Thursday, April 22, 2021

Thoughts On Eccentric Bottom Brackets For Single Speed

My OS Bikes Blackbuck's split eccentric bottom bracket
Once again, a reader comment/question has spawned a blog post. This time the question was from "Tomcat" and here is his question:

".... how are you liking the eccentric bottom bracket? Has it been mostly "set it and forget it"? More and more I like the EBB for a couple reasons, including: 1. It looks sleek 2. I don't have to worry if the wheel is centered 100% in the sliding dropouts or possibly slipping. I'm constantly paranoid that my wheel is not 100% center in the horizontal dropouts. I don't personally own an EBB nor have I tried one, but I'm liking the prospect of using one more and more." NOTE: Comment edited slightly for clarity.

Tomcat was referring to my eccentric bottom bracket insert on my Twin Six Standard Rando v2, specifically, although I have had experiences with several eccentric bottom bracket types throughout the years. In fact, as I researched this topic on my blog archives, I found bicycles I had forgotten about that used eccentric bottom brackets that I once owned. Let's see.....there was an El Mariachi, an early Raleigh single speed 29"er called the "XXIX", a Soul Cycles Dillinger single speed. There were also a couple of test bikes for the former "Twenty Nine Inches" website which used eccentric bottom brackets. This in addition to a Singular Cycles Gryphon I once owned, my Blackbuck, and of course, the Raleigh tandem I own. 

So, yeah, I have experience with eccentric bottom bracket use in road, mountain, and gravel  applications. Specifically to the Twin Six, I am really liking this Wheels Manufacturing eccentric bottom bracket insert for PF-30 style bottom bracket shells. It has held its tension on the chain and has not creaked at all. 

That's probably the number one complaint about any eccentric bottom bracket. I have certainly seen a few creaking ones come through my repair stand. I do have a few thoughts on why I have not had any troubles, not a lick of creaking, and why maybe some people do have issues.  

First of all, it has to be said that some individuals ride bikes really brutally. They seem to have little smoothness, subtlety, and seem to lack finesse in their riding style. Besides many other detrimental issues this sort of riding style can impart on a bike, eccentric bottom brackets don't get along with people like that much. Keeping in mind that any two assembled parts on a bicycle that shouldn't move actually do, ( a minuscule amount) and brute force, ungainly riding styles, and wrestling with the bike exacerbate that movement. Movement causes noises. Period. So, if you seem to never have had a quiet eccentric bottom bracket, this could be a reason why that is. 

The Standard Rando v2 has a reinforced bottom bracket shell which is a good thing for single speed use.
Okay, so with that out of the way, we can see that an eccentric bottom bracket is not for everyone.  But there are some things one needs to consider after riding style. One is that the eccentric should be a quality piece. The more precise it is in terms of shape, the better. Same goes for your shell in the frame. A warped shell from a welding procedure will result in a poor eccentric fit, more chances for noise, and chances for slippage in worst case scenarios. I've seen over-sized shells as well, so be aware that it might be a bad frame to begin with which is causing the issues. The Twin Six is a good base to start from because it is made well. 

The eccentric I used is from Wheels Manufacturing, a brand that makes high quality parts for bottom brackets. So, I am not sure you could even find a better insert. Maybe you could, but the Wheels one is top notch quality. Grease that thing up and stick it in a high quality frame like a Twin Six Standard Rando and you should have a great experience single speeding. 

Unless you ride like a gorilla, then all bets are off.  (Only sort of kidding there.)

So, to answer the question- Yes. I like it a lot. It is pretty much set it and forget it. 

Got any other questions about this or anything else? Hit me up in the comments or e-mail me at


NY Roll said...

We know I pedal like a gorilla ;) But the issues I have seen with EBB is the set/locking screws loosening. That could be cause by numerous things, but I am pondering the T6 FSU going to a EBB.

Guitar Ted said...

@N.Y. Roll - Your honesty is refreshing. :>)

Yeah, I could see where bolts are an issue. Of course, the Wheels Manufacturing insert applies pressure in a bit different way which combined with a thread locker seems to hold together well. My pinch bolt EBB on the Blackbuck (pictured in the post) holds its tension like a champ.

Here again I will say it is due to quality manufacturing and design integrity. Not all EBB's are created equal.

R said...

"You cut me deep, Shrek... You cut me real deep just now." - All the Apes who read your blog.

Skidmark said...

Ive seen cases where the rear hub allowed the rear cog to move but the eccentric BB gets blamed for slipping.

Guitar Ted said...

@R- LOL! I could hear Eddie Murphy's voice when I read that comment! Awesome!

@Skidmark - Yeah, a lot of weird things can happen when riding a single speed bike. Tons of stress on a drive train and frame for sure when you get to mashing out a climb.

Tomcat said...

Thanks for answering my question and giving us some insight on your experiences with the EBB. These really seem to be a novel solution to single speed a bike. As you mentioned manufacturing tolerances can play a significant role in your overall satisfaction of them - this is certainly something I will keep an eye out for if I ever plan to take this route.

S Sprague said...

In addition to the Wheels Manufacturing EBB, I have had excellent quiet service with my B.E.E.R./now Squid Oner EBB since the current one is manufactured by White Industries if you to support a US based company. The B.E.E.R. EBB was owned by me, sold to a friend with a frame and is back with me on another frame which has been trouble free.

MG said...

I too have had good experience overall with EBBs over the past 15 years. I currently have four Singular bicycles that all are equipped with (Phil Wood-style) EBBs, and all have been 100% silent and reliable. I do check the fastening screws from time to time, but have never had issues with them backing out. I think one of the most important things to do is to grease the EBB/frame interface well when the bike is built. That alone makes a big difference.

For singlespeed use, EBBs are my preferred method of chain tensioning. Hands down.

DT said...

So if you get a rear flat with an EBB, do you need to change the tension at the bottom bracket? Forgive my ignorance on the topic, my only SS experience is with traditional horizonal dropouts and bolt-on axles

Guitar Ted said...

@DT- No, you don’t need to do anything like that. That is another benefit of the eccentric in that it acts like a traditional vertical drop out bike. Once the tension is set with the eccentric you shouldn’t have to adjust it again unless the chain wears and gets looser than you’d like it to be.