Once upon a time all Bottom Brackets were threaded. Yours may well still be Then the Press Fit system came along and now we mostly fit BB’s in a similar way to how we fit headsets, ie by pushing bearings into a smooth BB shell. Simpler in many ways and it does allow us to pretty much use whatever cranks we want on our bikes, but if you’ve fitted a few of these you soon come to learn how careful you have to be to avoid the dreaded crank creaks that can develop. The reason for the creaks is the two bearings are not perfectly aligned. In short the fitting tolerance of PressFit BB’s combined with actual BB shell are really quite tight. If you have never experienced a creaky crank then congratulations – you fitted all yours within tolerances and all is fine. But for many, it’s not – including some experienced workshop mechanics.
The solution, at least according to Argonaut Cycles and Chris King (who they enlisted to help develop their idea) is to go back to the old ways and thread that BB. Theoretically, threading means there’s only one way the BB can be fitted and that should lead to a perfectly smooth and aligned, creak free BB – in theory. This new standard is called the T47 although according to Argonaut’s press release (Complete release at the end of this story), it’s, “...not another in a long line of constantly changing standards, but a solution to a pre-existing problem“.
The following video is Argonaut Cycles full press release on the new BB design. So over to them for the official line..
Can’t see the video? Click here
It’s not exactly the same system as the old threaded BB’s of yore. The Argonaut version has a larger BB shell to allow a larger range of frame tubes to be welded to it as well as making it a stiffer. Bigger shell means bigger bearings too which can take more load for longer and should mean longer lasting bearings.
The new system is compatible with all existing modern cranks and axles but you do obviously need a whole new frame with the new BB shell on board first. So if you like your current bike apart from it’s creaky BB30 then this isn’t going to help. On the whole though, we like the sound of a return to proper threaded BBs. Just make sure you don’t cross those threads doing it up super tight. Or was that just us?
The official launch of this new T47 BB is set for Spring 2016.
The full text based press release follows…
Argonaut / Chris King Precision Components / T47 Standard
from Argonaut CyclesPRO
Designed in collaboration with Argonaut Cycles, the Thread Fit 30i and T47 Standard is a solution to the common issues surrounding the Press Fit system. Press Fit bottom brackets revolutionized crank compatibility years ago, but the standard is prone to creaking on rides and requires constant maintenance. “The issue lies within the tolerance creep between frame manufacturers and component companies.’ Says Bob Scales, Marketing Manager for Chris King. “The threaded system removes the performance risks associated with the convenience of the press fit products and ultimately delivers a more reliable, high performance product to the rider.”
Argonaut Cycles saw an opportunity to add real value by pushing a new spec out to the industry and turned to Chris King to help develop a part that would still allow for an oversized bottom bracket shell and complete crank compatibility. The Thread Fit 30i is the product of this effort, and now comes standard on Argonaut Frames. The 30i is not another in a long line of constantly changing standards, but a solution to a pre-existing problem. Other domestic component companies are working in collaboration with Chris King to create a new standard which will be called T47. T47 will be an open standard in 2016 for all builders and component companies to use.
Ben Farver, owner of Argonaut comments, “The PF30 is convenient to build a frame around allowing customers to use any crank on the market. The issue, however, is with a press fit system, you have to hold a super tight tolerance in both the frame and bottom bracket. Often these tolerances work against each other.
All in all, a PressFit system is the wrong style of engagement in a bottom bracket. Threads are really the way to go, but a larger bearing is still ideal. The traditional threaded BSA is great from a durability standpoint, but it limits a customer’s crank options. As a frame manufacturer I don’t want to have to talk someone into buying one of my bikes while at the same time talking them out of a crank they might want to use. My production manager and I were talking about all the challenges of PF30 one day, and thought, why don’t we just make a new standard that solves both problems? I called Jay Sycip, who runs the Cielo arm of Chris King, and we discussed the true consumer benefit of creating a threaded spec that leverages the larger bearing used in the PF30. We agreed that it would yield a much higher interface success rate, and more importantly, a better ride. So, this project is an attempt to solve a problem the entire bike industry is suffering from, and lead the way to a better, lasting standard.”
Learn more at argonautcycles.com.
Comments (9)
Leave Reply
Post Comment
“The traditional threaded BSA is great from a durability standpoint, but it limits a customer’s crank options.”
It only limited choice once all the oversize, press fit options appeared. BSA FTW.
Aye- “Yesterday, you could fit anything you want. Today, we’ve created some incompatible products so you can feel that your options are limited”.
This is good news for custom steel. Watch this space…..
Not a fan of new standards but for once this sounds a sensible and well thought out option (although I’ll still be using old BSA). Maybe also allows some eccentric setups with external bearings.
It was the custom guys that made 44mm head tubes happen for simple and lightweight tapered compatible frames in steel / ti.
Excellent, I really hope this ‘new standard’ becomes The standard.
Let me know when I can buy a new UN91 square taper bb!
“Then the Press Fit system came along and now we mostly fit BB’s in a similar way to how we fit headsets, ie by pushing bearings into a smooth BB shell.”
Is this true? can you tell us what percentage of current MTBs have press fit compared to threaded? I’ve just looked through a few companies and they mostly seem to be threaded.
I’m confused because the external BB’s seem to work brilliantly and have never creaked in any of my bikes and cost a tiny amount. Functional, light, cheap and easily replaced what more could you want.
Where has MTBs good sense gone?
Looks like you may be able to get a tool to tap out an existing PF30 BB and then run this new setup in it, thus not needing a new frame:
http://www.bikerumor.com/2015/11/07/pbe15-more-on-the-new-t47-bb-from-white-industries-enduro-and-paragon-machine-works/
Now that interests me, especially if you could still run a PFbearing in it at a later date should you choose.
Being able to tap a PF30 would make sense and save a lot of folks a lot of money, making it more likely to become a ‘proper’ standard.