# motor oil as substitue for fork/shock oil?



## kwan (Jun 26, 2007)

I'm having a difficult time finding fork/shock oil in my area. They usually have 100% synthetic motor oils. Can these be used as alternatives to use in forks/shocks?


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## metelhead (Jun 1, 2008)

"you know you're a ******* when........" Jeff foxworthy.....sorry just saying...! but thats some varying damping!


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## RaindogT (Oct 2, 2005)

I don't know the answer that you seek, but I will say that any motorcycle/ atv shop will have fork oil. Don't know if that crossed your mind or not, but I would go that route before using motor oil in your fork.


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## gbosbiker (Mar 10, 2009)

i did that in a manitou stance fork. it was on my old dj bike that i sold 2 months ago. it helped alot (was DRY, no oil) it helped make the fork smoother and it didnt bottom out as easy. i wouldnt do it in my new bike, but if you dont have anything else, why not?


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## fallzboater (Jan 18, 2004)

Motor oil is likely too high viscosity. ATF may be closer.


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## DHidiot (Aug 5, 2004)

ATF is close to most 7-10w oils. If you must, use that as your damper oil. For straight lubricating oil (like in the lowers of a Fox 40), motor oil is just fine.


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## suicidebomber (Feb 10, 2007)

Don't do it.


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## juan pablo (Jan 17, 2007)

Axed this a month or so back and dropped some in the lowers of my Totem. So far so sweet. Not for the uppers though.


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## jimmydean012 (Mar 31, 2007)

Used 10wt in my Sherman previously. Did not seem to effect the performance, but I would do it only in a pinch. Possibly cavitated more than fork oil...


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## drsmonkey (Mar 21, 2008)

This is from the Enduro sSeals instructions for the Fox 36 talas rc2. Not sure what fork you have but you should check out the tech section here...

Enduro Tech

"32) Inject 15cc of multi-viscosity fully
synthetic motor oil into the bottom of
the TALAS side fork leg...

...The multi-viscosity, fully synthetic
motor oil we chose to use is made by
Amzoil®. Any other reputable brand is
acceptable. Note that Fox recommends
damper oil. Damper oil is OK, but does
not stick to the parts as well as the
mulit-viscosity synthetic motor oil."

So enduro seems to think it is fine, even preferable.

I haven't done this yet, but I'm planning on giving it a try when I re-build my wife's 36.

DRS

Edit to add: You may have better luck posting this in Shocks and Suspension.


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## XSL_WiLL (Nov 2, 2004)

Motor oil is fine for the semi-bath in the lower legs. This oil is for lubrication purposes only. Motor oil will not work in the damper. I would keep ATF out of there as well. If you don't have a moto shop or somewhere nearby, order a bottle from the internetz.


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## tuumbaq (Oct 6, 2005)

It'll be fine like other said if its only used for lubrication purposes...A friend of mine swears by automatic transmission fluid, I didnt personally liked it but it sure works! ( and it stinks ;-) )


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## Iranian-Mechanic (May 6, 2004)

Forget about it if its an open bath or even for the casing lubrication .Also Characteristics arnt any good for damping
As they ruin the Teflon bushings with the stanchions slide in .
Get my advise for free I paid a 66 RC2X for this experience !!


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## Jim311 (Feb 7, 2006)

SABER_MTB said:


> Forget about it if its an open bath or even for the casing lubrication .Also Characteristics arnt any good for damping
> As they ruin the Teflon bushings with the stanchions slide in .
> Get my advise for free I paid a 66 RC2X for this experience !!


Motor oil is safe for all the seals in your car's engine, don't see why it would affect the bushings. I rocked motor oil in my Domain 318 for a while, and I'm running it in my Vanilla on the spring side. I tried it in the side with the damper but it was way too thick and damping sucked.. bad compression, really harsh. It's fine for lubing the bushings in the lowers, bad for dampers.


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## qkenuf4u (Jan 24, 2009)

use 30w in my steering damper on my motorcycle and it will/would work fine in the forks as long as you find the *right weight*... its all about fluid dynamics/motion.... if its to thick then ya its gonna be a harsh ride in both directions.. to thin and gonna be a bouncy ride.... get it right and it will work as well as fork fluid (again ya have to find the right weight oil) trans fluid will work also but its gonna be a 7wt or so... have to play with it and see what/how it works and what works best for you...


