ISaacG

I just put on a new chain last week; the old one snapped. The old one rarely skipped; the new one skips all the time under load. The old was a 5 speed; the new is 7-8-9. I think the new has shorter links. Or they are just not stretched.

The gear cassette and chain rings are not at all worn. I took it to the LBS and they agree the gear cassette and chain rings are not worn. The LBS did mention they think the derailer is "showing air" (whatever the heck that means) and suggested I try moving the derailer and wheel back a bit; they say it looks like it is slipping forward or something. But that wasn't changed since I switched chains.

Why would it click?

Thanks

DannoXYZ 

Post a close-up picture of your rear cogs.

mcoomer

Do you still have the old chain? Is is wider than your new chain? That's where I'd start.

miamijim

There's your answer...if your old one skipped occasionaly a new chain would skip more. Sounds like you may need new gears.


I think your LBS is trying to say your rear derailleur isnt providing enough 'wrap'. This usualy occurs with a chain thats too short as a short chain will pull the upper jockey wheel away from the freewheel.

ISaacG

Well, the old chain was a 5 speed chain. The new one is 7-8 or so. So, yes, the old one is wider.

If the old chain skipped, it was once a week or less. The new chain skips several times each commute.

I'm pretty sure I sized the chain correctly... She indicated loosening the bolts and sliding the derailer and the wheel (separately) backwards.

miamijim

Exactly. New chains never make the situation better they only make it worse. Sliding the wheel back will allow for more chain wrap.

Place your chain on the smallest cog in the back and smallest in the front. I install them until there's 'sag' or until the derailleur rubs on it then remove 1 link.

ISaacG

I moved the derailer back in the dropout. The bike "shop" (university club that has tools and aims to educate) noticed my rear wheel shakes and the guy told me my cone is loose and I need to reassemble my hub. I'll be going back there. But that shouldn't be related.


https://img107.imageshack.us/img107/7171/img0438pa0.jpg

Front chainrings
https://img518.imageshack.us/img518/7786/img0436tq1.jpg

Bill Kapaun

I'm guessing someone that's a bit inexperienced in installing a new chain may have introduced a stiff link when they joined it. (How would I know?)
To check, slowly rotate the crank backwards. The RDER will "twitch" noticeably when the stiff link passes through. It's faster to check than to type this!

ISaacG

Sorry for the slow response. The chain was checked for a stiff link.

And the axle was just replaced, fixing loose cones and a pitted cone.

I went to a LBS again and this mechanic told me that if the chain skips, you got a worn out cog and that you can't visually tell if a cog is worn by looking at it. If he telling the truth?

If I do replace the cogs (a mere $20 - the guy tried convincing me to just replace the wheel as well for $50 more, can I replace a 5 gear cog with something higher? The chain is a 6-7-8. Or does the tire need to be re-dished for more gears?

Mhendricks

If you have a 5 speed freewheel then your rear spread is at 120mm which won't accomodate a 6-7-8 freewheel unless you can find one of Suntours' Ultra 6 freewheels. Best bet is to find a 5 speed freewheel on EBAY. Is you're existing one French Thread, Italian, or British?

Al1943

If the new chain has "shorter links" this means that the old chain was stretched, and that would account for the worn freewheel cogs. A 24 pin interval of chain should measure exactly 12 inches. A chain needs to be replaced by the time any 24 pin interval stretches to 12 1/16th inches. A stretched chain causes accelerated wear on the cog teeth. A chains links don't actually stretch that much, what happens is the pins and pin/link interface wears and the rollers wear. The interval between pins (pitch) is the same for all bike chains.

Al

DaveSSS 

True chain skip occurs if the chain stays on the intended cog, but skips over the teeth, refusing to transmit power with heavy pedaling pressure. It only occurs with a new chain on worn cogs. A picture won't help. An old chain should never skip on worn cogs because the two wear-in together.

operator

My god. If the chainring/cogs is showing air then they are worn out! If a stiff link was already ruled out the only other possibility is that the cogs/chainrings need to be changed out too. It took 12 posts not to realize this?

operator

Yes! Sometimes wear is hard to tell by looking at it, sometimes it is. If you change the chain it's nearly with 99% certainty you'll need the cogs changed *unless* you know that everything is brand spanking new.

ISaacG

I got no idea what it is, though I did remove it a time or two... How do I tell what it is?