Bicycle riders' knowledge and experience of structural weakness in bicycles
66 comments
·April 10, 2025matsemann
robertlagrant
> But honestly, I don't think this is where cyclists should be the most concerned. Separate infrastructure, lower speeds of passing cars etc will do a hundred times more in reducing risks and injuries.
They seem to be totally different people making those changes, though. Spending millions on cycle paths is not going to be stopped by people checking their frames for weaknesses.
pjc50
Everyone recounting their incidents in the comments has made me realize this should be brought up when discussing bike lane width, separation, and close pass distance; cyclists need to have enough space that a mechanical failure doesn't result in instantly going under a vehicle.
CalRobert
Was yelling at a driver who passed within 15cm of my cycling 7 year old daughter about this a few weeks ago. They apparently thought kids never fall down.
FirmwareBurner
In my wealthy European "cycle friendly" city, they put one of the main cycling lanes that goes downhill to the city center, between trams, cars and cubes of rusted steel with 90 edges. Every time I have to cycle through there I get Final Destination flashbacks.
boesboes
Vienna? I remember when it was considered suicidal to even go on the road with your bicycle there, atleast from what the locals told me haha.
As a Dutch person though, I see no safety issues in this picture :P On my morning commute people would be side by side on that lane, with two more people on the outside trying to overtake each other, relying on the cars to avoid them haha
matsemann
Heh, we have one of these in Oslo as well: https://maps.app.goo.gl/nzA2dicDReXYnVBx6 Note the tracks even crossing into the already narrow cycle lane.
Which is why I, on the board of the bicycle association here, spend most of my energy on the infrastructure. The main blocker for people biking is safety, and perceived safety. Lots of other stuff we can do as well, but this is the main point to make it possible for more people to bike. And since it takes long from planning a road to it being built, and it will remain that way for a long time, getting it correctly planned now is the biggest contribution I can do I feel. So spend my time pushing city planners and politicians.
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pjc50
"Corten" (intentionally rust-patina) steel is becoming a cliche.
Edinburgh managed a compromise design that absolutely everybody, cyclists, pedestrians, drivers, and bus drivers is unhappy with. https://www.edinburghnews.scotsman.com/news/transport/edinbu...
wil421
Ouch, I wouldn’t want to bike down that on a busy afternoon.
My US city has been buying abandoned rail lines and creating biking/walking path instead. I like being away from the streets. Some streets have a barrier that protects the bike lanes and I prefer those with my kids in tow.
Abandoned industrial rail line:
bluGill
While those are nice places to ride I still oppose such things because those paths are lost to useful transit forever and cities need long cooridores for transit
LargoLasskhyfv
Why so many skid-marks there?
andrepd
Everybody should just copy the Dutch and be done with it. It helps that their country has a max elevation of 4m but apart from that we can just transpose their lessons to our cities, and/or hire their designers.
robertlagrant
It doesn't just help; it is the key that enabled cycling so long ago.
Lammy
Bicycle breaks; still finds a way to complain about automobiles. Hilarious.
an_ko
Cars break too, but roads for cars are typically constructed such that you won't go off a cliff or under a heavier vehicle like a train even if it happens. I believe GP's point is that cyclists' safety in failure scenarios is often not similarly accounted for.
danielovichdk
Been riding steel, carbon and titanium frames. Steel failed the most, especially after many years (+30) of service. Weldings doesn't last.
Carbon frames and forks I have seen in freak accidents. Like snap-cracking by not even hitting some hard. This too me has been pure structural issues, since with metal, it has always been the weldings.
Titanium I have seen tore apart as well, again all about the weldings.
As for component failures, I have experienced rim-walls explode due to brake heat, rimes fall apart on flat tires, chain snapping and seat post clamps suddenly break and riders losing their saddle :)
I am going for a ride in a few hours. Can't wait!
