Fork oil substitution?

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Fork oil substitution?
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Posted: Aug 21, 2008 at 12:08 Quote
Hey I have a question about fork oil... Fork oil is really expensive but my dad works for petro canada and he can get hydraulic oil for cheap. So I was wondering if I could use the hydraulic oil if it was the same weight? OR is fork oil special? Because the hydraulic oil comes in the same weights I need.

Thanks in advance
flag Blomdahl
Posted: Aug 21, 2008 at 12:14 Quote
Fork oil is hydraulic oil, so i don´t think there would be any problems if you use the one your dad can get.
flag Hummeroid
Posted: Aug 21, 2008 at 12:15 Quote
Fork oil has additional additives in it that help prevent foaming (VERY important for consistent damping) and also a few other additives in it that hydro fluid does not. I would not run it. If it was the same, they wouldnt make 2 products.
flag Blomdahl
Posted: Aug 21, 2008 at 12:26 Quote
Hummeroid wrote:
Fork oil has additional additives in it that help prevent foaming (VERY important for consistent damping) and also a few other additives in it that hydro fluid does not. I would not run it. If it was the same, they wouldnt make 2 products.
UNLESS they could make alot of money from it.... Don´t think there´s any difference and if the foaming is a problem in a bicyclefork, imagine the damage it could do to a highpressure hydraulic machine. Buti f you want to be absolutely sure, ask the guys on your fathers job cause they should know. Or buy expensive super oil from your lbs, because after all Hummeroid could be right.
flag mongooser
Posted: Aug 21, 2008 at 12:30 Quote
i actully run street bike fork oil in my fox 40s and they run so plush, so i think it should be ok
flag the1nonlyj
Posted: Aug 21, 2008 at 12:33 Quote
ask your dad if it has anti foaming agents in it, i think it should as hydro oil gets pumped at a very high rate in machinary and would also foam up. If it doesnt have the anti foam in it then your dads work will probably be able to supply it as well.
flag Hummeroid
Posted: Aug 21, 2008 at 12:38 Quote
Blomdahl wrote:
Hummeroid wrote:
Fork oil has additional additives in it that help prevent foaming (VERY important for consistent damping) and also a few other additives in it that hydro fluid does not. I would not run it. If it was the same, they wouldnt make 2 products.
UNLESS they could make alot of money from it.... Don´t think there´s any difference and if the foaming is a problem in a bicyclefork, imagine the damage it could do to a highpressure hydraulic machine. Buti f you want to be absolutely sure, ask the guys on your fathers job cause they should know. Or buy expensive super oil from your lbs, because after all Hummeroid could be right.

Its not that foam is damaging, its that it causes poor damping. Its obviously not going to make your fork explode or anything like that.

High pressure machines also have reservoirs where oil is sucked from, and when foamy oil comes out of the circuit, it has time to dissipate in the reservoir. Remember, oil doesnt foam on its own, it has to pass an orifice with air present. (no air in a closed high pressure hydro system in theory)
flag redridesrule
Posted: Aug 21, 2008 at 12:46 Quote
it's fine, i didnt have the right weight hydrolic oil though, so i just used transmission oil in my dorados, everything is running smooth. and if you bleed the damper right, there shouldnt be any air in the forks anyways.
flag rydindirty
Posted: Aug 21, 2008 at 14:05 Quote
Contact the Manafacturer if you want a reasonably straight answer. Personally I wouldn't do it.
flag Blomdahl
Posted: Aug 21, 2008 at 14:58 Quote
Hummeroid wrote:
Blomdahl wrote:
Hummeroid wrote:
Fork oil has additional additives in it that help prevent foaming (VERY important for consistent damping) and also a few other additives in it that hydro fluid does not. I would not run it. If it was the same, they wouldnt make 2 products.
UNLESS they could make alot of money from it.... Don´t think there´s any difference and if the foaming is a problem in a bicyclefork, imagine the damage it could do to a highpressure hydraulic machine. Buti f you want to be absolutely sure, ask the guys on your fathers job cause they should know. Or buy expensive super oil from your lbs, because after all Hummeroid could be right.

Its not that foam is damaging, its that it causes poor damping. Its obviously not going to make your fork explode or anything like that.

High pressure machines also have reservoirs where oil is sucked from, and when foamy oil comes out of the circuit, it has time to dissipate in the reservoir. Remember, oil doesnt foam on its own, it has to pass an orifice with air present. (no air in a closed high pressure hydro system in theory)
Alright, you obiously know more than me in these matters so i humbly salute you Smile (But i still think it will work..)
flag knobzy
O+
Posted: Aug 21, 2008 at 15:47 Quote
fork oil is expensive?? it cost me 12 bucks for jug that can fill my forks up 20 + times.. if not more then 50.
flag newbikesoon
Posted: Aug 21, 2008 at 16:36 Quote
robc wrote:
Contact the Manafacturer if you want a reasonably straight answer. Personally I wouldn't do it.
Personally I wouldn't do it either....even if you asked then they would probably say that it would void your warranty if you did it because even if the hydro oil is the same weight it's not intended for forks.

Stick to regular fork oil and then you'll be 100% sure you'll have no problems in the long run
flag mkirk05
O+
Posted: Aug 21, 2008 at 19:26 Quote
dont do it, like the guy above me said, void warantee if you have it, and could make future servicing a mess, and yea, fork oil isnt that expensive...
flag hodge357
Posted: Aug 21, 2008 at 19:38 Quote
mkirk05 wrote:
dont do it, like the guy above me said, void warantee if you have it, and could make future servicing a mess, and yea, fork oil isnt that expensive...

This id say from teh bat is a no no because when you feel dot fluid compared to fork oil the viscosity is way too diffrent. id say DOT4 or 5.1 fluid is like 0.5w fork oil. and that just wont do, it'll just piss through the internals. So take care of your forks kyle, and just take them to a shop so youi dont have to worry about buying the oil.
flag nato
Posted: Aug 21, 2008 at 20:19 Quote
I have used Dirt bike fork oil cause it was like 1/4 the cost as the name brand stuff and it worked fine in my old shivers.
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