FH - tyres & brakes

 We're nearing the end now. I've got the tyres, tubes and rim tapes, the wheels are both built and the brake plates are stripped out. 

The plan was to fit the tyres myself so that I didn't have to have the bike off its wheels for too long, because I wanted to be able to develop the setting up of the brakes.

I started with the back wheel, trimming the spokes with a large half round file, fitting the rim tape and then the first bead of the tyre, making sure that the direction of rotation was correct. All went reasonably well. Next step is to put the tube in, so in the time-honoured fashion I put a bit of air into the tube and pushed it into the tyre. Getting the valve in through the rim and the rim tape was a bit of a hassle, but it's never an easy job. The next bit is to get the second bead on .

Fortunately I've had some large levers lying around for quite a long time for fitting tyres and these came in handy. Handy that is until the following day when I went to blow the tyre up and of course I had nipped a tube.

B*****. Just save any further messing about, I decided to do what I usually do and take the wheels to SPS Services in Horsford to fit the tyres for me, but first I needed to order a new tube .

While I waited for the tube I engaged myself in some more domestic duties, putting up some coat hooks and repairing the chainsaw which we had attempted to use to trim some damson trees at the allotment. I found poor crankshaft oil seals in the chainsaw and remarkably a run out of just under a millimetre in the crankshaft - and consider how small a chainsaw crankshaft is!

I sent the brake shoes to Villiers Services as usual for re-lining. I had asked for them to be riveted as well as glued, but Steve at Villiers Services explained that they had bad experience with Ariel brake shoes cracking around the rivet holes and didn't want to do it. I accepted the shoes with no rivets.

A few days later the new tube turned up and we made a rapid trip to Horsford to drop off the tyres and wheels and to buy an apple tree, scones and a cup of coffee or two on the way home. 

I was back there the next morning picking up the wheels with the tyres fitted and properly centralised. I have found it very difficult in the past to get the tyres concentric to the wheels, but these are perfect and fitted in the right direction.

They were back on the bike with the brake plates rebuilt and fitted by the evening.

SQ4 - New tyres

One of the things I have always admired about these old machines is the ease with which you can remove the wheels. OK, so I do have a QD rear wheel on the SQ4 and the W/NG is a little more difficult but at least I have two stands and can remove both wheels at the same time! Try doing that on a modern bike.

Something that is less impressive is the front brake cable adjuster, which doesn't fit any of the toolkit spanners - it appears to be 2 BA across the flats, but it is a pattern part so perhaps that is the reason. I have a 2 BA spanner in the toolkit especially for it.

The front stand is very useful, though you have to lift most of the engine weight to use it. The trick is to make sure it is slack enough to swing down, and then tighten it up again.

The reason for all this was that the Avon Speedmaster & SM MkII tyres are now 9 years old and it's time to replace them. I've bought a set of Avon Roadrider MkIIs, just like I put on the CX500 back in 2019.

I might tackle that damaged paint on the brake drum before they go back on. But then again, I could just as easily do that when it was on the bike and get riding it again!

For the record, I am running these at 28 psi and 36 psi, at least for the moment.

Sprucing up the CX

You might remember a few weeks ago I mentioned that the CX500 has very old tyres, amongst other faults. It's now wearing a set of Avon Roadriders, a tyre I have been keen to try out; these are the same size as I would fit to the Square Four, so this is a kind of test for that too since Amelia's tyres are 6-7 years old now.

I'm taking the opportunity to spruce it up a bit, while riding around in the last of the warm weather on the SQ4.

I'm painting the ComStar wheels:

I will also blacken the little 'Honda' logos that cover up the spoke to rim joints:

This one was done with silicone:

I've changed the fork seals:

I've replaced the torn gaiters with the original short covers:

I'll polish up the fork legs a bit:

I've acquired an original toolkit:

I've also acquired these little closing panels that fit in the back of the nose cowling:

I've repainted the handlebar clamp:

Now it looks like this:

This piece of tin covers the gap between the bevel drive and the wheel. It's got some black paint remaining on it:

The wire wheel makes short work of that, with some etch primer and Rustoleum Satin Black:

That was a mistake, they appear to have been silver. Here goes:

When I have finished this little lot, I will think about the cowl and the tank; then I will strip off the radiator and sort out the tacho drive.