Gualdrapo
Huh. I've been riding steel bikes pretty much all my life too (from local cheap-made with national tubing to Columbus SL tubing and the like) and never have seen a single one failing at any weld. When they break, and in the rare event they happen to break, it's about corrosion.
rich_sasha
Haha, so much for "steel is real".
I must say, the more I research this, the more I admire aluminium. Other than street cred and the alleged road vibrations, it's incredible how strong, light and cheap it is.
master_crab
Aluminum has noticeable fatigue life though, unlike carbon. Something to keep in mind if you are considering it.
rich_sasha
Well, sort of. But as I understand it, that limit is orders of magnitude over mine, or almost any cyclist's 5-year, say, mileage.
Over my 10k km or so mileage on my current alu frame, I had 0 issues so far, despite a few crashes.
potato3732842
Carbon is basically "fancy fibrous plastic" though. It still degrades. Just in different ways than aluminum or steel.
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michaelt
> Steel failed the most, especially after many years (+30) of service.
Congratulations on reaching your 90th birthday!
sliken
I've had 3 serious failures.
1. Santa Cruz aluminum frame, snapped a few inches above the bottom bracket, at a weld line for a reinforcement. I was sprinting and heard it, frame didn't fail/fold but felt weird, didn't realize till I looked close. SC had me a new frame in a few days after I sent pics.
2. Light weight road racing seat, I think they were aluminum rails, snapped when I leaned back on the seat, my hands weren't on the handlebars. I landed on the road on my back. No warnings at all.
3. Cannondale aluminum crit frame. Back before replaceable derailleur hangers. It snapped clean off, got a new frame for free, even asked which one and which color I wanted.
yccs27
I had two close calls: One time my down tube developed a large crack, starting from a faulty weld to to the head tube. Luckily, the lost stiffness made the bike start wobbling so much that I got off to inspect it. On the replacement bike, they didn't tighten the Hollowtech crank arm enough, so it slowly slid off over a few months and finally fell off. I'm glad that I was away from traffic and in my saddle at the moment it happened, so I could just walk the rest of the way home and put the arm back onto the crankshaft.
fiftyacorn
I think the source of the bikes is important - you see a lot of unbranded stuff like carbon frames, wheels or bars bought from temu or similar. I wouldnt assume this stuff has been tested to the same level as known brands, and wouldnt trust them
I also think the age of the bike is important too - especially carbon where the lifespan is expected 5-8 years
lm28469
More than ever everything on internet is just a fucking ad.
> ARN reports a relationship with Cycle Inspect Pty Ltd. that includes: equity or stocks. ARN has patent ##PCT/AU2022/051284 pending to Cycle Inspect Services Pty Ltd
Which is a company doing "Computer assisted inspection and modelling of fibre-reinforced plastic bicycle frames"
atoav
I had two cases of structual breakdown as of now on a vintage KTM bicycle:
1. The right half of the handle broke off while I was mid traffic, gladly I could recover from this without falling since the left part was still firmly attached
2. The crankshaft broke off on one side with a sharp edge of greased up metal slicing into my leg, this happened on a bicycle lane when trying to accelerate from standstill.
I am still riding the same bicycle, I just had used it a lot back when those things happened and as a student I didn't really have the funds to maintain it properly when somehing made a creaking sound.
LargoLasskhyfv
Regarding your 1) Easy peasy! Imagine accelerating out-of-saddle (Wiegetritt) from around 45kph to intended 55 to 60, to get through an underpass fast, to get ahead of traffic, because wanting to cut the sharp curve at the end and have enough speed for effortless uphilling.
Crunch-Bang! Got my handlebar including the stem painfully into my chin. Guess what? Astonishingly (to myself) I did NOT fall, but managed to wobbly and swayingly brake to standstill, by the still attached brake wires, evacuating to the small sidewalk, and pushing it out of the underpass.
There https://maps.app.goo.gl/D26VGpXXZ3TJmbGTA from left to right.
I think it was a good thing to be ahead of traffic, and not between/beside it in that moment.
