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Shimano CS4160 Nexus Sprocket (20T)

Free shipping on orders over $29.99

$10.99

$ 5 .99 $5.99

In Stock

About this item

  • Will also fit any 3 tabbed coaster brake or internally gear hub
  • Will work with either 1/8" or 3/32" chains
  • Shimano Reference Number: SG-3R40


Shimano Alfine and nexus cogs work with either a 1/8 or 3/32 chain. Will also fit any 3 tabbed coaster brake or internally gear hub.


Michael Bayley
Reviewed in the United States on January 5, 2025
Poor quality, material not hardened.Teeth wear out quickly.
Jerry B.
Reviewed in the United States on January 15, 2024
Build quality is good exactly what I need for my clunker bike
Rich C.
Reviewed in the United States on October 12, 2020
Items it perfect looks good runs good the chain runs on it perfectly
SERTravis
Reviewed in the United States on August 12, 2018
Awesome replacement on your Mongoose Beast. It will make it easy to start of pedaling and seems like the proper gearing for the Beast.
J. T. Buck
Reviewed in the United States on August 2, 2014
Purchased for my Mongoose Beast and Mongoose Dozer. Pedaling is lighter over loose terrain - perfect for burning man. Replaces original rear sprocket. Only tool needed was a flat-head screwdriver to remove some sort of ring clip - check youtube for instructions. Original bike chain did not need to be modified or replaced - it has the correct number of links.
Bruce T.
Reviewed in the United States on June 27, 2014
This, plus 150mm cranks and 40t chain ring gives us the gear ratios needed for my wife's Raleigh Sports update. Sprocket is usable with 3/32 or 1/2" chain. Many thanks to excelcycle for good pricing and quick shipping and to Amazon.com for offering this item.
Mr. One Speed
Reviewed in the United States on July 26, 2012
Shimano makes nice cogs and chainrings they are thicker than most which adds rigidity to the driveline. And they look good too.
Learn More
Reviewed in the United States on June 28, 2011
It fits perfectly on an old single speed coaster brake hub. It makes my beach cruiser noticeably easier to pedal into the wind and up hills compared to the old and worn 19 tooth sprocket it replaced. It delivers a nice, straight chain line with the concave side facing toward the hub. No problems with the part after 11 days and 261 miles of cycling.It's wonderful for local rides in town. Start and stop riding is easier. Merging up onto the highway is easier. Heavy cargo is carried smoothly. Climbs that used to be slightly strenuous are a breeze now. I think it's better for the bike not to stress the cranks and chain the way higher gears tended to do.It's easier to keep clean than the old sprocket. It's physically larger, so there's more clearance between the teeth and spokes for a gear brush and towel to remove road grime.After a few test rides and bearing cone adjustments, the bike rode silently with the new sprocket. Shimano did a great job manufacturing this product. It was shipped with a thin coating of oil, which I presume protected it in storage.I will definitely buy this brand again when the time comes. This sprocket starts to spin out the 44:20 drivetrain at around 18 mph, but I've gotten the bike up to 22.2 mph on a downhill run. My average speed is 10.5 mph, so I might try an even lower gear some day. It feels good to ride at 13 to 14 mph in tailwinds with minimal effort, so this 20 tooth sprocket is close to ideal.
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