Shimano Nexus 8 IGH : recommendation or changes in bike setup for high altitude ride I have bought a second hand bike (VSF T-100) which incorporates Shimano Nexus 8 IGH. The balls wobble inside the gear. So gear is not smooth. I have to change the IGH with a new gear and rim. I will do that in a bike shop (as I am not expert for IGH). I bought this bike for touring. So far I like it even with wobbling balls inside the hub. I want to ride in Alps region (not gravel/mountain roads) with this bike for multi-weeks/days touring. The chain cog/teeth has been changed from 19 teeth to 22 teeth for high altitude ride.
What can I change or upgrade in the bike so that I can even ride faster in the high altitude with Nexus 8 IGH? Any suggestions are highly appreciated :)
note: I am very rookie for IGH incorporated bike...
Correction The rear cog has been changed from 18 to 20 teeth.
It sounds like your hub needs basic service and you'll likely be fine. It may just need bearing adjustment, but on a used bike it's a good idea to go a little further to make sure all is well.
Take it to a shop that's proficient with modern IGHs and ask for a dunk. The Shimano hubs are intended to have their core pulled, externally cleaned, dunked in an oil bath, certain parts greased, and the core reinstalled and the main bearings adjusted. While you're in, you can get a visual that the pawls and gears are looking good (every once in a great while you see a broken one, and they can typically be replaced.) The bearing races can also be inspected, but it takes a lot to mess them up on Nexus hubs. I've only really seen it much in maritime poor storage/maintenance type cases. The whole thing takes maybe 30-45 minutes, a lot of which is spent getting things clean. If there are problems that really warrant replacement, the shop will typically not charge you for the time spent to figure that out if you do them the courtesy of having them do the replacing. But that's not usually how it goes.
Shimano has lowest allowable gear numbers for all their hubs. This is their way of keeping you from breaking something by putting too much torque through the parts. Ask the shop to get you that gearing setup. They may do it by changing either or both the gears, depending on the bike, clearance considerations, what you have now, etc.