How does a 3 speed hub work?
Three speed hubs use a planetary gear system to achieve a gear ratio between the sprocket and the wheel. In this gear system the sun gear is fixed in place while the planet carier is rotated. This causes the planet gears to rotate which in turn causes the ring gear to rotate. The rider selects a speed using a shifter.
How do you lubricate internal gear hub?
Clean the inside of the hub shell. Apply grease to the bearings and clutch rollers. I also inject 3cc or 4cc of the special Shimano oil (ice cream topping) between the gears before putting everything back together. Reinsert the cartridge and wipe off the excess grease.
How do I maintain my hub gear?
Internal gear hubs are easier to maintain than standard derailleur systems. The main thing you need to do is keep the proper tension on your chain and lubricate it periodically. With a derailleur and cassette system you have to regularly clean your rear cogs and derailleur to keep them shifting smoothly.
What is the difference between the sg-s500-a and Nexus sg-8r25 hubs?
A difference in the SG-S500-A hubs (and some Nexus models) is that the roller retainer is castellated (has points which protrude to the left to engage the drag spring) whereas the Nexus SG-8R25, SG-8R27 (Rollerbrake/brakeless also, later coaster-brake and Alfine) hubs have no castellations on the roller retainer.
Where is the cable loosest on a nexus 8-speed hub?
For all Nexus and Alfine 8-speed hubs except the S7000 series Alfine hubs, the cable is loosest in the lowest gear. The S7000 series is the opposite, and the cassette joint and axle assemblies are significantly different. It is very easy for parts (pawls or balls) to come adrift during assembly.
What is the overlocknut spacing of the Nexus 8-speed hubs?
The Nexus 8-speed hubs have a overlocknut spacing ranging of 132 to 135 mm, as sold: see Shimano’s overlocknut spacing chart. It is possible to reduce the spacing of the Nexus Rollerbrake/freewheeling models to as little as 126 mm by leaving off the Rollerbrake and using a narrower locknut. See our Rollerbrake page for instructions.
What is the difference between a nexus hub and a coaster brake?
Coaster-brake models have at most one roller clutch. A red band on the shell identifies a Nexus hub with needle-bearing pinions, for higher efficiency. The lower efficiency of 4th gear compared with the direct-drive 5th gear is noticeable on Nexus 8-speeds with plain-bearing pinions.