There is an on-going battle between bike makers, retailers and customers over press-fit vs threaded type bottom brackets, with a large number of riders and bike shops opting for threaded cups. Frame and bike makers, however, have been systematically switching to press-fit types and if the trend continues, it will only be one or three years before all production mountain bikes will be converted to threadless bottom brackets. Before all you Knights of the Royal Order of the Threaded Bottom Bracket draw your swords, please understand that technically, ALL bottom brackets are press-fit designs. The only physical difference is that the conventional BB's bearing is pressed into a cup, while Press-fit types. like the popular BB30, have their bearings pressed directly into the frame. After they are pressed or tightened into a functional bottom bracket, both systems operate in exactly the same way.
Arguments in favor of threads are numerous, but only three are viable: Threaded cups can be serviced with simple wrenches that almost everyone owns; threaded cups allow component makers to have complete control over every moving part of the crankset from pedal to pedal; and finally, threaded type bottom brackets seldom creak, while at present, press-fit bottom brackets often creak.
There is a mechanical reason why seatposts, headsets and bottom brackets creak when they are stressed. When a smaller diameter tube is being held inside a larger-diameter tube, there is a significant difference between the stiffness of the larger and smaller members. When a bending moment is applied to the smaller tube, the smaller-diameter member flexes more than the larger-diameter one which is holding it. The smaller tube elongates slightly as it flexes and it slips inside the larger one. That microscopic movement causes the creaking noise. The slip can be exaggerated when a bearing is pressed between the two members, such as a bottom bracket, because flex in the bottom bracket axle is multiplied by the distance from the axle to the outer diameter of the bearing.
Because bicycles have a number of places where this situation can occur, and because cyclists in general are enflamed by any recurring squeak or rattle, designers have spent many sleepless nights figuring out ways to silence seatposts, hubs, pedals, headsets and yes, bottom brackets too.
Those naive enough to believe that threaded bottom brackets emerged from the cycling industry's womb creak free would be dead wrong. One hundred years passed before bike makes got a handle on that one. Headsets creaked like baby toads until mountain bike designers ditched the threads and adopted oversized steerers.
There are strategies in place to silence bottom brackets. Some thread-in cups have Teflon liners which allow the bearings to rock silently. Some are glued in tightly with thread-locking material. Some makers, like Chris King, rely on precise manufacturing tolerances and insider secrets to ensure silence. There is also a theory that aluminum external threaded cups flex just enough to prevent slip between the shaft and the bearings and thus naturally prevent creaking at the source. The point is moot, however, because over time, natural selection has eliminated all the brands that made noisy thread-in bottom brackets.
Proponents of threads either ignore or forget that even a perfectly faced and threaded frame can require the skills of a safe cracker to get the cups started without cross-threading them.
Anyone who has cross-threaded a cup the night before a race or ride can attest that it is game-over unless luck is on your side AND you have a sharp set of bottom bracket taps in your tool box.
A large number of press-fit supporters come from the manufacturing sector because threading and facing frames is costly and bolloxed threads can be a significant manufacturing and warranty issue. Pressed-in bearings are simpler to install and replace, and press-in BBs are less costly. More important, though, is that carbon construction can produce a beautifully precise press-in interface, but it does not lend itself well to threads, so typically, a threaded-aluminum insert is bonded into the BB shell. Press-fit BB shells are made the full width of the bearings (92mm wide instead of 73mm) which also gives frame designers room to widen the frame tubes and make the BB area much more rigid. A number of home and shop tools now exist that make removing and replacing press-fit BB bearings a three-minute operation, and bearings can be purchased from any number of sources, including on-line industrial suppliers in any country. It would seem then, that the last real barrier to press-in is noise.
