Monday, July 30, 2012

Creaky Toy Part II

The creaky subject...
Saturday I wrote about my creaky Mukluk. I tested the bike after removing the bottom bracket, cleaning up a small fistful of dirt, and then re-anti-seizing the cartridge unit. But although that needed to be done, it did not eradicate the squeak. I still had the exact same amount and kind of annoying creaky-squeaky as before.

Now this is where a lot of folks might just throw up their hands in disgust and get angry. I understand that feeling. However; I've been a bicycle mechanic long enough to know that just because a noise sounds like it is coming from a certain place, it doesn't mean that it is. Such is the way of bicycles and noises. So, instead of giving up it was time to get crackin'.

Altenator B-bad
So I started thinking about what else it could be. While it seemed at first the noise only happened when I pedaled, I noticed small amounts of creaking when I hit bumps, and if I changed directions suddenly. Hmm......It could be something else entirely.

By-Tor The Titanium Mukluk has the Salsa Cycles Altenator drop outs. These are essentially a modular plate that bolts on to the rear of the frame at the chain stay/seat stay junction and can be "swung" by its upper bolt to adjust wheel base or to tension a chain on a single speed set up.

Anytime you bolt two pieces together on a bicycle it is a potential noise maker. Especially if those two peices are part of a high stress area on the frame, like the drop out area is at the rear of a bicycle frame. In this case, it became apparent that either contamination, oxidation, or both may have occurred between the titanium of the frame and the aluminum of the drop out plate. Obviously the rear drop out area is a place where dirt and grime is going to be constantly coating the frame through riding off road. No surprise that the Altenantor might make noise then. I did a few more tests and my strong feeling was that the Altenator was the source of my creak. There were a couple of other hypothesis, but this seemed the more likely of my choices.

Two bolts- simple!
By-Tor went in the repair stand and within a few minutes I had one Altenator off. Salsa's drop out design, called a "swinging type", due to it's pivoting motion when adjusted, is dead simple. Easily taken on and off with  5mm and 6mm Allen keys.

When I inspected the mating surfaces, I could see a white, powdery looking substance, which may have been oxidation, near the swinging bolt on the frame. There was a fine coating of dirt as well over everything.  A similar looking situation was discovered when I removed the non drive side drop out.

Obviously, a quick clean up was in order. Once I had the surfaces free of anything that smacked of foreign substances, I began to re-install the Altenator plates. I re-applied Loctite to the bolt threads, and put a very small amount of grease under the bolt heads where they would spin against the frame as I snugged everything back up.

I installed the Altenators dry otherwise. Some may think that a fine coating of grease would be good here, but I don't adhere to this way of thinking myself. The plates don't slide against the frame in use, (other than if one was to tension a single speed chain or alter a wheel base), and grease would only serve to attract more dirt, to my way of thinking. This would only yield a creak anyway, since dirt and contamination are what caused the creak in the first place. This is different than a bottom bracket shell, which isn't directly exposed to the elements, like the Altenators are. My opinion is that a coating of grease would get washed out of there right away after anything wet was encountered anyway. So- I didn't do anything but assemble the plates back together with the aforementioned Loctite on the bolts and grease under the bolt heads for secure fastening.

And did it work? Why yes. Yes it did. No more creaky-squeaky, and all is well with By-Tor The Titanium Mukluk and me once more.


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