by Mario Covalski
One of the biggest challenges for a modeler who builds motorcycles in 1/12 scale, is to modify a wire wheel and make it look realistic; specially without having to buy an aftermarket kit. Anyway, there are no kits for this kind of modification (except for one of the Acu-stion for the Tamiya XV1600 kit), so it’s not possible to get one. So any modeler attempting to do this task must rely in his/her ability in order, to get a good result.
Wire wheels are nearly as old as wooden ones, and vehicles have been using them from the beginning of the 20th century. Essentially, they are very simple: a metal rim, a center hub that generally acts as a brake drum, and steel wires placed in such a way, that, their structure turns out more solid than the new alloy wheels
The spoke diameter depends on the type of motorcycle, the time which it’s from….etc, but normally it’s about 5mm, perhaps thinner for a motocross or thicker for a Harley. So, the spoke diameter in 1/6 scale would be 0,8mm, and in 1/12, would be 0.4mm, or less.
In the1/6 scale motorcycles I used to build, the plastic spoke diameter was 0,7mm (it looks like this was the minimum thickness for an injected “spoke), so, they were in scale. I love working with plastic so I preferred to “clean” them removing the flash and “rounding” them until I got to an acceptable result.
But this is not the situation with a 1/12 scale wheels. I’ve checked all the kits that come with wire spoke wheels and neither of them had less than 0,7mm diameter. So, even if we work with plastic, we’ll never get a result in scale.
This note aims at explaining a step by step procedure on how to modify a plastic wheel adding wire spokes, using simple materials and no special tools.
There are two kinds of wire wheels, those using drum brakes, and the ones using disk brakes.
The first kind are very old and as simple as a bicycle wheel; that is, the spokes go through a center hub (they are visible), which at the same time acts as a brake drum.
The second kind of wire wheels use brake disks; so the hub is much smaller, the joint is more sophisticated, and can’t be seen most of the times.
Here, I used the wheels from a 14018 Tamiya kit, a Honda motocrosser of the 80s, with drum brakes, which makes the job more complex, because the joint between the spokes and the drum is visible.
The Tamiya kit provides each wheel in two halves, making the detailing task a little bit easier, but at the same time it’s difficult to get a nice finishing, as we’ll see at the end of this note.
There are two basic ways of working
1) To cut away all the plastic spokes, glue both wheel halves, drill all the parts and thread the new metal spokes. It sounds simple, but it’s not so, you should make a jig for this purpose (like the one used when building the real wheels because you lose all the references once you cut the plastic spokes), the jig will keep an accurate wheel alignment.
It’s possible to achieve this task, but would probably demand more skill and time, and I thought that it would not be worth spending 20 hours on building a couple of wheels while constructing the whole model would take me 10 hours.
2) Nevertheless, it’s hard to get a nice job and you will have to be very careful not only when joining both halves once finished, but also at the moment of painting the ring.
To illustrate this note, I decided to carry out this second and easier method. The final result wasn’t the expected, because of the lack of practice, and because I was eager to write this note. Anyway, I think this method is ideal, and you’ll get a surprising result, just by paying attention to some details.
Here’s the list, nothing special:
-A scissors or side cutter for plastic
-A flat file.
-A pin vise ( I recommend the Tamiya’s).
-A 0,3mm drill.
-Good quality CA (it should be used cold)
-Two flat pliers.
-0,4mm tinned cooper wire ( used in telephony or PC connectivity).
-A magnifier ( a must-have tool, although your sight were excellent).
Building step by step a wire wheel
Before starting, you should draw a diagram of each wheel, showing the spokes location; but if you have another kit similar to this one, or a digital camera to take photos of each half, you can omit this step.
Although the front and rear wheels are somewhat different; I chose the front one to illustrate this note, because is a little more complex.
I started by cutting the plastic spokes away from a semi-wheel; to avoid breakages, I did a first cut, removing, the parts left, being careful not to break the nipples which will be essential later.
I removed the surplus plastic from the nipples, filing them thoroughly (using a flat file) to be painted later.
Actually the most difficult part was drilling the nipples, so the wires could go through them.
