10. Wheels and Brakes
As I know most Vincent enthusiasts are aware, post war racing Vincents
(both Black Lightning's and Grey Flash's) were fitted with uprated brake
systems over the standard road going Vincents.
The most obvious differences were the use of ribbed drums (also fitted
to the Black Shadow) and cast alloy brake plates instead of the standard
pressed steel affairs. The front cast brake plates also included separate
cooling scoops that were held on with cheese head screws. There were also
other more minor differences, but these were the most visible changes
from standard.
The earliest press photographs of a Black Lightning shows it fitted with
the pre-war racing brake plates (no scoops), but I am not sure if one
was ever sold to this spec, I suspect this an early incantation of Gunga
Din.
Catalogue photo of early Black Lightning, with Pre-War racing brakes fitted. I do not believe any were actually sold with this arrangement
Gunga-Din fitted with the standard Post-War racing brakes. Note air scoops
As the title suggests, wheels was one of the areas most lacking when I first acquired my Vincent. In amongst the bits and bobs there was a good condition bare front hub but not very much else!
There was also one standard rear brake drum, to which had been shrunk on an alloy-finned muff. Although this had been well executed it was not original so I decided not to use it. There were also a pair of reproduction Lightning plates, of which one had been obviously bent around the cam spindle bearing (the seller had made it clear to me that this was for a pattern only, in fact I think I remember his racing crash that had caused this). As I say, these plates were reproduction and of the variety where the scoops had been cast integral to the plate, which personally I have no love for (I was told once that they might actually be stiffer than the originals because of this, not sure if that is true).
Reproduction brake plate (similar to those that came with my bike). Note 'cast in' air scoops
Not sure if sprocket carrier (casting) that came with bike is original Black Lightbning or later Egli component?
As I find twin brakes on the rear of dubious advantage anyway (I don't even use the back brake on my Fireblade) I liked this idea, it also had the added advantage of reducing unsprung weight that the second drum/shoes etc would add.
Since first purchasing the bike I have seen a photograph of an Egli that has an almost identical sprocket carrier, so am not sure if it might be an Egli component or if Fritz Egli had got hold of an original Lightning part. Not really too worried actually.
This 1969 Egli photo just shows similar item
. . . and this photo shows complete bike with similar carrier
Luckily, at the time I bought the bike (1988'ish), almost all wheel parts were readily available, which meant all I had to worry about was the money! I decided I would go the full hog, and buy everything I needed new, and blow the expense. It was here that I first took a step I was to repeat many times over the next few years, I sold one of my other bikes to finance the build!
I bought a complete set of alloy brake plates, 2 fronts and one rear, from Ted Davis. These included the separate scoops and were of beautiful quality. I am not sure if they are still made, but they do look the business. I believe that some original Lightning plates were made of Magnesium, although I don't know if they were all made such? If they were I would be a bit concerned about their strength for racing by now.
Lightened cam lobe (H10/1)
Nice collection of new parts awaiting assembly. Note Timken bearings in lower left corner of photograph
Building the Wheels
I started the assembly by pressing the bearings into the hubs, These are
the traditional Timken bearings and the inners are fitted over a distance
spacer (H15) and shimmed to give 5 thou clearance. I found this easiest
by mounting the hub in the lathe and setting the clearance using a dial
clock. I then mounted the brake drums, using the special H19 bolts and
Nyloc nuts to secure them. Black Shadow's and Lightning's had 10 bolts
holding each of the back drums/spoke flanges to the hub, instead of the
normal 5. Although I was considering making this mod to my rear hub, for
originality purposes, in the end I decided that the extra weight of the
additional 10 bolts and nuts was too excessive, so have left them with
only 5.
Once the hubs were in situ with the hub, I mounted the whole unit in the lathe and gave the brake drum surface a very fine skim. This ensures the drum are absolutely true to the hub and is something that used to be done by many racing people to ensure the brakes were as perfect as possible.
All drums were lightly skimmed after assembly for trueness. Note special securing bolt heads
. . . as were the brake shoes, to ensure they touched drum across complete surface. Shoes are bonded not riveted
Once the shoes were mounted on the brakeplates, I added additional shims so that the shoes were opened sufficiently that they would not fit into the brake drums with the cam in the 'off' position. This might sound a little strange; however, I then mounted the brake plates on the lathe and carefully turned the shoes down, so that they were a perfect fit into the drum. Having then removed the additional shims, it ensures that when applied, the shoes have perfect contact all round the drum.
