Chainring BCD - Will it work??
03-07-12 | 07:38 AM
#1
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Chainring BCD - Will it work??
Hi.. Ok so I just bought a rossin bike and found this engraved chainring... I want to buy it but I'm not sure how to tell the seller to measure the BCD...
Does anybody know the BCD for campy Nuvo / Super Record cranksets? I will probably buy a crankset on eBay and pop this ring onto it..
I believe it belongs on a super record crankset??? Not sure
Side note: that crankset is obviously the wrong model... Maybe someone knows the BCD of the G.S. crank arms so you can sell me righ away if it will work??
The seller wants $40 for just the Rossin chainring or $75 for the whole crankset... what should I do? Is the cleanser worth more than $35 if I sell it?
Thanks!
Does anybody know the BCD for campy Nuvo / Super Record cranksets? I will probably buy a crankset on eBay and pop this ring onto it..
I believe it belongs on a super record crankset??? Not sure
Side note: that crankset is obviously the wrong model... Maybe someone knows the BCD of the G.S. crank arms so you can sell me righ away if it will work??
The seller wants $40 for just the Rossin chainring or $75 for the whole crankset... what should I do? Is the cleanser worth more than $35 if I sell it?
Thanks!
03-07-12 | 07:43 AM
#2
Bianchi Goddess
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A NR/SR is 144BCD and GS seems to have come in both 144 and 116 so this must be a 144 crank.
check sheldon's website for measuring the BCD without the tool that Park foolishly stopped making.
I generally dig into all the dusty catalogs I have around here but this is a great site lovingly maintained by one of our members (or maybe a former member?) and has lots of great stuff on it.
https://velobase.com/Default.aspx
check sheldon's website for measuring the BCD without the tool that Park foolishly stopped making.
I generally dig into all the dusty catalogs I have around here but this is a great site lovingly maintained by one of our members (or maybe a former member?) and has lots of great stuff on it.
https://velobase.com/Default.aspx
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
Last edited by Bianchigirll; 03-07-12 at 07:48 AM.
03-07-12 | 07:45 AM
#3
Tyrannosaurus Rexitis
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03-07-12 | 07:56 AM
#4
quick check - measure the distance (mm) between 2 adjacent crank bolts and multiply by 1.7013 = bcd.
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"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
03-07-12 | 08:46 AM
#5
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As I mentioned it too bad Park no longer makes this tool. should anyone know the where abouts for one no one needs....
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
03-07-12 | 09:00 AM
#6
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03-07-12 | 09:00 AM
#7
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03-07-12 | 09:26 AM
#9
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1.7013 ??
Really? You think we can measure the c-c of the bolt holes to the accuracy required where the .0013 comes into play?
sorry, couldn't pass that one up.
And the GS stuff is getting more expensive; I guess because the survivors are rarer as compared to Record stuff. I'd pay the extra for the crank.
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72 Frejus (for sale), Holdsworth Record (for sale), special CNC & Gitane Interclub / 74 Italvega NR (for sale) / c80 French / 82 Raleigh Intl MkII f&f (for sale)/ 83 Trek 620 (for sale)/ 84 Bruce Gordon Chinook (for sale)/ 85 Ron Cooper / 87 Centurion IM MV (for sale) / 03 Casati Dardo / 08 BF IRO / 09 Dogma FPX / 09 Giant TCX0 / 10 Vassago Fisticuff
03-07-12 | 09:58 AM
#10
Haha ^ I was using a 1962 edition of "CRC standard mathematical tables", it has a neat chart for figuring "area, radius of inscribed and circumscribed circles for regular polygons". It carries every thing to 5 decimal points.
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
03-07-12 | 10:09 AM
#11
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1.7013 ??
Really? You think we can measure the c-c of the bolt holes to the accuracy required where the .0013 comes into play?
sorry, couldn't pass that one up.
And the GS stuff is getting more expensive; I guess because the survivors are rarer as compared to Record stuff. I'd pay the extra for the crank.
Really? You think we can measure the c-c of the bolt holes to the accuracy required where the .0013 comes into play?
sorry, couldn't pass that one up.
And the GS stuff is getting more expensive; I guess because the survivors are rarer as compared to Record stuff. I'd pay the extra for the crank.
Thanks! I just got confirmation that it is 144 from the seller (just like everybody had said)
I will buy the whole crank then =)
Also I'm assuming nuvo and super record are both 144 as well?
03-07-12 | 10:14 AM
#12
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03-07-12 | 10:22 AM
#13
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I don't know why the manufacturers won't just measure cranks using bolt center radius instead so one can just pit a ruler against the mounting bolt center and the chainring bolt center.
Chombi
Chombi
03-07-12 | 10:39 AM
#14
Bcd = bcr x 2
03-07-12 | 11:11 AM
#15
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From: OZARKS
Math Equals nothing without proper measuring
1.701x is also only on a 5 arm crank if you have 3 4 6 or 8 there is other math involved Also center to center measuring is ridiculous just measure edge to edge much easier
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Last edited by kc0yef; 03-07-12 at 11:12 AM. Reason: math
03-07-12 | 11:30 AM
#16
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From: Oakville Ontario
I don't know if they still do this, but FSA chain rings used to come in a cardboard sleeve that had a BCD template for just about all known sizes printed on the back. I had a couple, but I think they were lost when I closed my shop.
03-07-12 | 11:38 AM
#17
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Since pretty much every manufacture marked/marks crank length on the back of there cranks and other details on the rings. Would it kill them to mark the BCD also?
03-07-12 | 01:17 PM
#18
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03-07-12 | 01:49 PM
#19
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Yes, unless you're talking about very early Record cranks, which were 151mm BCD.
03-07-12 | 02:01 PM
#20
Bianchi Goddess
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We need an "APP" for this
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
03-07-12 | 02:22 PM
#21
03-08-12 | 12:49 PM
#22
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03-08-12 | 04:13 PM
#23
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03-08-12 | 06:05 PM
#25
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I've got one of those, thought it was some kind of artwork.