How to build 26" fiberglass wheels

My 1st set of big wheels were a bit rough around the edges so I figured I would have a crack at another set using the ideas I like from both Paul and Chook's methods.
Having just recieved a lovely pair of 80mm fat bike rims all the way from china here's what I have done with them.

Hope this helps.

Part 1: Make forms, jigs and hubs.

A, Home made guide for routing circles


Glass cutting template, bout 10mm larger than the overall rim diameter.



B, Centering jig, I cut this 5mm oversize then spun it and sanded the edge down to get an exact fit this is critical to get your rim centred on the form in relation to the hub. (Failing to do this properly last time is where I think most of my problems came from)

Mark the outside edge of the rim on the form base. Form base should be cut to about 60mm larger than the rim dia.
With the rim stil in place dril and set some steel rods as guides. Take care to set them hard against the rim.



C, Form base with rim positioning guides



Rim on base



D, Make hubs and bearing spacers. I used 48mm OD alluminium scafold tube and 6004 bearings. The hub is 20mm wider than the rim and will protrude past the disk on one side of the finished wheel.



E, Nylon hub blank on form base. I wrapped the nylon with a layer of duct tape because I made the about 1mm to thin. (still learning to use a lathe properly)

Part 3: Prepare one rim edge to join to the top disk.

Remove the anodising from the rim edge with a coarse sand paper, and cut 75mm wide strip of glass to lay up the extended rim edge




Lay up the glass as shown keeping the rim holes open



Finished edge ready for trimming.
Trimmed holding the router in place and turning the wheel in the guides.

I love watching these threads

Select to expand quote

Hiko said..
Interesting how the building of these wheels is evolving and improving with the sharing of ideas
Are you using epoxy resin for the aluminium rim connection and hub insert ?

all poly resin..here in the hot interior you get a really poor shelf life for epoxy.i wouldnt have used chopped strand for the glass flange personally. i also note thet he didnt mention the use of cotton flock mixed in with resin ,layed onto the roughed up ally rim before the glass went on . this is the material that creates a mechanical bond to the ally. just resin and glass without flock is an almost non existent bond. very weak

Part 5: Layup bottom side and assemble
(this part should be completed as one continuous lay-up process to achieve best bond between components) This takes about as long as all the other steps combined. Double check that you have enough materials and have precut all the right bits of glass.

- Bolt hub into position on form base
- Lay-up tissue and 2 layers of CSM
- Lay-up reinforcing to hub same as 4.d
- Lay-up rim edge extension same as Part 3
- Place the 5 spokes into position (I pre-mark the top edge of the rim to get an even radial spacing) For 5 spokes multiply the radius by 1.175 then use a compass to step that distance around the rim.
- Apply a good bead of resin mixed with cotton flock to all bonding faces: rim edge and extended edge, top edge of spokes and both sides where hub contacts hub support on top disk
- Place top plate over assembled wheel and clamp around rim edge until cured. Use at least 5 clamps (more is better)

Ready to start


2 layers down building up around the hub



Rim marked with spoke positions and contact face rough sanded



Rim in position and 1 layer of edge reinforcing on



Extra layer of woven tape around the hub



Tape over the CSM on the edge



Top disk on (forgot to get a shot of the spokes in place and the bead of resin/floc paste)



Spokes looking through the holes in the rim



All done fingers crossed and waiting to cure.

Big wheel construction method:
Just in case anyone wants to print out the process steps

1. Make forms and jigs

a. Base form 60mm > rim dia form ply
b. Top plate 5-10mm > rim dia form ply
c. Glass cutting template 5mm > rim dia light ply
d. Centering jig exact fit to internal rim dia light ply
e. Use centering jig to center rim on base form then drill and set centering guides around outside edge of rim Spoke jig same as total or outside edge rim width – 2mm Turn hubs and bearing spacers
f. Turn nylon hub blank same outside diameter as hub

2. Make Spokes

a, Lay up 2 layers of glass Cut to even length 5 spokes per wheel
b. Rough sand contact faces

3. Prepare top side rim edge
a. Prepare base form with release agent
b. Place rim onto base form using the centering guides
c. Lay-up strips of glass from inside face of rim to form base about 50mm wide. I use 2 layers of 75mm tape but 1 layer of CSM works fine.
d. When cured trim newly created inside edge to an even width
e. Coarse sand rim edge and extended edge face to provide a good key for gluing top side disk to rim edge

4. Lay-up top side disk

a. Bolt hub blank to base form
b. Paint flock resin mix around hub to fill any gaps
c. Lay-up tissue and 2 layers of Chopped Strand Mat (CSM)
d. Lay-up glass strips to anchor hub to disk run strips up hub blank to a height = to ½ rim width and 100m out onto disk
e. Lay-up third layer of CSM Cover wet glass with cling film then place top plate on top and clamp (this step helps give a neater finish between the rim edge and the glued top disk
f. Remove disk from form and hub blank, trim the lip that was built up on the hub blank to an even height which is a bit less than ½ the overall rim width

5. Layup bottom side and assemble
(this part should be completed as one continuous lay-up process to achieve best bond between components) This takes about as long as all the other steps combined. Double check that you have enough materials and have precut all the right bits of glass.

a. Bolt hub into position on form base
b. Lay-up tissue and 2 layers of CSM
c. Lay-up reinforcing to hub same as 4.d
d. Lay-up rim edge extension same as 3.c
e. Place the 5 spokes into position (I pre-mark the top edge of the rim to get an even radial spacing) For 5 spokes multiply the radius by 1.175 then use a compass to step that distance around the rim.
f. Apply a good bead of resin mixed with cotton flock to all bonding faces: rim edge and extended edge, top edge of spokes and both sides where hub contacts hub support on top disk Place top plate over assembled wheel and clamp around rim edge until cured. Use at least 5 clamps (more is better)

6. Clean and balance

Trim the edges where the disk meets the rim edge by rotating the wheel while sanding carefully with a flap disk
Cut access for air valve
Balance; spin the wheel a few times, when it stops spinning mark top dead center.
If it’s close to the same point add some balancing weights and repeat until the wheel stops landing at a predictable point.

NOTES:
So, to sum up: The finished product is still noticeably of center but much less so than my last pair. If you want perfect wheels I recommend consulting Chook and Greg. If you’re not quite as capable a craftsman and prepared to live with a little bit of wobble, then this method is pretty good.

When laying up glass on a form always use a release agent. On flat forms I use a good quality car wax polish, cheaper and easier to get than resin release agents. Apply as per instructions smooth on, dry, polish off.

To make the disks I use 3 layers of 450gsm chopped strand mat with an outside layer of glass tissue for a smooth finish. Cotton flock filler is added to resin to make a glue to stick cured surfaces together.

Cotton flock adds desirable mechanical properties to the resin improving the bond between surfaces and should not be substituted for other fillers. Add flock to resin to form thick paste that does not flow.

Happy wheel building.

Could work but dont know if its worth the effort.
There's a guy in Perth Dean who has made his wheels from fat bike rims, motorcycle guage spokes and a mountain bike hub he has machined out to fit a larger axle. I think all that might be a very good solution. Just waiting to see how they hold up to a bit of rought treatment.