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## XSL_WiLL (Nov 2, 2004)

Oils have viscosities, not weights.

I see no reason for motor oil to harm Teflon as many motor oils have teflon additives. And my car has a teflon crank scraper as well. I have been using synthetic motor oil in the semi-bath lowers for years.


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## frorider (Apr 2, 2005)

tech dept at manitou recommends synthetic motor oil for semi-bath fork lowers. 

i know plenty of people like me who've run synthetic motor oil as a fork lube for years and years with no issues.

but not as a damping chamber oil.


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## SHIVER ME TIMBERS (Jan 12, 2004)

can't get fork oil in your area

hmmmm did you try the *INTERNET*

buy some online:madman:


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## qkenuf4u (Jan 24, 2009)

XSL_WiLL said:


> Oils have viscosities, not weights..


cant have one without the other.........


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## XSL_WiLL (Nov 2, 2004)

qkenuf4u said:


> cant have one without the other.........


Explain... Viscosity has nothing to do with weight. Viscosity is a fluid's internal resistance to flow. Viscosity is measured in centistrokes.

The w in 5w30 is not for weight, it's for winter.

And labeled viscosities (such as Torco RFF 7 vs Rockshox 5 being the same viscosity) are hardly an accurate measure of viscosity.

I imagine that using motor oil in a damper may cause foaming as well. And most motor oils are multi-viscosity. A fork or shock can build up quite a bit of heat.


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## qkenuf4u (Jan 24, 2009)

ya i already know that... just got done reading for the last 15 mins about all this... its just another designation for how a oil flows/characteristics/designation.... its all mashes together in the bottle. lol guess maybe they just call it that to make it simpler for people... ??? weight is thrown around in all the reading i did ALOT but nothing that really said why WEIGHT was used......but yes they did explain viscosity...which i already knew....
but one way or another it can still be used in forks as long as ya find the right "viscosity"-"weight" ....... atf is used in motorcycle forks all the time.. no different than engine oils.... will all protect the internals and flow as needed if the right "weight/viscosity"


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## XSL_WiLL (Nov 2, 2004)

In my opinion, weight is the wrong terminology as it holds a different meaning.

ATF may contain seal swellers that could damage the seals. And again... it could foam up.


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## Iranian-Mechanic (May 6, 2004)

I dont khow but it ruined the bushings in my RC2X and made me to trow it away .
i wont make that mistake again. I used STP synthetic motor oil. But now i use Fox ' Sram suspension fluids wich are now available over here in Iran. Or some times Citroen LHM plus mineral.


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## kwan (Jun 26, 2007)

so motor oil is ok for forks with open bath system? How about motor oils used in rear shox? any comments?


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## qkenuf4u (Jan 24, 2009)

as said above if you can get *FORK OIL* its gonna be the best way but if not then MOBILE 1 ATF seems to be a good substitute that im reading about.....
where are you located that you cant get fork oil ? like someone else said just order it off the net since you have access....


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## rmb_mike (Jun 12, 2007)

XSL_WiLL said:


> Explain... Viscosity has nothing to do with weight. Viscosity is a fluid's internal resistance to flow. Viscosity is measured in centistrokes.
> 
> The w in 5w30 is not for weight, it's for winter.
> 
> ...


Weight and viscosity are interchangeable terms when it comes to oil, but thanks for being hoity toity about it with the rest of us, Terminology Nazi.


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## XSL_WiLL (Nov 2, 2004)

rmb_mike said:


> Weight and viscosity are interchangeable terms when it comes to oil, but thanks for being hoity toity about it with the rest of us, Terminology Nazi.


Weight and viscosity have different meanings... this is true to any fluid, not just oil. Weight is a misused term. This is what I have always been taught. Wikipedia each... they're different. Weight is never mentioned or used in the viscosity article, and vice versa. This is also true in my text books.

Still bitter that I called you out on your SPAM? Get over it. You don't have to be an ass for me trying to clear up some confusion.


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## thuren (Jul 29, 2009)

Wow some crazy info in here.

Don't use ATF as it has friction modifiers to help the transmission bands grab. We don't need any _more_ friction.

Viscosity describes a fluids thickness, and doesn't translate well unless measured at the exact same temperatures and measures. 7w(weight) fork oil at 20 degrees could be thicker than 5w30 motor oil at 80 degrees. If you live in cold temps don't use thicker oils than spec, and if you live in hot climates you can play around.

