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Freewheel Adapters and Disc Brake Adapters

Delta Trike Axle Adapters – Freewheel Adapter (left) and Disc Brake Adapter (right).

Both the Freewheel Adapter and Disc Brake Adapter are black anodized aluminum and fully drilled and tapped for a standard 6 bolt bicycle disc brake rotor. The hardened 1/4 inch axle mounting bolt is also included with each adapter, so they are ready to install onto your 3/4 inch axle.

We understand from your feedback that often a local machine shop will charge a bundle to make only a few parts and you may have to wait months to receive them. Another risk is a part that may not fit perfectly, so we are stepping in to help ensure that your build goes smoothly.

These Delta Trike Axle Adapters will fit any 3/4 inch trike axle and allow you to install a Shimano type freewheel and a bicycle disc brake to the axle for drive and braking.

Our Delta Trike Axle Adapters will fit onto any cold rolled 3/4 inch steel shaft, allowing you to install both a Shimano type freewheel and a standard 6-bolt bicycle disc brake rotor. The adapter shown on the left is designed for a disc brake rotor only, and the adapter shown in the right will take a disc rotor as well as a Shimano type thread on freewheel. The thread on freewheel can be a single speed BMX type, or and multi-speed type with 5 to 9 chain rings. A hardened 1/4 inch bolt (included) passes through the axle to secure the part to the axle.

Being able to mount a freewheel and disc brake to an axle means that you can create practically any kind of delta trike or quad cycle using standard bicycle components. All of our delta trikes such as the KyotoCruiser and LodeRunner use this adapter, as well as our StreetFighter quad cycle.

These parts can also be used on any of our other trike plans by using a 3/4 inch axle in place of a 5/8 inch axle. All future trike and quadcycle DIY plans that we intend to release will be using these parts as they are easy to install and service.

Hub Flange Discs

Our laser cut Hub Flange Discs will make it easier for you to build your own delta trike wheels and save you time on your project. This Hub Flange Disc is made with 24 spoke holes so that you can build wheels directly onto any 3/4″ axle using rims with 48 spokes.

The Hub Flange Discs are made of steel and are approximately 1/8 inch thick as required by the plans. Spoke holes are 7/64″ in diameter so that standard bicycles spokes can be used.

Our Hub Flange Discs come in several varieties with various spoke hole counts and axle hole diameters. Each of our DIY plans offer a recommended axle size and spoke count, but you can certainly change this to suit your design needs or parts availability. For instance, the Aurora Trike can be built using rims with 36 spokes rather than 48 spokes, or the DeltaWolf can be made using a 3/4 inch axle rather than a 5/8 inch axle. Please make sure that you order the correct Hub Flange Disc size for your project.

To keep costs to a minimum, our Hub Flange Discs are laser cut from flat sheet metal. Each disc will have a small imperfection on the outer edge and inner edge where the laser started cutting out the disc. There is also a mill scale on the surface of the metal that will need to be removed using sandpaper or a sanding disc. Neither of these imperfections will compromise the strength of the disc, and once they are built onto your hubs and painted, the imperfections will be unnoticeable.

The surfaces of the Hub Flange Discs are coated with a mill scale at the factory to help protect the metal from oxidation. This coating easily be removed using a sanding disc to prepare the part for painting. The laser cut edges are also somewhat sharp, so they need to be smoothed off using the sanding disc by running it lightly around the edge once.

Once the mill scale has been removed from the Hub Flange Discs, the spoke holes will need to be beveled slightly to remove the sharp edges around the holes. This is done so that the spoke exiting the flange is not cut by the sharp edges of the hole. To bevel the spoke holes, use a 3/16 inch drill bit and push lightly into the hole until a small bevel is made.

The beveled spoke holes are shown here after running pressing lightly with the 3/16 inch drill bit to remove the sharp edges. The Hub Flange Disc is now ready to be welded to your delta trike axle.

Remember, our Hub Flange Discs are sold as a set of four matching discs, and there are several versions available, so please choose the correct number of spoke holes and axle diameter for your project. These discs are manufactured to keep costs to a minimum, so you will need to bevel the spoke holes and prep the surface for painting, an operation that will only take a few minutes per disc.

All of our DIY Delta Trike Plans make use of these Hub Flange Discs, which allow you to lace a rim directly to the rear axle. By integrating the flanges directly onto the axles, you’ll save some money instead of needing to have complex and expensive machined hub parts made. Our trike plans also include instructions on how to make these parts from scratch, as well as a drawing that can be sent to a machine shop in case you want to make your own hub flanges.

Our goal is to offer parts that save you both time and money when building your own DIY bike or trike project. For more details and to order, visit the AtomicZombie store.


Bike builders news Jan. 29 – Build a velo Part 5

Feature article by RadicalBrad of Building a Velomobile – Part 5
In this week’s issue, the frame begins to take shape!
Hub flanges and axle adapters for your trike and quad bike projects
*** Great news for our international bike builders! ***
Bike builders community chat – stimulating conversations
Builders Feedback you tell us what’s on your mind
Bike builders gallery – new additions: recumbents, trikes, choppers, cargo bikes & more
This and archived newsletters are here.


Thanks for your feedback, and keep those suggestions coming.

See you in the Builders Forum.

Rebar GreenHouse now closed!

It has been a great success, and has stood up to our extreme winds with no problem at all. 2 months ago our brand new car shelter collapsed in a huge wind, doing $3000 in damages to Kat’s car, but the greenhouse was barely even moving. I won’t even have to remove the snow since I can actually walk across the top of it!  More >>

Show us your workshop!

Take a look at one bike builder’s workshop. “My son Jesse’s black and yellow powder coated 20” bike frame, orange buckets, work bench, air compressor, Clarke 110 wire feed welder.”
Share pictures of your workshop in the AZ builders gallery. More >>

Bike builders news for October 1

In this issue:

NEW DIY plan – Short and tall unicycle
Hub flanges and axle adapters for your bike projects
Bike builders community chat
Bike builders gallery – new additions
AtomicZombie family mourns
The Deacons of Deadwoods Chopper – Houston’s Chopper Shop
This and archived newsletters are here.

August 7 newsletter

  • Featured article: “Build the SideWinder folding bicycle”
  • Freewheel and disc brake adapters for your bike projects now for sale! 
  • The latest Atomic Zombie bike project:  FrontRunner Front Wheel Drive Recumbent, a unique front wheel drive bike that is fully adjustable and can fold in half for transport or storage.
  • Bicycles from around the world in the Builders Gallery
  • Builders community chat
  • Find us on Facebook
  • Summer special: 6 plans for only $36!
This and other AZ newsletters are here.

May 24 newsletter



Feature article by Brad Graham (Radical Brad):
*** Building a rebar greenhouse – Part 4 ***


In the Atomic Zombie builders gallery
Coming soon – manufactured parts for your bike projects
Head tubes and bottom brackets
Bike builders chat
Spring into bike building – offer ends May 31
This and other AZ newsletters are here.