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Bottom brackets?

Antennas

Chimp
Apr 2, 2019
19
0
NY
I'm trying to build up an old frame I have and I need a bottom bracket. I'm pretty sure it's 68mm. There are a few different types of 68mm bb various splines and the pass through spindle type. Can I use any as long as I have the right crankset?
 

Nick

My name is Nick
Sep 21, 2001
15,166
3,462
behind you, don't wait up.
An older frame likely uses 68 pr 73mm spacing. That's Just a matter of a 5mm spacer. You want to make sure the spindle length is correct for the frame and the bottom bracket bearings matches the spindle diameter.
 

Antennas

Chimp
Apr 2, 2019
19
0
NY
So I can use square taper, ISIS, octalink, or the pass through I guess they are called bsa30 or bb30 as long as I get the correct matching cranks/spindle?
 

Antennas

Chimp
Apr 2, 2019
19
0
NY
Just noticed if I click it works. That still doesn't clear up if I can use any of the 68mm BBs along with square taper, etc
 

Antennas

Chimp
Apr 2, 2019
19
0
NY
So I have no cranks or bottom bracket right now just a bare frame. I also don't have a caliper but with my tape measure I get about 68mm wide and 33-34mm inner diameter threaded.

When I go to a place like chainreaction or jenson and check 68mm. I get square taper, powerspline, ISIS, octalink which aren't in the chart you put up.

I'm not asking about bb crank compatibility
 
Last edited:

Jm_

Turbo Monkey
Jan 14, 2002
9,445
1,848
AK
So I have no cranks or bottom bracket right now just a bare frame. I also don't have a caliper but with my tape measure I get about 68mm wide and 33-34mm inner diameter threaded.

When I go to a place like chainreaction or jenson and check 68mm. I get square taper, powerspline, ISIS, octalink which aren't in the chart you put up.

I'm not asking about bb crank compatibility
isisBB.jpg
 

Antennas

Chimp
Apr 2, 2019
19
0
NY
Trump said ISIS has finally been exterminated, so he has that going for him
Obama is still alive though. Trump will need to watch out for him restarting it.

Unfortunately neither Trump or Obama are going to help me find a BB.
 

jstuhlman

We noticed.
Dec 3, 2009
9,750
4,514
Cackalacka du Nord
yes it depends on the crankarm interface. pick a set of cranks first, see what the interface is, then find a compatible bb. most normal bbs are either 68/73 (work with both) or 83 (usually dh bikes only).
 

Antennas

Chimp
Apr 2, 2019
19
0
NY
yes it depends on the crankarm interface. pick a set of cranks first, see what the interface is, then find a compatible bb. most normal bbs are either 68/73 (work with both) or 83 (usually dh bikes only).
So any 68mm bb should fit the bike? It dosent matter if it's isis, square taper, even outboard bearing whatever as long as its 68?
 
Last edited:

Antennas

Chimp
Apr 2, 2019
19
0
NY
That I knew. I've never switched between different 68mm BBs so I wasn't sure if all the different types were the same diameter. I didn't want to buy cranks and BB just to find out it didn't fit the bike.
 

maxyedor

<b>TOOL PRO</b>
Oct 20, 2005
3,262
418
In the bathroom, fighting a battle
Obama is still alive though. Trump will need to watch out for him restarting it.

Unfortunately neither Trump or Obama are going to help me find a BB.
I don't know, Obama is semi retired, and seems like a pretty nice guy, he'd probably help you out if you asked.

Identify your cranks, after that any 68/73mm threaded BB with that crank interface will work.
 

canadmos

Cake Tease
May 29, 2011
9,945
5,798
Canaderp
As others have said, don't bother with the bottom bracket until you know which crankset you will be using.

What frame is it?