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"Memoria est thesaurus omnium rerum e custos." - Cicero
On Wed, 23 Mar 2005 07:06:39 -0700, Qui Si Parla Campagnolo wrote: John Dacey wrote: I cannot recall ever having seen the taper type specified in any official Mavic literature (why don't more manufacturers do this?), but I believe the claim found elsewhere in this thread that it's JIS is in error. Of the Mavic cranks I've ever seen installed on Shimano bottom brackets, the crank did not drawn up on the spindle to the same engagement depth as when partnered with a Mavic bottom bracket. Well, my memory tells me that the taper was the same as UN-72, and they did draw up and produce the samee chainline as the Mavic one. The world of bicycles is replete with examples where the sum of various errors either equals zero or comes close enough to be considered to "work". Mismatching a blunter Shimano taper with its shorter right side spindle overhang with a Mavic crank was a common kludge where the combined cost of the apposite Mavic bottom bracket and its installation was considered a barrier. In some cases, the installer simply didn't have the requisite cutters to install a Mavic 610. That doesn't make it "correct", especially in the context of rbt. Consider the photos below where a caliper is set at the end of a Dura-Ace spindle (JIS) and then, without disturbing that caliper setting, moved to one from Campagnolo (ISO) and finally to Mavic (draw your own conclusion). http://www.businesscycles.com/graphics/taper.jpg http://www.businesscycles.com/graphics/taper2.jpg http://www.businesscycles.com/graphics/taper3.jpg ------------------------------- John Dacey Business Cycles, Miami, Florida Since 1983 Comprehensive catalogue of track equipment: online since 1996. http://www.businesscycles.com |
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#12
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In article 1111499769.5044348d752f98237789d90d56056b74@teran ews,
Qui Si Parla Campagnolo wrote: Baird Webel wrote: In article 1111355373.d4e41b739c67375c3294b37cc8a2d8a0@teran ews, Qui Si Parla Campagnolo wrote: James Thomson wrote: I've just bought a pair of the last incarnation of Mavic's distinctive "Starfish" cranks, date stamped 1995: the spider is slightly less extravagant than the earlier model, and the arms are slightly 'low profile'. Can anybody tell me what bottom bracket lengths Mavic recommended for use as a single, double or triple? Single and double were 114mm, JIS taper, so any shimano one of this length will work. would not using the same spindle length on both single and double result in a bad chainline for one of the applications? Are you sure the taper is JIS? Were the older Mavic cranks JIS too? Baird They were JIS, we used un-72s all the time when somebody didn't want to face the BB shell at 45 degrees for the Mavic BB. I assumed as a 'single' you would put the single ring on the inside, which would need a 114mm for frame clearance. I never saw a Mavic last gen track crank that looked like the road one. I guess this would make sense if you are using a ring smaller than would fit because of the size of the spider and thus need the spacers. Otherwise, I'd tend to put a shorter BB spindle and forgo the spacers. I don't believe Mavic made a true 631 track crank, i.e. one with 144 BCD, though you could easily use a road 631 with a single ring. They did do one that was numbered "636" but I believe it was more like the 637 MTB crank. I have what I believe is a set, pics are at: http://homepage.mac.com/bwebel/cycli...toAlbum18.html Baird |
#13
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In article ,
"James Thomson" wrote: "Qui Si Parla Campagnolo" wrote: Single and double were 114mm, JIS taper, so any shimano one of this length will work. Thanks Peter. I've just made a test fit on a UN72, and the taper fit doesn't look the best. Are you certain it's JIS? If John Dacey is correct and it is 114 with a longer right spindle, then I wonder if a current campy Centaur BB for a triple wouldn't work well? It is 115 with a longer right spindle, but who knows if the offset is the same. Another possibility might be the TA bottom bracket, though I'm not sure if they are JIS or ISO these days, Or Phil Wood, which would let you micro adjust the chainline a bit. I've been meaning to sit down with the Mavic cranks I have and a bunch of BBs and try to work out the best fit but haven't had the time. I'd be interested to hear what you end up with. Or, of course, troll Ebay for an actual Mavic one. Some of us still have the tool to cut the champfer, though I haven't actually done it as I found an old Vitus frame with it already cut. Doesn't look too hard, though. Baird |
