Bottom Bracket help

Discuss light weight issues concerning road bikes & parts.
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floppyb
Posts: 10
Joined: Mon Oct 03, 2016 3:29 am

by floppyb

I'm struggling to understand bottom brackets and how they relate to what cranks I can use. According to my frame spec sheet, the bottom bracket shell is 68mm, English threading. I'd like to purchase a Chris King bottom bracket, but I can't quite figure out which one I would need. Also what size of crank diameter can I use with all this?

Thanks

by Weenie


ToughInTheStreets
Posts: 60
Joined: Sat Dec 09, 2017 7:28 pm
Location: Florida

by ToughInTheStreets

I'll chime in because I understand how overwhelming it is trying to understand what's what.

Here's some info that will get you started. Your frame is 68mm english threaded which is relatively easy since you don't have to press any bearings in. First you need to determine what cranks you want to use, then you can pick your bottom bracket. Thats all good and great that you want to use a CK BB, but first you have to figure out which one you need based off of your cranks. There are tons of different Chris King BB's (different interfaces, multiple diameters, etc etc) Does that make sense?

Essentially, here are your steps to take-
1- pick a crankset
2- pick a threaded bottom bracket compatible with your frame and crankset

I know that was a vague explanantion, but it should help point you in the right direction.

floppyb
Posts: 10
Joined: Mon Oct 03, 2016 3:29 am

by floppyb

ToughInTheStreets wrote:
Mon Aug 12, 2019 8:23 pm
I'll chime in because I understand how overwhelming it is trying to understand what's what.

Here's some info that will get you started. Your frame is 68mm english threaded which is relatively easy since you don't have to press any bearings in. First you need to determine what cranks you want to use, then you can pick your bottom bracket. Thats all good and great that you want to use a CK BB, but first you have to figure out which one you need based off of your cranks. There are tons of different Chris King BB's (different interfaces, multiple diameters, etc etc) Does that make sense?

Essentially, here are your steps to take-
1- pick a crankset
2- pick a threaded bottom bracket compatible with your frame and crankset

I know that was a vague explanantion, but it should help point you in the right direction.
That's great to know! Looks like I was doing it backwards. Thanks!

Am I correct in thinking that I should be looking at 24mm cranksets?

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Lewn777
Posts: 804
Joined: Thu Mar 09, 2017 5:35 am

by Lewn777

It's fairly easy. Do you have a Shimano crankset? If so you need this: https://www.wiggle.co.uk/shimano-dura-a ... 8753674878

ToughInTheStreets
Posts: 60
Joined: Sat Dec 09, 2017 7:28 pm
Location: Florida

by ToughInTheStreets

Well without confusing you with exceptions and overly specific stuff, GENERALLY shimano uses a 24mm spindle diameter on their modern stuff.

SRAM uses a few different ones, one of the most common is BB30, which is a 30mm spindle diamter.

Be mindful that GXP standard uses TWO DIFFERENT SIZES on the same spindle. On the Drive side, it is a 24mm spindle and then it tapers down to 22mm diameter on the non-drive side. GXP is NOT the same as Shimano's 24mm spindle.

It's a bit overwhelming, but its not as hard as it seems right now. Basically, just pick whether you want Shimano or SRAM and go from there.

floppyb
Posts: 10
Joined: Mon Oct 03, 2016 3:29 am

by floppyb

Many thanks for the advice.

I'm going to be using Shimano groupset, but I've never been a fan of their crankset aesthetics, so initially I was considering getting some SRAM Red cranks and different chainrings. Now, I am considering just sticking with a Shimano crankset so I don't over complicate things.

Valbrona
Posts: 1526
Joined: Fri Oct 28, 2011 3:25 am
Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

You could use SRAM Red, but be sure to get the GXP and not the BB30 version. The GXP version will work in your frame assuming you fit a suitable SRAM bottom bracket.

Check out the BB386 standard from FSA. It uses a 30mm spindle ... but which will fit into your frame if you fit a suitable FSA bottom bracket. BB386 offers good compatibility if you switch to a new frame in the future - BB386 cranksets fit just about every frame there is going when you get the correct FSA bottom bracket.

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posaunemeister
Posts: 21
Joined: Fri May 24, 2019 12:32 pm
Location: Tulsa, OK

by posaunemeister

Valbrona wrote:
Tue Aug 13, 2019 3:13 am
You could use SRAM Red, but be sure to get the GXP and not the BB30 version. The GXP version will work in your frame assuming you fit a suitable SRAM bottom bracket.

Check out the BB386 standard from FSA. It uses a 30mm spindle ... but which will fit into your frame if you fit a suitable FSA bottom bracket. BB386 offers good compatibility if you switch to a new frame in the future - BB386 cranksets fit just about every frame there is going when you get the correct FSA bottom bracket.
This is my spindle of choice due to its versatility and stiffness. Even on my Raleigh Militis (which is for PF30), I'm having a PF30 -> BSA aluminum shell installed tomorrow so that I can use one of my FSA SL-K cranks in it without the use of the external adapters I've been using. I'm absolutely tired of the BB30/PF30 creaking sounds, especially when I ascend or descend in 52/11. The sound is loud and embarrasing, and I am forced to hold back... :oops:
"When I was young, I admired clever people. Now that I am old, I admire kind people." - Abraham Joshua Heschel

by Weenie


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