Avatar for Scott_Bontz


Member since May 2013 • Last active Jul 2020
  • 1 conversations

Most recent activity

  • in Mechanics & Fixin'
    Avatar for Scott_Bontz

    M_V, the references to the UN55 BB say it's JIS taper. The 7600 crankset is ISO taper. So the narrower -- 107mm vs. 109mm makes sense, though from what I've read -- Velodrome Shop, Sheldon Brown -- the difference should be 4mm -- a 105mm JIS BB. But if 107 worked for you, that's good to know.

    Wildwest, my headline was misleading: my chain is not NJS, but a high-end MKS . Previously I ran the SRAM PC-1 and before that cheaper MKS. It's early to conclude, but the more expensive chain does seem bound for a considerably longer life. Anyway, they're all bushingless, non-NJS chains, I believe, and all sound about the same.

    HarmanMogul, Track Supermarket's Rene has tried to help me, but the Hatta R9400, at least in my case, is not ideal. Maybe I shouldn't be such a perfectionist, but it seems that a chain line is unacceptable if it wears down the side of chain ring. I might consider the 7710 Octalink, but would prefer to stick with square taper. And I'm a bit bothered and reluctant to buy from Shimano again, since they don't see it fit to still make BBs for cranks that are not that old and remain plentifully in use.

    Aniki, I bought the hubs five years ago from Track Supermarket, where they are identified as 7710. Low flange. So I have the reverse of your setup. I have measured the hub chainline repeatedly, and am sure it is 42mm, plus or minus 0.5mm.

    Thank you all for your help. I've all but decided to get the Sugino 75 with dedicated BB, which is actually advertised by the company -- no other seems to bother -- as giving a 42mm chain line.

  • in Mechanics & Fixin'
    Avatar for Scott_Bontz

    I use a Dura-Ace 7600 crank on Hatta 109mm bottom bracket, which should give the standard 42mm chain line. I recently measured, and the line is actually 45mm or a bit more. The D-A hubs give a 42mm line. I think this explains why my chain ring is worn on the outside, and might explain a drive train louder than what I have been led to expect from fixed wheel. (I'm the only fixed rider around here, and so have nothing to compare with.) A Shimano rep couldn't help me, and I have been unable to find a 7600 BB, new or used. I am about ready to move on to another crank, one with a dedicated bottom bracket. But first I thought I'd ask if anyone on this site has had the same experience, and found a solution -- other than a Phil Wood BB, costly in itself, and requiring special tools. And in case nothing comes of that, I wonder if anyone has experience with both Sugino 75 and the modern Campagnolo track crank and can compare. Knowledgeable US bike parts dealer Peter White has the highest praise for Sugino's precision, smoothness, and quietness. They appear to make nothing but cranks and rings, and perhaps should be best at getting it right. The Campy is more beautiful, and one site says it has a 131mm Q-factor (a k a stance), considerably narrower than the 75 and 7600's 139mm (though mine is higher). But it's not clear if that measurement is of the modern track crank, or the fluted design from decades ago, when all good cranks gave a narrower Q. With appreciation for any helpful education ...