Wheels again...

Work on the engine has stalled for a moment whilst we wait for FW Thornton to see if they can help out with a ring problem. The bench is now clear, so we can start on one of those other 'waiting in the wings' jobs that we use to fill in when the main workface stops for some reason. Bike building is like that - there is always something else you can do to fill in when waiting for parts.

And so to building the wheels. The 'jig' I use is just a piece of 19 mm ply that used to be part of a desk. The cutaway sections make it really easy to get to the nipples. It has a hole on the middle for the wheel spindle, which is a piece of 1/2" round bar. Using the spindle as a centre, I mark the outer diameter of the rim on the board. Using the offset measurements I made from the wheel earlier (before I stripped it) I make up four wooden blocks to lift the rim off the board to the correct offset. The brake drum, which I use as the datum, is placed face down on the board.

And that is it. There is a much more sophisticated version of this idea in Frank Farrington's excellent book 'The Vintage Motorcyclists Workshop' which includes blocks to control the concentricity of rim & hub - I don't go this far, since when rebuilding a wheel from an intact but rusty version I can buy spokes to exactly the right length and I find that I get very good concentricity by virtue of that spoke length.

So here we go. Set the hub up on the jig:

Add the blocks to establish the rim at the correct offset:

Start adding spokes according to your lacing pattern. You did photograph these wheels before you cut them apart didn't you? It helps if you lift the hub above the jig at this stage, so that you can insert the spokes from both sides. As you add the spokes, try to lay them out according to the lacing pattern. Start with half of the spokes on the lower flange, placing them in alternate holes, pointing in the anticlockwise direction (in the Ariel's case, these spokes have the nipples on the outside of the hub). Then, add the other spokes on the lower flange, pointing them clockwise and crossing the anticlockwise spokes according to the lacing pattern (in Amelia's case, these spokes are threaded from the inside out, have the heads on the inside of the hub, and cross under the anticlockwise spokes).

Then you move on to the spokes in the upper flange, again starting with the anticlockwise spokes. When you have finished, you will have this nice little nest of wire:

Next, lower the hub back on to the jig and lay the rim over the top. Look carefully at your reference photographs, paying close attention to the location of the holes in the dimples in the rim, and make sure you get the rim the right way up. You can easily assemble the whole wheel with the rim upside down, and not notice until you are snugging down the last of the nipples. I know - I have done it!

Now, again we must be careful and work to a pattern, but a slightly different pattern this time. We don't want to scratch that shiny new paint! Starting again with the spokes in the lower flange, and your handy lacing pattern, locate the dimple nearest the valve hole that corresponds with an anticlockwise spoke on the lower flange. Insert one of those spokes in that hole and screw a nipple on a couple of turns. Then, moving clockwise round the rim, insert all the anticlockwise spokes in the lower flange. Then, start on the anticlockwise spokes on the upper flange and continue until you have a nipple on all the upper & lower anticlockwise spokes.

The reason for doing it this way is twofold:

1. Working on spokes that point in the same direction means that the wheel is very flexible, and you can rotate the rim to get the spokes in the holes without endangering the paint.
2. Working on the upper and lower spokes in the same direction means that you cannot 'trap' the unfitted clockwise spokes whilst you fit the anticlockwise spokes. Because the clockwise spoke crossings are inside the anticlockwise spokes, they can't get stuck behind spokes that are already fitted.

Keep the nipples really loose to maintain flexibility - you are only trying to establish the lacing pattern and get the spokes in the right holes at the moment.

Next, fit the spokes pointing clockwise. Start at the from the valve hole, and fit the first spoke from the lower flange, followed by the first spoke from the upper flange. Moving clockwise around the rim, fit the spokes in turn - lower, upper, lower, upper - until you have all the nipples fitted.

Now, take the wheel off the jig and have a good look at it. Give it a shake. Make sure all those spokes are entering those holes easily - there should be no tension anywhere at this point. If you are happy, put the wheel on the jig and wind the nipples in until there are 3 threads showing, and repeat the look/shake process. You will probably need to use a screwdriver now, as the wheel will stiffen up.

