BB question (about measuring, etc.)
03-05-06 | 02:25 AM
#1
Thread Starter
Senior Member
Joined: Jul 2005
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From: Charleston, SC
BB question (about measuring, etc.)
So I measured my bottom bracket. The width of the BB on the frame is 68mm. The spindle length is *approximately* 132mm.
My front chainline is about 47-48mm. My rear chainline is about 46 mm.
I heard the Sugino RD cranks go well with a 103mm BB (From Shants). Where does this 103mm come in? Does this mean spindle length...??
Does my spindle right now just seem abnormally long? I was sure not to measure the screw parts, just to the end of the trapezoidal parts.
How are the Sugiono RD cranks going to fit? Should I get a new BB?
Thanks!
My front chainline is about 47-48mm. My rear chainline is about 46 mm.
I heard the Sugino RD cranks go well with a 103mm BB (From Shants). Where does this 103mm come in? Does this mean spindle length...??
Does my spindle right now just seem abnormally long? I was sure not to measure the screw parts, just to the end of the trapezoidal parts.
How are the Sugiono RD cranks going to fit? Should I get a new BB?
Thanks!
03-05-06 | 07:23 AM
#3
jack of one or two trades
Joined: Jun 2005
Posts: 5,640
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From: Suburbia, CT
Bikes: Old-ass gearie hardtail MTB, fix-converted Centurion LeMans commuter, SS hardtail monster MTB
Originally Posted by moz138
what kind of bottom bracket? someone might correct me here but this might be a case of iso verse jis?
The OP's BB is pretty long, but it's nothing that can't be fixed. For each mm that you want the chainline moved in, subtract 2mm from your existing spindle length. I'm assuming you already have the RD cranks set up on the 132mm spindle, and have a 48mm chainline. If so, then since you probably want to lose about 6mm (for the fabled 42mm chainline), you should use a 120mm spindle, if at all possible.
That said, I have RD's too and I have them on a 110mm spindle with no problems. Are you sure you're measuring things right?
