Shock oil

[Elvis]

What kind of oil are used inside a mtb shock. it looks hydraulic oil to me. can you use any hydraulic oil?

[AndreZA]

Ons het motorbike shock olie gebruik op die kursus. Maak net seker jy gebruik die regte dikte.

[Daxiet]

definetly not hydraulic.

Fox 7.5W (5ml - air sleeve 80W Gearbox Oil)

Rockshox 15W - not sure if this is both legs, never paid enough attention.

 

Get the manuals to be sure, plus to get amounts needed per leg. As Mampara eluded to, you can get it from motorbike shops. Seemingly not 7.5, you need to mix 5W and 10W (50/50).

 

Daxiet2009-05-22 06:33:49

[AndreZA]

Daxiet, maybe you can tell me the formula to get 7.5w using 5w and 15w.

[GoLefty!!]

Henri,

 

Suspension fork oil is indeed hydralic oil. the difference is that in a suspension the oil viscosity (weight in yankee speak) is expressed in SAE numbers (thats Society for Automotove Engineers) while hydraulic oil is expressed in terms of ISO classification numbers based on the kinematic viscosity of the oil.

 

Most fork oils are around 5W which is an ISO viscosity of around 9centistokes.

 

Such low viscosities for a bicycle application are difficult to find in small enough qualities. You will need an ISO 15 type oil which is already pretty thick.

 

Stick to Fork suspension oil which is available from Motorcycle dealers. I recommend an oil with a high Viscosity Index (VI) so that the damping characteristics does not change much with temperature

 

 

[Daxiet]

Daxiet' date=' maybe you can tell me the formula to get 7.5w using 5w and 15w.[/quote']

 

Mampara, did you have the black Fox? Because we could never get that formula right. I haven't even tried since that day. I have just decided to try source 5w and 10w.

[Bos]

YAMALUBE its suspention oil for  MX bikes. R60 bucks a bottle. get it from your local Yamaha dealer

[AndreZA]

Daxiet' date=' maybe you can tell me the formula to get 7.5w using 5w and 15w.[/quote']

 

?

 

Mampara' date=' did you have the black Fox? Because we could never get that formula right. I haven't even tried since that day. I have just decided to try source 5w and 10w.

[/quote']

 

 

 

yip, still trying to get to that formula.

[knersis]

Bel Ray makes 7W and 7.5W fork oil for motorbike shocks,

Craigs in Parow (Cape Town) sells it. No mixing required.

knersis2009-05-22 06:40:42

[knersis]

http://www.cyberall.co.za/webpages/craigs.htm

[GoLefty!!]

definetly not hydraulic.

Fox 7.5W (5ml - air sleeve 80W Gearbox Oil)

Rockshox 15W - not sure if this is both legs' date=' never paid enough attention.

 

Get the manuals to be sure, plus to get amounts needed per leg. As Mampara eluded to, you can get it from motorbike shops. Seemingly not 7.5, you need to mix 5W and 10W (50/50).

 

[/quote']

 

 

BS: a 50/50 mix of 5W and 10W will not give you 7.5W but 6W. Viscosity does not blend linearly!

 

You will need a mix of 1:2 5W:10W to get 7.5

i.e.

33% 5w + 66% 10W is more or less equal to 7.5W

 

Give me the oil brands and I will find the correct ration in centistokes. this SAE nonsense really should not be used for Hydraulic oils

[Daxiet]

[ 

 

Give me the oil brands and I will find the correct ration in centistokes. this SAE nonsense really should not be used for Hydraulic oils

 

Please do: 

Fox owners need 7.5W. We can get 5W, 10W and 15W. So can you work out the ratio for 5W and 15W to = 7.5W. Mamapara and I would be very grateful.

 

This said there are a number of source on the web that disagree with your non-linear statement.

Daxiet2009-05-22 06:56:12

[GoLefty!!]

Oils used blend for Lubricants (Base oils) do not blend linearlywrt to viscosity.

 

This is a fact, so sorry If I sound obnoxious but I don't care for the web based statements that claims otherwise. People who claim the relationship to be linear are doing one of two thing;

 

1) Use a thumb suck method for blending i.e approximating and getting it very wrong

 

2) are refering to blending to synthetic hydrocarbons of similar molecular structure.

 

None of the above ever happens in practice.

 

Can you please supply me with the ISO viscosities of the Fox Oil?

SAE viscositiy ranges are never used to determine a final blend viscosity because the range for a 5W can vary from ISO 6 to ISO. 16 (centistokes) It makes a difference to the calculation.

 

Thanks

 

If Not< I'll dig up the info.

[Wyatt Earp]

I am with Go Lefty all the way on this one.

[vanniri]

Before going out to buy, in my experience the grade is not the only variable to take into account.

 

I used to service my Manitou in the dark ages using the correct grade etc.

 

Sometime later (+6months), the lockout was only a memory. When I finally sent it to the pro?s they told me I used a wrong type of oil - mineral/blah/blah. Apparently it contaminated the seals/washers/whatever.

 

 

[GoLefty!!]

thats workshop nonsense.

 

Seals do not get contaminated by a change of fork oil whether you move from mineral to synthetic or vice versa. the main problem was the 6months between services.

 

I've stripped forks with a 2 weeks worth of riding and forks with 3 months worht of riding and the fork with 3mnths worth of riding had oil in better condition. Why? because the fork that was serviced 2weeks prior had done the Cape Epic. it was jet washed and exposed to harsh terrain and temperature extremes, the other fork was ridden once or twice per week by an average rider who did not work the fork too hard on singletrack.

 

Synthetic fork oils are hydraulic oils, and not too dissimilar from lower spec API SF/SG CD/CE engine oils.

 

Gearbox oils can be totally different kettle of fish if the base oil is PolyAlkylene Glycol (PAG) based.

Hydraulic oils and fork oils are mainly PAO, XHVI or HVI based oils. These are ALL compatible. So unless some twit pourer a PAG based oil into your fork (unlikely since they are industrial products only) there was absolutley no compatibility issues. What they saw was oil and seal degradation due to a lack of maintenance.

But hey, it's only a bicycle fork and you can service it whenever it suits you.

 

GoLefty!!2009-05-23 02:47:28