Shimano Deore LX FH-M550 135mm Rear hub

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Hub Data
Manufacturer Shimano
Model Deore LX FH-M550
Position Rear
Axle Type 10mm
OLN 135 mm
Spoke Interface Type J-Bend
Brake Compatibility rim brake
Drive Interface Shimano 7 (30.9mm)
Internal Gearing none
Dynamo Type none
Spoke Hole Diameter 2.6 mm
Left Flange Diameter 45 mm
Right Flange Diameter 45 mm
Left Flange Offset 32.5 mm
Right Flange Offset 22.5 mm
Mid-Flange Offset -5 mm (to the left)
Weight 0 g
Hub ID 520
Record Status Public
Created Aug 5, 2019 5:38pm
Contributed By Karl Stoerzinger
hub dimension diagram
PLEASE NOTE: Shimano publishes hub dimensions in a relatively confusing manner on They seem to provide the outside-to-outside flange spacing, and an overall offset of the flanges as a whole. Wheelbuilders are interested in the distance from the midpoint between locknut faces to the middle of the flange (not the inside or outside face). When necessary, I convert Shimano's data into useful spoke calculation dimensions with some simple arithmetic, and factor in 3mm thick hub flanges (an approximation). The formula is to divide spacing by two, add or subtract the overall offset, then subtract half of our assumed 3mm flange thickness. Please check the notes to see if the values for this part are derived from Shimano's published data or actual measurements of a hub specimen. -Karl
Dimensions measured (quickly) in a laced-up wheel. Spoke hole diameter is a guess. Not able to weigh hub. Locknut to flange distance is 37mm. Freehub body is from the transitional time period between UG and HG and has both internal and external lockring threads. Note that the tip of the freehub body does not have truncated splines, so many modern cogs will not quite seat down enough to compress the rest of the cassette, and loose cogs will result. You could file or grind the last 2mm of the splines down to the smaller diameter, or I had success by adding a 1mm spacer behind the modern 7spd cassette (CH-HG41-7) I was installing. -Karl