Almost all oils these days have anti foaming properties, so motor oil won't foam more than a true suspension fluid. If there is air in the system, you are gonna get foaming.

If you can't find suspension oil, a *thin* hydraulic oil(tractors-equipment) is almost the same stuff. In fact, I'm 90% sure most suspension companies buy normal, but good quality hydraulic fluid, and re-bottle it or use in their suspension.


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## masterodamountain (Mar 21, 2009)

Call your Fork manufacturer.....they will tell you whats up. Then go to the internet.


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## XSL_WiLL (Nov 2, 2004)

The SAE classifications characterizes the viscosity at low and high temperature of the lubricant. The grade is given by two numbers separated by the letter W (meaning winter).

Neither number corresponds to an actual 'weight,' even though that is the term most people use when referring to motor oil. The viscosity (flow resistance) is tested by allowing a small amount of oil to flow through an aperture. The quicker the oil flows, the lower the rating numbers.

The first number rates the viscosity of the oil at a temperature of 0 degrees F, mimicking cold winter weather, which is why the 'W' designation is added at the end of the first number. The second number repeats the test at 210 degrees F., or normal operating temperature for a fully-warmed engine.


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## juan pablo (Jan 17, 2007)

Nice one Will, I always wondered how that worked. Seems so simple now I think I will go clean my chain.


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## sicktim (Dec 30, 2007)

this is old and maybe i can get a reply from someone..... what about brake fluid. Its a hydraulic fluid and it is definitely thinner than engine oil or tranny oil. Would it be too corrosive?


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## SHIVER ME TIMBERS (Jan 12, 2004)

sicktim said:


> this is old and maybe i can get a reply from someone..... what about brake fluid. Its a hydraulic fluid and it is definitely thinner than engine oil or tranny oil. Would it be too corrosive?


man oil is available online....it is under 25 bucks and last 3 or 4 oil changes...get the right stuff and don't mickey mouse stuff


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## lalocotequinta (Mar 28, 2007)

sicktim said:


> this is old and maybe i can get a reply from someone..... what about brake fluid. Its a hydraulic fluid and it is definitely thinner than engine oil or tranny oil. Would it be too corrosive?


Or, or, or, how about canola oil? since it is still a fluid...


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## SHIVER ME TIMBERS (Jan 12, 2004)

lalocotequinta said:


> Or, or, or, how about canola oil? since it is still a fluid...


or 
non carbonated beer:nono:


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## 006_007 (Jan 12, 2004)

SHIVER ME TIMBERS said:


> or
> non carbonated beer:nono:












...


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## SHIVER ME TIMBERS (Jan 12, 2004)

006_007 said:


> ...


that one sucks...get the cherry flavor....better for ATM...chicks dig it


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## XSL_WiLL (Nov 2, 2004)

Somebody once put brake fluid in their 5.7L LT1. It did not work. Its fail is all over the interwebz.


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## Dynamatt (Oct 14, 2007)

Don't use motor oil. It may work, but use fork oil. You clearly have the internet. USE IT


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## Tim F. (May 22, 2006)

Wonder how Stans would work in an air fork?


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## homeless junkie (Jun 3, 2009)

I was watching TV last night and KY is making a bunch of oils. Maybe one of those would work?

Oh..Just think if all that works you could ask for sponsorship. Then you would be wearing a KY jersey and pants. AWESOME!!


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## Tim F. (May 22, 2006)

SHIVER ME TIMBERS said:


> that one sucks...get the cherry flavor....better for ATM...chicks dig it


Cherry flovored anal lube? Maybe chocolate covered cherry flavor. How would you know the taste anyway, aren't you usually on the receiving end?


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## trailadvent (Jun 29, 2004)

ffhb

Right man as some said ya can jump on here then buy the FLUID [not oil] online!

Viscosity Im not going to get into, check out at an LBS next time ya go there, what they have in there mechanics bay, I'd be surpised if they can work on a DH bike if they don't use Moto cycle fork FLUID [not engine oils or Automatic oils etc]

For Damper side, you may be best with std bike Fluid, for lower legs depending on fork type ya have, I would use a Moto X FLUID. same wieght rec or with rec speccs of ya fork manufacturer.

e.g Motorex would be my number on choice, Motul, or Bel Ray

Moto X Fluid comes in the same FUILD weight as MTb one key thing is the quality of the FLUID, Motorrex for example is one of the best for maintaining its viscosity over time adn during use, e.g like any fulid it breaks or tries to break down under dissipation heat and cooling, and can contaminate, so best is best,.