My Norton uses a similarly prepared front brake and I can vouch that taking these steps makes the difference between mediocre and 'on yer nose' braking. Hope it works in this case!
The nice thing about Vincent wheels is that all this can be done before lacing the hubs to the rims, meaning it can be performed on a reasonable sized lathe.
I believe Lightning's were not as a rule fitted with Tommy Bar spindles, however, I like these so much I decided to fit them anyway (yes I know, they are heavier!). I think my rationale with these was that if I do decide to race the bike seriously, then it is a simple job to replace these with plain lightened spindles. Tony Maughan supplied these in Stainless Steel and (as always) the finish is gorgeous.
Completed front wheel showing speedometer blanking plate
A friends Black Lightning back wheel.
This one is fitted with an original 3.25 x 20 rim and Dunlop Racing
tyre. You can also see the 10 bolts per flange in this photo
At the time I was building the wheels (approx 10 years ago) I had every intention of racing the bike seriously, therefore I was more concerned about the race rubber available than originality. For this reason I had decided to opt for 18" rims.
Original Black Lightning's were fitted with 21" rims front and 20" rear, both in alloy. I believe they were stamped 'Rekord'. Even if I could have found alloy rims in this size, there is to my knowledge no race rubber available in this size (I am still looking for rims in this size now though, in case anyone out there has a set!).
I did toy with 19" rims briefly, but at the time the only 19" race tyres available were Avon GP's. These are excellent tyres (I had them fitted to my Norton), but going 18" allowed a better selection and slightly wider rear profiles. I opted for WM2 front and WM3 rear. Dunlop rims are no longer available new so I went for Akront beaded rims, which are never the less very pretty.
Lightened Brake Torque Arm (H44/1) above, and
other rear brake linkage parts, including Torque Arm Clip (FT166), below.
Note that what looks like a brake arm is actually for the brake crossover
shaft (F67), identified by square hole, rather than serrated face.
My completed back wheel, showing 18 inch rim
fitted with competition Avon AM22 tyre fitted.
This photo clearly shows single brake drum and sprocket carrier
Final Build
As with all my wheels, I had the rims laced to the hubs by Bob Warner
in Leicester (behind the railway station). Bob builds the wheels himself
in the back room of his Edwardian style shop and is extremely good. It
is always a pleasure dealing with him, as it is one of few suppliers where
you can leave a job and not have to worry about it getting lost/bodged/broken.
Finally I had Avon AM22/23 tyres fitted in matching racing compound. Effectively,
this means that the front tyre is of a softer compound than the rear,
helping to ensure that the rear should lose grip before the (more dangerous)
front. They certainly feel like liquorice! The back tyre was of a very
large profile, but should just fit in the Type 'B' RFM (Rear Frame Member).
Last job after fitting the tyres was to have the wheels balanced, which
about completed the job. I still have to fit a sprocket to the sprocket
carrier but will leave that job until I start assembly.
As far as other ancillaries are concerned, I had each of the brake arms
chromed, having first drilled them for lightness. These have serrated
faces, that mesh with serrated washers that lock with the brake cam. This
system of serrated washers to be easily adjusted to any angle, very clever.
Again, these washers were bought new. As can be seen from one of the accompyning
photographs, I also lightened the rear brake torque arm (FT44/1), as per
genuine Black Ligntnings and had it chromed. I always thought the spring
loaded quick release catch used to retain the brake plate was a very clever
design touch, allowing the wheel to be removed in moments. It will be
even quicker on my bike as I am only using a single rear brake!
Since I originally built the wheels I have had second thoughts about how
seriously to race the bike. I would still like to do a bit of sprinting
but don't have serious plans to short circuit race it anymore. With this
in mind, I might decide to fit larger but more original rims at a later
stage, which will undoubtedly make the bike look more correct for demonstration
runs. I will probably leave this until I have at least got some use out
of the current rubber. As always, if anyone has a set of original rims
(or 20 inch rear tyre) out there I might be interested!
The finished wheels, ready to fit