Hub gears
Internal hub gear systems have all the gearing inside the hub casing, protected from road grime and potential damage. Shimano makes a really nice three-speed internal geared hub, which, according to them, should go “thousands of miles and many years without ever needing service.”
Single–speed
If you’re fairly fit and your commute isn’t mega hilly, opt for a single speed drivetrain. Just like a hub geared system, your drivetrain is less prone to damage and will stay cleaner. It will also last longer due to the chain maintaining a constant line and due to its simplicity, will cost less to replace when it does wear out. You can also convert any derailleur geared bike to single speed using a conversion kit.
Belt drive
Carbon-belt-drive bikes are a growing trend among commuters — and with good reason: They’re grease-free, low-maintenance, and offer a longer and smoother ride. The belt is very similar in construction to the kind used for car engine timing belts, which last for around 60,000 miles of heavy maintenance-free duty, so should be the ultimate in low-maintenance cycling. The belt drive is a lube-free affair, so you never have to add grease, and rust shouldn’t be a problem. And as a bonus, you don’t need to worry about ruining your favorite pair of pants.
Hub or foot brakes
Just like gears, there are completely-sealed-from-the-elements braking systems out there that will give years of maintenance-free stopping. Shimano or SRAM offer maintenance-free drum brakes, which will work consistently in all weathers with very little adjustment. As an option, you can have a bike with a foot brake. Good to know that foot brakes have come a long way since we were kids and don’t skid out like they used to.
Chainguards
Completely enclosed chains, protected by a full chainguard, are not only good because they keep the users’ clothing clean. They also keep water and road dirt off the chain, meaning that it will only need oiling once in a blue moon.
Slime tires and Kevlar tires
If you want to spend more time riding and less time at the roadside swearing, you want puncture proofing. You want tires with a Kevlar puncture-resistant layer. These will resist all kinds of potential damage from glass, nails, thorns, etc. As a second line of defense, use slime tubes, which are heavy-duty inner tubes filled with a self-healing slime which seals small punctures almost instantly. In combination, these two measures will virtually eliminate flat tires.
Mudguard
Bikes with mudguards stay cleaner, meaning your chainrings and headset will last way longer than on a bike without a mudguard.
Single front chainring gear set up
If you don’t like single-speed or hub gears, a bike with a single front chainring derailleur is a good trade-off. On an average commute you won’t need the gearing range provided by a double or triple front ring setup, meaning you can lose that unnecessary complication and weight.