Singlespeed & Fixed Gear - cheap alternative for 151 bcd chainring? drill out a 144?

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Paultso
08-23-10, 06:48 PM
I got some old campy pista cranks that i want to use but the chainring is 151. All NOS ones are extremely expensive.
Would it be possible for me to buy a 144 bcd track chainring and drill the prexisinting holes into ovals so that theyll fit?
Squirrelli
08-23-10, 07:09 PM
Unless you are super precise when you are drilling the holes...otherwise it is better off buying a new set of cranks.
TejanoTrackie
08-23-10, 07:11 PM
Good luck with that. Unless you have access to a cnc machine, you'll end up with something that isn't concentric and / or loose and won't stay tight. Furthermore, the bolts will only contact a half circle and might bend or split the chainring. Anyways, you can get NOS 151 bcd Campy track chainrings for about the same money as modern Campy, Shimano, Sugino from places like Velomine >>> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330422602728&rvr_id=128957940170&crlp=1_263602_263622&UA=%3F*I8&GUID=f47b86291290a040b10021d0ff83ba2e&itemid=330422602728&ff4=263602_263622
Squirrelli
08-23-10, 07:16 PM
Also, using a 151 bcd crankset will limit the choice of gear inches you are able to use.
TejanoTrackie
08-23-10, 07:19 PM
Also, using a 151 bcd crankset will limit the choice of gear inches you are able to use.
Not really. Other than a 42T or 43T, all other sizes are available.
rustybrown
08-23-10, 07:20 PM
Nawww, bad idea bro-bro.
Squirrelli
08-23-10, 07:23 PM
Oh, I thought the difference would be larger...
http://www.starstore.ca/productimages/270.jpg
evilcryalotmore
08-23-10, 07:25 PM
The lug pattern is easy to dril.. Get a hunter and a laser.
CharneK
08-23-10, 07:30 PM
njs-keirin.blogspot.com has some 151's for 58usd. I don't know what shipping is like from them or whether or not the are reliable but...
Paultso
08-23-10, 07:42 PM
njs-keirin.blogspot.com has some 151's for 58usd. I don't know what shipping is like from them or whether or not the are reliable but...
dang brahs, looks like i'll have to shell out some dough for this vintage crap. i would just sell the cranks but i spent the weekend polishing em to a mirror finish blang blang biatches
Squirrelli
08-23-10, 07:47 PM
blang blang biatches
:notamused::notamused:
CharneK
08-23-10, 07:49 PM
If you feel like getting nostalgic they do have quite the inventory of used NJS partage.
Ragooch
08-23-10, 09:06 PM
It's actually not that big a deal to do, although a vertical mill (not a CNC machine!) or a drill press should be used. Some old-timers do this to Campy 44T 144bcd rings to use on 151 road cranks, as originall 144bcd 44T's are really expensive! Way more than the Pista stuff.
If you have 151bcd ring to use as a pattern to transfer on to the 144bcd ring it's really a pretty straight forward job.
Paultso
08-23-10, 09:46 PM
couldnt i just use a dremel bit and gradually ovalized the holes?
couldnt i just use a dremel bit and gradually ovalized the holes?
http://thebrokenone.files.wordpress.com/2010/02/square-peg-round-hole.jpg
you need round holes for the round bolts.
Batavus
08-24-10, 04:40 AM
Oh my god, is it that difficult?
http://www.cycleunderground.com.au/chainringdesigns.htm
scroll down; choose from 12 designs, 3 or 4 mm plate, 3/32 or 1/8, plain finish, polished or anodized.
simplest version costs 50 bucks and shipping is ultracheap. I had mine shipped to the Low Countries for something like 5 dollars.
Hirohsima
08-24-10, 09:59 AM
Oh my god, is it that difficult?
http://www.cycleunderground.com.au/chainringdesigns.htm
scroll down; choose from 12 designs, 3 or 4 mm plate, 3/32 or 1/8, plain finish, polished or anodized.
simplest version costs 50 bucks and shipping is ultracheap. I had mine shipped to the Low Countries for something like 5 dollars.
Word of caution. I bought some of their rings. Soft. Pretty. But soft.
Batavus
08-24-10, 03:47 PM
Word of caution. I bought some of their rings. Soft. Pretty. But soft.
Oh, well that wasn't my experience and I had a ring made from the thinner 3 mm plate, coincidentally also a 151 bcd ring.
Hirohsima
08-25-10, 10:52 AM
Oh, well that wasn't my experience and I had a ring made from the thinner 3 mm plate, coincidentally also a 151 bcd ring.
Mine was the thicker plate. 500 miles on my SS, and I saw visible deformation of the teeth. Such that, if I were to move the chain over 1-tooth the inner-plates would bind up on the deformed teeth. I had to file then down gently. Still works... now looking again for more back-up rings.
Batavus
08-25-10, 12:40 PM
That doesn't sound good... I should say that I didn't put a lot of miles on it before I sold it to fund other projects, probably less than 500 miles. They do call it 'armour plate' aluminum. Thinking of having them make a ring for my Stronglight 49d crankset, may have to rethink.
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