Carrier Project Update

 

After some use I learned that the main rails were flexing under load and I wanted a proper carry box as well – one that was watertight and strong . The case I found is one of those sold for camera equipment and has a very good seal around it. It also has holes in it where you can put a padlock.

I then added some aluminium rail brackets underneath so that it slides onto the rails on the carrier.

The carrier needed to be remade to fit the case and when I did I added some reinforcing bars to stiffen it too. I also added a lock so that the case can be locked onto the bike.

I am now very happy with it, and the bike in general. I ride it to work every day and take it on long rides when the weather is good on weekends. 

The last thing I have to do now is to make the bike rust proofed. Some of the nuts and bolts have surface rust on them due to a lot of rain lately so I am replacing them with stainless steel bolts where possible and I have some special paint to deal with other parts.

 

The Carrier Project

Why a carrier?

I want one so that instead of taking my stuff to work in a backpack I can put it on the carrier. It can also be used for shopping. I bought one but it is tiny and not very straight – considering the size of my bike it will probably need a special design anyway.

Time to make my own. I started by designing things in Blender.

Carrier design Mk.1 and 2

Carrier Mk 1

Model 1 was designed using hollow extrusion for the frame. This was fine apart from the need for longer bolts. Then I saw a battery pack designed to fit a rear carrier that had the rating of 36V20AH which is more than my current pack, so I decided to make Model 2 which uses “L” section parts and thus has a hollow inside that fits the new battery pack.

I am still not sure that I will buy it but I have not cut any metal yet either.

Carrier Mk 2

Mk.3 Carrier

I thought some more about the design and figured it might be better to make the frame from one part and bend the corners if possible. This would mean getting a solid tubular object to bend around but there are big gains: a lot less nuts and bolts and hole drilling, smooth rounded corners that won't catch and a weight saving. Provided it can be bent neatly it will be well worth it. I would need to do a test bend of course.

Carrier Mk 3

Mk. 4 Carrier

Carrier Mk 4

I thought about it some more and realised that I will probably want that larger 20Ah battery pack so I redesigned the carrier to suit that option – as well as making it a little easier to fabricate by only having two bends instead of four. A second copy of the frame could then be added on top to make a hollow carrier to allow sliding the big battery pack in while still offering cargo space on top.

Carrier Mk 5

I found some brackets that will fix the carrier to the frame very well – pipe clips that arrived quickly. I had to buy a whole box of various sizes but so what? They were cheap. They are stainless steel strip with holes at the ends in a “b” shape that can be put around a tube or pipe and they have a rubber pad to insulate them. I can probably use them to fix other addons to the bike too.

The Mk.6 Carrier

I realised the best way to make the carrier was to make it from angle with the flat ribs protruding so that a cargo box can be slid onto the rails as required. If the ends of these are rounded then they are safe without needing the complication of curving metal corners.

Carrier Mk 6

The Cargo box could then have a frame of flat metal bars attached to the bottom with slots that will slide onto the rails and lock onto the carrier. The holes are probably going to weaken too much although they look neat.

After a lot of money spent and messing around I gave up on the idea of chopping the extrusion with the power saw (don’t get me started) and cut all of the parts for the carrier with a hand hacksaw. All went quite well. Then I had to go buy a new set of drills since the one I wanted was blunt and I have no sharpening equipment.

Then I had an idea: why not superglue the parts together instead of bolting everything? It is simpler, does away with the problem of drilling aligned holes in parts and is light.

Glued and painted the parts. Painting with spray cans turned out to be harder than I expected though: lots of it went into the air and after I had finished I discovered areas that needed more - well, I am no expert with spray cans. I might need to sand the parts and repaint them.

I will make a box up as a spray booth to cut down on the waste spray too.

Next Morning, the painting looked terrible. I had to wet sand it all to get a smooth surface and lots of it just came off way too easily despite me sanding all of the bare metal with P800 before painting. The “self priming” paint just didn’t quite work out as expected. There are a few reasons why it failed: first, my own incompetence at spray painting with cans. Then there is the conditions: hot and windy out in the backyard so a lot of paint never reached the things being painted, the parts all hung loose from wires which meant they moved about, and finally maybe the surfaces were not as well prepared as I thought.

I began wet sanding it all down with P400 and after a little pressure the glue joins popped apart. (At least it didn’t happen on the bike.) So now I need to drill and bolt all of the holes as originally designed and finalise the parts, then rig the finished parts in a wire frame and repaint them.

It would have been a good idea to drill all of the bolt holes while the parts were glued together: that would have guaranteed that the holes all lined up. Sadly I didn’t do that but I got them right with care and patience. Lots of patience. The parts matched up by glue areas – I could see where some glue stayed on one side and some on the other so by matching glue patterns you could fit it back together. It all bolts together and after some on-bike adjustment it fits on. Now just one small puzzle: identifying the parts. When I go to repaint them (properly this time I hope) I need to mark them so I know which part goes where since the hole patterns are not exactly the same. Some surfaces don’t need paint and where they meet up no paint would be better so in theory I could write the markings there and then cover those areas with tape.

The final fitting of all parts on the bike showed that I could fix the small support bars to the bolts at the front of the carrier rather than drilling more holes. All of the support bars only got their top ends drilled and lengths cut at this point - regardless of how well you might design things in CAD, nothing beats actual fitting.

I wired the carrier parts into a frame for painting. I did this so that they don’t move around as I am spraying them, something that happened in my first paint spraying.

I was also more careful about heat and wind so it worked out right this time.

Assembled everything today. The paintwork is still not great in that it is easily scratched, which I did during assembly. Never mind. It is good enough. It’s strong and solid.

Here are two pics of the carrier before I added the mudguards.

 

It is held together with M4 bolts and nylock nuts and is fixed onto the back of the frame with two pipe clamps under the seat and two M5 bolts to hold the side bars on.

The back mudguard bolts into that hole in the middle of the carrier.

As a bike to get me to work and back it is real good. Yes, it still looks better without the guards but that doesn’t stop the rain coming down.

                                              Bike with carrier and guards

This is the final design done in Blender of the carrier made from aluminium extrusions from the hardware store. The parts are few and I could carry them all in one hand easily.

The main rails, ends and right- angle joiner parts are all cut from 30 x 30 x 1.5 mm “L” section. The main supports are 15 x 5 mm bar.  Everything is held together with M4 stainless bolts and nylock nuts.

Considering that you can’t buy a carrier to suit a bike like this (well, not that I have seen), and how cheap the materials were, it was a pretty good project to spend a weekend or two on.

If you want to build your own, drop me an email and I’ll send you some plans and a parts list.

 

 

THE SHOLLEY PROJECT

I have a shopping trolley. It is made in Germany and quite good, it has lasted me several years of weekly shopping trips during which I would push it to the mall and shop and then push it home full - and over that time I learned that there are problems with the design – and since I could, I started designing my own to replace it.

Original model weaknesses

1. Front wheels are too small. Even a small ditch can stop the cart.
   

2. Bendy. Some would call it a feature but the plastic frame bends a little on uneven ground. I want something a bit stronger. I am concerned that this will eventually result in it breaking.

3. Folding. The current model has a lot of complexity and parts because it folds flat while I don't need that. Yes, it is nice but unnecessary.
   

4. Low ground clearance. When I  take it up steps the bottom gets scraped.

Basic Dimensions in cm:

length minus handle 64

width 54

height 84

ground clearance 8

main wheels 17

front wheels 9

upper bench height 57

handle overhang 23

Handle height 104

Bin internal 50 x 34 x 26

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DESIGN QUESTIONS

ONE: To fold or not to fold?

This is the big one: a solid frame is a lot simpler to make but not as useful.

I have designed a number of folding models but the existing model has almost never been folded. This, however, does not mean it will continue this way: I could in future move to a smaller place that makes folding necessary – but the complexity also brings weakness.

TWO: Stair Climbing

This means putting tri-wheels on the back - I would need to take these off an existing hand trolley. A useful feature as there are a lot of places where even a small step can cause a lot of trouble. The plastic trolley has its bottom gouged from these – the tri-wheels would not solve this but an aluminium frame will. Better ground clearance will help too.

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DESIGN VERSIONS

Version 10

This is based on the mostly plastic folding trolley I already have.

Version 30

Trying to make the lower tray accessible I split the tray. Not bad but I would need to find or probably make the split trays, not easy.

Version 40

Shifted the main wheels back to allow sliding the lower tray out sideways . This not ideal engineering wise however.

Version 63

This is the peak of folding designs – I even worked out a locking system for the front and back verticals. The down side? First, the complexity, second, the bottom tray has no protection against getting hit upward on bumps or steps. This was directly because I was trying to make it fold small and keep it light.

Version 67

At this point I was still thinking of folding it up and loading on the back of my bike so I put the folded design onto a virtual bike to see what it looked like and it looked bad. Clumsy and heavy.