One can extrapolate that it is only a matter of time when bike and component makers will silence press-fit bottom brackets. Shimano has made great strides by encasing the bearing in a press-in nylon cup (other BB makers are now using similar cups). The thermoplastic has just enough give to absorb any bearing movement, and also, it can overcome a slight amount of misalignment or out-of-roundness in the frame. Nylon also does not transmit sound well, so the cups act as a silencer, which is a key feature, especially when one considers how carbon frames tend to amplify sounds like musical instruments. Eliminating creaky press-fits can't be easy, otherwise it would have been done long ago, but "difficult" is not "impossible," so:
totally agree, that things have been hugely exaggerated, it's not about the customer, it's about sales, always will be in order for there to be a bike industry.
perhapse a it would be better to do a pole of the bike industry called - Progress for the sake of Progress?
There are so many errors, ommissions, and naive assumptions in RC's article that I won't even bother to address them. This is essentially another one of his classic troll polls where he knows most riders dislike PFBB's and he is trying to get a reaction from them by disingenuously pretending that Press Fit is taking over and that its a superior design.
Notice that he didn't mention the fact that you can easily take threaded BB's out and swap them to another frame. Not so easy with Press Fit: just another reason it is assinine.
Santa Cruz won this debate years ago and nothing has changed.
This includes my own experiences owning BB30 and PF30, BB90 and BB92 bikes with original equipment bottom brackets and aftermarket / conversion systems.
The problem was so bad on some of the bikes we sold (a big brand with "OSBB" shell) that we were instructed to actually glue the press-fit cups into the BB shell using a low-strength, flexible epoxy made by 3M called DP420.
This was following numerous customers having repeat problems with creaking, premature bearing wear and the cups "walking" out of the shell under pedalling loads.
On my current PF30 MTB (a big brand ÂŁ3K carbon fibre bike), the BB diameter is slightly too large, and my Praxxis Works conversion BB for HT2 crank had to be fitted using Finish Line Fibre Grip (carbon paste) to get the darn thing to stay put.
Bear in mind the Praxxis BB uses an expanding "collet" design which expands to grip the inside of the BB shell, and it shows you how critical good tolerances are on press-fit systems.
Previously with the stock PF30 and BB30 OE nylon cups on 3 different frames from same brand, and the stock SRAM BB30 axle crank I had nothing but trouble with the cups, bearings and creaking.
Personally? I'd prefer the good old english ISO threaded shell, cannot say I've ever had any issues with using it or fitting it.
You have to be very cack handed to cross thread that design, perhaps best left to a mechanic if you think you are not capable of screwing in 2 threaded cups.
I also think the lack of a BB drain hole on many carbon bikes doesn't help. Even with that O ring between the cups water still gets in when it's sitting in a water bath inside the frame.
People I know who run King BB's have had zero issues.
There should be this option: "I would support Press-Fit BB's if they were reliable and guaranteed to be creak-free"
I'm guessing a nylon Sram BB?
Did you try anti-slip carbon compound as hampstedbandit mentioned? If not maybe loc-tite blue threadlock compound?
The nylon Sram cups are slightly oversized and compress on install so usually there is quite a lot of +/- tolerance unless the frames BB shell is oversized?
or similar chinese version .
Then you can enjoy a threaded bb.
you might remember the grief Cannondale had with BB30 - aluminium alloy BB shell (on aluminium and CF frames), metal bearings pressed straight in, metal crank axle resting on metal bearings = customer and shop mechanic nightmare
metal on metal on metal =
loctite? anti-seize? waterproof grease? copperslip? did not seem to make any real difference
I've seen PF30 systems where the bore tolerance has been too tight on the BB shell, and even with a SRAM PF30 system using nylon cups, the bearings become compressed on installation, causing premature bearing wear, clicking / creaking and need for constant maintenance
Its a weird one to witness, brand new bearing pressed into PF30 nylon cup, as soon as PF30 cup installed into frame, bearing is rough / graunchy when turned with fingers. Remove cup / bearing from frame, bearing feels "as new"....
Waiting what solution YT suggests, as the bike is still in warranty.
Conversion cost is still an option... But 450€ for a bike that already cost 3700€... Hmm....
The best part of this article is the comments from people in local bicycle shops expressing their endless frustrations over this failed design and the thousands upon thousands of shop hours wasted because of it, not to mention the thousands of frames that have been wasted and warrantied because of it.
