Front suspension oil

[Mic]

Not just for Aprilia owners but for all those with sliding pillars.

In recent times there have been a few comments in the Forum about oils for the front suspension.  It is years since I had my Lambda and I have no idea now what oil I was using.  Now I have an Aprilia which oil should I be using?  Earlier comments only make me more confused and there seem to be a wide variety of suggestions from Aprilia owners.  How about these?

90 lower and  20/50 upper. 
10/40 both upper and lower rather than 20/50
10-40 upper and lower
80/90 lower 20/50 upper.
Classic light top 50W bottom
Straight 90 both.
Straight 30 or 40 both.

The original instruction book suggests
Gargoyle A or Veedol medium 3 which were both straight 30.

Help!  Is there any majority recommendation??  What do you experts use nowadays and why?  I just wonder how many different ideas we will have.  Does climate make a difference?  Here it is a touch warmer than U.K. but this is NOT the Algarve which is six hours drive away.  Answers on a postcard – well, no, on the Forum.

[JohnMillham]

I firmly believe that you should use the thinnest oil which will stay where it's meant to be. My Lambda likes 10/40, but it does tend to leak out, so needs regular topping up. I would imagine using 90 oil, or anything anywhere near as thick, will damage the shock absorber valves, which are very thin spring steel.
Regards, John

[brian]

For Augusta and Aurelia B10 I have "always" used SAE 30 and had planned to do same for Aprilia. Having said that, I bet I have used 10/40 or 20/50 at some time without appreciating any change in handling.

[ben]

Hi there Mic
           Your research suggests to me that the choice of oil is not critical.
           For myself I keep things simple and use the same oil as I use in the engine---20-50 for top and bottom.
           Under normal driving conditions I doubt that the oil heats up very much so the benefit of a multi-grade is not really required and a        straight 30 grade would therefore give similar performance. However I see no disadvantage in using the more conveniently available oil that I use in the engine. I would argue strongly that there is certainly no merit in using anything different in the bottom.   

[nistri]

Following the Lancia instructions booklet, I use 10-40 oil for the top reservoir (unless 30 is available) and 800-90 for the bottom filler.

[simonandjuliet]

I cross referenced the original oils with the closest Penrite oils - all listed below:

http://www.lancia.myzen.co.uk/forum/index.php?topic=5009.msg46137#msg46137

I have done a few miles with the current set up and seems to work well

[chugga boom]

always used 20/50 in the appia augusta etc with no problems

[Mic]

And the winner is....  from nine opinions and in order of popularity -

Upper    Lower-

10/40     10/40                       Three and a half votes (half is a suggested alternative for upper of 10/60).

30            30                       Two and a half votes (half is for one alternative to 10/40 upper).
                                            This of course is same as the factory recommendation which was either Gargoyle Mobiloil A or Veedol Medium 3, both straight 30.

20/50      20/50                       Two votes   

Thickest oil mentioned is by two people which is 90 for lower.  Apart from that in general people keep to the thinner side and two acknowledged experts suggest 10/40 with the comment that 20/50 is just a touch on the thick side.  So I shall follow that recommendation.

Interesting that all but two people use the same upper and lower.

[BlueSky]

A late entry!

I use SAE 20 or 30 in the top and SAE 50 in the bottom. My theory, based on all the advise from the experts down here, is in the bottom you just need something that will stay in there, lighter oils tend to splash out the top, it just has to lubricate the king pin and the bottom thrust bearing that the main spring sits on. In the top, as well as lubricating all the sliding parts, the oil controls the damping, so use whatever works best for your car.

Make sure when you fill the top for the first time you work the piston up and down to extract all air from the lower chamber.

Noel

[Mic]

Thank you, Noel.  That makes sense and I shall consider all possibilities but nothing too thick at the top end.

Incidentally, slightly off topic, does anyone have any experience/knowledge of an additive called Metal Lube - Anti friction engine treatment.  My fettler swears by it but new to me and I am cautious on these things.

[GG]

Another late entry -

20 or 30 weight straight oil up top, 90 below.
Some have suggested oil standards have changed and that today's 20 is too thin, and recommend using 30.

It seemed Lancia was changing  oil standards during the life of the Aurelia, per the following chart. Work in progress.

[daniel.bangham]

Thanks so much for this thread as it is helping me out with the restoration of my Belna Sliding suspension. Having read the thread, I have also been reading up on the differences between SAE oils (engine oils) and ISO hydraulic oils. They can have the same viscosity ie SAE 30 and ISO 30 weight, but very different characteristics under load. The viscosity is important for the speed at which it can flow, the load characteristics determine the ability to lubricate under pressure. So hydraulic oils are the ones I imagine I need to use in my suspension. I started by contacting a Motorbike garage and asked for Front fork oil, which is exactly the same style of suspension that we use. They only went to 20 weight. I eventualy found 32 weight hydralic oil at Toolstation. This is what I will be using.

[Mikenoangelo]

Interesting research Daniel. In the absence of any contrary advice I used Castrol Classic 20/50 in my Augusta and it seems to work. I'll try the fork oil you suggest next time I top up.
Mike Clark

[daniel.bangham]

Another update. I have had more success researching the the Veedol grade 3 mentioned in the original manual,  rather than the Mobil A grade. The image below of a Bottle of Veedol 3 medium, clearly rates it as SAE30 which on the chart below corresponds to SAE GEAR oil grade (not the same as SAE crankcase) of around 80 to 85w or an ISO VG 68 to 100!!! The ISO VG rating is what I think we should be using, as it is a gear oil grade.

https://www.machinerylubrication.com/Read/213/iso-viscosity-grades is a description of oils.

I understand that modern HP or hypoi gear oils should not be used as they have additives that attack bronze and brass (as found in our suspension) So, as many people have already stated, use old spec oils. There also seems to be a problem with crank case oils (engine oils) even of the same viscosity, as they handle dirt and water very differently from gear / circulating/ hydraulic and "way oils"

In the end, the only oil that is available on a bank holiday is the Dynolite Gear 40  and a ISO VG 68 hydraulic oil, that I use in my Harrison Lathe. I will use the 68 in the top chamber and the 40 in the bottom. In the end, I don't think I have got to the bottom of this, but I hope you can understand why I have ended up where I am.