Now, with the wheel back on the jig, wind the nipples in until there is no thread showing. As you do, make sure the spoke heads are seating properly in their countersinks. Look & shake again. Next step, run all the nipples down until the end of the spoke is level with the bottom of the screwdriver slot in the nipple; then go around again until the end of each spoke is level with the very end of the nipple - you will need a spanner or a spoke key this time. Off the jig again, you should find you have a very stiff wheel. If one or two of the spokes are still loose, snug them down now, as evenly as possible.

This gentle step by step approach to spoke fitting ensures that the wheel comes off the jig needing very little trueing up.

So next, trueing up.

Hopefully, having built the wheels on the jig, we will have very little truing to do. However, there is usually some runout, but the offset is probably good. By the way, the offset I measure from Amelia's original wheels was:

• Rear 9/16" on the brake side
• Front 1 1/4" on the brake side

Now, what is runout? There are two types of runout - lateral runout and radial runout, as illustrated by this handy picture I made:

Radial run out is, pretty obviously, an eccentricity of the rim relative to the hub. Lateral runout is when the axis of the rim is not parallel to the axis of the hub. Easier to explain with the pictures!

So, how to fix it? Well, you can do miracles with a spoke key, but first you have to figure out what is wrong. To establish this, you need to set the wheels up in a jig, like this:

This is made from two pieces of timber, glued and screwed to a cross member, held in the vice. There is a V-notch in each piece for the wheel spindle to rest in. At the bottom, adjacent to the rim, are two pins:

One is set up so it almost touches the side of the rim; the other so it almost touches the outermost edge of the rim. Spin the wheel in the jig, and you will be probably be able to see both lateral and radial runout. Move the wheel slowly, and you will be able to quantify the run out in both directions - it is essential to mark the rim where the runout is worst.

You'll want to get the runout down to 1 mm, or 1/32", in both radial & lateral directions. You've probably got about 3 mm or 1/8" now, right?

So the key to tackling runout is the proper adjustment of the spokes. Here's another of Simes' handy diagrams:

Ain't that pretty! A few words about it:

• The dotted lines show the spokes on the non-brake side
• The solid lines show spokes on the brake side
• The 'upper half' and 'lower half' relate to positions on the wheel relative to a mark you will make on the rim during the truing process
• The green spokes go ant-clockwise
• The red spokes go clockwise

Tackle the radial runout first. Roll the wheel in the jig again, and  relative to your pointer, mark the rim where it has most runout, i.e. where it is lowest against the pointer, where the distance from the outside of the rim to the centre of the axle is greatest.

Roll the rim until that marked point is at the bottom, and now you will have  spokes in the lower half and spokes in the upper half. Because we have the worst runout at the bottom, the spokes in the lower half need to be shorter, and the spokes in the upper half need to be longer, to reduce the runout and make the rim concentric with the hub.

So, you must appreciate that the spokes which are more or less horizontal, and radiate from the extreme left and right of the hub don't have any effect on the runout. Conversely, those running vertically are controlling the runout and it is these that will be adjusted most. Those that run diagonally from the hub have more or less effect depending upon how vertical or horizontal they are.

So, using this diagram:

We can see that the spokes within the red arrows have more effect on the runout than those that are outside the arrows. To correct the runout, hold the wheel in the same position (with your mark at the bottom) and loosen the spokes within the red arrow at the top by, say, 1/4 turn. Loosen ALL the spokes within the arrow - the red, green, dotted and solid ones. Then tighten the ones at the bottom, within the arrow, by the same amounts.

When you have finished, measure the runout again. It should have reduced a little. Now  repeat the process until you are satisfied that you have minimised the runout.

Correcting lateral runout is a little more complicated. Remember:

So again, locate the point where the runout is worst, and mark it. In this case, 'worst' means the point where the BOTTOM of the rim is furthest to the RIGHT, like the diagram above.

