T47 BB's - here to stay or a passing 'standard'?

What’s the consensus? Seen the new Emonda has been kitted out with one.


Based on a simple scan, I think it is a nice option to have. It may open frame design beyond potential BSA limitations, while still giving us the control and ease of use that I think most of us treasure from threaded setups. If we narrowed down to those two threaded options as the main ones in use, I think many of us would be quite happy.

I say that as someone who has not directly experienced PF issues, but have seen more than a few through my shop work. PF BB’s need to go away. They were a bad experiment, like chainstay mounted brakes, and should be pushed into the history books instead of active production.


Thanks Chad that’s good to hear. Trek appear to be moving towards it across the board which at least means it should have a decent lifespan, but I haven’t seen it appearing elsewhere and becoming a universally adopted standard - I assume it’s more expensive to produce (not knowing quite how it’s done)

I appreciate the nature of a threaded component, and especially so in a carbon frame, raises a few questions though.

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It was announced in late 2015, and sadly, adoption has been slow. Some is the pure delay in a “standard” being created, to the actual nuts & bolts that start with designs using it, and manufacturing actually putting it in place.

The basic return to BSA that we have seen from the smaller brands like Santa Cruz, Ibis and such has grown to Specialized on most of their new models. Not sure why they chose that over T47, but I think we are all happy to see them push threaded in any form right now.

Trek adopting T47 (even if it is their “smooshed” BB width version, to give more tool bite on the BB flange) is a big endorsement. It’s started with the Crockett, then the Domane, and is growing in use now with the new Emonda. We can only hope it makes it into their other models set for future release (Checkpoint, and then their entire MTB line, since they skipped it on the recent release of the Fuel EX, Top Fuel and Supercaliber).

Fingers crossed that these big players (and others??? I have not followed Giant or Canyon in particular) will keep pushing this direction. It does cost them more, but the uproar over PF has been heard (I think) and they are just being a bit slow in reaction.

T47 appears to be a standard everyone is gravitating towards. I think if you search it for Kogel you’ll find their first article saying they’d never adopt the standard for their bearings then a more recent one says they are happy to offer bearings in that standard. Lol.


Had to search:

The bad

Like almost any product, T47 faces a few problems too. One of the main drawbacks of carbon is that it is close to impossible to cut threads in it. Therefore the standard is only for metal frames. One could build an aluminum insert in a carbon frame, but that would require bonding this insert in the frame. This adds weight and cost, two things most cyclists are not big fans of. Also, if these aluminum shells decide to break their bonds with the frame, we are back to creaking, the number one problem T47 promised to fix. This time it’s a warranty case instead of a simple bottom bracket reinstallation.

When the new standard came to the scene, it was said that it could be retrofitted on existing bikes with a PressFit 30 shell. So far I have not seen a single successful execution of that. From my talks with people that know their way around thread cutting, it is definitely not something that could be done at a bike shop with hand tools. We have to write off this story as wishful thinking.

  • Funny that their “problems” are the very same ones that could have been complained about for BSA in carbon, but they worked far more consistently than the more common issues with PF designs.

But what about Kogel T47?

One of our marketing slogans is ‘Any crank, Any frame, No adapters’, so it is not surprising we have received a few hopeful questions from customers. Given the lukewarm response from the frame makers and the intense competition on the components side, we have decided to sit this one out. Between White, King, Enduro and Praxis, there probably is not a bad option on the market. I’m sure if you need a bottom bracket to fit your new titanium wonder bike, you will find a product of your liking with any of these quality brands.

T47 Bottom Bracket Standard Explained

The T47 standard was developed to offer the best of both worlds: a large bottom bracket opening, fit for 30mm spindles and the convenience of a threaded bottom bracket shell.

Building on the reliability and simplicity of threaded bottom brackets, a T47 BB uses a 46mm inner diameter shell threaded to M47x1.0mm.


To phrase it all in a meme you shouldn’t look up

Anything is a standard, if you’re brave enough

  • Abraham Lincoln

At the end of the day, the issue with PF BB is that the tolerances are tight. You need good manufacturing for that to work.

But most bikes are built abroad in factories far away from the HQ and at such a volume, you’re just statistically bound to not have as tight of a tolerance as needed for PF BB to work out.

Yes threaded has issues but its much more forgiving in a manufacturing setting. But it costs more. Hence everyone got PF BB

At least T47 gives enough to make everyone happy.

Edit: While a die-hard lover of BSA BBs, I also believe that as handmade bikes continue to be a thing with huge upcharges, T47 will be more widely adopted as that sector uses it as a defacto standard. Eventually this will drive other major companies like Giant and what not to adopt T47 in their other bike ranges to add value.

Have you seen the new Specialized Epic? :exploding_head:

That’s a new disc brake is different beast, than the late '80’s MTB U-Brakes and road bikes with an aero leaning, that tucked the brakes under the stays, right behind the BB and well obscured by the cranks and chainrings for access.

