Sutherland’s Handbook For Bicycle Mechanics (1st Edition)
Date: 07/11/2009
Views: 213
Hubset - 01
HUBSET:
MAVIC 550 RD - quick release hubs - small flange design - forged 2014 aluminum alloy bodies with Clear anodized finish - 2030 aluminum alloy axles with anodized finish - post 1981 with channel inset "MAVIC" logo along the centerline of the hub barrels - pre 1991 without White on Black "MAVIC" logo with model designation band on non-drive side of the hub bodies - non drive side bearing end caps marked with date code "9007A" for July 1990 - annular sealed bearings / outboard mounted bearing on drive side of the rear hub - 28h front hub (100 mm spacing) - 28h rear hub (126 mm spacing) - 1.370" x 24 TPI English freewheel thread - model 550 RD : MAVIC 500/550 RD (Duralumin) - curved handle quick release mechanisms - Clear anodized aluminum alloy end caps and knurled adjusters - stainless steel skewer rods ... [A variation on the model 500 RD hubset, the first edition of which debuted in 1976, the improved 550 RD appeared in 1982 coincident to introduction of the second edition 500 RD and was a modification begot of feedback derived from MAVIC’s unique relationship with professional riders in the European pro peloton. While it is true that the 550 RD does have a protective anodized surface finish on both its hub body and axle unlike its predecessor, perhaps more importantly with respect to its being able to better withstand the rigors of racing, it also has an outboard bearing on the freewheel side of its rear hub absent the end cap found on the corresponding model 500 RD. By virtue of placing the drive side bearing such, this version of the MAVIC rear sealed bearing hub allows for a wider distance between load bearing points with particular emphasis on the amount of outboard axle overhang on the freewheel side, thereby minimizing the opportunity for bending said axle under extreme duress such as when a powerful rider is sprinting or climbing hard out of the saddle. This feature was later incorporated into both the 501 and 531 freewheel threading road hubs which succeeded the 500 RD and 550 RD models in 1991. It should also be noted that those 500 RD and 550 RD hubs dating from 1977 to 1990 and 1982 to 1990 respectively were made available with quick release mechanisms having a choice of either chrome plated steel end caps or lighter weight aluminum alloy versions as seen here.]