To tackle this lateral runout, adjust the spokes in this sequence:

1. Loosen the SOLID spokes in the lower half of the wheel by 1/4 turn
2. Loosen the DOTTED spokes in the upper half of the wheel by 1/4 turn
3. Tighten the DOTTED spokes in the lower half of the wheel by 1/4 turn
4. Tighten the SOLID spokes in the upper half of the wheel by 1/4 turn

Here is the diagram again to remind you:

When you have finished, measure the runout again. It should have reduced a little. Now  repeat the process until you are satisfied that you have minimised the runout.

And that, ladies and gentlemen, is that. All that remains is to file off the protruding spoke heads:

File them flush with the nipple, so there is no danger of them popping a neat hole in your inner tube. Fit a nice new rim tape, put the tyre on and go and have a beer in the garden.

Wheels

Sample spokes

Amid engine machining and gearbox rebuilds, I decided it would be good to actually ride Amelia at some stage. Standing in the way of this was a set of very rusty spokes on both wheels. I'd hoped to get away with commissioning the bike on it's own wheels, without any form of rebuild (continuing my 'Phase 1' rebuild with no chroming or painting) but it was not to be. Both wheels had at least one broken spoke, and the remaining spokes were very thin in places.

So, a rebuild it had to be.

Amelia has half-width cast iron hubs, front and rear. The front is the 'Qualcast' half width hub fitted to all telescopic-fork Ariels prior to the appearance of the full-width alloy hub in 1956, and the rear is the 5-stud QD hub. Tyres are 3.25-19 front on a WM2 rim & 4.00-18 rear on a WM3 rim.

Max has found some tyres

So, gathering parts. I used Central Wheel Services for spokes & tyres, since they give outstanding service and their prices for tyres were very good. I bought traditional Avon Speedmaster & SM MkII tyres, still made today in a modern soft compound.

Close inspection of the spokes revealed plain spokes on both sides of the wheel at the front, with butted spokes on the drive side at the rear, plain on the other side. This matches the description in the parts book perfectly. However, it didn't match the records at Central Wheel, so I had to provide sample spokes for them to manufacture against. I chose stainless spokes and plated brass nipples this time, since I was not at all happy with the nickel plated steel nipples I bought for the Bantam which, 2 years on, are rusty.

The first thing you must do when rebuilding a wheel is to remove the old tyre. Don't think about using an old tyre for a second - even if it has tread and sound sidewalls, the rubber will be hard as nails and will have you sliding down the road. 

Interesting paint under the original rim tape

Removing tough old tyres can be a challenge, and I often dispense with the traditional levers in favour of a set of bolt cutters, which I use to cut the wires in the bead. On an older tyre, I'll cut the rubber with a Stanley knife to ease the passage of the bolt cutter. Don't bother trying this technique with a modern tyre though, there's wire everywhere!

Rear rim offset

Next, find yourself a nice stiff flat board. A piece of 3/4" ply would be good. We need to measure and record the offset of the rim to some datum on the original wheel - the brake drum is very convenient. Place the brake drum face down on the board, and measure the distance from the edge of the rim to the board

Amelia's front wheel offset is 1 1/4" to the rim on the brake side;

On the rear, it is 9/16" to the rim on the brake side. On the rear, the offset is measured with the brake drum removed.

The next step is to photograph the spoke patterns. Make sure you have pictures of which spokes overlay others, which holes the go into on the rim and please also look at the dimpling on the rim holes and makes sure you know which way round the rim goes. 

Those of you who have read my Bantam pages will know I have rebuilt at least one wheel with the rim the wrong way round - the result is not pretty as all the spokes will be bent.

My reference photos are shown further down the page.

The next step is a real turning point in the rebuild: take your best bolt cutter, and cut the all the spokes. Do it within an inch or two of the hub. If you cut near the rim, it will be much more laborious to feed all the rusty spokes through the dirt encrusted holes on the hub.

Bolt cutters - did I really do that?

The next step is to get the rims off to the platers. This takes a while, so don't hang about! While they are gone you can clean up the hubs, get them painted, recondition the brake plates and replace the bearings.

Incidentally, I spoke to Tony at JD Wyatt Contract Polishing, who told me that it would reduce the cost of the polishing if I were to leave the painted rim centres in the blasted condition. Since this would provide a key for the paint, this is what I decided to do.

Spoke Patterns

Spoke patterns for the rear wheel:

Spoke patterns for the front wheel: