jdbleed

Im new to biking. Thought I'd try training for a tri, and instead of buying a new road bike, I brought my brother's old Italian ride down to the shop. A guerciotti from the 80s. Sweet looking ride but it had the original rings and chain on it, along with who knows what kind of problems. The local shop cleaned it up, put new rings on, added a new chain, made it sing. And I love it. Only problem is the drive train - at first, the chain would jump off the rings whenever I was in low gear. They fixed that. But now it skips like crazy whenever I'm climbing, which is a lot (I live in Arkansas; we have a lot of hills). Anyway, I was looking over those new rings and just noticed that some of the teeth are chipped and slightly bent. And generally, both rings look like they're getting pretty chewed up. And I've only had them for a couple weeks. So Im wondering - is this typical for chain rings or should I be at the shop tomorrow morning, asking for a fix? Also - any hints/pointers on changing the drive train on older bikes would be helpful. It doesn't seem like the new rings and chain are meshing too well with the rest of the bike, which is all original as far as I can tell. Thanks -

FBinNY 

It might be OK. Todays chainrings made for index systems have shifting gates, or cut down, skipped, or otherwise modified teeth in certain locations to improve chain pickup during shifts. If there's some uniformity in the "chips" it might be normal.

On the other hand, poor shifting technique, especially hard shifting under load can chip or bend chainring teeth, along with causing excess stress on chain plates. Given that you have chain skipping problems besides, I'd let the LBS have a look, and do what's needed to fix the problem. While there also ask about the condition of the chainrings. At the very least you'll have peace of mind.

iareConfusE

If your chain is slipping off of your chainrings, then they need to be replaced. I'm not sure how thats happened though since you say that they're new rings. Take a picture of the rings so we can see it.

joejack951

If you needed a new chain and chainrings yet they did not replace your cassette, it's no wonder you are having issues with the chain skipping. Get a new cassette on there before you put too many miles on that chain and things should be back to normal.

silver_ghost

+1

Are you sure they didn't replace your cassette (rear gear cluster) at the same time? If you put a brand new chain on a worn cassette, it's likely to skip.

jdbleed

Thanks - the casette is original and that might be a big part of the problem. Seems like if you're going to replace 75 percent of the drivetrain, it may not mesh with the remaining 25 but that's just a hunch.

Here are some photos. Kind of hard to see what I'm talking about but you can see how a few of the teeth are definitely shorter. But I appreciate the feedback. This is just what I needed. Thanks.

illwafer

some funny comments on this thread. ive run some waaay worn down rings/sprockets with new and old chains and it stayed in gear and generally shifted great.

i think your problem probably lies with your shifting. if you are using friction shifting, perhaps you are between gears or your shifters are too loose and they are moving slightly as you pedal. if you are using indexed shifters, maybe they need to be adjusted.

also, i'd check to see if your chain isn't a little too big (wide). if you can shift to every gear and get it to sound smooth, then it is probably ok.

cassettes are expensive! i would never change one out unless there was something noticeably wrong with this. this notion that you need to change your chain when you change cassettes or vice versa is nonsense.

garage sale GT

The sprockets in back are supposed to wear out before the rings do. A new freewheel is in order.

I have had nothing but problems when a freewheel or cassette gets worn. You pedal a bit harder and it skips like crazy.

iareConfusE

Those chainrings look fine to me. Some of the teeth look worn down because they're meant to be a little shorter than the others to aid in shifting down and up. Its normal. The problem may probably be in your cassette.

garage sale GT

It's probabaly a freewheel Unless it's a Shimano 600 or Dura-ace.

Those rings look new. There's gotta be a way to get the black crap off and polish them up, though.

jdbleed

Well, now im just confused. It sounds like having someone with a veteran eye look at the cassette would be a good idea. Mine has the "shark fin" look, which makes sense; I'm fairly certain that cassette dates to the second Reagan Administration. It at least warrants a good looking over. I won't ask why the LBS didn't do that in the first place.

iareConfusE

Which bike shop did you go to?

Take a picture of the cassette so we can see it. How many speeds is it? Replacing the cassette might be really hard to do because of the rarity of those "vintage" parts. The indexing (if your shifters have any) is different, and the spacing between the cogs is also probably different than todays cassettes. Not to mention the lock ring is a little different as well. You'd need to find a bunch of old tools and a new old stock cassette for it.

DannoXYZ 

That is WAY, WAY WORN well past the replacement point. Especially if it had the original chain and chainrings. If you can see that the teeth profile aren't symmetrical, it's very worn. Just get a new freewheel/cassette-cogs and you'll be fine.

joejack951

Virutally every drivetrain out there has a cheap cassette option unless you insist on running Dura Ace/XTR/Record/Red level cassettes. The OP likely has a freewheel and even good ones can be had for well under $50 (much less than the OP has likely already spent on restoring his bike).

IRD freewheels in a variety of sizes:
https://www.universalcycles.com/shopp...&category=1665

Homebrew01

Bingo !

New Chain + Old Cassette =

New Chain + New Cassette =