Shimano Alfine SG-S7001-8 and SG-S500 (8-spd) 135mm Rear hub

Add this hub to your bench

Hub Data
Manufacturer Shimano
Model Alfine SG-S7001-8 and SG-S500 (8-spd)
Position Rear
Axle Type 3/8" (9.5mm)
OLN 135 mm
Spoke Interface Type J-Bend
Brake Compatibility disc, Centerlock
Drive Interface single cog driver
Internal Gearing 8 speed
Dynamo Type none
Spoke Hole Diameter 2.9 mm
Left Flange Diameter 92.8 mm
Right Flange Diameter 93 mm
Left Flange Offset 30.9 mm
Right Flange Offset 23.6 mm
Mid-Flange Offset -3.7 mm (to the left)
Weight 1680 g
Hub ID 169
Record Status Public
Created Feb 12, 2010 10:36am
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
Strongly recommend considering 2x lacing instead of 3x for better spoke/nipple angle at the rim.

Axle threading for most (all?) modern Shimano internally-geared hubs is 9.5x26 (aka 3/8"-26tpi), which is important if you need to install special axle nuts for Bob or Surly trailers, etc.

Wondering about the difference between SG-S500 and SG-S501 8spd Alfine hub versions? Shimano says: "Roller clutches are used in place of ratchet pawls to reduce noise. The new hubs are now almost completely silent, there is only a ratcheting noise when backpedaling. There is also a new torque limiter which will make it harder to damage the hub with too much pressure from the pedals."

More subtle version differences:
SG-S500 "A-type" (no underline) uses 2 roller clutches.
SG-S500 "B-type" (underlined) uses 3 roller clutches.
SG-S501 also uses 3 roller clutches.

How to identify A or B type?
Look at the hub shell. The A-type is labelled "SG-S500" with no underline, and the B-type is labeled "SG-S500" with an underline.


Wheelbuilding measurements taken by Karl 3/27/2010

Chainline is about 42mm with the cog flipped inward, and about 47.5mm with the cog flipped outward. (Measured on an actual hub by Karl 3/28/10)

4/17/12 -- more accurate measurements taken on a brand new hub. Flange diameters, spoke hole diameter, and flange spacings updated very slightly. Weight of hub (with no parts installed) confirmed. -Karl
part image