Top Tech Tips: Fitting A Threaded BB

Top Tech Tips: Fitting A Threaded BB

By Paul Smith

Seeing as it is ‪#‎fixitproperlyfriday‬ (*)

Here’s how I’ve been doing threaded bottom brackets for years. I do it this way because we have clean bare aluminium alloy threads in the frame, and normally anodised threads on the bottom bracket cups. Essentially that mix should be a no go. But ho-hum, we have to deal with what bike companies give us, eh?

1. The basics are still the same as always. Clean and good condition threads in the frame and bottom bracket cups

bb bottom bracket fit paul smith singletrack magazine

2. Apply your grease of choice (**) to the frame threads. But ONLY to the inner 3/4 of the threads. You want to leave at least four full turns of thread clean and dry

paul-smith-BB2

3. Apply threadlocking liquid or paste to the last four threads of the bottom bracket cups (make sure to fit any spacers used before you do this step)

bottom bracket fitting paul smith singletrack magazine

4. Screw ’em in as normal, torque or tighten to ‘two grunts and a groan’. Fit your cranks, don’t ride the bike until the required cure time for your threadlock has expired.

5. Bask in the glory of having a bottom bracket that won’t come loose, and can be removed easily in ten years time (or a week, depending upon the quality of bearings in yours and how parallel they are)

(*) If that’s not a thing, then it is now, and I invented it ‪#‎hashtagglory‬
(**) I use Redline assembly lube. It is like a moly grease, but thinner and with better sealing properties

bb bottom bracket fit paul smith singletrack magazine

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10 thoughts on “Top Tech Tips: Fitting A Threaded BB

  1. Is this the same Paul Smith whose recommendation (maybe twenty years ago) for Black Gold waterproof grease left me with black fingers, clothing, etc? Like shit to a blanket that stuff hope the assembly lube isn’t as bad.

  2. Thread lock on BB cups? Really? Anti-seize and the correct torque setting is standard industry practice. I’ve certainly never had one come loose.

  3. I think this is a great idea for an ongoing feature, but it’d be even better to have an explanation of why this is a good idea.

    I haphazardly grease the threads and I’ve not had problems with threaded BBs coming loose or with them getting stuck. If what I’m doing is wrong, why?

  4. I still don’t own one of the new fangled BBs like that in the picture, but the installation is the same on older ones from square taper on – I’ve even done loose ball ones. Like others I’ve never had a BB come loose when installed with grease and the correct torque – can’t see any reason why you’d need threadlock

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