jpc2001

I have a 20 year old bike with a shimano nexus7 IGH. This bike is in brand new never used condition!

Seems to operate fine.

WWYD? Hop on and go? Drip some oil in to re-wet the hub gears? Do a complete teardown and regrease?

sch

Well you could start with Sheldon: https://sheldonbrown.com/nexus-mech.html
and a briefer note at How To Maintain Your Internal Geared Hub, Nexus 7 IGH » bMHR

But you could start with just a bit of lube, riding and see how it operates. If funky at some point then a partial
rebuild might be in order. Relube with oil might soften up any grease and improve functioning for a time.
If it runs ok now then I would leave it alone except for a bit of oiling.

Rest of the bike might need attention: FW, BB, Headset bearings. Cables and housings for rust, brake pads for
hardness, tires for cracking.

Andrew R Stewart 

Some here have pulled the "guts" out of the hub shell and soaked the internals in a can of ATF then after some drip off reinstalled the internals. Andy

wroomwroomoops

A Nexus 7 IGH is neither antique nor unusual. But to the core of your question: try to move the pedals with your hands before you hop on and ride? I don't expect there would be anything wrong with the IGH - I'll give it a 94.7% chance that it's still fine.

jpc2001

Thanks. I may drip some oil in there in the future, maybe the near future. Let it soak in, drain off the excess, repeat. That doesn't sound hard and probably worth doing for longevity. Maybe with ATF, maybe with a heavier weight.

The hub is paired with a rollerbrake. The rollerbrake is in a separate enclosure so there should be no risk of contaminating it with too much oil on the IGH.

I was initially worried because the wheel didn't turn as freely as you'd like to see. Luckily, that was due to overly tight brake adjustment. Backing off the brake got the wheel spinning as freely as any other IGH.

This is the bike. Its twin, a step-through frame in equally time-capsule condition, is still for sale on NH craigslist. Not a spot of rust on it.

harshbarj

Far from an antique. It's still quite modern. Before you ride it, check that it shifts between gears fine and also check that the hub is properly adjusted .
You will want to be VERY careful with oil in that hub as it's made for grease. If you do use any oil, go light and make sure the brake side bearings are well sealed in grease first. You don't want any oil getting into the rollerbrake, else you will not have brakes.

sweeks

I've been servicing my Nexus 7- and 8-speed hubs by dipping the gear clusters in 75W-140 gear oil for several years; the bearings get "Nexus grease". I use the same gear oil for my Alfine-11 hub.
I doubt a little oil would harm the roller brake; the (Shimano) roller brakes on my bikes are greased.

harshbarj

It would not harm them, but it would drastically reduce effectiveness. Which would defeat the point of having brakes. You may as well flintstone it at that point.

jpc2001

Here's what I actually did:

1) Remove the rollerbrake.
2) Remove the cone and locknut on the brake side. Then the hub guts pop right out. This hub has bearing cages on both sides; otherwise get ready to catch and juggle some bearings.
3) Dip the guts in ATF for a few minutes. Turn the gears some to work it in. Drain icky grimy stuff out. Repeat.
4) Replace the guts, and repack the drive side bearing cage in heavy grease.
5) Flip the wheel over. Leave the brake-side bearing cage out for now.
6) Dribble in 80W-90 gear oil until it stops draining in quickly and starts to drain in more slowly -- implying that the big voids are filled.
7) Replace the bearing cage, repack in heavy grease.
8) Replace cone and set the locknut.

Please not, I am not claiming that this is the right or best way! Nor do I strongly expect that it won't leak oil. It's a first attempt and a guess, we'll find out if it works. If you would have done it differently, maybe I'll try it your way next time.

I hope that it'll retain enough oil to fill the lower half of the "oil pan" (hub shell) and circulate that over the gears when the bike is moving.

It was startling to see how little lubrication the factory applied. They were generous with air. They didn't "pack" the hub with grease the way the word suggests.

sweeks

That's pretty close to the generally accepted procedure for dip-lubrication of Shimano hubs. After a final immersion in your gear oil, let it drain for a few minutes before reassembly. Bearings get greased; there is specific "Nexus Grease", but regular wheel-bearing grease or even waterproof "boat trailer" bearing grease is acceptable.

EDIT: You might enjoy some of the images HERE.