Edit to add fun old references for @Walkley to shake his head :stuck_out_tongue:

MTB: Got tough to adjust, packed with mud and generally performed like garbage.

Road: No mud issue, but the same basic problems as those above.

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I see - I’m late to the scene, only started riding in 2016, so always had it easy tech wise :laughing: :

I hadn’t realised that Specialized were running BSA on plenty of models, everyone I know with a Spesh bike has an SWORKS Tarmacs SL6 so no thread.

Extremely curious to see what new Tarmac has fitted when comes out though.

On a side note I tried the new Emonda today and off the shelf the fit didn’t work for me so I couldn’t really get a feel for the bike. Even if the BB system and rest of bike look great in paper it’s not in the shortlist.

The new SL7 Tarmac BB is definitely threaded. We’ve seen spy photos on the forum already.

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Yes but to my eyes at least it didn’t look to have enough sticking out to be a Hollowtech BB.

I think T47 is a brilliant standard: open, threaded, large-bore, and wide if you want it. It seems entirely sensible to me, and no other standards come close for me. Support from Chris King is another plus in my book, and all the other usual suspects are joining.

It was a criteria on my latest gravel bike, and I ended up with a Felt Breed because of it. I’d be surprisdd if it doesn’t become a main standard.

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Yet another BB standard :upside_down_face:
I don’t know whether this will actually solve BB problems, but rather create new ones while eliminating others. AFAIK one of the big problems with press-fit BBs are that frame manufacturers are not keeping up their end of the bargain when it comes to manufacturing tolerances. On carbon frames at least, threaded BBs require more complex design and depending on how you do it, you’d still end up “press-fitting” your bearings — in a cup, rather than the frame.

I’d rather that bike manufacturers and equipment manufacturers take tolerances more seriously to be honest.


I read this a lot but curious as to what the issue is on the manufacturing side when discussing frames. I work with steel and aluminum mainly so I don’t have much concept as to carbon fiber’s limitations. I’ve had my share of part costs come back so high it wasn’t feasible to market or couldn’t find a supplier to make the part due to tolerances specified.

Is the tooling not good enough? Is the tolerance zone set too wide to reject parts? Quality control lacking? Are the employees not of quality or lack of attention to detail? (More importantly?) are we talking $200 or $2000 increase in price per frame to make changes?

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It depends what you believe from the mix of information out there.

I’ve seen everything from supposed QA spec sheets showing measurements are left blank or outside of spec but let through, to logical engineering based reasons for issues.

Thinking out loud if those buying bikes fit aftermarket BB’s rather than challenge the manufacturers and shops then things are unlikely to change. Most seem happy buying a premium bike frame but few seem to have corresponding expectations of quality.

There is also the fact that for most consumers it isn’t viable to properly check a frame over. We can all do visual checks, measurement checks with verniers, symmetry and alignment checks with string/rulers, but most cannot accurately diagnose say an out of alignment BB versus the head tube.

I would suspect a lot of issues come down to design and spec versus reality of when things are built. Things that could cause issues like alignment before and during welding, and carbon shrinkage through the drying process, are really hard to control when a third party is doing the construction. Are they doing it totally to spec every time, is the tooling fresh and unworn, is someone doing QA exactly as specified?

The one thing that makes sense to me is buying from a manufacturer who either does manufacturing in house, and is putting their own name on their own product, or to buy from someone with true ‘customer first’ warranty policies and put the onus on them to sort issues.

Then take that ethos and find a bike shop that share it, one who isn’t scared to push back on a distributor or manufacturer and is competent at validating things are as they should. This is a really tough but given margins in the industry but trust me they exist.

Then the challenge is to find a guy at that bike shop who cares as much about cable length, bar tape finish, hood alignment as you do to build it :slight_smile:


I recommend you search for Hambini on youtube. He is the BB expert, although his manners leave something to be desired. (His humor and demeanor is not my cup of tea.) But he is an aerospace engineer who in his spare time makes amongst the world’s best BBs. Apparently, they are so good that a few pro teams use them and that some big-brand bike manufacturers rely on them to fix faulty bike frames. (Even though Hambini BBs are quite expensive, they are cheaper than a few frame in many circumstances.)

While I should preface that there may be some selection bias going on (in the sense that firemen see a lot of fires), he does explain what tolerances should be and how bike frame manufacturers and crank manufacturers fail at getting their tolerances right. I think Look gets the best grades from Hambini in terms of tolerances. Hambini surmises that in some instances, there can’t have been quality control. (He has milled a few standard BB “plugs” that are under- or oversized slightly in order to quickly check.) While @Boombang mentions some reasons why this may be hard, I think it is fair to expect top quality for top dollars. Even for moderate money, you should be getting a great frame to spec.


Agree with the above - the layman may not find a problem with a BB until something wears prematurely or they come to do routine maintenance (bearing swap, crankset removal), and then average bike shop might not be able to do much, but I believe it’s totally fair to expect something to be of the right quality - and by that I mean made to spec. Sure there is a range to specs a high and low and all inbetween, but it even a £500 frame should fall within that.

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