Like a car put cheap oil in get high engine repair bills, same with fork, put in quality FLUID [specific] not engine oil and you get what you get.

If I don;t service my car myself I buy my oils and take it in and watch them do the work, I only use Mobil in my cars, in my bikes I prefer Motorex for suspension and ATF in my Coke n bourbon, usually while doing maintenance 

check ya specc's then order online any of those 3, some may prefer others, Motorex is hard to pass up, BR for you USA boys or Maxima :thumbsup:


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## XSL_WiLL (Nov 2, 2004)

Mobil One synthetic is no longer the leading oil as they have changed the formulation.

The labeled viscosity of one brand may be completely different from the labeled viscosity of another. A perfect example is that Torco RFF 7wt is the exact same as Rockshox 5wt. Rockshox purchases and rebrands Torco. Maxima RSF 7wt is actually lighter than Spectro 5wt and Silkolene Pro RSF 7.5wt is actually heavier than Showa SS-8 10wt. Also viscosity may be measured at different temperatures.These are in fact oils, Torco RFF is a blend of VI synthetic and mineral oils. It is a petroleum product. In fact, Bel-Ray, Motorex, Torco, Motul (and many others) even call it an oil themselves.

Synthetic motor oil is fine for the lowers for semi-bath forks, and is often recommended in service manuals.

http://www.belray.com/consumer/product.fsp?pid=1330
http://www.motorexusa.com/prod_detail.asp?id=81
http://www.motul.com.au/product_line_up/fork_brake_others/others01.html


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## mtbnozpikr (Sep 1, 2008)

RaindogT said:


> I don't know the answer that you seek, but I will say that any motorcycle/ atv shop will have fork oil. Don't know if that crossed your mind or not, but I would go that route before using motor oil in your fork.


Isn't motorcycle fork oil the same as bicycle fork oil?


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## trailadvent (Jun 29, 2004)

Maybe the case with Mobil in the US, I don;'t know what formulation they use here but we have out own refining company here, Mobil here create all formulation for all companies to there specc [re car oils]

After many years using Mobile and knowing some in the drag racing industry with Mobil I won't use anything else also a little bit biased I guess, but Its never let me down unlike some that I won't mention here. Still not really related to Fork Fluids lol


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## CaveGiant (Aug 21, 2007)

For the record guy 'synthetic' oils are now rarely what we would classify as synthetic.

They used to be until some cemist and a lawyer got together and would out a way of making a crude oil distilate fit into the synthetic term.
So none of the advantages of synthetic, but half the price to produce, same cost to sell, more money.

A few companies out there still make true synthetic, but it is expensive, but you get what you pay for.

my 2c agrees with a lot of the above, put fork oil in the dampener, for lube not so important.

Every motor bike shop in the world should have fork oil.


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## frorider (Apr 2, 2005)

CaveGiant said:


> For the record guy 'synthetic' oils are now rarely what we would classify as synthetic.
> 
> They used to be until some cemist and a lawyer got together and would out a way of making a crude oil distilate fit into the synthetic term.
> So none of the advantages of synthetic, but half the price to produce, same cost to sell, more money.
> ...


hmmm. got any links discussing this?


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## CaveGiant (Aug 21, 2007)

nope, just read an article that seemed genuine enough to convince me (scientist, most BS marketing crap ignored).


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## XSL_WiLL (Nov 2, 2004)

CaveGiant said:


> For the record guy 'synthetic' oils are now rarely what we would classify as synthetic.
> 
> They used to be until some cemist and a lawyer got together and would out a way of making a crude oil distilate fit into the synthetic term.
> So none of the advantages of synthetic, but half the price to produce, same cost to sell, more money.
> ...


Yes, many synthetics are a blend of synthetic and mineral oils. There are full synthetics as well.

There different base stocks and blends.

