[hardtales]

so, I borrowed some cogs & spacers from my friend, and I'm trying to go SS on my Cannondale Chase. (2004 model, stock drivetrain: Truvativ Hussefelt cranks, Alivio front der, LX rear der, ? chain, 8 sp cassette. Have cogs to try: Surly 17t, endlessbikeco 15t, & an unmarked 12t)

He said he could only get the even numbered tooth cogs to work on his bike. The odd numbered ones skipped. (wtf?)

I've got things set up properly, it seems. Looks like a pretty straight chain line, the rear derailler has been pushed (via limit screw) into alignment with the cog and is working as a tensioner, the chain has been shortened so there's less slack, still have 2 gears in front which seems okay.

The problem is, the chain is skipping when I pedal hard. (It always seems fine when the bike's upsidedown and I crank it by hand, but once I'm on it - skippity doo da) On the 15t and 17t cogs, I can see the chain hop on the cog when it skips. The chain just doesn't seem to mesh right. On the 12t, things were going a bit better (and it was an even number - should that even matter?) but it skips when I pedal hard. I can ride around casually with no issues, but crank a little or pop a wheelie and it skips. I can't seem to see it happening, like I can on the other cogs, but it feels the same.

What could be going wrong? I don't seem to have any stiff links. Maybe my chain is stretched? What else should I check?

Thanks.

 

[hardtales]

actually, I CAN see the chain hop (on the rear cog) when it skips on the 12t.

Will I have more luck, generally, with the larger cogs, since there's more contact area?

Should I be eliminating ALL slack in the chain? How tight should it be?

I only adjusted one limit screw on the rear derailler, cuz that seemed to get it in place. Is there more I should do there? If I push the whole derailler body forward, the 1st wheel holds the chain really close against the cog. This looks like it'd work better, but I don't see how to keep it in that position. Should the limit screw right near the der hanger be adjusting that? That screw seems to do nothing...

 

[particle bored]

sounds like your chainline is off.

and yes, you should try to take most of the slack out of the chain. when you look at the driveline from the drive side of the bike, the chain should not be sagging.

 

[hardtales]

should I even mess with 2 gears on front?

or, just pick one, and get the chain locked in...

 

[BMXman]

I say get ride of the double up front and the rear derailleur it makes running SS a lot easier...D

 

[noname]

I had that same problem with mine, took a few more links out of the chain and all was well.

 

[hardtales]

I had to put the 8sp back on so I could ride last weekend. The chain broke 3 times after that. !! Perhaps it was hasty chain work on my part. So, I reconnected it carefully, marking the link where the work was done so if it breaks again I can see if it's the same spot... haven't had any more problems (but my chain's too short to reach the big rings. doh!) Might be time for a new chain.

And my friend seems to think the SS will work once we try the 16t cog. I remain skeptical.

thx for the replies.

 

[Mudpuppy]

This thread has pictures of how tight I had mine setup with a nice shortcage road der. for tension. Now it's actually around twice as tight. I took out a few links.

 

[BikeGeek]

This thread has pictures of how tight I had mine setup with a nice shortcage road der. for tension. Now it's actually around twice as tight. I took out a few links.

I think that's the key to using a derailleur as a tensioner: run it tight. I used to use an LX derailleur for tension and ran it stretched out, almost parallel to the chainstay.

 

[noname]

you want as much wrap around the cog as possible. My chain tensioner is almost parallel to the chainstay, there is just enough slack in the chain when the tension is removed to remove the wheel from the bike.

 

[clokstar]

I was thinking it wouldn't make sense if you had everything set-up right for it not to work. I used to have a few of the same problems with mine. First, just tightening the chain as much as possible until you'd need a half link and the derailer should work fine if alined properly. Then it seemed wierd that only the 12t would skip, a bent tooth is sometimes hard to spot, I'de say look around all the cogs and check for anything unusual. Sometimes even a chip under the teeth cause it to come off.

 

[hardtales]

Works great, now!
16t on rear, new chain, 2 gears in front, derailler for tension. Love it!