Bottom Bracket - 03

BOTTOM BRACKET:
MAVIC 610 RD (modified) - cartridge type bottom bracket for 68 or 70 mm shell - chrome molybdenum tempered steel hollow spindle - square taper - 116 mm width with symmetrical offset - non drive side bearing end cap marked with date code "9309F" for September 1993 - SKF annular sealed bearings - "threadless" style 2030 aluminum alloy cartridge system - C.N.D. (...Couche Noir Dure) hardened anodized 2030 aluminum alloy lock rings having a 3 mm bevel on their backside - concave plastic compression washers - series 610 RD / model 612 RD : Stronglight Competition crank bolts and washers - aluminum alloy - M8 x 1.00 x 20 mm bolts with 15 mm head / M8 flat washers - model 59D (bolts) / 60D (washers) ... [Indeed, the MAVIC 610 RD bottom bracket assembly was quite a novel concept upon its introduction in the early 1980’s. An innovative variation on the original 600 RD floating style of cartridge bottom bracket, the 610 RD was designed in such a manner as to enable its use in conjunction with any standard bottom bracket shell irrespective of threading - no need to worry about whether you are dealing with English, Italian, French, or Swiss convention. In fact, you can even successfully install one of these units when confronted with a bicycle where the threads of its bottom bracket shell have been seriously compromised or even stripped out entirely. The secret to its incredible versatility is the requirement that your bottom bracket shell be surface checked and re-faced if necessary to insure that its edges are both perfectly flat as well as parallel, and thereafter, cutting a three millimeter chamfer at forty-five degrees into both sides of said shell (...and no, when done properly this chamfer does NOT preclude using a more traditional threaded type bottom bracket at some point in the future). Once prepared in the fashion, simply slide a MAVIC 610 RD cartridge assembly into the bottom bracket shell, place a concave plastic compression washer onto each side against the chamfered shell facing, and then secure the whole unit in place using a pair of aluminum lock rings fitted one each per side. Of course, this same floating cartridge design also facilitates one’s ability to very precisely fine tune their chain line for optimal performance to the extent that it allows ample lateral movement within the shell itself to reposition the terminus of the drive side spindle, and consequently, the chain rings of any attached crankset. Having a durable precision machined steel spindle and over engineered annular sealed cartridge bearings which are positioned at the extreme ends of the component in order to provide maximum axle support and promote prolonged bearing life expectancy, the complete MAVIC 610 RD minus crank bolts weighs in at a respectable 290 grams assuming a standard pre 1989 double 116 mm width spindle (...post 1988 610 RD standard double spindles began to be offered in a slightly smaller 114 mm width coincident to the introduction of the MAVIC model 631 or "starfish" crankset while the older 116 mm version was thereafter designated as a "long" double) - perhaps not the lightest bottom bracket to be seen in the pro peloton during that era, but certainly one of the smoothest and strongest.]