Even more funny, at that time there was a large bicycle store only a few 100m away, so I got a new stem in about half an hour, while calming down a little ;>
2) Yah, thats ugly. Almost tore up my ankle that way, but luckily it was only a deep cut, which took 2 to 3 weeks to heal.
Otherwise? Torn chains, mostly.
the_third_wave
I've been using bicycles as my main mode of transport since I could walk, one of the side effects of being born in the Netherlands and living there until about 25 years ago. I mostly use steel-frame bicycles but I do have an aluminium-framed racer, now about 45 years old. During those years I've experienced (among others):
3 frame failures of which 2 caused by broken tubes, 1 by failing solder joints - bikes with lugs are soldered, not welded.
2 front fork failures, 1 of which caused me to roll over the handle bars at high speed.
1 front drum brake failure which caused the front wheel to lock, rolling up the front fork like the lid of a sardines can and me to fly off at high speed
1 broken crank axle
1 broken crank
1 rear derailleur failure which caused the rear wheel to lock up, sending me flying
Several handle bar raiser failures
Thus far no broken bones, all the failed frames were replaced at no cost, the other failures I've fixed myself - I always maintain my own bikes, did that since I was about 14 (now 59).
I also maintain our cars, motorbikes and other vehicles (tractors) which does give me some insight in the frequency of failures due to structural weaknesses in these categories. Bicycles do experience far more failures due to such causes than any of the other categories, most likely due to their lighter construction as well as a possible lack of quality control - those frame failures, especially the one involving the failure of the solder joint at the rear risers should have been discovered before the (BSA-branded, manufactured by Raleigh) frame left the assembly line.
Does that mean I want the government to get involved, mandating regular inspections? Certainly not, one of the big appeals of riding bicycles is the lack of any government involvement and I'd like to keep it that way.
yapyap
Is Australia full of daily bicycle riders or just for sport type of people?
Here in the Netherlands I’m not aware of any such thing going on in our bicycles.
roelschroeven
"11.4% of respondents had experienced at least one crash that they suspected was due partly to structural weakness".
11.4%?? Are Australian bikes trying to eat their riders?
I live in Flanders, where bikes are used quite a lot for commuting, doing groceries, going to school, all that kind of stuff (less than the Netherlands, probably quite a lot more than many other countries), and also quite a lot for sport. The bikes are a mix between new and old (sometimes very old), and everything in between. Crashes because of structural weaknesses are really exceptional.
scott_w
Bear in mind, Australia has strict bicycle helmet laws that mean fewer riders (higher % of enthusiasts), so maybe it's a higher chance that they're ragging their bikes harder? It could also be the classic bad workmen blaming our tools, too, of course, and a less "competitive" rider is just less likely to blame their bike.
robertlagrant
> Australia has strict bicycle helmet laws that mean fewer riders (higher % of enthusiasts)
Why would this mean fewer riders? Are the helmets very expensive?
CalRobert
I wonder how many crashes resulted from Babboe’s issues
globular-toast
So what is the procedure for checking a bike? I've been very into bikes my whole life, never had one fail, and I confess I do not know how to test anything other than looking and riding one.
WillAdams
The classic check is just "ABC"
https://bikeleague.org/videos/basic-bike-check/
>Air: Be sure you have enough air in your tires
>Brakes: Look to see that your brake pads are not worn
>Chain and Cranks: Pull on your cranks to see that they are not loose and look to see that the chain is not rusted and it is free of gunk
Newer bikes add:
>Quick Release: Make sure all quick releases are closed
and it's a good idea to:
Check: Take a slow brief ride to check that your bike is working properly
and of course the recommendation has always been to take a bike in to a bike shop in the spring before resuming riding.
The notable mechanical failure I had was a broken gear on the rear cassette (and this in a lifetime of riding which has included a couple of bike tours, a lot of general riding, and a couple of years of almost exclusively commuting by bike (which I'm hoping to get back to)) --- fortunately, was able to pick up the pieces, set the bike on a particular gear, then continue riding --- getting hit by a car on the first day of summer vacation when I was 14 was far more momentous.
kqr
I don't have any specific knowledge about this, but one of the things I do when buying bicycles second hand is lift them up and give them a good shake. Any noise should be easy to attribute and once addressed, it should be quiet. This helps discover weak joints between components.
