Drive train noise: need pointers...

[572cv]

Well, clearly there are many experts on this forum with skills and insight well beyond mine... so... On my Serotta Fierte, when I crank hard, going up a hill or just plain pushing hard, there is an audible clatter. When I ride with moderate force, it is quiet. The noise appears to come from the drivetrain. Standing doesn't make it go away.

Here's more about the bike:
-56cm Fierte ti frame with the wishbone carbon seat stay. AlphaQ fork with cane creek headset. Thomson seatpost. Ultegra drive train and components. Time ATAC pedals. Between 4-5K miles on the bike.

Here's what I have done to try to address the clatter/crunch:
Taken out the cranks and cleaned. Torqued to spec on reset
loosened the seat post, removed, cleaned,replaced, retorqued
Removed fork, cleaned, reset, retorqued everything, inc. the stem/bar bolts
Replaced the chain. This made it better, but not for long.

Any suggestions on what I am missing or should try next? Thanks!

[rnhood]

Take off the rear wheel, inspect the spokes well for tightness and integrity, then take the cassette off, clean and reinstall. Tightening the end retainer cap well (to spec).

[dnades]

chain rub on front derailleur?

[dnades]

I'd check rear derailleur alignment and adjustment if it isn't chain rub on the front derailleur.

[jmc22]

Replacing the chain made it better but not for long - do you lubericate the chain?

[skijoring]

Worn chainring, perhaps? I once replaced chain, cassette and RD and had a clatter than I eventually found was the worn small ring. The chain slipped a bit under load.

[false_Aest]

1) FD rub
2) wash/lube chain
3) RD alignment
4) rear wheel check
5) cassette check
6) chain ring bolts.

[572cv]

Thanks all...
I checked the FD, should not be rubbing.
RD alignment, possible.
Chain is lubed, but I can wash and relube again,sure,
Rear Wheel and cassette....good thought. Have not checked.
but I did Torque the chain ring bolts!

How do you check the chain ring for wear?

All this helps me focus. Thanks again.

[Ozz]

I'd check rear derailleur alignment and adjustment if it isn't chain rub on the front derailleur.
+1

Very easy as a do-it-yourself job.

[572cv]

I was prepared to try each one of the ideas, one at a time for isolation purposes.

It was in the first suggestion, so , I started on the rear cluster. Noticed immediately that the lock ring was not tight at all.... could not have been close to the 40Nm suggested. Cleaned everything, put it back together, tightened up properly, and went for a little loop here with a good 12 % grade on part of it, and plenty of other climbing. What a nice, quiet ride!

Cheers to all and to rnhood for the diagnosis. You da man.