* Polyalphaolefin (PAO) = American Petroleum Institute (API) Group IV base oil
* Synthetic esters, etc = API Group V base oils (non-PAO synthetics, including diesters, polyolesters, alklylated napthlenes, alkyklated benzenes, etc.)
* Hydrocracked/Hydroisomerized = API Group III base oils. Chevron, Shell, and other petrochemical companies developed processes involving catalytic conversion of feed stocks under pressure in the presence of hydrogen into high quality mineral lubricating oil. In 2005 production of GTL (Gas-to-liquid) Group III base stocks began. The best of these perform much like polyalphaolefin. Group III base stocks are considered synthetic motor oil ONLY in the United States. Group III based lubricants are not allowed to be marketed as "synthetic" in any market outside of the USA.

Group II and Group III type base stocks help to formulate more economic type semi-synthetic lubricants. Group I, II, II+ and III type mineral base oil stocks are widely used in combination with additive packages, performance packages, ester and/or Group IV polyalphaolefins in order to formulate semi-synthetic based lubricants. Group III base oils are sometimes considered as synthetic but they are still classified as highest top level mineral base stocks. A Synthetic or Synthesized material is one that is produced by combining or building individual units into a unified entry. Synthetic base stocks as described above are man-made and tailored to have a controlled molecular structure with predictable properties, unlike mineral base oils which are complex mixtures of naturally occurring hydrocarbons.

Hydrocracked/Hydroisomerized = API Group III base oils. Chevron, Shell, and other petrochemical companies developed processes involving catalytic conversion of feed stocks under pressure in the presence of hydrogen into high quality mineral lubricating oil. In 2005 production of GTL (Gas-to-liquid) Group III base stocks began. Even though they are considered a synthetic product they are still mineral base stocks and counted as the mineral part of all semi-synthetic lubricants. Group III base stocks [with certain amount of mixture of PAOs and esters and Group V] are considered synthetic motor oil ONLY in the United States. Group III based lubricants are not allowed to be marketed as "synthetic" in any market outside of the USA.


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## SamL3227 (May 30, 2004)

will brought the dirt.....and the bigasss wordz


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## mr.niles (Feb 5, 2007)

Tim F. said:


> Wonder how Stans would work in an air fork?


hmmmm.......i'll have to try that....:band:


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## Tim F. (May 22, 2006)

XSL_WiLL said:


> Yes, many synthetics are a blend of synthetic and mineral oils. There are full synthetics as well.
> 
> There different base stocks and blends.
> 
> ...


I think I just had a brain aneurysm.....:eekster:


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## LonesomeCowboyBert (Apr 11, 2008)

....the cut and paste king strikes again........:drumroll:


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## XSL_WiLL (Nov 2, 2004)

LonesomeCowboyBert said:


> ....the cut and paste king strikes again........:drumroll:


I don't often copy and paste, but yes, I should have cited my source as wikipedia. I felt it was easier and more thorough than me explaining base stocks.


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## Instigator (May 10, 2006)

I have used motor oil in a fork before and had not many problems, its lasted from before i joined this site until just last week in a rock shox judy. i used penzoil, pretty stiction free. the only problem i saw with it was that the oil contains additives (detergents, metals to prevent contact, condtioners etc). what went bad was the top cap seals (easily repairable) starting shooting oil from pressure build up (overfilled it big time on a refill service). I wouldnt do it again though, especially given correct fork oil is about the same price as a quart of any decent oil.

also keep in mind (despite claims from oil companies) alot of the products do not like mixing. i work and train in the auto industry and i can tell you first hand that valvoline and penzoil hate each other with a passion when combined (just an example). same goes for synthetics and non-synthetics, of even the same brand.


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## Anychemist (Jan 6, 2021)

qkenuf4u said:


> ya i already know that... just got done reading for the last 15 mins about all this... its just another designation for how a oil flows/characteristics/designation.... its all mashes together in the bottle. lol guess maybe they just call it that to make it simpler for people... ??? weight is thrown around in all the reading i did ALOT but nothing that really said why WEIGHT was used......but yes they did explain viscosity...which i already knew....
> but one way or another it can still be used in forks as long as ya find the right "viscosity"-"weight" ....... atf is used in motorcycle forks all the time.. no different than engine oils.... will all protect the internals and flow as needed if the right "weight/viscosity"


Weight of oil is temperature related. Example 5w-30 oil will have a viscosity of a 5w oil at low temp and viscosity of 30w at high temp. From a chemist at an oil company it is 5weight oil with an additive to make it perform like 30w at higher temp. So it is all viscosity, but completely temp dependent.


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## shwinn8 (Feb 25, 2006)

fork oil is probably closer to transmission/hydraulic fluid


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