How to replace the spokes on 1/12th bikes

[Mumbly]

Not sure if this is the right forum, I am sure a mod can move it if necessary.

 

This is my preferred way to wire spoke a wheel, it is probably not the best way and it certainly is not the only way.  Of the methods I have tried, this works well on Hasegawa and Aoshima rims, and I assume Tamiya and others will be OK too.  This method should work well with Protar, especially as the tyres don’t stretch over and have the rims assembled around them.

 

I am currently building the KH250 from Hasegawa, so I have decided to keep the OOB chrome on the rims, but the hubs will be painted.  If bare plastic is what you are given or wanting to paint chrome or whatever, then the process will need to factor that in, but should not deviate too much.

 

For cars, I have no advice, especially as the scales can be smaller and the number of spokes are often greater as there can be a third layer.  If anyone wants to add their tips on this then add it to the thread and we can alter the title to reflect accordingly.

 

Tools and materials:

 

 

You will need:

• Flush plastic cutters – I use Tamiya TAM-74001-000, but any that cut super flush, unfortunatley these are usually expensive.
• Wire cutters – I use NWS 160mm side cutters.  They need to strong enough to cut through piano wire, and these have not let me down.
• Files – I have a 100mm round and triangle files, plus a 150mm flat
• Scalpel – Swann and Morton 15a blade in a number 5 handle and a 10 blade in a No. 3 handle.  Not necessary to have multiple handles, but it makes life easier
• Chisel blade – Olfa 8mm flat blade in a Tamiya handle (which are Olfa anyway)
• Flat nose pliers – Again, these need to be good, mustn’t twist and be able to work with piano wire.  I think mine are CK, the name has worn away over time.
• Pin vice and drills.  I have used 0.5mm wire, so use a 0.6mm drill bit.

For the spokes:

• 0.5mm piano wire from Albion Alloys.  This comes in 1-meter lengths in tubes and is straight.  Don’t use coiled wire.
• 0.8mm alloy tube for the ferrules, also from Albion Alloys.  The internal diameter is 0.6mm, so makes threading easy.

 

I have since found a supplier of 0.4mm piano wire, which for 1/12th scale is probably better, especially if making an older or small capacity bike, but this is what I had.  I also don’t know if this is sold in straight lengths.  4D modelshop FYI https://modelshop.co.uk/Shop/Item/Piano-wire/ITM6806.  If 0.4mm piano wire is used, drop the alloy tube down to 0.7mm.

 

First thing that I recommend is to dry fit the wheel halves together, then on an area which will be hidden by the tyre make some deep cuts across both halves.  This is to make it easier when fitting them together for test fits, especially as the locating lugs have a habit of getting knocked off/broken or worn away.  This is on an Aoshima wheel:

 

 

If the chrome is to be removed, then use whatever works for you.  On the KH, I wanted to keep the chrome on the rims, but the hub is to be painted, so I used thick bleach.  I used plasticene donuts to make a small well around the wheel hubs underneath and over the spokes to contain the bleach and keep it off the rims.  For the Hasegawa chrome, it takes a matter of minutes for the bleach to work which is good as the containment method will not hold for long.

 

 

 

Once the chrome is gone, drill out the holes in the hubs for the spokes.  Each hub has inside and outside spokes, not sure if there is a better term for this.  The inside spokes are easy to drill, for the front facing spokes the moulded spokes need to be cleaned off and I cut them away back to where they cross over then drill the hoes out.  This also allows the hub face to be cleaned ready for paint.

 

 

For cleaning the plastic up after the spokes have been trimmed, the flat chisel blade and the 15a blade are ideal.  To be safe, mask the rims if the chrome is to be kept, just to protect it – learnt that the hard way!  Spend as much time as is warranted.  By that I mean, if discs are to be fitted, or these are the inner surfaces then a that’ll do finish might be OK.

 

I also remove as much spoke material from the rear of the hubs as I dare.  It is important to keep some strength in the moulding.

