Heavy Duty Bicycle Training Wheels
This summer we got a new bike for my son, it was the first time he was trying to ride one and he was hesitant and a little afraid to fall. I decided to install training wheels, the classic ones, but, they broke just after 2 minutes.
I was interested to build ones a little more robust. I started looking and I found urbanmx instructable https://www.instructables.com/Quiet-training-wheel... I liked the robust and silent wheels but I decided to use even bigger ones.
The final outcome was very good, even a full size adult can use them without a problem and the design concept can be used on full size bicycles.
Supplies
Material.
- Two 8” x 8” 3/32” thickness sheet metal plates
- Two cart 10" wheels: https://www.amazon.com/NK-Rubber-Tubeless-Utility...
- Two 3/4” diameter Steel rod, length: 500mm (20”)
- 6x U-Bolts with plates and nuts
- 4x 3/8" x 1 1/2" long hex bolts with washers
- 4x 5/8" hex nuts
- 12x 1/4" dome nuts (optional)
- Black paint
Tools:
- Metal lathe
- Bench vise
- Hand grinder
- Bench Drill and/or Hand Drill
- Metal saw
- Drill bits: 3/8, 5/16, 1/4
- Wrenches
Modify the Steel Rod
The steel rod had to be machined to include some of features.
- 5/8 diameter, this feature will receive the wheel
- 5/8 thread
- Add a couple of flat sections, ** this step is optional
- Include a 3/8" x 1 1/2" slot ** This step is optional, a single 3/8" hole is also ok
- One 3/8" hole (do this later after you are sure there are no conflicts with the bicycle frame)
Bend the Steel Rod
Use a heavy duty bench vise to bend each rod twice using a 1" diameter pipe.
Before bending add a couple of notches with a hand grinder to guide the bend at the desired spots.
The final angle is 90° between the horizontal and vertical sections.
Map the Bicycle Frame
Use a 8"x8" rigid foam and hand drill a 3/8 diameter hole. Use this feature to install the rigid foam to the rear wheel shaft.
Next, use a pen and start mapping the bicycles frame.
Map the Frame, Part 2
Include the individual frame segments and specific features
Add the Fixing Hole Locations
Find the locations to install the U-Bolts and present the bended rod to find a good location
Transfer the Design to the Steel Plates
Hand drill the rigid foam.
Locate the foam on top of one steel frame, align the bottom and left edges, then, transfer the holes locations
After hand drilling the holes please take the rigid foam and try to install it on the bicycle, use all the u-Bolts and bolts, this could eliminate a future headache if there are holes out of position.
Drill the Holes on Both Steel Plates
Align and drill both steel plates at the same time.
Each u-bolt will have 2 holes. On the steel plate, the bottom one must have the u-Bolt diameter, but, the other one could be a little bit bigger to absorb any assembly tolerances.
Cut the Steel Plates
I used a regular metal saw to slowly cut the steel plates to its final size and to add a big chamfer as that part is not necessary.
File the Parts
With a regular file I removed all the sharp edges
Paint the Steel Plates
Just clean the surface and paint with an acceptable color depending on the original bicycle color.
Assemble the Components
Now I started the assembly.
And, there was a pending hole on the plates, the upper hole for the round rod. I decided to do it last to make sure everything was located and aligned fine at the end, with this single hole I blocked any possible slip between the rod and the steel plate after repeated bicycle rides.
Tightening Everything
The u-bolts I got were larger to ease the assembly, and at the end I just cutted the extra length, leaving just enough space to later install dome cap nuts.
Testing
Testing was very good, I just added a second 5/8" nut for each wheel to block any nut movement.
One Happy Kid
And now lets keep riding with confidence. The final user approved the result with constant rides in the park.