Hello,

I have been looking at new bikes, and have been seeing "BB30", and someone explain what that exactly is?

It's a pressfit bottom bracket. (as opposed to the older English threaded BB).

Manufacturers claim that BB30 is stiffer than English but unfortunately, it's also squeakier. You can run cranks for an english threaded BB on BB30 bikes with an adaptor (for example, Shimano doesn't make any BB30 equipment as far as I know, so you may see a bike with all shimano drive train and a FSA crank)

HTH.

^ yes, and is it really any better? I think not. Mostly marketing hype IMO.

I'm always uneasy about frames that do not conform to the most widely accepted standards. Headsets gave me a headache to understand. Incompatible with Shimano sounds pretty risky.

IIRC, The purpose for BB30 is that it enables frame manufacturers to build more stiffness around the bottom bracket without adding excessive weight.

Marketing?

No one "sells" BB30. Cannondale developed the standard and put it into the public domain - meaning any manufacturer can use it at zero cost. Hence - not marketing...

Bikes with all Shimano and FSA cranks are actually very common. But incidentally - SRAM does make BB30 equipment, and it's common to see Force cranks on bikes that are otherwise all-Shimano.

And replacement bearings at $8, cheaper than a regular bb.

https://www.slowtwitch.com/Tech/Botto...ards_2573.html

Someone with bicycle manufacturing experience (can't remember who) was on awhile back and posted this explanation for BB30: it is cheaper for carbon bicycle manufacturers. With the press fit BB's, they can control position and alignment easier without the opposing threads of an English BB. I can't remember the exact explanation, but I believe that they bore a straight through bore into the finished frame, so there is no potential for misalignment side to side.

So if Cannondale was the only one doing it, no one would tool up to make cranks or BB's for them. They open sourced it, and pumped up the advantages of axle size and bearing size. The advantages are real, but weren't the real intent.

I may have butchered the guts of the story, but it is the gist of what a credible poster reported.

Interesting - thanks!

It's true that the frame makers (or the people who make the BB insert) can machine a BB30 bore in a single cut, making it easy to get it precise and aligned. (there are also circlip grooves to machine). That's a good thing for us. It means that frames no longer need to be chased and faced before being built. And a design that makes precise manufacturing easy means that the frames are more likely to be made precisely.

Some carbon frames make the BB entirely out of carbon but often there is an aluminium BB insert for the BB30. They always have an insert for BSA ("english threaded") BBs. Bonding the insert to the carbon has sometimes been a problem in the past. But it's mostly solved now.

IMO BB30 (and other press-fit bottom brackets) are all a significant downgrade from threaded BBs. Because the disadvantages are real, too. The parts of a bicycle that are probably subject to the greatest stresses and forces are only pressed together.

And it certainly is marketed - because it's all about lower production costs for manufacturers. So they figured out some things that it can do slightly better than standard threaded bottom brackets. Not that standard bottom brackets actually perform unacceptably in those regards. Kinda like saying that a pair of pants that are strong enough to tow a cruise liner are better than a pair of pants that would rip. True, but so what? It's better at something that doesn't really make any difference.

Most of the cranks thread together, holding the cups/bearings in place.

Marketing- Selling something as new &improved...latest-greatest...you-need-this...when in fact, it is inferior and just a convenience/cost-cutting measure for the mfg's. Or so it seems to me.

BB 30,
Seems like there could be some weight savings over the threaded version.

Think I did just this three months ago, but my memory is just not that good.

i notice that giant carbon frames have cranks that are shimano and no outboard bearings. So if shimano does not work with bb30, what is the bb on the giants?

Well said sir.

Conspiracy theories abound on Bikeforums.

After about 10 years of riding this stuff (introduced around 2000), I disagree. But also understand that the real intent of things like this is to get weight out of a bike for a professional. And since virtually everyone on a road bike fancies themselves a pro (Walter Mitty types) the manufacturer's allow these standards into their line up. Because one of the first three questions I get from a prospective road bike customer is "how much does this bike weigh???"

Lot's of people want to ride paper weight light bikes but do not realize that those bikes, at the pro level, are serviced every day. Like a NASCAR stocker or an Indy Car (designed for high horsepower short duration). So, I ask the customer if they want light or do they want a bike that they can ride for a while without thinking about it? If it is the latter, I tell them to save their money and buy a less expensive bike with more durable components. They will be a lot happier.

I have been riding BB30 since before it hit the commerical market but I also know how to service it (as do our mechanics) so it has never been a problem.

