On 26/10/2020 14:14, T i m wrote:
On Mon, 26 Oct 2020 14:05:47 +0000, newshound
wrote:

On 26/10/2020 08:48, T i m wrote:


I appreciate Tribology is your thing g but do you have any
experience of any diy-able fittings that can takes the sorts of
pressure you might find in such a system?


I've never DIY'd hydraulics apart from flaring brake pipe (easy enough
with the right tools)

Noted.

or buying and fitting ready made commercial hoses.

Ok.

In another life a colleague of mine used to recharge Citroen suspension
spheres (I'm not sure what pressure they ran at). Another poster gave a
link for DIY hose terminations that looked quite interesting.

Yeah, I will follow those up, when I get the pressure testing gadget
thing.

Since I
replaced my tractor with an ATV I don't have any hydraulic kit except on
the cars and vans (and I only touch those in emergencies).

Understood. ;-)

Cheers, T i m

p.s. Whatabout what difference it might make if I put 5W oil in a
motorcycle fork as opposed to the recommended 10W?

I ask because one of the issues that most people suffer on motorbikes
is 'dive' under braking and unless your bike is fitted with any 'anti
dive' solutions (one of mine is), I don't think going between most of
the std weight oils used in such roles would impact that much (given
how much the suspension has to move 'normally' to give a reasonably
smooth ride)?

The one anti-dive system I had that really worked was on an MZ 250 with
a leading link fork. The torque reaction on the shoe carrier plate
(can't remember the proper name for it) made a huge difference. Contrast
that with the Aerial Leader / Arrow with their trailing link suspension,
I'm convinced that even with the tiny 6 inch drums the braking effect
was deliberately weakened to reduce dive.

I don't know about modern anti dive systems, is there some cleverness?
The only passive effect I can see with a telescopic fork is that the
torque reaction will increases the loads on the plain bearings. (On the
MZ you could actually feel the front lift when you braked hard).

Putting in a thinner oil will just reduce the damping a bit. But 10 to 5
is not a very big change. I know all the design theory about EHL film
thicknesses, but (within limits) gearboxes are not actually all that
sensitive to oil viscosity because a thicker oil will run a bit warmer,
and that will drop the viscosity significantly. The same is probably
true of fork oil, especially on bumpy terrain.