Trunki_pack

Trunki s are great!

Seriously, they are worth every penny and definitely worth it if you ever travel through airports with small kids.

Here is the official site:
https://www.trunki.co.uk

They were developed here in the South West, and famously were rejected on dragons den for really childish and ignorant reasons.

Definitely buy one, they will appreciate the business.

They are pretty robust. Yet I managed to break one last year.

It was stored with the rest of our luggage in our loft, and got a bit manky. So I washed both trunkis in a bath of hot water and a few drops of Milton.

Sadly, Trunkis are designed with plastic planar bearings. These work great with small children (under the age of 7) and when the grease has not been washed out of the planar bearings.

So after I'd given it a good clean my 9 year old rode it through Dublin airport, and it developed a gradual problem. The bearing had increased PV load, and the increase in friction cause both faces of the bearing to melt.
This has made both parts unusable.

The other problem with trunki design is that the wheels are held on by snap fits down blind holes. So to remove the wheel, you have to cut at least one part off.

Bottom line, as great as they are, if they go wrong they are basically toast.

Until now.

So my (now 10 years old) daughter is too big to ride on hers, but she still loves it. And I don't have to carry her carry on luggage, so I decided to give the broken trunki the BathRobotics treatment.

As the bearings with an ID big enough to fit on the centre hub were bloody massive, and intended for motorcycles, I shied away from that solution.

Instead the wheel is replaced with a bogey that is shaped like a wheel. This bogey has axles for 2x two 608 bearings.

Here's where it's interesting.

Print with support. Print standing up so the layers of ABS are taking the cantilevered load well. Print at about 0.3mm layer height. Acetone vapour Bath.

This works well. I've asked Emma not to sit on it, or ride on it, but it works as pull along cabin luggage.

It's in use now.

Needed:
2x clips
1x wheelbogey
2x wheels
4x 608 bearings.

I've included my version of the original wheel, this isn't "true" to the original and it can be told apart by a casual inspection.

Enjoy.