Hold on a minute
We have one of the busiest repair shops in the industry, and we solve more bottom bracket creaks than you can shake a stick at. The first thing we've learned is to eliminate the easy things first so we don't go chasin' a rabbit down the wrong hole and come up empty.
Every year we have a few customers email us to help them solve a bb creak. Most of the time we get it solved before ever addressing the eccentric itself. There are several places that a bottom bracket creaking noise can come from that we need to eliminate first. These are things that happen to bicycles with or without eccentrics in them and we see every day in the repair shop here in Seattle. I apologize in advance if you've already done all of these things, but we do need to eliminate them as a possibility first. If one of these things is creaking, no amount of work on the eccentric will solve the creak.
For instance: A creak that happens every pedal revolution is almost always quickly diagnosed as a bottom bracket creak by the rider, and by the inexperienced mechanic. A young mechanic, by nature, seems to go for the time consuming, difficult fixes first. But you reading this, will benefit from our experience in the school of hard knocks;-)
So, first we need to eliminate the non-bottom bracket stuff.
The Seat How about if your standing up and pedaling? If it creaks on when sitting and pedaling, but not when standing and pedaling, then the creak is not related to the bottom bracket or any of the components there. It's more likely a common cause of creak....the seat rail. Fix: Drip some triflo on the rails where they attach to the seat until it quits.....or get a new seat.
Stem/Handle bar bolts Another thing that we commonly diagnose here in the shop when a customer complains of bottom bracket creaking is handle bar stem bolts. This can be diagnosed by not riding the bike, but holding the bars and pretending to ride and see if the bars creak. It's surprising how many times even our mechanics miss this one until after they've messed around with a bunch of other stuff. Fix: Remove each bolt one at a time and grease the threads. Re-install them, test to make sure your bars are tight, then give it a go.
Still creaking!!? The spindle itself may or may not require grease before installing the arms. Square tapered spindles should NOT be greased, but installed tightly and checked frequently (if there is grease on them, it should be wiped off before installation). Splined bottom bracket spindles (Mega-Exo, Octalink, etc...) require grease most of the time. We find that a lot of these spindles will creak without grease on them. Also, if there are binder bolts on the left crank arm, the threads of those bolts need to be greased and tightened frequently. Again, these are things that the manufacturer expects that the dealer will do.
We have changed our assembly procedure to include greasing everything during the eccentric assembly process, but that affects the parts manufactred in 2010 and going forward.
Over time, especially in bad weather, the grease will get old or just 'go away'. You'll want to grease the ebb occasionally.
If you are unsure about the installation of your Bushnell ebb, you'll want to follow the instructions linked here (456k download) to ensure that it is greased properly and installed properly. Make sure to have plenty of your favorite beverage on hand as it helps cut down on swearing during the procedure. A list of recommended beverages can be provided by request.
To the right is a picture of his ebb the way it came back to us
Make sure your wedges are NOT like this
Thanks for reading