Indoor training seasons starts and I'm again about to set up my direct-drive trainer this weekend. Before doing so and after experimenting with different methods of lubrication over the years, I'm wondering:
What kind of lube should I use for my indoor trainer?
I tend to use light-running oils or dry lubes because the drivetrain stays cleaner. At least in my experience, even on a chain/cassette that have been cleaned thoroughly, some grit/excess oil occurs over time using "just" oil, something like a dry lube (or even wax) isn't prone to this effect so much.
On the other hand, riding indoors pretty much eliminates dirt sticking to the drivetrain for obvious reasons, and that's the main reason why many people refrain from using thick/cheap oil for outdoor riding. It does the job but pulls too much dirt and grit to the chain and all the moving parts. On the other hand, tradtional oils stick to the drivetrain better and typically last longer.
I'm aware of drivetrain efficiency differences between those products, yet marginal, but I would argue that a few watts don't matter for most of us on an indoor trainer during winter.
Second aspect: Does riding indoors extend periods between required (re)lubrication, can I just go for way longer than I would outdoors because there is practically no dirt buildup?
My feeling is that at least for dry lubes, the drivetrain gets noisier after riding around ~150 km (or even less), so I would re-apply lube even if the chain is reasonably clean. Dry lubes/wax sometimes seems to peel/chip off, is this the same for plain mineral oils? I haven't seen any dripping oil on my floor/bike, so do lubricants go anywhere at all if there are no external factors like water and dirt?
In case of doubt, I would still go by ear and shifting feel, but I'd be interested in other's experiences.