It's a press fit BB86 Shimano. Except for the TCR Advanced SL 2 which is equipped with SRAM Red,so they use SRAM GXP Blackbox

I am curious if you can post some factual information about how this is a "convenience cost cutting measure" for manufacturers? Thanking you in advance for the industry information I cannot come up with.

Just so you know, this stuff was designed for a professional and having had a decent glimpse into the world for a while, their ain't no cost cutting measures.

Road Warrior,
I repeated a post that I had seen previously, and have no specific knowledge of the bicycle industry.

I do have over 20 years experience as a manufacturing engineer in metal cutting and forming. From the standpoint of just making a metal BB shell, a press fit shell has the potential to be significantly less expensive. Now, this is based on many assumptions, but if the opposing threads have to be in line in a tight enough tolerance to support separate bearing cups, you may be looking at single pointing threads. Everyone thinks you just slap a tap in a hole and get threads, and you do, but you do not control location of the pitch diameter.

Location never mattered with square taper bb's, because the bearings were located to the spindle in a stand alone assembly, and the shell alignment had no impact on the bearings, only on crank alignment to frame. With outboard bearings, the bearings are only as good as the PD alignment half to half.

Anyway, I'm not saying that it didn't bring weight reduction or other advantages. But to say it didn't have cost benefits to the manufacturer may not be honest either.

A treatise could be written comparing BB30 to theaded BB. I believe largely what you have written because of course it is rooted in fact and experience.

I do have to ask however. I believe you still ride a fair amount of miles. How often do you service your BB30?..based upon miles or time? Do you regrease?...or automatically replace the bearings which are inexpensive?

Further to others comments...this discussion is about BB30 and PF30 hasn't been mentioned...PF30 involves Delrin bushings which have been statistically more problematic than BB30...because of the low yield strength and lubricity of Delrin bushings. PF30 offers a considerable cost savings to the frame mfr...in terms of mfg cost. Specialized uses a narrow version of PF30 on their flagship Sworks bikes and many have suffered. As RW stated, pro racers who race these bikes can change bearings every couple of days if they want...a pro mechanic can change them in ten minutes. BB30 versus threaded carbon shell...almost a wash cost wise. BB30 bores have to be machined and precise...best to finish machine for co-linearity after insert molding the alloy cups. If you Loctite in BB30 bearings, they shouldn't make noise. PF30 is more challenged from a maintenance standpoint.

Speaking of which, Roadwarrior, have you owned PF30 bikes?

For those running PF30 BB the new CK BB should be available this spring. I believe Moots has been beta testing the BB on their C/X bikes in extreme conditions and the feedback has been very positive. Like all other CK products it is suppose to be bullet proof with a 5 yr warranty and a grease injection port for easy servicing. Available in 24mm spindle size (Shimano) as well as 30mm.

https://www.bikeradar.com/news/articl...ke-2012-35277/
https://www.bikerumor.com/2012/08/29/...sfit-bbs-more/
https://www.cyclingnews.com/features/...is-king/238930

Opportunity meet demand. That is what you are seeing in the industry and will be seeing moving forward. Where are aftermarket bike companies putting their R&D? Where they believe the future is. I agree. PF30 is the future...not BB30. This is all in the face of PF30 being more technically challenged compared to BB30 as of now. That is changing however. If PF30 is done right however it is better than BB30 and cheaper to make...at least the frameset. The simple fact is...a short 6mm press for BB30 bearings isn't a solid support when a combination of vertical and lateral forces are applied to bearings due to the pedal stroke...and hence the advent of Loctite to mitigate this moment aka lateral torque. A PF30 BB can be much more stable. So how is PF30 evolving? Longer press and integrated bearings. Why do most PF30 BB's fail? Delrin bushings come loose due to short press into BB and BB30 bearings start to creep and move in Delrin bushings. New aftermarket designs like C-bear, now Chris King and even Praxis collet BB design maintaining Delrin bushings is much more robust. What do they all have in common? Integrated bearings. Bearings can't break free from press into Delrin bushings...instead they are captured in place and not a pure press. Further, a longer press into pure carbon 46mm ID PF30 shell is much more robust than short press of Delrin bushings which tend to come loose and why Specialized now specs Delring bushings be 'epoxied' in place.

My prediction is...in the next 5 years you will see a move away from BB30 and in favor of PF30. This will put the emphasis on BB design which we are already seeing. There is no reason for mfr's to toil with insert molding alloy cups into carbon BB's as with BB30 and then precision machining aka aligning bores for good cylindricity. A single 46mm carbon ID hole aka PF30 is all that is necessary. The rest is left to the BB design for robustness. This is where bike makers have stumbled and the aftermarket is picking up the pace to make a more reliable BB.