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"Baird Webel" wrote:
I don't believe Mavic made a true 631 track crank, i.e. one with 144 BCD, though you could easily use a road 631 with a single ring. They did do one that was numbered "636" but I believe it was more like the 637 MTB crank. I have what I believe is a set, pics are at: http://homepage.mac.com/bwebel/cycli...toAlbum18.html The 637 arms were closer in shape to those of the 631, but the spider was a more conventional 110/74 triple, of course. Boardman's Lotus bike as shown here uses a crank that strongly resembles the 637: http://www.chrisboardman.co.uk/newpics/cbwall8.jpg I've seen a set like yours on eBay once, but I don't know its model number. James Thomson |
#15
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"Baird Webel" wrote:
If John Dacey is correct and it is 114 with a longer right spindle, then I wonder if a current campy Centaur BB for a triple wouldn't work well? It is 115 with a longer right spindle, but who knows if the offset is the same. I understood that the Campag 115.5mm spindle was symmetrical. A 111 with a spacer might do the trick. Another possibility might be the TA bottom bracket, though I'm not sure if they are JIS or ISO these days, Or Phil Wood, which would let you micro adjust the chainline a bit. I've been meaning to sit down with the Mavic cranks I have and a bunch of BBs and try to work out the best fit but haven't had the time. Stronglight still make a Mavic-style bottom bracket - the JP1000 - in various lengths with ISO tapers: http://www.zefal.com/stronglight/pag...keyProd=jp1000 I'd be interested to hear what you end up with. I'll be sure to let you know. James Thomson |
#16
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John Dacey wrote:
"Memoria est thesaurus omnium rerum e custos." - Cicero On Wed, 23 Mar 2005 07:06:39 -0700, Qui Si Parla Campagnolo wrote: John Dacey wrote: I cannot recall ever having seen the taper type specified in any official Mavic literature (why don't more manufacturers do this?), but I believe the claim found elsewhere in this thread that it's JIS is in error. Of the Mavic cranks I've ever seen installed on Shimano bottom brackets, the crank did not drawn up on the spindle to the same engagement depth as when partnered with a Mavic bottom bracket. Well, my memory tells me that the taper was the same as UN-72, and they did draw up and produce the samee chainline as the Mavic one. The world of bicycles is replete with examples where the sum of various errors either equals zero or comes close enough to be considered to "work". Mismatching a blunter Shimano taper with its shorter right side spindle overhang with a Mavic crank was a common kludge where the combined cost of the apposite Mavic bottom bracket and its installation was considered a barrier. In some cases, the installer simply didn't have the requisite cutters to install a Mavic 610. That doesn't make it "correct", especially in the context of rbt. Consider the photos below where a caliper is set at the end of a Dura-Ace spindle (JIS) and then, without disturbing that caliper setting, moved to one from Campagnolo (ISO) and finally to Mavic (draw your own conclusion). http://www.businesscycles.com/graphics/taper.jpg http://www.businesscycles.com/graphics/taper2.jpg http://www.businesscycles.com/graphics/taper3.jpg ------------------------------- John Dacey Business Cycles, Miami, Florida Since 1983 Comprehensive catalogue of track equipment: online since 1996. http://www.businesscycles.com I thought you said you didn't remember? |
#17
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(draw your own conclusion). http://www.businesscycles.com/graphics/taper.jpg http://www.businesscycles.com/graphics/taper2.jpg http://www.businesscycles.com/graphics/taper3.jpg ------------------------------- John Dacey Business Cycles, Miami, Florida Since 1983 Comprehensive catalogue of track equipment: online since 1996. http://www.businesscycles.com The last picture...it doesn't look like a mavic BB spindle....wonder what it is?? |
