Fork oil

[00Vs1400GLP]

I recently changed the fork seals and refilled with 10wt oil because that is what the manual called for. I feel like my forks move way too freely. How much effect will different weights of oil have? I guess I’m wondering if I go to 15wt will of make a pretty noticeable difference?

[Designer]

When building the Forks on my two Choppers, They had quite different Rake angles between the each of them. and steeper angles than Stock.
I wanted the best possible Ride I could get, so I read up on Fork Oil Viscosity and was amazed to find that what the Oil Weight advertised on the Container was more often than not,.........not the actual Weight installed.


Here's a chart that I hope will help you.;

[hillsy]

You'll probably find the biggest improvement you can make is new / uprated springs.

[sgtcall]

ATF worked fine for me and is easier to find.

[hillsy]

ATF worked fine for me and is easier to find.

Yeah - I ended up buying a 4 litre container of DEX3 which was the same price as one litre of fork oil. Should be enough to do over 6 sets of forks.

Seems to work OK - in fact that's what was specified to use by a lot of bikes back in the 70's when dedicated fork oils were pretty hard to find so it would work fine on Intruders. Not a really high tech fork on these bikes - hence the biggest improvement would be upgraded springs.

[Lechy]

For many years I have had good service from EP68 Hydraulic (not gear) oil. Easier to find over here than fork oil and not expensive.

[hillsy]

For many years I have had good service from EP68 Hydraulic (not gear) oil. Easier to find over here than fork oil and not expensive.

That's a pretty heavy oil from what I can see? ATF viscosity is far lighter and closer to regular fork oils.

Not doubting it would work - but there are probably better options for this application.

[Lechy]

Hydraulic oil is a lot thinner than than the number implies, the reason I said NOT GEAR. I tried EP 32 just to see how it compared, OK for a well maintained highway but way too thin for the canal roads I usually ride. Probably looking at the difference between SAE 5 and SAE 20. Hydraulic oil is specified by ISO standards, SAE and ISO use two different scales to measure viscosity. SAE 10W is equivalent to ISO 32, SAE 20 is equivalent to ISO 46 and 68, and SAE 30 is equivalent to ISO 100.
Hope this clears things up a bit.

[hillsy]

Hydraulic oil is a lot thinner than than the number implies, the reason I said NOT GEAR. I tried EP 32 just to see how it compared, OK for a well maintained highway but way too thin for the canal roads I usually ride. Probably looking at the difference between SAE 5 and SAE 20. Hydraulic oil is specified by ISO standards, SAE and ISO use two different scales to measure viscosity. SAE 10W is equivalent to ISO 32, SAE 20 is equivalent to ISO 46 and 68, and SAE 30 is equivalent to ISO 100.
Hope this clears things up a bit.

So your ep68 is equivalent to 20 weight? If thats the case then its a pretty heavy oil.

But yeah - if it works for you - all good