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Old 10-06-10, 12:34 PM   #1
AllezCompBoy
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Brand New Road Bike, gears/chain skipping? Help please!

Hi,

I recently purchased a roadbike from Evans cycles and am instantly hooked!

The uphills can be painful as I'm just starting out, and my ass is killing but it's all worth it for that downhill buzz!

I do have one problem though that started happening tonight when I was out: the chain or gearing mechanisms are making a rattling noise and there is definite slipping going on.

It's really annoying me because the bike wasn't cheap, and I am just getting into something that I am truly enjoying.

I can see there are some really knowledgeable people here, so I thought I would give it a try. Hopefully it's something easily fixable that I can do myself.

Looking forward to any responses

Thanks!
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Old 10-06-10, 12:43 PM   #2
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Dealer has a post sales service . stay and watch if you can.
likely a cable break-in stretch..
Indexing takes synchronizing the clicks on one end with the RD motion on the other end.
work with the adjuster on the RD on the workstand while you turn the pedals.
and see what the effect of turning the adjuster is.
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Old 10-06-10, 01:13 PM   #3
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Thanks for the advice man, but I don't understand it at all, I'm totally new to biking (except from a BMX I had when I was like 13!)

Any chance you can break it down for me? What's the RD motion?

Cheers
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Old 10-06-10, 01:31 PM   #4
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RD Motion Tied To Shifter "Clicks"

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Originally Posted by AllezCompBoy View Post
Thanks for the advice man, but I don't understand it at all, I'm totally new to biking (except from a BMX I had when I was like 13!)

Any chance you can break it down for me? What's the RD motion?

Cheers
You'll get the hang of it. When you press your shifter (either the large lever or the small lever), what you're doing is changing the length of the inner shifter cable relative to the fixed length from the shifter to the rear derailleur (RD).

A tightening (shortening of the cable) pulls against the derailleur's spring mechanism and makes the derailleur move toward the next larger rear cog, shifting the chain. When you click to loosen (lengthen) the cable, the RD moves to the smaller adjacent cog (under the force of the spring).

With click "indexed" shifting, the amount of cable movement for each click is exactly matched to the amount of RD movement to place the chain on the next adjacent cog. A new bike will go through a period of cable stretching, where the derailleur will no longer be aligned properly for each click, until you adjust the cable length manually.

This can be accomplished by re-installing the cable at its anchor bolt (from scratch) - your local bike shop can show you how this is done; or by rotating the barrel adjuster the you'll find just on the cable housing side of the RD. Back the barrel adjuster out to re-lengthen the housing to effectively cancel out the inner cable stretch you've experienced. Once you have this dialed-in now, you'll be good to go for a long time.

Phil G.

Last edited by Phil_gretz; 10-06-10 at 01:32 PM. Reason: further explanation
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Old 10-06-10, 01:42 PM   #5
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Read up on rear derailleurs here: http://bicycletutor.com/part/rear-derailleur/
Scroll down to the tutorial on adjusting RD.
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Old 10-06-10, 02:18 PM   #6
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Good instructions for setting up and adjusting derailleurs can be found at www.parktool.com. It is important to do all of the steps in proper sequence.
For a new bike the dealer should do the first tune-up at no cost. These are good skills to learn.
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Old 10-06-10, 02:28 PM   #7
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New bike from LBS? Bring it back for post sales service. Most LBS offer free tune-ups for 1 year with each bicycle purchase with them. USE IT!!!!
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Old 10-06-10, 02:32 PM   #8
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All new bike sales from a local bike shop (LBS) normally have a year of free service included. This is for adjustments and retensioning the spokes. Take it back to the dealer for the adjustment, that should fix the problems. It is suggested that you watch what they are doing to your bike so you can adjust the derailleurs yourself.
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Old 10-06-10, 04:49 PM   #9
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Most likely you have a "cable stretch" issue. That's common with new bikes.

As others have mentioned, you can take it back to the shop and I'm sure they'll be glad to adjust it for you. If you want to try doing it yourself first, try this:

Look at where the shift cable enters the rear derailleur. Do you see a little barrel surrounding the shift cable? When looking a the bike from the back, turn that barrel counter clockwise 1/2 turn.

DONE!
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Old 10-07-10, 01:23 AM   #10
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Excuse my pedantry, but it's not cable stretch. It's housings bedding into ferrules; particularly noticeable with plastic ferrules.

The OP's hassle could be avoided by shops if they'd just mash the shifter into low without pedalling, before adjusting.
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Old 10-07-10, 06:39 AM   #11
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Quote:
Originally Posted by Kimmo View Post
Excuse my pedantry, but it's not cable stretch. It's housings bedding into ferrules; particularly noticeable with plastic ferrules.
That's why I put "cable stretch" in quotes.
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Old 10-07-10, 08:38 AM   #12
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Cables stretch. It's why steel string guitars go out of tune, and almost always go flat, not sharp (unless a tuning peg gets bumped); because the string has stretched. Guitar strings and derailleur cables stretch the most when they're new. (Okay, I think this is true for derailleur cables, but I KNOW it's true for guitar strings.) The derailleur cage position is dependent on the cable. If the cable stretches, the cage moves and is no longer in proper adjustment.

There's an adjustment barrel where the plastic cable housing goes into the rear derailleur. Turning it moves the derailleur slightly. When a bike is new, or when you install a new rear derailleur cable, this barrel needs to be adjusted rather frequently. Over the life of the cable it will probably still need periodic adjustments, but less frequently as the cable matures.

Your shop should adjust it for free - it just takes a minute and involves no expense and very little trouble - just putting the bike on a stand and fiddling a little. Find a mechanic that will let you look over his/her shoulder and will tell you what to look for.

It's a totally simple operation and one you can plan on doing from time to time if you want your bike to shift smoothly and run silently. My biggest hurdle was trying to remember which way to turn the barrel to move the derailleru which direction. (Okay, I'm a bit of a space case.) Now I have it memorized (Yay for me!) and can adjust things, when necessary, in seconds.
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Old 10-24-10, 08:34 AM   #13
AllezCompBoy
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Thanks to everyone for contributing to this thread!

I took it in to Evans and they did a free tune-up/tutorial and pretty much told me what most of you are talking about, and sorted it out for me (all it needed was putting on a stand and tightening until the noise ceased in every gear.

Did my first long ride yesterday, covered just over 30 miles and loving it!

Cheers all
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