Need some help with a drivetrain problem.
 

Super Record crankset, front and rear derailleur and a new Sram chain. On the big ring its smooth and quiet, but on the small ring it sounds like the chain is rubbing on something when I put pressure pedaling. Its smooth in the stand but sounds like crap when I'm riding it. I can't see anywhere that it would be rubbing. I have no idea where to go from here. I pulled the cranks and bottom bracket, checked everything and reinstalled them. I even thought the spider on the cranks might be cracked but I can't find any damage.

Can you tell if it's rubbing on the big ring? Hard to see, but it happens.

Looks like there is plenty of space, doesn't appear to be rubbing the chainring. I'm wondering if I'm getting to much flex somewhere.

Flex shouldn't make it happen. Back wheel nice and secure? FD clamp nice and tight? Even with braze-ons, they move.
Check small front, biggest back, and see if it makes noise, then slowly drop the chain down the rear to see what happens.
Then do it with someone else riding with you, focusing on the front rings. Or maybe on a trainer under max tension.

Rob, everything is tight. Ive triple checked everything. When the chain is on the front small ring, it makes noise on every rear cog. Its fine on the big front ring. Could it possibly be the chain? I'm at work and don't have access to another chain, but if I was at home I think I would at least throw another chain on just to rule it out.

Since it is a new chain and is making noise mainly under load I would suspect that the inner chainring is worn, if this is the case it will likely be noisiest in the low low gear combinations. In a lot of cases a worn chainring will be noisy problematic with some chains but run fine with others.

so it doesn't rub on the big ring and any rear cog, right?

it does rub on the small ring, right?

does it rub on the small ring and any rear cog?

are you riding in the small/small? (don't do that!)

does it rub in the small ring and middle of the rear cluster?

if yes to the last, this shouldn't be hard to figure out. i'd check fd alignment and chain length first.

Maybe the chain's too long. Jockey pulley rubbing cogs so possible B screw adjustment and/or link removal?

F/d is aligned right, and chain is measured correctly. It makes noise on all the rear cogs when it's on the small front chainring.

I agree that I would suspect the small chainring is worn.

There was no mention of what combo was noisiest, if you rule out large chainring rub, and possibly a bad chainline, then worn out ring.

I wear out small rings far faster than large.

remove the fd from the frame and go for a ride with the chain on the small ring, shifting the rear thoughout the cluster. this should narrow the problem a wee bit.

It was the chain! I ran home and grabbed a used chain and threw it on there. Smooth as butter.

I flexed the frame of my Lemond to rub, downshift or shift off the small ring. Only bike I've had that flexed like that.

what sram chain?

and what super record components?

are we talking a 2x6?

Glad to see you sorted it

cool.

but why? was the chain too narrow?

80's Super Record, 7 speed Regina freewheel. SRAM PC 850 chain.

http://i1134.photobucket.com/albums/...psgdkcspvn.jpg

I have no idea why.

beautiful bike.

with a 7-speed fw, i like to use kmc 9-speed chains.

with a 5- or 6-speed, i like to use sram 8-speed chains.

...it's a little hard to tell from reading the thread, but it sounds like you had noise with a new chain on the smallest sprocket in the rear, which you fixed by putting a used chain back on the bike.

That sorta sounds like wear on the small sprocket. Your fix is fine if you're happy with it, but eventually as the chain continues to lengthen through wear, you start to wear the teeth on the chainwheels up front, which are a lot more expensive to replace than your cog cluster or freewheel in back. I would probably just ride with the new chain and stay off that small cog until I could get a replacement......if that's really what's going on.

You didn't give any measurement of the stretch in the used chain, which will tell you a lot more than my guesswork.

I had noise on all 7 cogs in the rear when the chain was on the small front chainring. No noise at all while using the big chainring. There appears to be hardly any wear on the front rings or the cogs on the freewheel. I used a chain checker on the used chain that I used and it measured fine.

...chainline or chainwidth ? :foo:In truth,noises are better confronted in person. :)

Sloar,
Is the small ring seated properly? Now that it is working correctly, I have no idea about what caused it other than the SRAM chain somehow not being correct. I have that same SRAM chain on a 2x5 set up, (NR) and it is fine on both rings and all 5 cogs. What brand is the used chain, I missed that if you said in your above replies.

Bill

Yes, the small chainring was seated properly and tight. I went through everything twice before changing chains. I have no idea what the used chain is, I'm going to try another new chain.

K' , I hope you figure out what was wrong with it, I figured you had checked the small ring, just seeking something to grasp at from my feeble brain cells. I have no issues with my 850 chain, but I am looking for a period correct Regina chain, either an Extra (to match the NOS freewheel/cluster I got from Scott,) or a nice Oro, if it isn't more price wise:foo: than I out into the entire bike:notamused:

Best of luck, the Merckx sure turned out nice.:thumb: