Crank and BB question

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  • Hey folks.
    I'm waiting for my new BJ frame to arrive, and am sourcing parts. I want an all-black (racist) crankset/chainring in 1/8" and don't want to spend loads of cash.
    Can anyone think of any non-aesthetic reasons why the following combo wouldn't work?:

    Miche Primato BB 107mm English thread w/ ISO taper
    http://www.probikekit.com/display.php?code=A9909
    +

    older Campag Mirage crankarms
    (like this: http://www.highonbikes.com/2006-campagnolo-mirage-crankset-chainset.html) made for square taper bb



    Goldtec 135 BCD 1/8 track chainring
    http://www.mountainbikecomponents.co.uk/items.asp?CategoryID=32&Name=Goldtec+1%2F8th+Single+Speed+Chainrings

    =
    a nice looking all black setup for about 68 quid!
    Objections? Have I missed something?
    (If it matters - will be building wheels on Goldtec hubs)

  • Doesn't Campy use an oddball BCD? And don't you think 175mm arms are a bit long for fixie?

    Just askin'.

  • yes - newer Campag is 135 BCD, which the Goldtec rings fit.
    175 mm may be a bit long for fixed, but my current conversion has 172.5s and I've heard the BJ Vigorelli frames have crazily high bottom brackets. In any case, I can get the Mirage cranks in 172.5 also.

    Doesn't Campy use an oddball BCD? And don't you think 175mm arms are a bit long for fixie?

    Just askin'.

  • I haven't got Goldtech hubs but I seem to remember that they will need to be matched with a 110ish BB for a good chainline. Maybe someone else can tell you for sure.

  • I haven't got Goldtech hubs but I seem to remember that they will need to be matched with a 110ish BB for a good chainline. Maybe someone else can tell you for sure.

    It'll depend on the offset of the crank, which I'll admit to knowing nothing about, not having seen them in person. The 107mm was just a guess. If it's wrong, I'll just flog it on the forum for a fiver. :)

  • Have a look through this thread, go to last page. Nobody has mirage cranks but most peeps with goldtechs seem to use 111mm. https://www.londonfgss.com/thread3372-6.html

  • Have a look through this thread, go to last page. Nobody has mirage cranks but most peeps with goldtechs seem to use 111mm. http://www.londonfgss.com/thread3372-6.html

    That's an amazing list. Thanks for pointing it out.

  • yeah, this place does lists very well!

  • Go modern! Make yourself a Mirage UltraTorque set like this
    http://jorj.co.uk/pivot/entry.php?id=28
    I was so pleased with this hack that I've made a 170mm set for track use the same way.

    Ribble have 172.5 Mirage square taper at £24.99
    http://www.ribblecycles.co.uk/productdetail.asp?productcatalogue=CAMPCHAR300
    or 170mm Mirage UltraTorque at £62.01
    http://www.ribblecycles.co.uk/productdetail.asp?productcatalogue=CAMPCHAR901

  • @cbitterman i have a Goldtec 1/8th" 135bcd 42t chainring for sale minimal use, £20 + £2.50 postage if you"re interested? i'll post a photo asap....

  • oh...and have a friend with Campag 170mm 135bcd crankset who wants £25ish... i think, thought i'd throw that in as well....would make a nice set...

  • I was really thinking about that, actually, as I've got a Veloce UT crankset that isn't being used right now. I got as far as reading your post on the subject with keen interest. What's the chainline like the with UT cups? I presume there's no room for adjustment there. Thanks for the square taper BB advice.

    Go modern! Make yourself a Mirage UltraTorque set like this
    http://jorj.co.uk/pivot/entry.php?id=28
    I was so pleased with this hack that I've made a 170mm set for track use the same way.

    Ribble have 172.5 Mirage square taper at £24.99
    http://www.ribblecycles.co.uk/productdetail.asp?productcatalogue=CAMPCHAR300
    or 170mm Mirage UltraTorque at £62.01
    http://www.ribblecycles.co.uk/productdetail.asp?productcatalogue=CAMPCHAR901

  • Yup, interested in both. Especially the chainring. Why are you selling?
    What's the crankset?

    oh...and have a friend with Campag 170mm 135bcd crankset who wants £25ish... i think, thought i'd throw that in as well....would make a nice set...

    @cbitterman i have a Goldtec 1/8th" 135bcd 42t chainring for sale minimal use, £20 + £2.50 postage if you"re interested? i'll post a photo asap....

  • I was really thinking about that, actually, as I've got a Veloce UT crankset that isn't being used right now. I got as far as reading your post on the subject with keen interest. What's the chainline like the with UT cups? I presume there's no room for adjustment there.

    Yes, any adjustment would have to be made at the other end. My post about the actual chainline must have got lost in the server fail, and I've lost the Post-it note bearing the calculation, but a quick measurement gives me 46.5mm to the centreline of the chainring. The same measuring method on an old Goldtec hub gives 45.2mm to the centreline of an EAI 3/32" sprocket. I think the EAI 1/8" sprockets have the same chainline, and Phils about 0.5mm less. Fortunately, I use the slightly wider Mavic Ellipse which gives me a precisely aligned chain with a 0.4mm shim under an EAI 1/8" sprocket, but with a Goldtec you could be 1.3 to 1.8 out of line. You could get 1mm back by machining the inside mounting face of the Goldtec Chainring and not machining the cranks. You should take all that with a pinch of salt, as Goldtec have changed their hub design and I was measuring with the bike built up (on two different bikes), not on a workbench with a decent dial gauge, so take careful measurements for yourself before you start cutting any metal. Even quite good frames could be out of alignment by enough to make a material difference if you insist on getting your chain straight to within 0.1mm.

