucky he's not shopping for a new carotid artery.

[wxwax]

The guy at the REI seminar pointed out the barrel adjuster located where the cable goes into the shift level housing.

Originally Posted by Bimble

[Doc.Snyder]

[Bimble]

Originally Posted by wxwax

The guy at the REI seminar pointed out the barrel adjuster located where the cable goes into the shift level housing.

Yup. That is just one example. You'll sometimes find them down on the rear derailleur, too. Lots of ways to do it depending on the type and brand of shifter.

[Javarilla]

Originally Posted by Bimble

Yup. That is just one example. You'll sometimes find them down on the rear derailleur, too. Lots of ways to do it depending on the type and brand of shifter.

I've got them on shifter housing, on barrel connectors, on frame connectors, at the derailleurs...

And the only control mechanism I own that doesn't stretch are hydraulic brakes, and fly by wire electronic shifters.

Even my chains stretch.

[wxwax]

Originally Posted by Javarilla

Even my chains stretch.

The guy at the REI says.... oh, never mind.