Second best part of the article is hearing actual mechanics absolutely berate writer Richard Cunningham for mentioning the possibility of cross threading a bb upon installation as a weakness of the design. Guess that's the difference between somebody who spends most of their time typing on a computer and somebody who actually works on bicycles.
Nice try at trolling RC, but another one of your epic fails. "Enduro racers don't need chainguides....Kenda Nevegals are great...freeride is an irresponsible term that will doom mountain biking..." But you got a lot of clicks, right?
My next blog will be titled: Survey: RC's troll polls; Good or Bad?
I worked in 2 different Specialized Concept Store as workshop manager, and certainly warrantied a number of expensive S-Works frames with ruined BB shells caused by poor tolerances on their OSBB design - with the OE nylon press inserts housing the metal bearings.
These inserts were known to work loose, move around under load, causing misalignment of the bearings and damage to the BB shell and crank axle, as well as the bearings and nylon inserts. Eventually we were instructed to bond the nylon inserts with 3M DP420 low strength flexible epoxy.
Check this: ep1.pinkbike.org/p6pb10994408/p5pb10994408.jpg and ep1.pinkbike.org/p6pb10994440/p5pb10994440.jpg
Later models came with aluminium inserts already bonded into the BB shell.
Other issues I saw on older Roubaix ND Tarmac were the bonded aluminium BB insert suffering galvanic corrosion due to mismatch between materials, and bond failing / cracking, allowing the insert to spin inside the BB shell.
Have to say, all of these issues were taken care of very timely by Specialized at no costs to customer, and many got shiny nice new frames
Their 2014 and 2015 Nomad looks like my OTP tho.
www.bikeradar.com/us/gear/article/complete-guide-to-bottom-brackets-36660
You are correct sir.
Couldn't agree with you more, this article is a blatant con job! Most, if not ALL boutique bike companies still thread BB's because they know it's a huge problem, it's not worth cutting costs for unhappy customers. Big companies don't give a crap, they're still gonna sell bikes and they can afford PB to write up lies such as this.
Yes , i have seen my comments deleted too.
If your views don't agree with the author or the company paying for advertising is deleted.
Threaded BBs allow for an adjustable mechanical means of tightening the cup into a frame, which as you tighten the BB flange against the frame causes the BB threads to pull against the threads in the frame giving a stonger area of mechanical interface, ie if it's not tight enough, tighten it a bit more. Press fit relies purely on the tolerance of two (different manufacturers) manufactured parts and the skill of the installer pressing them in (relatively) perfectly aligned. On that basis I would say that threaded BBs are in fact more foolproof than press fit for an average mechanic.
In all the years riding bikes (most of which were second hand) I have managed to silence all creaky threaded BBs if creaking occurs, normally after hundreds of hours riding. The one bike I've had equipped with a press fit BB creaks after only a few tens of hours riding. There is nothing that seems to stop it creeping back.
Whilst technically speaking threaded BBs still have bearings pressed into a cup, the BB manufacturer has far more manufacturing control over the fit between the two parts and with the correct high precision tooling can be sure of a much tighter fit between cup and bearing. When you have two independent manufacturers working to the same tolerances the chances of not having a perfect fit increase.
There's a few paragraphs in this article that just don't quite ring true. 'It's easy to mess up the fine thread on an aluminium...'. I do have a tendency to be a bit gung-ho sometimes yet I've never knackered a BB thread with any combo of frame material or BB cup material even when I started out spannering my own bike when I was about 13. I know it can be done and has been done, I worked at a shop many eons ago and several people came in with LH BB cups wound in RH frame sides. Once we even removed a steel BB cup from a 20 year old steel frame after much swearing, Plus Gas and leverage. We ran a tap through the frame to ensure the threads were fine and it went through easily, only tickling the threads to remove a small amount of corrosion. New BB went much of the way in without a tool and just needed nipping up. You'd never have got a press fit BB to be in a bike for 20 years because the creaking after year 2 would have driven the owner insane and they would have thrown it in the skip or got a bike shop to change it.
