Fixing A Wheel

[Ji Gantor]

This is a front wheel from my CZ400 1973.
The hub has to be cleaned and painted,
the spokes have to be replaced and
the rim needs to be cleaned and painted.

The first step is to measure the offset between the rim and the hub.
You will need a straight edge, a small ruler, some pegs and a clamp with blocks.

Place the wheel on a flat surface and set up an offset measuring device. It can take many forms this is the system I use.
Remember to measure the offset on both sides and at 6 locations around the wheel.

Ji

[Ji Gantor]

As can be seen the offset on the off side or non drum brake side is 28.5mm.


Ji

[Ji Gantor]

Next remove the spokes.
Try to remove the spokes if you can rather than using your bolt cutters. The old spokes and nipples may come in handy later.

Ji

[Ji Gantor]

With the spokes ordered and on their way it is time to start the maids work, cleaning.
Use what ever is required, degreaser, paint stripper, wire brush...... and clean the hub.

It is always a good idea when replacing spokes to clean out the spoke holes.
I use a rifle barrel wire brush to clean out the holes.

Ji

[Ji Gantor]

When I visited John Titman's new building last year, I witnessed all the wheel building machinery and processes. I was amazed at what he does for the money. He also has a great team of young men toiling away making motorcycles run true.

One of the processes is reaming out the spoke holes. This allows easy installation of the spoke and free movement when truing.

Ji

[Ji Gantor]

When the spokes turn up they should be marked front, offside, inner or something like that.
Typically there are four different types of spokes per wheel. On my CZ there are only two types because the hub has offset holes. These spokes are stainless steel, 9 gauge or 3.6mm diameter (British Standard Wire Gauge).


Ji

[Ji Gantor]

The original nipples on my CZ are brass (they may have been chromed but there is not one speck of chrome on them now) and I think they may look good with the gold hub.
So I have taken my time removing them so they can be reused. The spokes I purchased already came with new chrome nipples but lets see how the polished and clear coated brass ones look at the end.

Ji

[Ji Gantor]

When truing a wheel or even when just tightening up a few spokes while at the track always use a designated quality spoke spanner. The nipples are only brass or alloy and with a few years of dirt they are easily stripped. This is just a suggestion after having to remove so many nipples with a pair of vice grips because someone used a pair of multi grips on them in the past.


Ji

[Ji Gantor]

Oh yes,
I should give first timers the heads up on replacement rims, this is another thing that drives John Titman around the bend.

The width of my standard chromed steel CZ rim is 59.2mm with an offset on the off side of 28.5mm. A replacement Akront mud catcher rim width is 63.9mm with an offset on the off side of 30.8mm.

Remember when you change the rim type you normally change the offset and sometimes the spoke length.

Ji 

[Ji Gantor]

Sorry,
I know the spokes are kinda boring but hang in there just a little longer.
Some will know this while others may not.
There are at least 4 spoke lacing patterns that I know of.
They are called 1x, 2x, 3x, and 4x.
1x is the weakest while 4x is the strongest.

This 1x stuff basically means how many other spokes a spoke crosses.
The image if you can make it out is a 3x or every spoke will cross 3 other spokes on its same side of the hub. If you go back and take a good look at the image in my first posting you will see that my CZ wheel is laced as a 2x pattern.

With 4x the spokes have to be made longer so these are the dearest spokes to buy. From conversations I have had with wheel experts 4x may prove to strong, and instead of the spokes bending the hub breaks or the rim buckles. The most common patterns for Pre 75 up to Evo VMX bikes is 2x and 3x from what I have seen.

I have never done a course on spokes or spoke lacing so all this info is what I have picked up. If someone knows more or can see a mistake please be kind and point it out so we can all learn.

Ji

[Ji Gantor]

I know what you are thinking
"Nice Nipple"
See a few minutes in the tumbler and old brass nipples look good enough to use again.

Ji

[Ji Gantor]

When ordering your spokes measure the old ones and let your supplier know what length you want. If the spokes you ordered are to long they should be resized prior to installation. That way the starting thread is repaired especially with S/S spokes. Some wheel builders just install the oversize spokes and grind the spoke and nipple to suite. S/S spokes will retain a bur which will chop out the thread in the nipple.

Ji

[vandy010]

I know what you are thinking
"Nice Nipple"
See a few minutes in the tumbler and old brass nipples look good enough to use again.


ok Ji, can you give us a little more info on this "tumbler" thing? what is it? whats inside it? {that cleans the nipple}

[Ji Gantor]

Hi vandy010,
Sure, it is no secret.
The tumbler that I referred to and used is for cleaning spent bullet cases. They are actually called case tumblers. You half fill them with a cleaning media that the gun shops sell, toss in your brass, switch it on and after a few hours you fish out your cleaned cases or in this case nipples.
Most competitive shooters have one of these things and even come up with their own quick clean media. The commercial media is corn cob fragments, but rice works well to. If you don't have much time pour in some Brasso and that speeds up the process. Unfortunately the Brasso makes the media sticky so it is a one off deal. I had a friend who sold me some old power lines that had been mashed up into a rubber, brass....... media and it worked Okay as well.
The media in my tumbler when I took the image is rice and I used some Brasso. As can be seen there is a black ring around the edge of the Tumbler. That is the spent Brasso and tarnish.


Ji

[Ji Gantor]

If you have damaged a spoke thread the spoke is dead.
There is not a die that you can buy to fix or continue the thread on a spoke.
The machine that produces the thread on a spoke actually presses the threads into the spoke.
This is easy to check, first measure the diameter of the spoke and then measure the diameter of the threaded area. The threaded area is larger.
There is a hand operated spoke threader for push bikes and it can be adapted to motorcycle spokes I believe and it looks like the attached image.

Ji