Re: [CR] what happens when ....... ? (of bb axle tapers & cranks -JIS, ISO stuff)


Date: Fri, 27 Jan 2006 10:43:25 -0800 (PST)
From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
Subject: Re: [CR] what happens when ....... ? (of bb axle tapers & cranks -JIS, ISO stuff)
To: scott davis <francopedia@yahoo.com>, Classicrendezvous@bikelist.org
In-Reply-To: <20060127180324.5096.qmail@web53803.mail.yahoo.com>


There was a standard that applied to mid-priced Japanese BB's. The axles are generally designated with a 3 character code, for instance 3H-B. I think only the first 2 characters, i.e. 3H are stamped on the axle. The B just means it takes a (conventional) crank bolt as opposed to a crank nut. 3 designates an axle for use with a 68mm BB, 5 for a 70mm BB. The second character designates the axle length.

I've always referred to these axles as JIS and I think at least one Edition of Sutherland's refers to them as such. It could have been an ISO standard, but I don't think so, and if it was, the high end European BB's ignored it. JIS axles, if that is what they are, have longer tapers than Campy NR and clones. Sutherland's, again at least one Edition, points out that that these axles can be used with Stronglight and TA crank arms, which will often bottom out on the shorter tapers of Campy axles. I've used them a lot with French cranks myself. Don't think I've used them with Campy cranks or clones, so I don't know if they work there.

Regards,

Jerry Moos Big Spring, TX

scott davis <francopedia@yahoo.com> wrote:

I think it's just a simple lack of standardization, not a JIS issue. As afar as I know, Japanese Industrial Standard JIS does NOT apply to Japanese BBs. I believe JIS applies only to headsets on bicycles. According to Sutherland's, JIS headsets are the same threading as ISO, BUT the crown race has the larger 27.0 mm diameter instead of 26.4 mm and the head tube cups are 30.0 mm instead 30.2 mm. JIS headsets are standard equipment on Japanese Keirin bikes. All parts on these bikes must be NJS certified for racing on the Keirin tracks in Japan.

Scott Davis Locally Warming St. Paul, MN USA http://www.sdbicycylegarge.com

Most high end Japanese BB's were not JIS. JIS was used on mid to low end stuff, of which Sugino Maxy was typical. The Sugino Mighty BB was a Campy clone. I think that might also have been true of early Dura Ace, although I believe the later Dura Ace BBs may have been sort of unique, neither Campy clones nor JIS. I also seem to recall that when Rivendell was selling some late Superbe cranks they stated that they took a special BB, although by that time, the Campy NR BB was long out of production, so an NR clone at that point might have been viewed as "special".

Regards,

Jerry Moos Big Spring, TX

Ben Kamenjas wrote: Hey all,

Maybe it's just an Aussie thing but most every used campagnolo crankset i've been looking to buy down here has been used with a shimano (or another brand) bottom bracket. Knowing that the tapers are different I'm wary of buying such cranks that may have been defiled. So .... what gives with mixing JIS with ISO and am I right to get all preachy with these neanderthals who are corrupting otherwise good cranks? Or is there no issue and they are OK to use? This matters most to me because Im thinking of track cranks and am hoping I'll have the right (or proper spec.) chainline.

oh yeah, speaking of cranks ..... WTB - an early chorus 170mm left crank arm. croce d'aune is a maybe, prefer visually challenged (meaning cheap) for my early 60's aussie built sport-touring grocery bike. OK OK .... the only groceries I'm buying is beer, but doesn't that make the bike even more crucial to my well being? Just want a mate for the right hand chorus orphan I have ...... lemme know if you have sumtin'

more importantly ... surf is 2 foot and OK for the mini-Mal. Water is a nice 22 degrees (celcius) and the 'kini crew are out in force (God bless 'em). Gotta head out before the wind changes direction .... a not too hot 29 degrees and not a cloud in the sky ;)

ciao,

Ben Kamenjas Bondi Beach, Sydney, Australia, Gondwanaland, Earth (I think)