Oil again

[Dave T_LAPSED]

What a can of worms! EP90 is hypoid oil developed for gearboxes and differentials with helical gears that have a sliding contact to some extent. Bike gearboxes have straight cut gears and therefore need only a mineral oil, it does ,however, need to be thicker than 20 grade which is what 20w50 is in a warm non-unit gearbox. If you can hold your hand on the gearbox then the multigrade oil will be nearer the lower viscosity than the upper!
People see 20w50 and think it's the same as 50w but it isn't, even at temperature when the viscosity is equivalent in both the base oil is still 20 in the 20w50 and the oil film is subsequently not as strong, that is how it was explained to me a long time ago and why I don't use it in engines with roller big ends.
It's a can of worms! Or long chain polymers!

[clive]

I suggest we solve this once and for all by checking previous forum entries on oil. There are only 17858 of them.

[Dave T_LAPSED]

Agreed! But what if they're all right?

[39speedtwin]

I was advised by an oil supplier that using EP oil in a vintage gearbox was not recommended, as the additives destroy the bronze bushes.
I use Morris AG 90 which does not contain these.

[clive]

17861 now

[bob121]

Why doesn't someone just contact an oil company and post the answers given.

[SPRIDDLER]

Why doesn't someone just contact an oil company and post the answers given.

They have, Bob, for the past 25 or 30 years and there are several comprehensive and detailed articles from Duckhams and Castrol (and probably others) experts in the Jampot 'Technical Topics' and in Christians Archive, but as so often happens folk either don't know they are there, don't know how to search, can't be bothered to look or are too tight to buy several types of appropriate oils.

Here's an extract from just one article by a Castrol man ....there are 'better' ones but I can't be bothered to search for them as I don't need to search for the rest as I just use the maker's recommended oils without any issues whatsoever.

Gear oil (640x185).jpg

The whole article is here:
http://www.jampot.com/article_read.asp?id=298

To view it the right way round Right click on the article and select 'Rotate clockwise 90deg' a couple of times.

[Mick D]

Why doesn't someone just contact an oil company and post the answers given.

Good idea Bob - look forward to you posting the responses

Opinions about oils are like a*******s - everybody has one but at the end of the day the manufacturer made recommendations and these oils are still available, if we decide to deviate from the recommendation we should take the responsibility for researching the compatibility of our chosen lubricant.

Regards Mick

[spitfire]

When people buy a brand new modern bike they look in the owners handbook for the recommended oil then go out and buy and use that.
When people buy an old bike they look in the owners handbook for the recommended oil then completely ignore it

[cfaber]

And when said manual was written; leaded paint, gas, and asbestos were all good ideas. The modern make up of new lubricants are far superior to what was available when the bike was built and manuals written.