Can anyone help tell me why diferent oil makers recomend such a huge range of recomendations for tourer gearboxes. They range from 20w-50w to 80w-90w . I am aware of the hundreds of oil topics but looking for a simple hot climate option.

Any one?

Sorry mate. I just know the first lower number is viscosity when cold and the second is when at operating temp.

Higher number would be better in hotter climates but no idea why the makers make it hard for average joe.

Pauly, one is an SAE engine crankcase rating and one is Gear oil rating.
An 80w90 Gear oil is similar in viscosity to a 20w50.
Do a google image search for viscosity index chart.
But you can't compare a gear oil to a crankcase oil, as the gear oil has a better EP additive package.
In other words, use gear oil in a gear box.

Very informative speedzer thanks, I don't suppose anyone out there knows why Harley Davidson refuse to put a API Rating on their Oils?

Harleys are Air cooled and hence they get bloody hot.
In summer higher speced oils are better and in Winter (If it gets cold) lower spec are better as they run better.
I'm not a mechanic but from what I gather, with Harleys thicker is better then thinner.

The oil manufacturer for the HD Motor Corp' can change every 3 years I have heard

Goes out to tender , the best price wins I presume ??

Right now it's Citgo . In the past it's been Mobil/Exxon , even Quaker state at one time !

In every owners handbook : " If you can't source GENUINE HD oil then use an oil meeting Diesel specs " ! Yeah , right on brother !!!

Since 1995 I have used Mobil 1 , 15W50 or V-Twin 20W50

Also Redline 20W50 or 20W60

Also Amsoil 20W50

All the above fully synthetic

Gear oil I have used Redline Heavy Shockproof or Amsoil Severe Gear , again both fully synthetic

I was always of the opinion that "Genuine " HD oil was way too exxy for the product in the bottle

Just my opinion of course...

As you see, I'm not a mechanic and can't read very well as well.
Anyway, I've got Jap and Yanky bikes and use 80/90 in both.
In the Shaft drive Jap bike, the 80/90 just lasts and lasts.
Always clean with good Viscosity.

Well finally one problem solved, i have ordered a litre of Redline Heavy shockproof for the gearbox. Now for the engine oil......

+1 on the strawberry thickshake in mine PB. (you will see what i mean).
P.S. heat it up first so it can pour out easier as the spout is ridiculously small, and use the whole bottle in- easy!

Redline in and all the things said about it are true. Much better shift feel straight away.

Yep it's good stuff. I've had it in for about 5000 kays and are real happy with it.

 

80W Motorcycle Gear Oil with ShockProof®
Popular for Sportster V-Twin transmissions, 65cc, 85cc, 125cc, and 250cc two stroke motocross transmissions, as well as shifter kart gearboxes, and CRF transmission cases

 

just sayin is all

Cheers fellas
I was having a look at other products on the web site my search led me to, I seen this product and thought how appt, the sportster was in the same oil as the mini bikes

So I emailed Rocket for a quote on the Redline Shockproof and got a rude surprise. $30 a quart(x2) and $30 postage to townsville. WTF, $90 for two quarts delivered. 

I dont think I'm as shockproof  as the oil.

Is there anywhere in Tsville that sells at a 'Normal' price.

Ebay AU also has it for sale....oil + Postage is about $30 which is what you pay in the shops.