Adding 20w shock oil to air shocks?

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#31

12-28-2018 | 11:28 AM

btsom

Grand HDF Member

Joined: Jan 2012

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From: Oklahoma

I did a little reading and found that engine oil also works in shocks.. I have engine oil in my front forks and will see how it does as the temperature warms up. I have an 08 Road King and it just has orifices to regulate oil flow/damping, no valves. Newer forks are more sophisticated and may not need such a thick oil. 30 wt. did well in cooler weather but got a bit soft in hot weather, hence the experiment with 20-50 engine oil. Not only is there no consistency in shock oil viscosity from one manufacturer to another, I have never seen any multi-weight (temperature compensating) shock oil. I have 20 wt shock oil in the rear shocks and am happy with that, but will probably try 10-40 engine oil next if a change ever seems to be needed.

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#32

12-28-2018 | 02:12 PM

wscott

Road Warrior

Joined: Nov 2014

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From: NY

Quote:

Originally Posted by not yours

I read somewhere that you can drain the oil out of the factory air shocks and add 20w shock oil and it’s a much better ride. How do you do this because I’d like to give it a try if its worth it. I can’t seem to find any information on it. Just a little project and any help would be great. Thanks

=======================

I did drain the oem oil (5w?) from the rear shocks omn my 09 FLHTCU and installed 10w shock oil(not fork oil!) whick did pi,mp-rove dampening & ride a lot.

Reason was the 2x thicker 10w shock/suspension oil improved dampening so much i was able to reduce the amount of air i had to run in rear shocks (esp riding 2up) by approx 45-50% to avoid bottoming out the shocks.

I also installed 1" lower progressive front fork springs (lowered rear shocks 1" too) and an mix of 70% std and 30% hvy wt Screaming Eagle fork oil too along with also installing 2 new Michelin C2 tires all at the same time which resulted in a huge improvement in overall handling & ride of the motorcycle.

That fixed the horrible mushy front forks esp dive when braking that was now mostly gone being much firmer but not too firm/harsh either and the rear didnt ride harsh anymore either with heavier 10w shock oil also being a bit firmer too.

So now with bike being firmed up on both ends along with the great handling new Mich C2 tires the bike is a pleasure to ride handling much better esp when hitting a bump or swell while cornering where it used to get loosey goosey and now staying stable in same road/handling conditions with the harsh ride now gone too.

BTW,I 1st tried a 50/50 mix of std & hvy wt Screaming Eagle HD fork oil which was too stiff & harsh at times being so stiff the front tire/wheel would bounce off the pavement which was scary when it happened when hitting a large bump while cornering so i dont rec using a 50-50 let alone 100% hvy wt HD shock oil in a touring FLHTCU HD which i wouldn't rec.

Happy motoring!
Scott

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not yours (12-30-2018)

#33

12-28-2018 | 02:15 PM

Motul

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Joined: Nov 2018

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While ATF and engine oil will work in the fork/shocks, I wanted to share some information about lubricants specifically formulated for shocks and forks that make them different.

As mentioned, ATF is generally somewhere between a 5W to 10W equivalent, when we typically recommend 10W to 20W for a Harley. Certainly up to the rider's preference.

Also, both ATF and engine oil are tested with the seals and materials used specifically in those applications, instead of seals commonly found in the bike's suspension. Our shock and fork oils are tested with the specific fork/shock seals found in most bikes and contains additives that have been tested to avoid seal breakdown and preserve the seals in older bikes.

The fork/shock oils also contain higher amounts of anti-foaming additives that help remove air pockets from the system as the fork/shock oils are more likely to take on air during operation.

-Nolan

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#34

12-28-2018 | 05:41 PM

SkyMaster1

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Joined: Apr 2016

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From: earth

changed to 20W about a year ago and its perfect

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#35

12-28-2018 | 06:39 PM

Sandcrab

Stellar HDF Member

Joined: Feb 2008

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From: Southern Maryland

Shock Oil

Here is a picture of the oil removed from my 2015 Limited rear shock. After 46,473 miles, I think it is in pretty good shape.

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#36

12-31-2018 | 05:27 PM

not yours

Thread Starter

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Joined: Jan 2015

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From: Texas

UPDATE: first off I’d like to thank Cobra 1 and everybody that posted on this thread because I really appreciated all the advise. Back to the begaining, I bought a pair of 12” adjustable OEM shocks knowing I was loosing an inch from the air shocks I had on my 2011 ultra 13”. I noticed a difference but worried about loosing the inch and that’s when I started with my project. $45 for a Mity vac, $15 Amsoil shock treatment and $5 for a measuring bottle vs $190 OEM adjustable shocks ( used ) vs the premium after market shocks. After going for a few rides with between 8 psi and 15 psi ( never 2 up ) I decided I liked 10 psi. Never bottomed out and I liked the ride. Bottom line, if you got the OEM air shocks and want a better shock start with a heavier shock oil, not to heavy, try it out first.
P.S. I have a pair of OEM adjustable shocks 12” centers for sale
HAPPY NEW YEARS EVERYONE, RIDE SAFE

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