This is a good one, but kind of long. Maybe bdop can convince the KMC guys to have a look, if he isn't actually burdened with knowing it all.

I put about 2,000 miles on my SRAM drivetrain: pg-1070 cassette, rival cranks, pc-1030 chain. The chain sounded like a sewing machine from day one. Pretty early on, I started using White Lightning Clean Ride. It's a wax-based lube and I applied it correctly, wiping it down infrequently and adding a little maybe every 12 hours of riding after getting a good base built up. The chain would go from "Singer" to "International Harvester" sounds so I knew when to lube.

I was fairly happy with this. The chain stayed cleaner than my other bikes, but I did notice excess wax building up on the derailleur pulleys, chainrings, etc. I shrugged.


Then I installed a new cassette because I wanted to move from 12-27 to 11-23. I'm in Kansas, after all. I installed a KMC X10-SL at the same time. (The SRAM chain is stretched less than halfway to worn out, but it sucks.) I made some attempt to clean the excess wax but I did not go full OCD on the bike, and per KMC's instructions I left the factory lube on the chain which lasted a while, but of course all good things come to an end. Some remnants of Clean Ride's wax still lingered, and it displeased me because of the clean cassette and chain.

Here's where things got interesting. I pulled out a long-forgotten bottle of ProLink instead of my trusty Clean Ride. I stopped using ProLink because it got black really fast. Several BF members said that if you wipe it daily and re-lube *less than daily, as needed*, ProLink was not that dirty. Sure. We'll see, right?

ProLink says for best results degrease chain, even brand new chain. KMC says leave factory grease on chain. I sided with KMC and applied ProLink. Over the next few riding sessions, the chain was VERY black and filthy. I cursed ProLink, but didn't switch. It seemed like it was acting as a solvent on the KMC factory grease... liquifying and shedding it.

I wiped down every day and re-lubed every other day. I still did not degrease the chain. (I use a FinishLine chain cleaner. Same as ParkTool.) It seemed to be improving. So I figured maybe ProLink suggests to degrease a chain because they know ProLink is going to dissolve whatever is on the chain anyway, and make a mess.

Stick with me! But ColinL, you long-winded bastard, the thread title is *gritty* chain, you are surely wondering. That's the really odd part. After a few hundred more miles, suddenly my chain is gritty. I'm talking crash-your-MTB-in-talc-sand gritty. If I pushed the sideplates or links I could hear a crunchy grinding sound. Any link. All of them. Whole chain.

Same noise as you pedal or freewheel the chain around, of course. By this time, it's midnight and I just want a chain that isn't gritty as hell for my morning ride. That can't be good, right? So I grab some blue shop towels (thick, lint-free paper towels, basically) and the ProLink. I lube, wipe, repeat. I get 3 shop towels completely black. I wipe every part of the derailleur and chainrings I can get without removing the chain. (I should have removed it, I know.)

The friggin chain is still gritty. 12:30 now. Screw it, going to bed.

This morning I rode with the missus (no ) and afterwards I poke the chain. To my shock it's not gritty. Not even a little bit. Touching it leaves a black spot on my fingers, but no grinding noises. I freewheel the chain backwards slowly, then faster. No grinding noises.


What in the heck was the grit and where did it go? I sure put enough ProLink on that despite wiping, it could well have flung off during the ride when I dialed it up to 400 watts and took the grit with it. That's probably what happened. But WHAT was it? Leftover wax? Bits of cassette? Of chain?

Langoliers

Baby bike bolts must have fallen into the chain.

Some lubes are very agressive and will push out any other lubes that may be on the chain. It's called 'wetting'. It will do exactly as you describe; It will leave your chain a black mess until all the lube and foreign particles are pushed out.

I used to experience this with the early Finish Line Ceramic lubes until they changed their carrier.







Oh, the burden...the burden...

I think the fierce pounding of his mighty guads turned the trick.

So, that means the grit on the chain was probably a combination of broken-down grease and wax, which came from the new chain and excess wax on the chainrings and derailleur pulleys. It sounded like sand or metal particles, but the wax I rubbed/wiped off was pretty crunchy. Totally plausible.

You also were using the X10SL with hollow inner and outer plates which we refer to as 4D expulsion:
"Hollow plates allow mud and other debris to be expelled from the chain on all sides". Marketing or fact!?

It's the chainset. The lube is only masking the problem until it wears thin.

Interesting. Could you elaborate? The noise was definitely not coming from the bottom bracket, it was grit in the chain. Grit that you could see on your fingers if you wiped the chain barehanded.

My chainrings look pretty good, with normal-shaped teeth. In fact I've only worn out chainrings once ever, and that was a MTB I got as a teen.
That's a fact!