Wheels - a Follow-up

At the Teach-In on wheel rebuild, I was even able to demonstrate how such a simple task of putting new spokes in a wheel can easily go so wrong. The only blessing is that members did not go away thinking it was all so easy that caution could be throw to the wind and you just put in the spokes, tighten the nipples and put the wheel on the car!

When things do go wrong the error normally manifests itself before the wheel is completed, The only exception is setting the spoke pattern so that you no longer have access to the wheel nuts. It is easy to do if you don't start off right and keep checking as you go along.

One or two points that came out of the session may be of interest to all members.

There are several types of hubs and more than one type of rim, you cannot mix the components of the 'open centre wheel', the type with the detachable trim disc fitted in the centre, or the 'closed centre wheel, the type which normally has the Austin script across the fixed closed centre of the hub.

There are 6" and 7" hubs, and military hubs, and there are 16", 17", 18" and 19" rims as well as many strange rims fixed to Austin Seven hubs for the racing boys.

wheels 1A wheels 2A

The two main types of wheels, the open centre and the closed centre have different spoke patterns, the open centre wheels have spokes bunched in groups of 3, one from the front and 2 from the back, around the rim in 12 bunches, the closed centre rims have spokes evenly spaced around the rim alternating from the front and back of the hub.

wheels 2

The rear spokes on the open centre wheels leave the hub from the face parallel with the road surface whereas the closed centre back spokes leave the hub through the raise lip which is at right angles to the road surface. There were also two different thickness of spoke used in these wheels and the holes in the hubs and rims were originally designed for the relevant size of spoke. By fitting the larger spokes any wear in the spoke holes in the hub can be removed when the holes are enlarged to fit the larger spokes.

Each rim laid on a work bench has an upside and downside. If you get these wrong the wheel will not spoke correctly.

The open centre wheel with 3 spokes grouped together is the easiest as the centre spoke goes to the front (outside) of the wheel, the closed centre wheels need close scrutiny. When you look at the spoke nipple holes they appear out of a 'blister' which projects towards the hub. The rear (shorter) spokes come out from the side of the blister whereas the long front spokes come out more centrally.

wheels 3

This article, written by Malcolm Watts, originally appeared in CA7C Seven Focus in Mar 2003 pp14-16.