The Knowledge - Velocette Owners Club

designed for use in manual transmissions, transfer cases and final drives in on-highway trucks and
off-highway equipment which require an SAE 8OW-90, non-EP, API GL-1, straight mineral gear
lubricant.
#4039 Now that you've been through all that, back to the Velocette application! The manufacturer's
recommendation for Velocette singles is to use exactly the same oil you use in the engine, whether it
be a straight 40 grade or 20/50 multigrade engine oil, the exception being if you chose to use Mobil oils
when they recommended their Monolube GX90 product which was presumably a 90 grade non-hypoid
gear oil. The distinctive smell of EP oils of most grades is attributable to the sulphur content of the EP
additive which is as you say, present in all grades but GL-1. It is this EP additive which does the
damage - if it is present at all it will still do the damage, it will just take a bit longer if there is less
additive. The only answer is to avoid EP Hypoid oils like the plague!
#4040 Thanks for the feedback, group. I let this one run for a while because the funny thing was I didn't
say what oil I was using in the initial post. Following investigation and a phone call to Shell, I'm satisfied
that even their hi-tech synthetic gear oil is the most likely culprit (GL-5 - ouch!)
#4042 A number of people had recommended that I put Mobile 1 synthetic gear lube in the tranny. I
pulled up the specifications on the web, and it states that it does in fact meet GL5 standards. Would the
potentially detrimental additives being discussed also be likely to be present in synthetic gear lube?
The same specification sheet says nothing specific about any additives, potential problems with certain
metals, etc.
#4043 I too have seen reports that 'modern' GL5 is yellow metal safe. Is the risk worth the reward? As
others here have stated, Velo boxes have lasted this long on motor oil and rain water.
#4044 I, too, put synthetic 80/90w gear oil in my Venom this summer, and my main bearings failed...
Actually, I looked carefully at this oil before using it, as its fairly well known (but not enough, clearly!)
here in the States that 'hypoid' gear oils eat bronze. There was no 'hypoid' on the label, but I'll check for
GL-5.
#4045 I called Mobile 1 Technical Support. They confirmed that their synthetic gear lubricants do, in
fact, contain the higher levels of EP additives that were previously mentioned. They further agreed that
these additives can be harmful to certain yellow metals, and stated that this product would probably not
be a good choice for this reason.
#4046 It may (or may not) be of interest to recall that Ralph Seymour always used R40 in his
gearboxes. It is of course well known that castor oils are far superior to all this synthetic stuff!
#4077 The effect of EP additives on bronzes may vary according to the type of bronze. I assume that
Velo gearbox bushes are phosphor bronze. Many car synchromesh gearboxes used something called
"aluminium bronze" for the synchro rings (or baulk rings, blocker rings if you prefer) with few problems
but not all manufactures specified EP80 for the 'box. Ford always specified EP Gear Oil (from about
1954 anyway) and even blanked off the gearbox drain plug to stop misinformed garages from draining it
and refilling with straight 50 grade.
#4079 It is the Zinc that is attacked and the more Zinc the worse it gets. Gunmetal (LG2) has 5% Zinc
(LG4 and Admiralty NES 830 have 2%). Phosphor bronze has the smallest amount of Zinc. Aluminium
bronze is a hard erosion resisting metal and not "normally" suitable for bearings, it resists Seawater
attack. It is sometimes used for Wormwheels under great load. In short the less Zinc the better but then
we get into the area of Tribology and have to decide whether we want the bearing to wear or the shaft.
L # 4847 Hi I have just purchased a 1960 Mac, the engine and frame are correct to the buff log
book. The bike is in good condition but the gearbox has a prefix of 14 (MSS type) as this is the last year
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