LAST EDITED ON Jun-07-02 AT 04:40 AM (Pacific)
For all their Herald based cars, Triumph used a style of wheel stud that seems a strange choice. Seven sixteenths at the shank, they narrow to only three eights for the threaded part. Although this asymmetric design would seem to concentrate the stress at the neck where the wide and narrow parts join, I have never heard of a fractured stud, and we must recognise their wisdom.
However, many people want to fit alternative wheels. Longer studs may be needed to accommodate wheels that are thicker or have wider rims so that a spacer is required to provide clearance. Wheel nuts should engage with the thread of the stud for at least one and a half times the stud diameter. Long asymmetric studs are not available. Stud extenders have been used in the past, short studs with a female thread in one end, but these are intrinsically weak and not to be recommended. The ideal are the 7/16th x 2 ¼” studs that are readily available.
The problem then is how to fit them. The old studs are easy to remove. With the brake drum, and preferably brake shoes removed, put a wheel nut on, with the top of the stud thread just below the top of the nut, and tap it with a hammer. The stud will slide out backwards, and fall out of the hub. You will see that it has splines that engage with splines in the hub. The difficulty is that new 2 ¼” studs are too long to fit between the hub and the parts behind.
Rear hubs.
Removing the hub of a Triumph rear axle is far from simple. The hub nut is ultra tight, or you are dealing with the weight and complexity of a Rotaflex set-up. If you are willing to do a little fettling, there is a way of inserting the long wheel studs, without removing the hub!
What is needed is a hole in the brake back plate. It needs to be just bigger than the head of the new stud, in this case ¾”. I drilled a guide hole and enlarged it with a burr in a die grinder. A round file would do the job, though with a lot more sweat and time. The inner edge of the hole should be as near to the back plate bolt retainer as possible, so that the new bolts go through at right angles or nearly.
Photo 1 shows a new stud lying through the new hole in the back plate and partially inserted into the hub.
The hole is seen more clearly in the Photo 2, with the stud inserted fully.
With the hub still on the axle, it is not possible to tap the new stud into the hub with a hammer, and it must be drawn in. Photo 3 shows the parts needed to do this, a short piece of tube, in this case square, a stout washer, here a scrap of 2mm sheet and a suitable nut, preferably not Nyloc. Ensure that the ends of the tube are as square to the length as possible, to ensure that the stud is drawn in perpendicular to the hub.
Photo 4 shows the parts assembled on the hub. Tighten the nut to draw the stud firmly into the hub. You will need a large screwdriver or other lever jammed into the yoke of the universal joint to provide a counter force.
The last photo, number 5, shows the assembly with brake drum fitted and a spacer added. The length of the new studs provides ample length for fitting alternative wheels.
The hole in the back plate can be sealed with Duck/tank tape on both sides, or with a rubber grommet, or even left open.
Front hubs.
Here, the hub must be removed and separated from the disc so that the new studs can go in. The work may be time consuming but straight forward. For hubs with drums the hub may easily be removed in the same way.
Some work is needed to the heads of the front hub studs. The space in the hub casting around the stud holes is only just wide enough for the narower heads of the original studs. The new wide head studs can be inserted, but will be slightly tilted. A flat filed on the side of the stud head will provide clearance and the new stud can be drawn, or tapped in perpendicular.
NB. The splines on these studs are not the same as those on the original studs. While inserting the new studs in this way produces a firm fit, the damaged splines will not accept the old ones again! A small tack weld on the back of the hub will lock any loose stud against turning while the nuts are tightened. Once the nut is tight the stud cannot turn.
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