#18
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John Dacey wrote:
Of the Mavic cranks I've ever seen installed on Shimano bottom brackets, the crank did not drawn up on the spindle to the same engagement depth as when partnered with a Mavic bottom bracket. I can't locate any written specifics about symmetricality of the various Mavic spindles. Working from memory (with all the attendant caveats), I believe the 110 and 112 spindles were symmetrical, whereas the 114, 116, 119 and 123 spindles all offered various amounts of right side offsets. I don't know the ins and outs, but my CRec crank seems to be happy, if a little distant from the chainstay, on a "chamfer style" Mavic 114 BB. I would have put Campy 111 in, but the frame is Ti, and a couple of the local shops didn't want to chase the threads in far enough for the cups to fit. Plus the outside edge of the BB shell is pretty thin where chamfered... I seem to remember "some" offset on this BB, and it comparing to the Campy Record 111 (farbon fiber cart) BB, except a few silly millimeters longer. Ahem, the OP... I've been told that the current (new, available for purchase) Stronglight items "are the same thing" as the OOP Mavic BB's. ("Yeah. Sure.") Well, they look pretty close, but no idea of taper on these: http://www.zefal.com/stronglight/pag...keyProd=jp1000 OR (spreading the love): http://tinyurl.com/6wkwd There's a "contact" link, which may help with tech questions. I had an importer link, lost. "Not cheap" and neither are the used ones on eeeebay. But you can probably use a Campy part, some styles of which are easy to find and pay for. The experts must advise on feasibility/selection (Centaur 115?). HTH --TP |
#19
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On Thu, 24 Mar 2005 07:16:57 -0700, Qui Si Parla Campagnolo
wrote: John Dacey wrote: "Memoria est thesaurus omnium rerum e custos." - Cicero On Wed, 23 Mar 2005 07:06:39 -0700, Qui Si Parla Campagnolo wrote: John Dacey wrote: I cannot recall ever having seen the taper type specified in any official Mavic literature (why don't more manufacturers do this?), but I believe the claim found elsewhere in this thread that it's JIS is in error. Of the Mavic cranks I've ever seen installed on Shimano bottom brackets, the crank did not drawn up on the spindle to the same engagement depth as when partnered with a Mavic bottom bracket. Well, my memory tells me that the taper was the same as UN-72, and they did draw up and produce the samee chainline as the Mavic one. The world of bicycles is replete with examples where the sum of various errors either equals zero or comes close enough to be considered to "work". Mismatching a blunter Shimano taper with its shorter right side spindle overhang with a Mavic crank was a common kludge where the combined cost of the apposite Mavic bottom bracket and its installation was considered a barrier. In some cases, the installer simply didn't have the requisite cutters to install a Mavic 610. That doesn't make it "correct", especially in the context of rbt. Consider the photos below where a caliper is set at the end of a Dura-Ace spindle (JIS) and then, without disturbing that caliper setting, moved to one from Campagnolo (ISO) and finally to Mavic (draw your own conclusion). http://www.businesscycles.com/graphics/taper.jpg http://www.businesscycles.com/graphics/taper2.jpg http://www.businesscycles.com/graphics/taper3.jpg I thought you said you didn't remember? I said I didn't recollect seeing it listed in any official spec's published by Mavic. My _own_ memory is perhaps a millimeter or two short of fully thesaural on the subject, but I liked the 610 bottom brackets quite a lot when they were current models and used to do a fair bit of work with them. From your other follow-up post: The last picture...it doesn't look like a mavic BB spindle....wonder what it is?? It is, in fact, a genuine Mavic spindle. ------------------------------- John Dacey Business Cycles, Miami, Florida Since 1983 Comprehensive catalogue of track equipment: online since 1996. http://www.businesscycles.com |
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