What does "B.C.D" mean for chainwheels?
08-29-12 | 12:07 PM
#1
Thread Starter
Member
Joined: Aug 2007
Posts: 32
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From: Ann Arbor
Bikes: Bianchi Europa, Trek 920, Cannondale RS500
What does "B.C.D" mean for chainwheels?
This is a dumb question but I didn't see it on the Sheldon Brown site and I want to order a replacement chainwheel. Thanks!
08-29-12 | 12:13 PM
#2
Dharma Dog
Joined: Mar 2006
Posts: 2,073
Likes: 2
From: Vancouver, Canada
Bikes: Rodriguez Shiftless street fixie with S&S couplers, Kuwahara tandem, Trek carbon, Dolan track
Bolt Circle Diameter. If you scribed a circle around your cranks, with the center at the middle of the bb axle and the circumference passing thru the center of all the bolt holes of the chainring, the diameter of that circle would be the bcd.
Standard road (and track) bcds:
Shimano road: 130mm
Campag road: 135mm
Standard track (also Campag Nuovo Record road, back in the 70's): 144mm
Old style Campag (going way back): 151mm (figure that one out!)
Compact cranks: 110mm
Luis
Standard road (and track) bcds:
Shimano road: 130mm
Campag road: 135mm
Standard track (also Campag Nuovo Record road, back in the 70's): 144mm
Old style Campag (going way back): 151mm (figure that one out!)
Compact cranks: 110mm
Luis
08-29-12 | 03:15 PM
#4
Life is good
Joined: Jan 2001
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From: Not far from the Withlacoochee Trail. 🚴🏻
Bikes: 2018 Lynskey Helix Pro
Sheldon Brown has all the details with pics.
Here you go. https://sheldonbrown.com/gloss_bo-z.html#bcd
Here you go. https://sheldonbrown.com/gloss_bo-z.html#bcd
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.
The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.
08-29-12 | 03:35 PM
#5
Senior Member
Joined: Jan 2008
Posts: 12,940
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In the same vein as RonH reply here is a link for our own list of shortcuts to Sheldon's topics:
https://www.bikeforums.net/showthread...-com-shortcuts
This is in the Bicycle Mechanics section, the list and the subsequent replies are worth their weight in spokes and rims for me. I use it when I need to get information from Sheldon's treasure trove of bicycle knowledge. The member that compiled this list for BF did a great job that took a while and a lot of effort. 23 Kudos!!!
Bill
https://www.bikeforums.net/showthread...-com-shortcuts
This is in the Bicycle Mechanics section, the list and the subsequent replies are worth their weight in spokes and rims for me. I use it when I need to get information from Sheldon's treasure trove of bicycle knowledge. The member that compiled this list for BF did a great job that took a while and a lot of effort. 23 Kudos!!!
Bill
08-29-12 | 04:10 PM
#6
I need speed
Joined: Sep 2009
Posts: 5,550
Likes: 1
From: Phoenix, AZ
Bikes: Giant Propel, Cervelo P2
Bolt Circle Diameter. If you scribed a circle around your cranks, with the center at the middle of the bb axle and the circumference passing thru the center of all the bolt holes of the chainring, the diameter of that circle would be the bcd.
Standard road (and track) bcds:
Shimano road: 130mm
Campag road: 135mm
Standard track (also Campag Nuovo Record road, back in the 70's): 144mm
Old style Campag (going way back): 151mm (figure that one out!)
Compact cranks: 110mm
Luis
Standard road (and track) bcds:
Shimano road: 130mm
Campag road: 135mm
Standard track (also Campag Nuovo Record road, back in the 70's): 144mm
Old style Campag (going way back): 151mm (figure that one out!)
Compact cranks: 110mm
Luis
08-29-12 | 09:08 PM
#8
just keep riding
Joined: Feb 2005
Posts: 13,560
Likes: 44
From: Milledgeville, Georgia
Bikes: 2018 Black Mountain Cycles MCD,2017 Advocate Cycles Seldom Seen Drop Bar, 2017 Niner Jet 9 Alloy, 2015 Zukas custom road, 2003 KHS Milano Tandem, 1986 Nishiki Cadence rigid MTB, 1980ish Fuji S-12S
110 was the old MTB size, later touring and lately, compact road.
08-30-12 | 04:13 PM
#9
rebmeM roineS
Joined: Jan 2006
Posts: 16,231
Likes: 364
From: Metro Indy, IN
Bikes: Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Nit-picking: Sugino Super Maxy came on '79 Schwinn LeTour and Super LeTour bikes, before more than a very small number of factory-built MTBs existed.
Question: Would a weight weenie go with a 110 crankset over a 130 with the same size rings? Smaller spider versus rings with more mass?
Question: Would a weight weenie go with a 110 crankset over a 130 with the same size rings? Smaller spider versus rings with more mass?
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Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
08-30-12 | 04:28 PM
#10
Nit-picking: Sugino Super Maxy came on '79 Schwinn LeTour and Super LeTour bikes, before more than a very small number of factory-built MTBs existed.
Question: Would a weight weenie go with a 110 crankset over a 130 with the same size rings? Smaller spider versus rings with more mass?
Question: Would a weight weenie go with a 110 crankset over a 130 with the same size rings? Smaller spider versus rings with more mass?
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A conclusion is the place where you got tired of thinking. - S. Wright
Favorite rides in the stable: Indy Fab CJ Ti - Colnago MXL - S-Works Roubaix - Habanero Team Issue - Jamis Eclipse carbon/831
A conclusion is the place where you got tired of thinking. - S. Wright
Favorite rides in the stable: Indy Fab CJ Ti - Colnago MXL - S-Works Roubaix - Habanero Team Issue - Jamis Eclipse carbon/831
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