I can understand the wider/bigger bearing argument but really, what's the problem with external threaded BBs. It seems a problem is being created (a la creaking press fitted BBs) by trying to solve a non-existent problem. On a cynical level we are being led to believe it's better so that we can be sold yet another type of frame which we need to change everything to fit and they can sell us new fandangled high price BBs because our old ones won't fit. The 'technical' explanation about creaking a differing stiffnesses seem sort of valid, but it just smells like reasons being cooked up to justify us buying into it.
Talking about price, the BBs I need for my press fit frame are more expensive than those I would have used on a threaded BB frame, so don't give me the 'cheaper bearings' BS. Also nylon/polymer cups, surely that's just masking or delaying the creaking problem, not actually solving/preventing it?
The one sentence that does ring true though is the cost to manufacture threaded BBs. Obviously there's more tooling involved and an additional process where alignment is key, but surely the importance of tolerances of ovality and alignment play a more important role in the manufacturing process since with a threaded BB there must be more leeway in size, simply because if it's a bit sloppy in the thread this can be hidden by tightening the BB cup and locking it in place. If a press fit BB is sloppy, you're stuffed basically. This heightend tolerance and manufacturing accuracy requirement must go some way to levelling the production costs of both types of BB, completely ignoring the fact that umpteen bike frame manufacturers have been making perfectly decent threaded frames for years and press fit BBs (although not a new manufacturing technology per se) requires setting up a slightly different approach to manufacturing and therefore more costs would be involved in setting it up.
Way to go Pinkbike, brand every threaded BB stalwart a 'Knight of the Royal Order...', start the article in a mature manner. Don't get me wrong, I like progress when the genuine benefits can be clearly put forward and validated with good supporting evidence, but when it looks like marketing I'm not swayed. And in this case trying to justify press fit BBs just doesn't fly when it all comes back to the fact that an awful lot of press fit BBs just end up creaking MUCH sooner than a threaded counterpart.
Sorry for waffling on, well done if you got this far.
Using hammers on a bike should be an absolute last resort, not a general practice, as in the consumer grade press fit tool in the picture. It's called "press" for a reason; they are meant to be pressed in and out with a press, not beat in and out with a sledge hammer.
Also, I've worked on my own bikes my whole life and worked as a mechanic in a shop for 3 years. I have NEVER cross-threaded a BB, nor have I had too much trouble getting them in. Usually it's when I'm trying to thread it in the incorrect direction or side.
The only potential benefit I can see is being able to widen and stiffen the BB area without widening the cranks. But does that single pro outweigh the lengthy list of cons?
The only way I could see this working is if they start making BBs more durable. Take for example, the swingarm pivot bearings on my moto. They are pressed in and have lasted through a decade of rain, mud, dust, rocks, jumps, etc. And they go through a lot greater forces than a mtb BB. How and why is that? Because they are serviceable, I would say. I can take apart my swingarm and grease all of the bearings without having to press anything out or back in, so nothing ever gets wallowed out.
I'm onboard with valid arguments, and you sir have a nicely crafting piece of work. Well played!
seems like all i do these days is go on articles to moan about conflicting sales bs but im just old enough to remember all the stuff that was said the first few times around so that when they start talking nonsense i cant help but say how i see it. Some people for whatever reason can't or choose not too. We need more people like you on here and then things would start moving in the right direction with actual improvements to bikes. Simply inventing a new way of doing something with a slight improvement is somewhat of a moot point if it introduces a negative effect to...ie press-fit bb's.
-increase the hollow section of the frame, making it a larger, lighter body with the same stiffness
-eliminate the Aluminium shell necessary for threads in carbon BBs. Not every mfg does it, but certainly is possible.
Wether or not this compromise is worth taking for a few grams is a different story. My Point of view is that: It ruins the business of "long life" bearings, because it is uncertain if you can remove the bearing without damaging it. Then there is the creaking issue, which wouldn't be a problem if the frames were more tightly tolerated - which would drive cost.
