Broken Brommie

[FrankCrank]

Thought I'd post this as a heads-up to the many Brommie folk on here


View: https://www.youtube.com/watch?v=sHILUbRJ4rw


I've watched quite a few of his vids, he's a folding bike fanatic for sure. He looks to be of a light build as a person, but as he explains he's really abused this particular bike, and I know many take these little gems way past their intended use. As stated, just a heads up

 

[raleighnut]

You can get Titanium rear triangles, this is a known 'fault' with the standard Brommie

 

[FrankCrank]

You can get Titanium rear triangles, this is a known 'fault' with the standard Brommie

Not gonna check the price, but reckon my eyes will water

 

[raleighnut]

Not gonna check the price, but reckon my eyes will water

Not as much as the price of a new Brommie though

 

[CaptainWheezy]

He's not really the sharpest tool in the box is he. Instead of posting a video constantly bragging about how hard he is on his bikes and how much he abuses them, he should have been straight on to whoever supplied the bike to make a warranty claim! He could then make a video detailing the result of the claim.

 

[FrankCrank]

Interesting to know if titanium would fare any better in this application.
Personally, I'd have thought steel would be less prone to fatigue failure, but I could be wrong.

 

[neilrichardson55]

titanium is 100x stronger and lighter than steel, but being honest who would ride a Brampton like that get a hybrid lol fold up bikes are not built for that much punishment. a stiffer suspension block spring . and a new pin would have helped taking out some of the sheering force.

but i am a electrician what do i know

 

[Drago]

Steel is stronger than titanium, with a higher tensile yield strength.

However, titanium gives a higher strength to weight ratio.

 

[raleighnut]

Steel is stronger than titanium, with a higher tensile yield strength.

However, titanium gives a higher strength to weight ratio.

A spiders web is stronger than steel in a strength to weight ratio however no-one has discovered how to weld it

 

[Fastpedaller]

The tensile strength is just a figure for the metal in a certain state (probably fresh off the factory), the heating and cooling of the metal can cause stress raisers which eventually lead to failure. In the Brompton highlighted, it looks like the tube has cracked in the heat-affected zone aligning with the brazed joins. Techniques such as reducing the rate of cooling (introducing the flame again during the cooling process) can sometimes help. I remember my framebuilder in the 80's was careful that nobody opened the door lest some cooling air entered!
Some say that using a jig for making a bike frame isn't ideal, as the jig holds the frame, preventing its natural movement during heating/cooling and can set up stresses. Many different views on this, and much is down to the years of experience, the manufacturing process (in a mass-production setting), basic design etc.

 

[wafter]

Well... that's concerning!

 

[neilrichardson55]

Well... that's concerning!

he was riding it very hard, im 120kg and min stands up to me.

 

[FrankCrank]

Here's another one. For those Brompton owners of a delicate disposition, best to avoid this video!


View: https://www.youtube.com/watch?v=TLg0NNjDBMQ

 

[rogerzilla]

The steel rear triangles rust out. The powdercoat on the outside keeps it looking fine until it cracks.

 

[neilrichardson55]

The steel rear triangles rust out. The powdercoat on the outside keeps it looking fine until it cracks.

ive sprayed underseal in my tubes to stop the rusting problems. mine is a 2006 but it has never been in the rain and is cleaned down after long rides also have used ceramic coat on the paint work which mayhelp we will see lol