noisy timing chain
 

We have a 2004 Cannondale road tandem, and it seems to me that the timing chain has always been really noisy. I don't remember that happening on my old '80s era Santana. Is it just too tight, or is this just a "tandem thing"?

A couple things to consider...

You're 80's era Santana used thicker, smaller diameter steel tubes in the frame that did not transmit noise as "efficiently" as the oversized, thin walled aluminum tubes do on your Cannondale. That would have accounted for the initial difference. As for what may have happened over time....

Your sync chain could be making more noise than it needs to if:
- it's too tight; 1/2" of up & down free play is about right, but even being "too tight" is relative. The act of pedaling puts more tension on the top run of the sync chain than you could with a spanner when adjusting it.
- your sync chain or rings could have worn to the point where you're getting a little chain suck as the chain comes off the bottom of the front ring. This typically happens where a new chain is installed on older, well-worn timing rings.
- your chain lube is too thin / not viscous enough.

Have you owned the bike since new? What sync chain are you running? How frequently have you changed it? Do your rings show signs of wear or have you also changed the rings?

TandemGeek:
I replied via email, and don't know if you received that, so here it is again: I thought the tubes were part of the issue, so nothing to fix there. The rings are original, with less than 4K miles on them. Any thoughts on how long the rings should last? What chain lube do you use?

Cross over rings will last 10,000+ miles easily if chain is cleaned/lubed properly.
We do not use chain lube but have used the hot wax method for 30-some years.
Quiet, efficient, no mess/chain tattoo, re-usable and easy.
Just our input/experience.
Pedal on TWOgether!
Rudy and Kay/zonatandem

Longevity of the timing rings varies and is dependent on sync chain maintenance approach.

Approach #1: treat sync drive like primary drive and replace chains when they reach 1/16" to 1/8" wear... sync chains will not wear out but you'll likely swap out chains every 3k miles, perhaps less often if your team's pedaling style is very efficient. Remember, sync drive is a direct drive and the chain only transmits the captains power to the rear cranks. A stoker who struggles to keep up with the captain will tend to apply back pressure on pedals and that will increase wear & tear on the sync chain & rings.

Approach #2: teat sync drive like dirt and let the chain and rings wear on each other until the timing ring teeth begin to hook; 8k - 12k miles?. Replace the chain, flip the chain rings around or swap them front to back and get a second life out of the rings. Never try to put a new chain on well worn timing rings and, conversely, don't put new chain rings on a bike with an old sync chain. This also applies to drive-side rings / chains.

As for lubricants, I use a lubricant that's well suited for our climate here in Georgia and road use in fair weather. Best bet for anyone is to check with folks in their locale who have similar riding habits to see what they find works well and try that. Frankly, if you don't care about how dirty a chain is, the original grease that comes on a chain will typically last the typical life of the chain if it's not exposed to solvents or heavy rain. If you use other lubricants, the trick is using a solvent that will truly strip off all of the original grease before applying your new lubricant of choice. Any good lubricant with the proper viscosity for your local temp range (Culver city is pretty mild so all but the very thinnest lubes is fine) and reapply when the chain noise becomes noticeable, i.e., squeaks or chatter.

Thanks to everyone. I think it's probably just too tight. I will loosen the tension tomorrow and see how it goes.