One piece crank dimensions
07-21-15 | 05:30 PM
#1
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One piece crank dimensions
I posted this in BMX also... I don't have a crank to measure... On a one piece crank what is the diameter of the threaded sections of the spindle section?....I need to compare size with a three piece setup with ISIS spindle
07-21-15 | 05:40 PM
#2
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From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Are you talking about a 1-piece (Ashtabula) S-shaped steel crank of the kind used on BMX bikes for decades, or a modern crank where the spindle is pressed into the right crank?
If the former, the question is a non-sequitor because there's total incompatibility in the designs.
Maybe it would help if you stated your problem, ie. what you;re trying to fit onto what?
If the former, the question is a non-sequitor because there's total incompatibility in the designs.
Maybe it would help if you stated your problem, ie. what you;re trying to fit onto what?
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FB
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“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
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FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
07-21-15 | 06:21 PM
#3
That Huffy Guy
Joined: Jun 2014
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From: Ashtabula, Ohio
Bikes: Old School Huffy Bikes
Not sure what you are trying to do, but if you need a measurement, I have an Ashtabula crank on my work bench at work and will measure for you tomorrow. So you want the thickness of the threaded part where the left hand thread nut goes?
07-21-15 | 06:30 PM
#4
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Thanks for the reply FB.... Now you have me thinking... Press fit?... As in a two piece unit?.. Well never seen one... And I hope my BB is not of that type.. Truth be told I have not as yet performed a disassembly...what I would like to do- if possible - is to change out the existing caged bearings with a conversion kit to a sealed bearing type... It has ISIS splined cranks which I would like to retain.... Bottom line... I need to get to the teardown... Again tks
07-21-15 | 06:34 PM
#5
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From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Thanks for the reply FB.... Now you have me thinking... Press fit?... As in a two piece unit?.. Well never seen one... And I hope my BB is not of that type.. Truth be told I have not as yet performed a disassembly...what I would like to do- if possible - is to change out the existing caged bearings with a conversion kit to a sealed bearing type... It has ISIS splined cranks which I would like to retain.... Bottom line... I need to get to the teardown... Again tks
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
07-21-15 | 07:51 PM
#8
Senior Member
Joined: Apr 2009
Posts: 39,897
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From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
OK, a picture is forming.
I believe you have an Ashtabula style unthreaded BB shell on the frame, and a bottom bracket similar to this except ISIS instead of Sq. Taper. If that's the case, the spindle threads of an Ashtabula won't do you any good. You'll need to replace the entire BB as a unit, or buy one of these BMX bottom bracket adapters so you can use an ISO 1.37" threaded bottom bracket.
BTW- here's a link to a database that you might find useful. It lists the Ashtabula BB shell as 51.3mm or 2" in diameter.
I believe you have an Ashtabula style unthreaded BB shell on the frame, and a bottom bracket similar to this except ISIS instead of Sq. Taper. If that's the case, the spindle threads of an Ashtabula won't do you any good. You'll need to replace the entire BB as a unit, or buy one of these BMX bottom bracket adapters so you can use an ISO 1.37" threaded bottom bracket.
BTW- here's a link to a database that you might find useful. It lists the Ashtabula BB shell as 51.3mm or 2" in diameter.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 07-21-15 at 07:58 PM.
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