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  1. #1
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    A couple of questions on bike components

    Hi,

    I'm in the middle of trying to assemble a bike for the first time from scratch. It being my first time, it's a steep learning curve so I was hoping I might get a few questions answered on these forums.

    So, I've aquired a Campag strada crank which has been converted to single speed, just 144bcd. Would I be able to fit a 144bcd 1/8 chain ring on this crank or does it have to be 3/32?

    And how can I tell what size the current chain ring is on the crank. All it says is 46 and 'campagnolo patent'...no sizes.

    The crank is 170mm year: 1984 if that helps.

    Thanks for any help.

    Should be a couple more questions to come.

  2. #2
    Senior Member BCRider's Avatar
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    Yes, you can fit a 1/8 or 3/32 ring on the crank arm provided they are the same 144bcd mounting bolt size. 46 would be the number of teeth. And that IS the size of the chainring. The rings go by number of teeth and BCD sizing. The diameter of the ring is fixed by the tooth count.

    Sounds like an interesting build if you're working with older classic parts of this sort. Best of luck with the rest of it.
    Model airplanes are cool too!.....

  3. #3
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    Hmm, so why are chainrings either listed as 3/32 or 1/8?

    I take it from your answer that I could fit a 48T 144BCD as well then. And what about crank bolts, should I be looking for a specific size?

    Gonna be building it all up on Sunday, spent a while getting the bits together. I'll keep posted on it.

    Thanks for the response.

  4. #4
    Senior Member canopus's Avatar
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    3/32 and 1/8 refers to the width of the chain. Most bikes earlier to say early 90's had one size chain width for "speed" bikes (10, 12, then referencing just the rear number of cogs, 7 and 8 speed) This was usually 3/32 (although there were some narrower chains during this time also). 1/8" chains were usually used on BMX and Fixed track bikes. Although during that same time BMX started using 3/32 chains because they were lighter.

    For your purposes one the measurements have nothing to do with the other. One is chain width and the other, 144bcd, is the circle diameter of the mounting points for the chain ring. You can run which ever chain ring you want, in any number of teeth, as long as it conforms to the 144BCD diameter of the crankarm mounts.

    If you want you can even run a 1/8 chain on a 3/32 chain ring and it will be fine since the pitch is the same (length from pin center to pin center). Although I think I would just rather run a 3/32 chain and chain ring if the rear cog/freewheel would allow it.
    1984 Cannondale ST
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    1981 Trek 710
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  5. #5
    Packfodding 3 caloso's Avatar
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    I prefer 3/32 chains for my fixed gear because they are more flexible laterally and therefore more forgiving of a less-than-perfect chainline. Just thought I'd throw that out there.
    Cyclists of the world, unite! You have nothing to lube but your chains!

  6. #6
    coprolite fietsbob's Avatar
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    3/32 worked in 5,6, then when 7 and 8 were added the chains started narrowing,
    9 and 10 are narrower still. roller width and overall width

  7. #7
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    So one more question re: chainring. If I were looking to do a swap on the Chainring I currently have. How would I find out if it's a 1/8 or 3/32? I suppose there's no easy way, at least my google searches suggest as much.

    I also have a question regarding headsets. It only occurred to me recently that Headsets vary massively. How can I know what headset I would use for my frame? Are there measurements I should be looking for?

  8. #8
    Senior Member canopus's Avatar
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    Quote Originally Posted by Pascalion View Post
    So one more question re: chainring. If I were looking to do a swap on the Chainring I currently have. How would I find out if it's a 1/8 or 3/32? I suppose there's no easy way, at least my google searches suggest as much.
    Just measure the width at the base of a tooth on the chainring.... Strada is a road crank AND IF they used the strada chainrings then they are 3/32. If you are buying one or swapping, ask the seller before purchasing.

    Quote Originally Posted by Pascalion View Post
    I also have a question regarding headsets. It only occurred to me recently that Headsets vary massively. How can I know what headset I would use for my frame? Are there measurements I should be looking for?
    Again, you can measure it. Or look it up online or from the Manufacturer, or tell us what brand\model\year frame and fork you dealing with.

    A vernier caliper can be a very useful tool. You can even get a 6" digital one from Harbor Freight on sale usually for 10 or 15. I highly recommend them.
    1984 Cannondale ST
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