From version 70 or so I decided to simplify and drop the folding aspect as it made things too complex. I also decided to add triwheels to make it easier to get up stairs and on and off public transport.

Version 74

The triwheels have arrived so here is the latest design with them as well as a solid (non-folding) frame.

This will make construction a lot easier and stronger but there is one down side: you can’t easily put brakes on triwheels. Still, this is looking the best yet. It is probably wildly overbuilt but as I don’t have FEA software I don’t care. It is made mostly of rectangle section alu with stainless steel bolts and nylock nuts. Brakes? Who needs them ! All of the parts are easily available and cheap enough - and now in my garage.  all that I need do now is get time and space to actually put it together.    Hopefully this will happen over the holidays. 

The TRX40 Build - Prices

 Purchase Date: November 2020

A major reason I decided to upgrade at this time was warnings from computer geeks that part prices would soon climb and that the shortages of parts would get worse.

This was highlighted by the GPU being $3000 and that was from a reputable supplier which listed several models of 3090 but could only guarantee supplies of one or two models.

I am still happy that I did get it though – it is the first computer that I am really happy with.

AMD TR4    3970X CPU (32Cores)                     $3279

MSI TRX40-PRO WIFI Motherboard                    $559

64 Corsair 3200 DDR4 RAM                                 $418

Corsair HX1200 PSU                                            $439

NH-U14S TR4-SP3                                               $159  (Special TR4 socket cooler)

Define 7 Compact Case                                        $199

Noctua NF-P12 PWM Fan x 3                              $147

Samsung EVO M2 SSD 500GB                           $145

EVGA RTX 3090 GPU                                       $2999

Samsung NVMe M2 2TB                                     $499

NF-A15 PWM Fan x 2                                            $98

TOTAL                                                               $9154

This was also my most expensive computer buy to date. I considered buying the AMD TR4 3990 64 Core processor but apparently Windows 10 does not run on it. Nope. You need Linux for that and I am not going to go there. Oh, and it cost $6000.

Looking at the same store now, the same model RTX 3090s are still available but now they cost $3600. All prices are in AUD.

This is all here for historical reasons: I am curious to see how this looks in future.

My new E- bike

I bought this to ride to work. My workplace is about 30 mins ride from home on my unpowered bike - fine, but when it gets late and I am tired I would prefer to not be getting so much “exercise” which is where this bike comes in.

From what I can find, it is completely road legal in NSW. It is pedal assist (you still need to pedal) and the motor is 250 watts and it is speed limited to about 25 KM/H.

I added a bell and a tail light to get it to road legal day or night – the headlight was already on the bike.

Although the front forks have suspension the rear does not so I bought a Suntour spring seat post which cost over $100 but it is well worth it. The solid tail on the bike means you can fit a carrier, which I have on order along with mudguards.

I also fitted a rear view mirror that fits on the end of the handlebars. This is a very useful item as it means you can see traffic coming behind you – I don't know why it is not a regulation.

At $1300, it is very good value compared to the assisted e-bikes for sale in other stores. It also a fat bike, that is it has big tyres and I wanted this because it makes the bike better for any offroad or rough surfaces. Oh, yes, it also looks awesome too.

You don't think it's such a good deal? Check out the common assisted bikes – they start around $4000.
I won't even mention the top prices, they are just crazy.
If you are good with spanners and wrenches it is easy to assemble and all the tools you need are supplied.
The only thing I did other than that was grease the chain.

I took it out for a 20 km ride today. Most of the trip was flat but there was a very steep hill at the far end – I could not have pedalled up that hill on my old 21 speed alu frame bike. Ever. The electric assist did it just fine.

There is one area of the bike that did give me slight reason for concern: the cables under the bike seem exposed and might get damaged during offroad riding – I might make a metal crashguard to fit there later on once my workshop is set up – but I am not expecting to go offroad so it is not a big deal for now. The front chain sprocket also protrudes well past this so in most cases it should protect the wires. 

I also considered adding turn indicators and the switch for them: chopping into the wiring loom is a serious matter and I am not in a hurry to do this - well, maybe later. It is still better than waving hands.

A special thanks to TDR Moto for the bike.  No, they did not pay me for this,  it's just a good product. 

If you want me, I'll be out every weekend, riding the city's bike trails . . . . 

ASSORTED WEIRDNESS

 

 . . . and finally, something on a more serious note. 

TRUTH FROM THE ROBOT REVOLUTION