Saturday, 15 March 2025

FH - wheel building

 With the hubs polished and the proper spokes delivered, we can start on the delightful job of lacing the wheels. 

These will use butted spokes like the originals fitted by Ariel back in the 1950s. The nipple end of the spoke is thinner than the head end - in this case the nipple end is 10 gauge and the head end, with perhaps 1" of spoke length is larger at 8 gauge. The idea is that the stressed part of the spoke is strong without making the wheel ridiculously heavy; this will have the effect of making the steering lighter by reducing the gyroscopic force on the wheel.


I'm building the wheels on a post which is of a suitable size to go through the wheel bearings. The bore of the bearings is 1"; the post I'm using is 1 1/8" so that the hub is happily suspended in mid-air. 

It's essential to get all of the spokes into their holes in the hub before you attempt to fit any of them through the holes in the rim. There is absolutely no chance of getting the spokes in the right place if you attempt to put some of them through the rim before they are all fitted in the hub, so be warned.

For this Ariel/BSA wheel Devon supply the rims in two packets - one for the inner and one for the outer spokes, that is the spokes whose heads are on the outside of the spoke flange but whose length is on the inside, and the converse for the outer spoke.

When polishing the hub I had used a brass brush in the Dremel to clean out the spoke holes. It was easy therefore to slip the spokes into place starting with the outer spokes. Because these hang down, it's a bit easier to do these first followed by the inner spokes.


You can see the butted spoke in this close-up:


Once you've got them all in you'll have this forest of stainless steel wire:


The next job is to offer up the rim. You have to decide which way the spokes are going to point-there is often a fret mark on the outer spoke flange which will show you how the originals fitted. I start with the outer spokes on the upper flange and follow the pattern shown in the spoke flange by the original spokes and fit three or four of the new spokes into their holes with their nipples screwed on by literally a couple of threads. These three or four spokes should all point in the same direction; then I will fit another one in the opposite direction still in the same flange which will serve to stabilize the rim. You can then carry on fitting the same spokes in the same flange until you have all the outer spokes fitted in the top flange. By this point you will have learned that for each outer spoke pointing in the same direction there are three holes in the rim until the next spoke of the same orientation.


When you've done that you can fit all the inner spokes from the top flange as well. This will enable you to ensure that all of the spokes cross in the proper orientation. Don't mix up the crossing, or you will end up with bent spokes.


You can then repeat the performance for the lower spoke flange but this time start with the inner spokes followed by the outer spokes, again to preserve the proper crossing.


Once you've got all the spokes in, you can do up the nipples gradually and evenly until the end of the spoke appears in the slot on the outside of the nipple, like this:


Now it's time to put your wheel in your truing jig or perhaps back in the bike. There's no substitute for using the bike frame as a jig to allow you to adjust the spokes so that the centre line of the wheel is aligned with the centre of the frame. This works beautifully on the Ariel swinging arm frame, but is much more difficult on the Square Four frame - because the Square Four frame is asymmetrical at the rear to accommodate the offset engine.


I made this spoke screwdriver years ago and it's very useful for tightening spokes when you can get to the nipple from the space usually occupied by a tyre. It makes it much quicker to tighten the spokes than using a spoke key.


I'm not going to explain the whole alignment process here because there are reams of material about it in this blog post, written when I was building the wheels for the Square Four. I must say though that these Devon rims and spokes pulled together to give a wheel that was virtually true and aligned out of the box.

Very nice indeed.


Now we just have to do it all again at the front!

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