Bicycle Mechanics - This problem is making me dizzy:P

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View Full Version : This problem is making me dizzy:P


Media
07-27-08, 03:42 PM
Ok, so I am upgrading my Raleigh 3 speed to a cotterless* crank.

So here is my problem.

I have now a shimano UN72 BB 70X115. I also have a dura ace fc 1702 crank (takes a 113mm) with a single 48t chainring. My bike fram takes a 71mm BB, but seeing that it is a Raleigh 3 speed I have the Phil Wood BB retaining rings (26 tpi, thanks, Sheldon)that can be recessed into the frame 1mm... I figured I was close enough. I at first I was a little cocky, and figured I had this one in the bag, but as the parts are now in the mail I am growing unsure. I am over 1mm in the math, Is this going to effect me very much, or even going to work?

I hope I gave enough information to figure it out.

<3 and much love.
~Media~


bikeman715
07-27-08, 04:13 PM
as long you have at lease 5mm clearance between the chain ring and the chain stay you'll be find and the crankarm and the chain stay too. the chain line should be good too.

DannoXYZ
07-27-08, 06:21 PM
Bah, don't worry about it. Even 1mm clearance is fine; any rubbing parts will self-clearance themselves.


Retro Grouch
07-27-08, 07:14 PM
I have now a shimano UN72 BB 70X115. I also have a dura ace fc 1702 crank (takes a 113mm) with a single 48t chainring. My bike fram takes a 71mm BB, but seeing that it is a Raleigh 3 speed I have the Phil Wood BB retaining rings (26 tpi, thanks, Sheldon)that can be recessed into the frame 1mm... I figured I was close enough. I at first I was a little cocky, and figured I had this one in the bag, but as the parts are now in the mail I am growing unsure. I am over 1mm in the math, Is this going to effect me very much, or even going to work?

I hope I gave enough information to figure it out.

<3 and much love.
~Media~

How did you measure your bike frame?

None of the numbers that you mentioned made any sense to me. A 70mm bottom bracket says "Italian threading" to me. That isn't going to fit into your English threaded bottom bracket shell. Without having seen your bike frame my bet is that it takes a 68mm bottom bracket.

Media
07-27-08, 09:33 PM
How did you measure your bike frame?

None of the numbers that you mentioned made any sense to me. A 70mm bottom bracket says "Italian threading" to me. That isn't going to fit into your English threaded bottom bracket shell. Without having seen your bike frame my bet is that it takes a 68mm bottom bracket.

________________________________________________________________________________________

It's a 67 Raleigh 3 speed, they have their own size and threading. No really, it's own deal, Raleigh Nottingham factory exclusive. So the size is 71mm for the bottom bracket. Lucky for me the I can kinda cheat that with this bottom bracket, the threading is not affixed to the cartridge, so I can use the Phil Wood retaining rings that have no side walls to meet up flush with the frame. Those same rings also have a 26 tpi(Raleigh 3 speed), as you know the British ISO is 24 TPI. So I know it will fit, I was just off ever so slightly with the spindle length, and got nervous.

FLYcrash
07-28-08, 11:18 AM
Don't worry. It will work.