Bottom bracket standards

bike

#1

Sorry for a non-TR related question but I know there’s a few hardware experts lurking here whose opinion I’d like to hear.

I’m considering a new endurance style bike which comes with a 46mm internal Ø (for PressFit 30 standard) bottom bracket shell. However, the frame can also be kitted out with the following alternatives: BSA Threaded, BB30, BB86, BB92, T47.

I’ve been told that the main benefit of PF30 is an improved power transfer and increased stiffness but also hearing that this BB is prone to creaking.

So my questions is whether anyone has experienced a meaningful difference between any of the above BB’s power transfer wise and what BB is actually easiest to service / most hassle-free?


#2

My CX bike is Shimano hollowtec II (so threaded, 24mm spindle and narrower BB width), and my road bike pressfit 30ish.

The road bike is miles stiffer, helps so much with power transfer and keeping it planted, especially sprints and steep climbs.

The hollowtech definitely has more flex but being a CX bike on rough ground you really don’t notice. Take the bike on road and it does feel wobblier when pushing big torque, but you don’t feel like you losing anything.

To replace the Shimano BB is about 10 mins and £20. Fine to do at home with some simple tools.
The road bike I have not had to do yet but would be more like an hour and even then not certain there would be no creaks. Need to knock out old bearings and press new ones in with threadlock to minimise creak risk. Could do at home if you happy to make or buy tools and confident doing bike mechanics.

If I had a choice it’d be threaded just for ease.


#3

My bike has the BB71 and it started creaking in less than a full season of riding. It’s been on my to do list on replacing so I’m interested in what responses you get too.


#4

My personal, non technical view is that press fit bottom brackets convey no benefit to the rider and are all about making life easier for frame manufacturers

Ok, I will caveat this that they are a bit lighter, but the massive pain in the arse nature of them, low life span and constant creaking outweighs that small benefit.

Yes, too many of my bikes have PF bb’s


#5

So I’ve gone round and round on these, and I’m of the opinion that the stiffness differences of all of the different interfaces just boil down mostly to BB shell width design in the frame. I’m riding a cross bike that has a PF30 BB that I’ve retrofitted a 386EVO crank using spacers for the extra width. I have a road bike thats setup with 386EVO originally, and I have two other older road bikes that run variations on threaded BBs. I went with 386 EVO on the two main bikes because thats the format of my Stages powermneter, so I can switch it back and forth with just a few minutes and a 5mm hex. A quick calibration before I roll out and I’m good.

The only bikes I can tell the difference on the bottom bracket stiffness is the older Cervelo thats primarily a trainer mule now, its got a narrow BSA and I can definitely sway that bad boy back and forth. As I say, I chalk that up to the width and stiffness of the frame around it. Park it next to my MJ or R3 road bike and the down tube is absolutely spindly compared to the wide, fat tubes on them. That being said, I have an older Pinarello Prince, and it is stiffer in the BB than any of them, and it uses an Italian threaded. It also beats the nether regions into submission like it was its job, so bad with good. I feel like I should mention that neither of my PF frames have creaked, but I KNOW I’m in the minority there.

Anyway, boil it down to, my opinion is that all the 30MM x 100+MM cranks are equally stiff in a good frame.


#6

Shimano threaded BB for the win, simple to install and bearings last for ages with no creaks…
Remember, no one gets dropped because their BB isn’t stiff enough.


#7

The great thing about standards is that everyone can have their own. I’m sticking with threaded bb’s for now. The main advantage to the press fit bbs is that they are bigger, so big tubes have something to interface with. All the rest is marketing and confirmation bias.


#8

Y’all gotta go Sram DUB - 28.99mm for the win! :stuck_out_tongue: (MTBikers amongst us will get the joke)

I am not sure how the OP can get what looks like basically every known BB standard in the same frame; or is this a custom frame and the builder is giving you the options?

BB’s explained here, if anyone is interested: https://www.parktool.com/blog/repair-help/bottom-bracket-standards-1


#9

IMHO this is the absolute truth.


#10

My race bike has a PF30, and I have yet to encounter any creaking from it (knock on wood). Not quite 2yrs old and just under 4k miles. Has been ridden in the rain, etc. too.


#11

You opened a can of worms here and very few topics anger me more than bb standards.

My experience has taught me one thing, get the wheels manufacturing bottom bracket. No creaking and easy to take out and clean.

Good luck!


#12

Threaded bb every single time given a choice in my view. So much easier to install and change and never had any issues with performance.


#14

Blockquote I am not sure how the OP can get what looks like basically every known BB standard in the same frame; or is this a custom frame and the builder is giving you the options?

Yup custom frame.

Threaded seems to be the consensus then - thanks for the opinions folks!


#15

Deffo threaded then! Lots of good threaded BB brands out there too. Get yourself some bling between your cranks.

Hope your bike comes out purr-fect!


#16

Having just swapped both bb on a cadd and Willars I would go thread BB simple to change and easier to get spare replacement parts


#17

After having a Trek Domane with their BB90 I swore I’d never get a press fit BB again. It creaked and it had an oversized bearing housing for which there is an oversized bearing available, and I’ve got to thread lock them both in to stop it creaking. Ignoring my own advice I bought a Focus Paralane where apparently they had sorted press fits out with a Token BB. Not so. Creaked and even spun in the housing and had massive difficulty removing it. I’ve replace it with a Praxis BB which fingers crossed appears to be OK. I will never get a Press fit BB again.