This is a problem that is not particularly specific to India, but common for anyone touring a long way from home and primarily through small towns and rural areas, even in major industrialized countries.
When you have the potential of a mechanical issues in areas far from a well equipped bike shop, you are faced with choosing some combination of a few options:
- Start by using tried and true components on the simpler end of design.
- Carry spares of parts most likely to fail.
- Plan "escape routes" to major cities.
Simple Bikes and Components
Many of the long distance tour riders that I hang out with are still riding decades old steel-frame bicycles equipped with 3x8 or 3x9 drivetrains and friction shifters. While this is decidedly old-school, on a bike like that you don't have to worry about things like the index pawls failing on your fancy shifters. In fact, in the course of a days ride, you can dial in your shifting by feel of the friction levers.
I know that some touring riders prefer wheels built on internal hubs, allowing them to pack a single replacement chainring and use a larger & sturdier chain.
By the same token you could stick with ISO 559 mm / 26" or ISO 622 mm / 700c wheels because tires and tubes for those wheels are far more common in most places.
There is even an advantage to the steel frame, in that if there is a significant frame failure, almost any welder can make a passable repair.
While you have to balance weight and bulk for spare parts against all of your other packing needs, most touring riders in this situation would carry spares of parts likely to fail.
For my touring bike I have a "rural" kit for multi-day trips that includes
- a folded tire,
- tubes and patches,
- a small selection of bolts/screws,
- a replacement friction shifter,
- a brake cable and shift cable,
- master link and short section of chain,
- 3-5 replacement spokes (taped to my rack),
- cable ties,
- appropriate tools.
On any long distance tour, you need to have an "escape plan" for what you will do in the case of a catastrophic equipment failure or illness. In places I have toured, that may be relying on the kindness of strangers in the next tiny town to get you to the next bigger town, where you can catch a bus or train to the next larger city.
Even in North America and Europe it is unreasonable to expect that the majority of small rural towns will have a well equipped bicycle shop, so you need to plan to get to somewhere larger.