...then I guess it's promptly thrown off a bridge into the river. The idea that a bicycle lasts 3 years, even with hard, year-round riding, is from the disposable tech consumer mindset. A well maintained commuter bike - not an expensive one - lasts 10+ years. These aren't really bicycles, but computerized, electric mopeds.
Three to five years is incredibly good for a bike that's potentially being ridden all day, every day under very harsh conditions.
worked as a cycle courier for almost 3 years here, full-time (6 days a week) + a commute of 20 Km (back and forth) as my parents lived in the suburb, wasn't rare to work in the rain (113 days of sun in a year)... NO FUCKING WAY you can destroy a bicycle chain in a matter of weeks! unless you don't know how gears work, which i doubt couriers don't know (and most of them use single/fixed gears, which the chain is waaay sturdier than 8,9,10 speed ones)
still have my +20,000 Km without previous experience 'hand' centered/aligned aluminum entry category wheels on my 1996 road frame
If you use a fixed gear bike, your tolerances for chain wear are far looser and you can always adjust the spacing to compensate. But for anyone using a modern drivetrain, you will rapidly wear the chain to the point where it will damage the cassette fast enough for it to be economical to replace the chain in order to avoid replacing the expensive cassette (and having poor shifting/skipping cogs).
On an e-bike you can wear your chain even faster, especially if you stay on the small gear too much.
At the end of the day it's not really an issue though, a chain is 10-15$.
That said you're right about the frame lasting far beyond, a good aluminum frame could certainly last over 100'000km
One of my frames did start to crack, but it is now 35 years old - it's an Olmo record
didn't read much on the internet but fixed gears is quite popular among couriers in flat cities (London, NY). maintenance is simple and cheap. salaries are quite low too :)
i never saw an electric fixed gear bicycle, nor much electric bicycles down here (i can remember only 1 guy with an electric bicycle back in 2017 and never saw him working much... maybe it was a occasional teen worker that was there to get some dime for parties (we had a bunch of them)). lately people here ride four-stroke engine adapted bicycles... it's quite rare to find a human-powered bicycle courier nowadays. basically Ycombinator liberated a grand for a super anti-competitive and non-ethical company (Rappi) and they destroyed the local courier scene here, later Uber also entered the scene. now you either work on a motorcycle (which also got effected) or you probably be working as most people back in my days; if you don't love cycling in 3 or 4 months MAX. you will give up from the job and you are doing strictly as an extra income or till you find something better (basically any legal job as far as i know)
1500 miles is what I get on my 12sp MTB chains, which get exposed to more severe service than urban bikes do.
I have taken a chain from new to letting the .5 gauge barely slip through on the chain checker in about a week though. It required riding through all manner of mud and crap for about 18 hours a day during an ultradistance race.
That is a urban myth.
I know several bikes with alu forks and bottom brackets who have been in use for more than 30 years and +50000 kms and they are all good. In fact the glue bond between the tubes is what fails and they have been reglued several times.
Stuff don't strip or seize if torqued correctly, the right kind of greases/compound are used and the bike is disassembled/reassembled once a year.
Having said that, I wouldn't expect a courrier to do it himself nor to have an LBS do this for him.
https://www.sheldonbrown.com/rinard/frame_fatigue_test.htm
An aluminium frame used in all weathers is vulnerable to galvanic corrosion. Aluminium is less noble than steel, so steel fasteners will rot out aluminium threads. In a perfect world this would be prevented by a suitable assembly grease, but a delivery bike being used through winter in London or New York is about as far from a perfect world as you could imagine. There's salt on the roads, the bike never gets a chance to fully dry out, so any amount of aluminium-to-steel contact is going to lead to very rapid corrosion.
This is still a popular method for frames built with mixed materials.
I'm no expert, but couldn't you just weld it up then? That's a fairly simple operation that shouldn't take more than 5 minutes and cost maybe $30.
https://www.pinkbike.com/news/To-the-Point-Heat-Treating-Alu...
The company is incentivized to get the most out of their investment. If the bikes can be maintained economically by staff mechanics, they will be — and these vehicles ought to be simple enough devices for mechanics to squeeze a long life out of them.
If there's a difference, it would be in the lack of an ownership mindset by the riders: they might abuse them akin to how drivers abuse rental cars.
Once you factor in that the bikes are fully utilized, rather than ridden a few times a week, and 3-5 years actually sounds pretty good.
And the original commenter is of course right about the "computerized, electric mopeds" part. That's what makes those bikes useful. The drive unit is likely the expensive part. It also means many parts get a lot more wear because the bikes accelerate faster (= much bigger forces involved) and drive faster on average (= heavier vibrations/bumps).
Combine this with accidents (from the bike falling over while stationary, to the rider wiping out, to car crashes) and the useful life of the vehicle is limited.
This.
I don't see how a bike can be used daily, year-round, for ten years, without falling or being hit by a car driver.
And I would never ride again an alloy or carbon bike that has been involved in a crash with a car.