Austin Seven 19" Wheel Re-spoking (for Solid Centre Type Wheels) - by Ian Moorcraft
The following article has been written by Ian Moorcraft. In this article Ian describes a method of re-spoking (or adjusting) Austin Seven 19" wheels that he has used successfully over the years.
With my usual desire not to pay anyone to do something that I could do myself I thought that I would build up my wheels from scratch with all new spokes, I made up a simple jig out of wood to get the initial relationship between the hub and rim and also the correct offset, I will give more details if you want. Back to your problem, If you are trying to reset an original wheel you may find that the nipples are rusted solid and the small square on the nipple will round off straight away, so a re-spoke may be the only way out, but if you are resetting a more recently rebuilt wheel you should have no problems. Start off by trying the wheel on the three positions on the hub and note at which position you have the least runout, you may be surprised how much off a difference this will show up, and also explain why wheels trued up on a jig will not run true on the car, the hub doesn't need to be out by much on a large diameter wheel to show a 1/4" runout on the tyre, mark the position so that you always put the wheel in the same relative position to the hub. Tap all of the spokes with the handle of a screwdriver and note the tone, you may have to hold some spokes apart to get the single tone tighten up any that make a flat tone to sound the same as the others, fit the wheel on the hub in the marked position and make up some means of holding a piece of chalk against the rim as you spin it, over the distance marked tighten the short spokes to pull the rim in or the long spokes to pull the rim out, If you feel that they are to tight you can loosen the opposing spokes in the area that you are working, again tap the spokes that you have adjusted, if they have a higher tone than others around the wheel you can just loosen the apposing spokes in the area you are working on only, only a very small amount is necessary to change the tone considerably. Provided you use the correct spoke key you need not worry about pulling the rim egg shape as you could on a bike wheel it is far to stiff for that to happen. when you have the rim running true go once again around the wheel tapping each spoke, you may have to tighten or loosen an individual spoke or two to make the tone match. After many years of use my wheels are still running true and have only ever had one spoke break which shows that they must all be taking a similar strain using the above method, you will soon get the "feel" it will be obvious to you if you are over or under tightening, have a go regards Ian
Details are as follows:
This jig is very crude but I have built over 20 wheels on it and they have all come out to be within 1/8" sideways and spot on up and down when spun on the car, then trued on the car to be spot on.
The jig is made with two pieces of 3/4" blockboard two feet square glued and screwed together with the grain at right angles to each other, it must be flat when finished, draw two lines from corner to corner to give a centre, mark two diameters of 7 3/8" and 20 1/8" (this is for a solid centre "Austin" 19" wheel), cut a 7 3/8" circle out of 1 1/4" thick piece of wood and screw and glue it on to the board on the small diameter marked, get some 1 1/2"x 1 1/2"x 1/8" steel angle iron and cut off four pieces 2" long, bolt these on to the board in the four positions where the diagonals cross the outer diameter with the foot of the angle pointing towards the centre, they need to be 1/8" further out i.e 20 1/4" from the centre. Now check that a rim will fit nice and tight inside the angles and rests on all four of them, also try a wheel centre on the block and drill three holes for 2" heavy screws, you will also need three large penny washers to cover the slotted holes, that is your jig finished.
If you can undo your spokes, completely strip down your wheels but make sure to keep one intact for a pattern, If everything is rusted solid you will have to cut them apart and get new spokes, look around the rim and you will see that some spokes have been ground off and others may be just below the surface of the nipple these are the ones that you need for a pattern for the new spokes, choose one spoke that goes in each direction that is below the nipple and remove them, the pattern is in multiples of four in two lengths ( some wheels I have done have had three lengths, the short ones at the back being the same but the long front ones being 1/8" different than each other) The Austin spare parts catalogue only lists 90 long and 90 short per car ( for solid centre wheels )Have your new spokes made up to the patterns, try to impress on the man that you want them all to be exactly to dimensions provided, as this will be a great help when you assemble the wheels. To assemble the wheel note that the rim holes are pressed in different directions in multiples of four, rest the rim on the pattern wheel that you kept, and line up the pressing pattern on both rims, fit three crossed pairs of short spokes in a triangular pattern between the rim and wheel centre to match the wheel underneath, if it looks OK put all the other short pairs in, but just catch the thread as you want the assembly to be as loose as possible at this stage, the inside row of long spokes can now be assembled followed by the outside ones, now go all around and do them up a few turns, check very carefully that all looks in order with spoke directions and that they are in the right pressing positions.
Now fit your wheel into the jig, screw down the wheel centre and make sure that the rim is resting on the angles at all four positions, tighten up the spokes so that each thread has just disappeared into the nipple, now mark one spoke with tape for a start point and working around the wheel finger tighten each spoke as tight as you can watching that the rim is not rising off of the angles now check a crossed pair of the short spokes to see if they are the same distance from the end of the nipples, use a small drill to measure the depth, also do this check on a couple of other pairs, If you find that say the left hand of each pair is longer it means that the wheel centre is too far anti-clockwise, so readjust the short pairs to be equal distance from the end of the nipples, now go around again as finger tight as possible, you can now use the spoke key a turn at a time watching as you go that the rim is staying on the four angles, be methodical start from the taped spoke each time, you need to carry on until the spokes give a nice tight "ting" when tapped, also if you squeeze a pair of the long spokes together with your fingers where they cross they should only move around 3/32", the short ones only half this much. If you have done a good job of the positioning of the wheel centre as above you should not have any spoke ends to file off, but check carefully anyway. You can now take the wheel out of the jig and put it on the car (that is as long as you have not put the spokes over the wheel nut holes!!!!). Keep in mind the comments at the start of this article and find the best combination of wheels and hubs. Remember to also try all three mounting positions when testing these combinations.
by Ian Moorcraft
The Austin Seven Motoring Pages