<---------- Bike World 09-1979 ----------> Proper Crank Arm Lengths - Resolution Of The Revolutions
Date: 07/11/2009
Views: 762
Crankset - 01
CRANKSET:
MAVIC 630 (modified) - post 1968 Campagnolo Record compatible 144 mm BCD - 42/50 Clear anodized and factory "drilled" Sakae Ringyo (SR) Royal-5 ESL aluminum alloy chain rings / no inner reinforcement webs / 50 tooth ring without chain "roll off" pin - 175 mm Clear anodized forged aluminum alloy arms / post 1983 and pre 1988 MAVIC solid "block letter" logo / pre 1987 without any date code / 9/16" x 20 TPI pedal threads / 22 mm x 1 mm cap threads - model 630 with SR Royal-5 ESL chain rings : MAVIC dust caps - aluminum alloy - model 630-003 : RaceBolts chain ring bolts - 6Al-4V titanium alloy - model TICRBOLT : Stronglight Competition crank bolts and washers - aluminum alloy - M8 x 1.00 x 20 mm bolts with 16 mm head / M8 flat washers - grouped model 59 : stainless steel protective pedal washers ... [Although they were distributed in one form or another as part of the MAVIC SSC (...Special Service des Courses) group from late 1978 through 1988, these crank arms are actually based upon forgings made by Sakae Ringyo (SR) - just as were those late 1970’s to early 1980’s proprietary Raleigh cranks as well as the O.M.A.S. branded cranks dating from that same period. In each of these instances, unfinished SR Royal crank arm forgings were sent along to those respective companies where they were machined, ground, polished, etched, and anodized to preference. This makes perfect sense if you think about it inasmuch as a full fledged forging operation requires a HUGE capital investment and ongoing expense - one that simply could not be justified by the likes of MAVIC, O.M.A.S., or Raleigh given those products that they offered requiring same. On the other hand, Sakae Ringyo, which has a history dating back to 1912 even though it was effectively re-incorporated immediately following the aftermath of World War II only to eventually be purchased by Japanese steel tubing manufacturer Mori Industries in 1989 and combined with the remnants of Maeda / SunTour when Mori assumed the assets and liabilities of that company in mid 1990 to form SR SunTour, was a massive company offering a diverse range of forged goods, many of which were not even cycling related. They were also the largest producer of bicycle crank forgings in the world at that time (...they would later slip to number two after Shimano got into the game forging their own wares at a newly re-dedicated Taiwanese facility). SR easily had the capacity to service any additional volume that the three aforementioned comparatively small companies might possibly generate on their own - and to do so many, many times over. As for the MAVIC version of these cranks seen here, just like their contemporaneous Campagnolo counterparts they have a 144 mm BCD, use a standard 22 mm x 1 mm cap threading, and they even bear a striking physical resemblance. While they originally came fitted with their own proprietary labeled Zicral (7075 T6 aluminum alloy) chain rings, for this bike build I elected to replace those with pair of Sakae Ringyo (SR) Royal-5 ESL chain rings exhibiting a factory "drillium" treatment (...a "fitting" substitution if you ask me - pun definitely intended). I will also freely admit to using lightweight Stronglight Competition alloy crank bolts and washers as well as aftermarket and non-standard stainless steel pedal washers to help protect the anodized finish on those alloy crank arms. For whatever it may be worth as background information, the long running 144 mm BCD Sakae Ringyo based MAVIC 630 crankset was eventually superseded in model year 1989 by a French built Stronglight of distinct design having a smaller 130 mm BCD and MAVIC branding which was then designated their model 631, or as it has come to be known colloquially, their "starfish" crankset.]