A nice example of a properly implemented "Press fit" bearing is the headset - it does not rely on tolerances to acheive alignment, but rather a conical bearing to ensure a correct seating of the bearings. Implemented like this I'd not have any problems with pressfit, but the current standard is not suitable for the task.
For that reason I don't buy frames with press fit bottom brackets. Press fit interfaces simply do not withstand repeated bearing installation and removal.
If you're cleaning and greasing the joint before each installation this shouldn't be the case at all. You're not going to plastically deform or fatigue fail the BB shell by inserting a dozen (or more) times, and you absolutely shouldn't be wearing away material as the bearing is inserted.
@Drew-O aren't threaded BBs equally disposable? All the ones I've ever used are sealed. If the BB needed to be changed (ie. wasn't working properly), why would you want to reuse it?
That said, you could design a threaded interface that accomplished the same thing. no reason you couldn't have a threaded BB shell with an ID of about 40mm to account for a 30mm axle & bearings. Heck, that's how english BBs originally worked, it's only in the last few years, with hollow axle cranks, that the bearings moved outboard of the shell.
There are two simple truths:
1. Mounting a threaded BB is as easy as turning a screw. You only need one tool, which is very cheap. That´s it. The threads can take high torques as well, so mounting and servicing threaded BBs should be doable for everyone who knows the difference between left and right. And not everyone is happy about using a large hammer on their expensive carbon frame, which RC states correct as being a bit "uncivilized".
2. A threaded interface does not get worse every time you mount it up. With press-fit cups, the tolerances are prone to becoming worse every time you remove the cups.
The true problem is, however, that the bicycle industry is not able to produce anything with decent tolerances in the first place. Brakes, suspension, frames, etc. If the tolerances for press-fit-BBs were good ... yeah, "IF"! But that´s "too expensive", it seems ...
My personal conclusion is that my next bike will not have this ... issue.
Pinkbike, you've had a sh#t week. First you release that piece of cr@p track walk article with bad photos and the same joke repeated twenty times (go see dirt, their track walk article is 100x better). Then you release this terrible one sided article with a poll at the bottom which just shows the average Joe goes along with whatever they're sold and will end up with a bike they can't service themselves.
Sort it out.
Sooner or later.
Due to ware.
It will be like throwing a hot-dog down a hallway.
Beware.
Please for the love of god will you pass on to your industry reps we don't want this stuff...
My last PF bike (a specialised stumpy), I'd would have to get a mechanic to replace the BB about once a month... that game gets old real fast! at 6ft 3inchs, 107kg broad shouldered monster, pounding down on a flimsy bit of plastic cup with shitty tolerances... the result was always gonna be a poor one. regularly the BB bearings would be shifted a degree out of line with the axle and it happily munch the bearings to a gritty pulp... creaking!!! I'd have killed for 'just' creaking
Currently have a chris King threaded BB on my old school SB66C that hasn't been touched in 12 months
To each their own I guess. I'm OK with press in headsets.
Not really convinced by pressing BB bearings direct in to the frame though. Hated the carbon integrated cups on my Mojo and wouldn't want integrated cups on my BB for the same reason. But could probably live with press in cups from Hope/ CK
Em bom portuguĂŞs: "Se a minha mĂŁe tivesse bigode, era o meu pai!"
To answer the question-- if BB's were silent I probably would still go threaded, simply because the noise is only a symptom of a larger problem. If the BB shell(Frame, or plastic cups) is made out of anything softer than aluminum the aluminum ring of the bearing will eventually gouge into it. Which will eventually lead all other bearings installed later having a poor fit.
Had a creak appear recently on out-of-the-saddle efforts and my first thought was the BB. Nope, traced the noise to stem and handlebar!
I think that most of BB problems that appear have to do with not preloading the bearings properly. When properly torqued crank preload makes the cranks spin very hard! It frees up with time but leaving it with little preload gives the bearing the space to start working loose and creating noises.
Just out of thought, I wonder why manufacturers haven't changed the pedal to crank interface, I think it's been a standard for too long, right?
