5 ms·

It's about mileage, not age. A chain is good for maybe 2000 miles - a commuter might get a year or two out of it, but a courier or serious roadie could wear it

It's about mileage, not age. A chain is good for maybe 2000 miles - a commuter might get a year or two out of it, but a courier or serious roadie could wear it out in a matter of weeks. The same basic equation applies to wheel rims, bearings, cassettes, chainrings and (in the case of e-bikes) batteries and motor-gearbox units. If you're changing those parts often enough, eventually something will strip or seize badly enough to write off the frame. Most casual cyclists will never experience it, but an aluminium frame will inevitably succumb to fatigue cracking around the bottom bracket after a few tens of thousands of miles, no matter how well it's cared for. Three to five years is incredibly good for a bike that's potentially being ridden all day, every day under very harsh conditions.

prmoustache 2y ago
> , but an aluminium frame will inevitably succumb to fatigue cracking around the bottom bracket after a few tens of thousands of miles, no matter how well it's cared for. 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.
- noja 2y ago
  Glue?!
  - prmoustache 2y ago
    Yes the popular vitus and alan aluminium frames of the late 80's to mid 90's had aluminium tubes glued to aluminium lugs. Also many early carbon frames of that era from TVT, Alan, Vitus, Trek, Giant or Specialized) were built the same way with carbon tubes and aluminium lugs. In the early 2000's there were also some frames with an alu front triangle and a carbon rear triangle bonded together. Usually they were mid tier bikes below full carbon ones. This is still a popular method for frames built with mixed materials.
- rzzzt 2y ago
  Tubes in the rear triangle are more susceptible to breaking as they twist ever so slightly during use. Steel will gladly take up this sort of springy torsion, aluminium not so much.
- jdietrich 2y ago
  I've seen it first-hand. The old lugged and bonded Trek frames are much more resistant to this than welded frames, because that construction method minimises the stress concentrations that initiate macro cracks. E-bikes are probably more vulnerable, partly because the structure is compromised to allow for battery installation and wiring, but mainly because there's a bunch of extra torque going through the chainstays. https://www.sheldonbrown.com/rinard/frame_fatigue_test.htm 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.
delusional 2y ago
> but an aluminium frame will inevitably succumb to fatigue cracking 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.
- eat_veggies 2y ago
  It's possible to weld an aluminum frame but you'll have to heat treat it, at which point it's no longer a simple and cheap operation. https://www.pinkbike.com/news/To-the-Point-Heat-Treating-Aluminum-Frames.html https://www.pinkbike.com/news/To-the-Point-Heat-Treating-Alu...
deleted 2y ago
[deleted]
luqtas 2y ago
> but a courier or serious roadie could wear it out in a matter of weeks 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
- ericyd 2y ago
  I didn't know fixed speed bikes were popular among couriers. Do you know if this is regional? I've always thought fixed speed would be a nightmare in somewhere with any elevation gain like the hills of San Fransisco. Or, is fixed speed with electric assist the combination that makes this tolerable?
  - luqtas 2y ago
    Brazil here... city had lots of hills tho i always said it was a 'mild hilly city', my cycles when i measured were around 700-2000 meters of altimeter, between 35-60 kilometers; sometimes we had bad days of few workers (motor and bicycle), so they had to send bicycles far away from the center (which was flat). i remember 3 or 4 people having fixed gears, some single (i had one for a short time, with a ratio of 1.6 or 1.8:1 i think) speed but the vast majority used gears 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)

prmoustache 2y ago

> , but an aluminium frame will inevitably succumb to fatigue cracking around the bottom bracket after a few tens of thousands of miles, no matter how well it's cared for. 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.

noja 2y ago
Glue?!
- prmoustache 2y ago
  Yes the popular vitus and alan aluminium frames of the late 80's to mid 90's had aluminium tubes glued to aluminium lugs. Also many early carbon frames of that era from TVT, Alan, Vitus, Trek, Giant or Specialized) were built the same way with carbon tubes and aluminium lugs. In the early 2000's there were also some frames with an alu front triangle and a carbon rear triangle bonded together. Usually they were mid tier bikes below full carbon ones. This is still a popular method for frames built with mixed materials.
rzzzt 2y ago
Tubes in the rear triangle are more susceptible to breaking as they twist ever so slightly during use. Steel will gladly take up this sort of springy torsion, aluminium not so much.
jdietrich 2y ago
I've seen it first-hand. The old lugged and bonded Trek frames are much more resistant to this than welded frames, because that construction method minimises the stress concentrations that initiate macro cracks. E-bikes are probably more vulnerable, partly because the structure is compromised to allow for battery installation and wiring, but mainly because there's a bunch of extra torque going through the chainstays. https://www.sheldonbrown.com/rinard/frame_fatigue_test.htm 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.

delusional 2y ago

> but an aluminium frame will inevitably succumb to fatigue cracking 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.

eat_veggies 2y ago
It's possible to weld an aluminum frame but you'll have to heat treat it, at which point it's no longer a simple and cheap operation. https://www.pinkbike.com/news/To-the-Point-Heat-Treating-Aluminum-Frames.html https://www.pinkbike.com/news/To-the-Point-Heat-Treating-Alu...

deleted 2y ago

[deleted]

luqtas 2y ago

> but a courier or serious roadie could wear it out in a matter of weeks 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

ericyd 2y ago
I didn't know fixed speed bikes were popular among couriers. Do you know if this is regional? I've always thought fixed speed would be a nightmare in somewhere with any elevation gain like the hills of San Fransisco. Or, is fixed speed with electric assist the combination that makes this tolerable?
- luqtas 2y ago
  Brazil here... city had lots of hills tho i always said it was a 'mild hilly city', my cycles when i measured were around 700-2000 meters of altimeter, between 35-60 kilometers; sometimes we had bad days of few workers (motor and bicycle), so they had to send bicycles far away from the center (which was flat). i remember 3 or 4 people having fixed gears, some single (i had one for a short time, with a ratio of 1.6 or 1.8:1 i think) speed but the vast majority used gears 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)