 

On the inside of the rim, using a triangular or round file, make notches for the wire spokes to sit in later on.  Follow the moulded spokes, also create the channels the spokes for the other half.  Do this on both halves.  Care must be taken to not go too deep.  This process might need to be repeated later when joining the completed halves together.

 

 

My intention is to leave the wire natural finish, which is a dull steel.  This with the chrome rims, alloy ferrules and the hubs painted contribute to colour contrast, which is the most apparent difference that this process makes.  So, paint the hubs time.  Personal preference is to use AK Xtreme Metals, as I believe they are more robust compared to Alclad.  I have not tried other brands.  I have seen the whole wheel painted in one colour after the process and they look good as well.

 

Before I start cutting and bending, I make the ferrules.  This works for brass and aluminium. 

 

Firstly, make a jig.  A straight edge of stiff plastic sheet and some plastic strip which is thickernthan the tube being cut is needed.  Glue the strip with a gap to the edge the length that is required, I go for 1mm. 

 

 

With the strip side down, the tube can be held, and using a scalpel blade held against the jig, rolling it back and forth will cut through the tube.  Aluminium is easy, brass takes a little longer.  The great aspect of this jig is that the cut piece does not ping off into the void.

 

 

Make more than you need!

 

Now for the spokes.  I work on this inside row of spokes first, then the outside, rather than by spoke pairs.  Cut off every other spoke and clean up the hub.  AK can be brush painted, so the hub can be touched up before the spokes are added.  With these spokes removed the wheel is quite flimsy, so care is required.  The key benefit of using this method is the hub and rim are always attached, no jig is needed to keep everything in position.

 

 

Bend a right angle into some of the piano wire and trim it back.  Add this to the hub and mark the length off on the rim.  Just add enough overhang to allow it to be glued to the rim.  Thread on a ferrule and glue.  Repeat this for the remaining removed spokes.  Once all 5 wire spokes are attached, the wheel will be more rigid, but still not too strong to be able to withstand any heavy handling or work.

 

Remove the remaining spokes and repeat the process.  I leave the short lengths to help me remember where the outside spokes go.

 

 

Once this row of spokes has been done the outside can row be started.  The wheel is now quite strong so should be strong enough to withstand any work.  Cut the spokes, clean the plastic and touch up the paint. 

 

With this row, the spokes need to be angled out, but apart from that the process is the same as before.  All the spokes can be done in one go.  As a footnote to this section, I will be using some Top Studio tyre valves, so the moulded ones are removed, and the location hole is prepared in the same way as the spokes at this time.

 

 

Before repeating this process on the other half of the wheel, check the fit and remove any additional material to allow the new spokes to fit cleanly. 

 

Spoke the other half and do a final check fit and adjust.

 

I use CA on the rim beside the spokes, clamp the halves together with some clothes pegs and ran some Tamiya Extra Thin around the outside.  Job done!

 

 

I have tried the jig method too where the wheel is assembled then all of the spokes are removed, drilled through and then spoked.  This is fine but gets quite difficult to locate the spokes if they are short lengths (if drum brakes are being used) as the piano wire does not bend or flex that easily over short distances.  A disc brake hub needs a longer spoke, so they can bend.  This is important, as drilling the correct angle through the rim is not as simple as it sounds. 

 

As I said at the start, this is the easiest method for me, but I am sure other ways are possible which I have not thought of which might work better. 

 

Hope this is of use.

 

Thanks

 

Tony

[NigeG]

Great article Tony, I will read it again when the day comes and I feel confident to tackle something like this. 

[Mumbly]

Just an update on this.

 

I bought some Entomology (insect) pins for something else, and these will make excellent spokes.  They come in various sizes and colours, but Continental size 0 with metal heads provide many uses.  These are 0.4mm in diameter, stainless steel with flat metal heads and come in packets of 100 - enough for a front and rear with spares for other stuff.  The metal is not as stiff as piano wire, so is easy to form.

 

The brand are Asta and they are referred as Ento pins.

 

 

Thanks

 

Tony