My head is spinning with confusion on BB terminology, I'm hoping somebody can clarify things.

I'm interested in building a road bike with the Dengfu FM098 frame and an Ultegra groupset that I would like to purchase from Chain Reaction Cycles.

The frame is here:


And from Chain Reaction the Ultegra groupset can be purchased here with some options:


or here with pretty much every conceivable option:


So here is where the confusion begins. The Dengfu link above lists the FM098 Bottom Bracket as "BB: English BB/BB30", I'm under the impression that this means a choice of an "English BB" or a "BB30" bottom bracket, is this correct?

Now considering the Chain Reaction Ultegra Groupset links, the one with fewer options does not list an option for BB, rather it states "Incl. Hollowtech II Bottom Bracket SM-BBR60 BSA". The Ultegra Groupset builder with the many options has 2 choices for BB after choosing the Shimano Ultegra 6800 Bottom Bracket option, "English 68mm" or "Italian 70mm"

So I checked the Wikipedia page for BBs:


The table towards the bottom (see the column heading "Bottom Bracket Thread Name") seems to imply that ISO/English & BSC (British Standard Cycle) and BSA all effectively mean the same thing, and that the shell with for these is 68mm.

At this point I'm under the impression that the Denfgu "BB: English BB/BB30" means a choice of an English Bottom Bracket or a BB30 Bottom Bracket. I'm also under the impression that the Chain Reaction Cycles Ultegra Groupset with "Incl. Hollowtech II Bottom Bracket SM-BBR60 BSA" would match the Dengfu frame with the English BB option, since BSA seems to mean the same thing as English, and English seems to be 68mm, is this correct?

If not, would the Chain Reaction Ultegra Groupset Builder with the "English 68mm" option fit the Dengfu FM098 frame with the "English BB" option (supposing this is actually a separate option from the "BB30" on the Dengfu FM098)?

Sorry if this is a beginner question but BB terminology can be quite confusing!

  • Welcome to the site. Bottom bracket "standards" confuse even longtimers.
    – RoboKaren
    Jan 26, 2017 at 1:04
  • Thanks for the comment. Can you provide some clarification on the above?
    – cdahms
    Jan 26, 2017 at 1:21
  • Hahaha, I'm an oldtimer still stuck in the French vs. Swiss vs. British. These new cartridge bottom bracket standards have me scratching my head too. That's why I upvoted this question and look forward to the answers.
    – RoboKaren
    Jan 26, 2017 at 2:10
  • where are you actually purchasing this frame from? I can't seem to find a way to order the frame from their website..
    – Paul
    Jan 26, 2017 at 3:48
  • Check their page towards the top right, you can email "[email protected]" Skype contact "dengfusales1". Unfortunately they are on vacation for the week for the Chinese new year, but I'll update this post when they get back and respond.
    – cdahms
    Jan 26, 2017 at 11:46

1 Answer 1


Honestly I would try to get in touch with the company further, as their explanation of the bottom bracket makes no sense. And as is often the case with these companies, some things get lost in translation.

Bottom Bracket Standards

This could be a mile long explanation, so I'm only going to address the two in question here: BB30 and BSA. A couple good articles are here and here. The first one gives a nice little history of why the ^&%$@ we have to try to understand so many different standards.


This, I would have to assume is referring to British/BSC/BSA (acutally in some places on DengFu's website they refer to it as BSA and others as English). As explained by Sheldon Brown:

B.S.A. (Birmingham Small Arms) was a major British manufacturer of firearms, and later of bicycles and motorcycles. It reached its peak in the 1920's. The standard thread sizes that B. S. A developed for its bicycles were ultimately adopted as the standard British (B.S.C.) sizes, which, in turn, were mostly adopted by the I.S.O.

So BSA is actually a thread pitch/diameter standard of 1.37"x24tpi for bottom brackets. This thread pitch is found in several widths (68/73/83mm and probably more) for bottom brackets, which describe "English" Bottom brackets. It also applies to things like freewheel and headset threading.


BB30 is a standard that was created by Cannondale to help create stiffer bottom bracket/crank interfaces. It utilizes a 30mm spindle (vs 24mm for shimano hollowtech II/GXP/FSA MegaEXO/etc). You may visit this page and click accept to view the (now open) patent. The frame must be 41.960±0.025mm in diameter and be 68.0±0.2mm wide at the bottom bracket. Effectively a standard 'English' BB shell but larger diameter with no threads cut. Also, do not confuse this with PF30 - BB30 has bearings directly in the frame that rest against a retainer clip.

This Frame...

Looking at the photos of the frame, this is definitely a pressfit bottom bracket as photographed, which would rule out English/BSA. Why they would ever say English/BB30 is beyond me. I'm leaning towards there was some translation issues and/or some confusion on the part of the person writing the web page. It is not uncommon to receive something that is not quite what you expected when you buy things like this direct from overseas. I would definitely try to get in touch with them further to confirm exactly what is going on.

BB30 to HollowtechII/GXP/MegaEXO/etc (24mm spindles)

If it is BB30, what are your options? As far as I know Shimano doesn't make a BB30 compatible bottom bracket. This would be a bottom bracket with 42mm OD bearings x 24mm ID. Here's a few options in order of my preference:

Probably your best bet in this particular case is something like this adapter from FSA, although I don't have any experience with them as far as reliability. This would allow you to choose a standard BSA bottom bracket with the component package and actually be able to install in the frame.

Praxis makes a bottom bracket that would work. As well as Rotor. I feel this is preferable if you weren't already forced to buy a BSA bottom bracket as having less parts floating around is generally more reliable.

Wheels MFG makes lots of cool stuff in the USA and they make delrin adapters that will reduce the ID of a BB30 bearing to 24mm (hollowtech II). Probably less desirable in your case, as then your hollowtech II bottom bracket is useless and you have to buy a BB30 bottom bracket.

Also, press in bottom brackets require bearing presses and can be pretty tricky. Usually not tools that the home mechanic has around.

once again: I would strongly suggest getting in touch with these folks before buying anything. The lack of clarity is really not confidence inspiring. Maybe they do offer the frame in two different BB options, but that doesn't seem particularly likely to me.

  • Great answer! Hope to see you around more here and in the velodrome chat.
    – RoboKaren
    Jan 26, 2017 at 3:37
  • Thanks for the info. I up-voted your answer and I have contacted the company, I'm curious what they have to say. The funny thing I should have mentioned is that in this video youtube.com/watch?v=1C7FpLVnK9M the person is assembling a Dengfu R02 (which has the same "English BB/BB30" description) + Ultegra BB so it can be done somehow. I'm still hopeful the "/" means "or" but I'll see what Dengfu has to say.
    – cdahms
    Jan 26, 2017 at 3:52
  • Well, clearly his frame is threaded. And if you go to the R02 frame on the Dengfu website you can clearly see the threads in the frame they have photographed for that particular model. So.. yeah.. get in touch with them as clearly the English/BB30 description can mean either?
    – Paul
    Jan 26, 2017 at 3:57
  • +1 You are quickly getting a reputation for quality answers :-)
    – andy256
    Jan 26, 2017 at 5:07
  • 1
    @andy256 thanks! got a gap in work and trying to stay sharp and help out :) and karen I didn't know there was a SE chat, I'll check it out!
    – Paul
    Jan 26, 2017 at 17:11

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