Playing a bit with the results in the Brompton bike handlebar case

On my previous post I got to discover that the new design for the 2017 Brompton bike model is much more robust. Didn’t get to understand if it was designed on purpose or was a technical difficulty. My hunch was that they enjoyed the design and it made construction simple. However with experience they concluded that it was a problematic design and went for a new design. They could have just reduced the central bar length but instead almost removed it to a more challenging design at least for manufacturing.

Bent and unbent version
Bent and unbent version

FreeCAD produces nice images and this one is an undeformed vs deformed shape. Here I think it is visible that near the stem is where most of the stresses will be generated. So if you have a handlebar from a bellow 2017 model take special care to not pressure in an exaggerated manner the handlebar down.

Special thanks: I would like to thank the FreeCAD forum team and in particular Bernd for providing troubleshooting for FreeCAD  and showing how to do the deformed and undeformed image.

The Brompton Handlebar Case II

While browsing the Internet I found some past references to Brompton Handlebar cracks near the bending elbows. I noticed my colleague Brompton had a different design and thus concluded that probably the Brompton bike team, decided to turn the  handlebar more robust.

Brompton handlebar
Brompton handlebar

Check out my previous post to know what I am talking about. Click here

I notice that I make some force to the ground direction when pedalling and curving, special when the road has bumps.

HandleBar model constraints
HandleBar model constraints

In wich elbow will the stress higher and the cracks be formed? I will be continuing on this subject, so please stay tuned.

The Brompton Handlebar Case

I started my week looking at my Brompton bike handle bar and noticing that a friends bike had a different one. Same model type but with a different design shape.

Brompton handlebar
Brompton handlebar

My Brompton version is a 2017 model however my friends model is a 2015 model.

2015 Brompton handlebar
2015 Brompton handlebar

Notice the length of the central U shape arms. Smaller?

2017 Brompton handlebar
2017 Brompton handlebar

In my bike version there was a reduction of the length of the straight tube and the two bending zones are pretty near .

I have to mention that this  changes a bit how the Trigo Brompton bike acessory fits. Why? On the first design (2015 version) the accessory at the bike folded state will be positioned much higher far away from the wheel axel giving space. In my version it gets aligned/touches making my life just a bit more difficult to fold the bike with the go pro attached.

I am wondering why they made the change. Was it due to reduced stiffness? Cracking of the handlebar?

I really liked the biking handling the new handlebar offers it feels great and allows me lean a bit when curving.

 

My beloved Brompton Bike

Everyday I have to bike to work. In my day to day comute I can only imagine a Brompton to the help. I am fast and furious biking and when I arrive to my work destination like a transformers I can reshape my bike to soothing small that doesn’t look like a bike. Thats nice!!! This bike is my companion it goes with me to work and takes me back, day and night. A bike full of engineering, that looks simple but has a few thoughtful engineering details that make it’s design unique. Firstly let me introduce the symbols. One of them is the Brompton tag a reference mark for every Brompton bike lover.

The Brompton Tag
The Brompton Tag

The next detail is near the pedal the folding guide.

The pedal in the metal
The pedal in the metal

Not part of the Brompton brand but my personal favourite tyres the Marathon tyres which also fit very well with the big but also give the night effect circular reflection.

Brompton tyres
Brompton tyres

And I could not forget the pentagon clip holder. For those who prefer to carry luggage on the front these are the two screws that hold everything together.

Brompton bag connection
Brompton bag connection

This bike has a lot of interesting things happening all around.