Half of the nipple (injected in the plastic) overhangs the semi-rim line, and you have to drill 18 holes using a pin-vise and a 0,3mm drill, (to each semi-rim ); choose the angle that better allows you to drill the plastic nipples without problems. Once the drill has hardly penetrated the plastic, you should change the angle (while turning around the pin-vise), to let the drill tip come thru the center of the nipple. With patience, and the help of a magnifier, I successfully achieved this task in almost all the nipples. Don’t lose hope!!!!
I went on by drilling the drum and removing the surplus that remained from the plastic spokes. So as not to lose the references, I made 18 drillings, 9 on each side, following, the injection marks corresponding to the plastic spokes, as a guide.
Then, using a cutter, I removed all plastic flash, sanding and polishing appropriately.
In the picture, you can appreciate the drum that has already been prepared and the drum in the wheel, just as it comes in the kit.
Here, I started to place the first wire spokes. I decided to use tinned cooper wire, (used in telephony or connectivity cable), because steel is so rigid that could break the plastic, specially on the area of the nipples that it’s quite fragile, both of them look very similar.
As it’s very difficult to get the cooper absolutely straight, you will have to stretch it, taking advantage of the material plasticity. I cut 5cm long pieces, holding them between two flat pliers and stretching them until one of the extremes broke.
The picture shows the wire, before and after having been stretched. Note that the original diameter was 0,4mm, but once it was stretched it decreased to 0,3mm, quite right to this purpose.
When the wire was ready, I took 1mm from one of its ends bending it at right angle. After repeating this operation ….. all the spokes were ready to be used!!!
I placed the ring, that had been prepared in Step 2 on the semi-wheel, which was still without being modified, I used the guide pins from Tamiya, joining both halves with masking tape temporarily.
As it can be seen in the Image 1, I began by (1), passing the first wire through the nipple from inside, it’s “L” (the end), was inserted in the drum from above These will be called upper spokes.
I CHECKED the relative position by looking at the unmodified wheel that I had. Once the drum and the first spoke position was verified I applied a small amount of CA (with the help of a 5cm long wire) to both ends, in order to fix its position. The CA must be cold, this will diminish the fumes and set faster.
Then, I repeated all the above operations, with the wire, as shown in the picture as (2). It is very important to fix the drum’s position and avoid its rotation while we place all the upper wires. The “L” end of the wire has to be inserted from beneath in the next hole of the drum, and I will call them “lower spokes”.
The final stage was to locate the upper spokes, which have to be placed every other free hole.
The picture shows the semi-wheel look once all upper spokes were in place.
The wires´ surplus may be marked with a cutter and cut away turning them very carefully so as not to break the nipple, however, at this part of the job the whole assembly is quite solid.
After the previous step was finished, both semi-wheels were detached, and the lower spokes were placed without trouble as you can see in picture.
The picture shows the finished semi-wheel. Here the drum may be either handpainted or airbrushed, masking the spokes and removing the paint that remained on them, using a cotton swab moistened in thinner.
In the same way, I worked with the other semi-wheel, but now, using the finished one as a jig.
Both semi wheels before being glued to each other
Now let’s join both halves, if everything was correctly done, there would be no problem. I just had to file some surplus wire so both halves fit accurately.
The rear wheel
The rear wheel’s conversion was easier, one of the semi-wheels’ drum didn’t need to be drilled I just glued the wires to it, look at the pictures. Otherwise, as the spokes were shorter, this task turned out to be a lot easier.
As you can see in the pictures, the joining line is very visible, this is due to the method I choose and of course, If you decide to spend more time, the result would be great indeed!!, and the joining line will be almost completely hidden.
The nipples can be handpainted gold , and the rims with Alclad, I choose to paint them with a X11 Tamiya marker, it’s quick and the result is a very realistic flat aluminum.
It took me 6 hours to prepare both wheels and I enjoyed every minute of them, provided that you are sure about what to do and that you won’t spoil the model; that although not expensive, it may be difficult to find.
The same work can be achieved in bigger scales. In this case, it will be necessary to use steel wire, however, the size of the parts will simplify things.
I look forward to hearing your comments by email!
I was measuring spokes in real bikes and found out that they are different depending of weight of them.
For light motocross bikes (up to 450 ccm) max diameter that we can use in 1/12 scale is 0.3mm, for some small bikes like Imai did (Honda 50 ccm roadpal – I have it) should be used 0.2mm, for Yamaha XV1600, 0.4mm