I also visually inspect the frame – especially on the underside and around the bottom bracket and head tube, and look for any deformations or cracks.
I have always wanted to try to apply bending forces to the frame and listen for creaking, but I haven't figured out a good technique to do so with a stationary bicycle. The best I can achieve is a test ride where I try things like accelerating hard on a high gear, doing little front-wheel hops, etc.
secondcoming
Flaking paint is usually a sign of a hairline fracture
fian
As I teenager and then poor uni student, I rode a number of bikes or bike parts to failure.
I first snapped the top tube of a stell framed BMX near the stem after many years of using it for a local paper round with a milk crate roped onto the handlebars. The weight of the papers was certainly a contributing factor.
I've snapped a chain while out of the saddle, accelerating a road bike. Nothing too serious, just banged by knee on the bars. Still, do not recommend.
While riding up a long steep hill, I snapped the nut off the outside of a clipless pedal. Luckily the pedal didn't slip off the axle and I could get to a safe stopping point.
I had a carbon top tube delaminate from some aluminium lugs near the stem. Something felt off with the handling so I glanced down and could see ~1.5 cm of the lug showing. Decided to walk the bike the rest of the way to work that day. Got a local carbon repair specialist to re-bond it and it lasted a few more years.
That carbon frame eventually developed a crack in the bottom bracket and frame from front to back right next to the seat tube on the chain ring side. When it failed, the bike started feeling "noodly" to ride, so I looked down and saw the crack opening and closing as I pedaled along.
Somehow I snapped the rear suspension pivot in a Trek Y3 without realising it until the next time I went to ride it. I jumped on it to ride to uni and something felt off. Then I noticed the front and rear wheels were both tracking straight but significantly offset from each other. Took a while to get it repaired as it was a custom part.
When borrowing my brothers (pre-suspension era) MTB I tried a little jump up a kerb. The front fork folded in half. I bent it back straight enough to get sufficient wheel clearance to finish the ride (slowly).
I have buckled many rims over the years on BMX, MTB and road bikes. The early aluminium rims were expensive and really easy to buckle compared to steel rims.
Had the freewheel pawls fail in a rear cassette suddenly one day. They would catch once every few pedal rotations for maybe 1/3 of a rotation. Initially I thought I'd dropped the chain. It was a long walk home.
I was having trouble keep my front QR wheel on a road bike from vibrating mildly as I rode on it. I thought the bearing were loose, so I took the wheel off then found the hollow QR axle had snapped in the middle.
From riding with many others over the years, I'm also aware that larger (taller) riders can break stuff more easily as well. One work colleague who was probably 6'3-4" snapped a cog off the rear cassette almost perfectly in half while accelerating. He wasn't a strong rider, he'd started bike commuting a few months earlier. Maybe the crank length he needed brought extra torque.
Another very strong 6'1" guy I rode with for a few years cracked 3 carbon Bianchi frames within the first few months of owning them. All replaced under warranty. I think he was just heavier and stronger that the frames were generally designed for.
Frames are typically weakest at the joins as that is where the stress is concentrated.
Any rotating part will eventually wear and fail.
Ride a bike long and often enough and something _will_ give out.
I think most people I know in the cycling community actually is quite aware. But we're enthusiasts. Daily someone post a picture of some crack in the frame and people discuss if it's into the carbon or only superficial.
A common problem I've seen, where it's invisible damage, is rust on the handlebars below the bar tape. Especially bikes used on indoor rides during the winter where you sweat much more than on an outdoor ride, corroding the material below.
But honestly, I don't think this is where cyclists should be the most concerned. Separate infrastructure, lower speeds of passing cars etc will do a hundred times more in reducing risks and injuries.