And yet after making the production of frames less costly, the prices just keeps on going ridiculously higher. I just wish that all these cost cutting in the production of our bikes would somehow reflect on the price we riders have to pay.
I answered "I don't care - ...", by the way. Because, really, has any standard change stopped any of us from riding?
Besides, hobbies are suppose to cost money! and if it has boobs ore wheels you are going to spend a lot of money! that is just how it is.
Nobody needs them to keep reinventing the wheel to get us to buy new bikes, we already do buy them.
"Besides, hobbies are suppose to cost money!" Yes they are but you don't just lie down and get buttf***ed by the manufacturers.
What? In the picture there clearly are raised areas around the bottom bracket. If those didn't exist and in their place there would be external cups, the stiffness would of course be exactly the same.
But that's a non- argument anyway, since external or internal bottom bracket cups have nothing to do with threaded or non- threaded. If there is going to be a new "standard" anyway, and if width/stiffness was of any concern, it would of course also be possible to have internal bearings with threaded cups.
However manufacturers insisted on putting lips in, not bothering to machine at the end of production, etc, etc. Then decided to put the bearings in plastic cups to take up some of the inaccuracies, shrinking the bearings and introducing a source of creaking.
Press fit BBs correctly implemented are great, my BMX BBs have never, ever, creaked, and why would they? Stuff fits right. Someone in MTB had a stupid idea, now we've PF30, PF92 etc, when if it was just done as BB30 was meant to be in the beginning, there wouldn't be any complaints.
Same happens in my opinion with the 15 mm axle. If the 15 were the standard they would come up with the 20 mm axle and its stiffness and so on....
Pure busine$$!!
Now would I prefer the ease of installation of a threaded bb? of course. So far I'm content with (but constantly listening/checking) whats on my Kona.
The common threaded is essentially bearings that are housed in a set of cups which thread into the frame.
Then there are press fits where the bearings themselves are pressed directly into the frame. (which seemed to be the ones talked about in this article)
And then there are also "press fits" that have a press fit cup, which the bearing is then mounted/pressed into. (this type seems to have been glossed over in the article.
Do I have the basics correct here?
Overall, I'm bummed with all the new axle widths / bb pressfittting blah blah becoming Industry Standards where you CANT EVEN buy a new bike anymore with certain things you may have been a fan of and are forced to adapt and pay for the new stuff that may not necessarily even be any better!!! I know the bike industry has to progress, thus change must happen at some point but there is just to much happening too fast
be sure to check back next week for the next batch of new standards in hammer fit bb's and ++ tyres and 3" diameter bar clamps cos using anything else would just be silly.
i know its tempting to hate on all old tech but please cant we honestly just view everything with a little bit of apprehention...after all its your hard earned cash that gets this stuff and if you cant be bothered to try and figure out if its actually worth the cost and effort to get the latest stuff then.....i have some new 17.5"mm diameter bolt through hubs that are gonna be way better than anything your using now (well except 20mm but only losers use them right?) there a snip at 500 euros each oh and there completely incompatable with anything you own so look foward to changing to new forks and frame but i guess everyone likes this sort of thing these days.
The money saving thing is full on bullshit. Really??? a couple bucks labor at best on a $1500-$3500 frame.
So full of shit I can't believe it.
Wish they'd just stop f*cking around.
That said, I have two press-fit BB bikes now, one that has gone year and a half in service with two wet seasons in there and the BB is just as good as the first day. The other one is still new, but so far so good. Also, they are aluminum frames.
I have never removed/installed a press-fit BB, but until then, I reserve judgement. I prefer to work with threaded interfaces.
Creaking BB Suck
Now if the shell face isn't true then you have a different problem.... but that's a frame problem, not a PF problem. In that case then you can probably face the shell (which you have to do with threaded BBs anyway sometimes).
1. easier removal and install
2. better frame design and cheaper manufacturing
3. lighter weight
4. and quiet
who wouldn't want that?
It's not about technology and the ride anymore. It's about making that $$$ as fast as you can.
Pinkbike at it again with false info.
Now I know what it feels like to be robbed in a bike shop.