  • Go modern! Make yourself a Mirage UltraTorque set like this
    http://jorj.co.uk/pivot/entry.php?id=28
    I was so pleased with this hack that I've made a 170mm set for track use the same way.

    Love this.

    Modifying cranks is pretty common for SS off-roaders, who want the latest kit. Bout time the fixie crew caught on ;)

    I have a modified and ceramic coated, set of crank arms in the post at customs.

  • Wow. Thanks for that. One stupid question remains:
    Couldn't you get the 1.3mm back by (sacrilegiously) mounting the chainring on the inside of the spider, or am I missing something?

    Yes, any adjustment would have to be made at the other end. My post about the actual chainline must have got lost in the server fail, and I've lost the Post-it note bearing the calculation, but a quick measurement gives me 46.5mm to the centreline of the chainring. The same measuring method on an old Goldtec hub gives 45.2mm to the centreline of an EAI 3/32" sprocket. I think the EAI 1/8" sprockets have the same chainline, and Phils about 0.5mm less. Fortunately, I use the slightly wider Mavic Ellipse which gives me a precisely aligned chain with a 0.4mm shim under an EAI 1/8" sprocket, but with a Goldtec you could be 1.3 to 1.8 out of line. You could get 1mm back by machining the inside mounting face of the Goldtec Chainring and not machining the cranks. You should take all that with a pinch of salt, as Goldtec have changed their hub design and I was measuring with the bike built up (on two different bikes), not on a workbench with a decent dial gauge, so take careful measurements for yourself before you start cutting any metal. Even quite good frames could be out of alignment by enough to make a material difference if you insist on getting your chain straight to within 0.1mm.

  • What's the advantage of ceramic coated crank arms?

    Love this.

    Modifying cranks is pretty common for SS off-roaders, who want the latest kit. Bout time the fixie crew caught on ;)

    I have a modified and ceramic coated, set of crank arms in the post at customs.

  • Wow. Thanks for that. One stupid question remains:
    Couldn't you get the 1.3mm back by (sacrilegiously) mounting the chainring on the inside of the spider, or am I missing something?

    Moving to the inner ring position shifts the chainline inboard by about 6-7mm, and with no possibilty of moving it back out by using a longer BB spindle. No hubs are that narrow. Also, you'd need to fabricate a spacer for the hidden bolt, similar to the one which is usually sandwiched beteen the rings on the stock set up but longer to take account of the absence of the outer ring. Oh, and if you use a ring much over 42, especially on a track frame with no dimple or curve in the chainstay, it will hit the chainstay.

  • See, I knew it was a stupid question! :)
    Thanks again.

    Moving to the inner ring position shifts the chainline inboard by about 6-7mm, and with no possibilty of moving it back out by using a longer BB spindle. No hubs are that narrow. Also, you'd need to fabricate a spacer for the hidden bolt, similar to the one which is usually sandwiched beteen the rings on the stock set up but longer to take account of the absence of the outer ring. Oh, and if you use a ring much over 42, especially on a track frame with no dimple or curve in the chainstay, it will hit the chainstay.

  • Yup, interested in both. Especially the chainring. Why are you selling?
    What's the crankset?

    I'm selling the Chainring as i was using it with a set of Miche Primato crank arms, unfortunately on the Miche design the chainring bolts screw directly into the alloy crank arms, the threads on 2 of mine have been stripped meaning the arms are pretty much useless now, i'm just waiting on a new set of cranks from Bens Cycles in Milwaukee... i'll post a photo of the chainring in a mo'

    The crank arms are Campag Record i think? Voidcore on the forum was selling them, he will obviously have more info


  • Both sides of the ring (they're reversible) some rubbing where the crank arms were and some of the black anodize worn from teeth

  • on the Miche design the chainring bolts screw directly into the alloy crank arms, the threads on 2 of mine have been stripped meaning the arms are pretty much useless now

    Bore the threaded holes out to 10mm and use standard chainring nuts. If you want to be flash, do the 12x1 counterbore on the other side, or just spot face it to make sure the nut shoulder sits properly flat.

  • did think of that but there's very little extra metal around the existing drilling, plus i need to run a smaller chainring than 42t which isn't possible with the 135bcd unless i use a 3/32nd" inner ring...

  • What's the advantage of ceramic coated crank arms?

    Less fricton as they cut through the air......

    .....OK maybe not.
    Its just a very hardwearing and nice looking coating, that will resist anklerub longer than most.

  • On the topic of cranks, has anyone used the stronglight mygal messenger from planet x or the lasco crankset on velosolo? cant seem to find any reviews anywhere
    thanks

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Crank and BB question

Posted by Avatar for c.bitterman @c.bitterman

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