Grey Flash 2751

The history and restoration of a Vincent HRD Grey Flash

The rear hub features a hollow axle which passes through the hub and is secured by a nut at each end. These nuts sandwich the hub/bearings and brake plates together allowing the entire rear wheel assembly to be installed into the rear fork as one unit. This is also the method employed for the front wheel. We have already noted that the two H55 grease retainers were omitted – Peter Johnson has commented that this was to reduce friction. He mentioned that the bearings were lightly oiled before each race to compensate for this omission – a crafty race tip! Clearance is taken up by adding shims between the bearing and the shoulder on the hollow axle on each side. This was noted to be spot-on. Brake plates are then added to this “sandwich” and, with the thin retaining nuts tightened, shims further added so that the hollow axle doesn’t protrude beyond these nuts. It was noted that there was an absence of these shims which had allowed the hollow axle to stand a little proud at either end. This had caused the fork to come into contact with the protruding axle and slight damage to the threads had been sustained. This can easily be rectified and the original hollow axle retained.

The hollow axle standing slightly proud from the retaining nut. Damage to the threads at each end of the axle meant that this nut was difficult to remove.
The notorious eared nut…

This nut secures the special bolt (T-bar on road models) that passes through the hollow axle fixing the wheel/hub assembly in the fork. The tab fits into the drive chain adjusting slot and requires no spanner as it is held in place and won’t rotate. Many a Vincent rear fork has been damaged by an uninitiated owner apply a spanner to this nut… Surprisingly, instead of the tab shearing off the casting tends to split and brazed repairs to the casting are a common sight. 2751 is, unfortunately, no exception to this.

The missing H55 grease retainers and H25/4 bolt.

Instead of the T-bar, featured on road-going models, the racers employed a special waisted bolt which will have to be manufactured as it’s not present.

One thought on “Rear Hollow Axle

  1. Somer Hooker says:

    The torque reaction also will make them crack. Always seen on one side on twins ( chain side). On my flash, it was cracked on opposite side; the chain side!

    Liked by 1 person

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