Fork Oil replacement question.

[KDEE]

Question for all the clever chaps out there.. and even those who just think they are clever because you are likely to know more than me..

 

RockShox Duke XC.. 2 to 2 and half years old.. never been used... should I have it serviced or just replace the oil or do nothing and whack it on and ride it in...

 

[xak1]

If you do not see any oil leaking, just a drop of oil on dust wipers, wipe the stanchions (you can even put a drop or 2 of oil onstanchions and then wipe) and ride it.

[Johan Bornman]

Whack 'em on and go for a ride.

[GoLefty!!]

where was it stored?

[KDEE]

Thanks for the replies,

 

Fork was stored in the garage presumably.. very little dust on it.. Not sure if it was laid flat or stored upright.

 

Another question ( forgive the ignorance ). I am presuming the oil is for damping and the air for ride height? I played with the air last night and the height the shock ( unladen ) changes a lot when air is let out and vice versa. I then presumed that the air pressure as indicated on the shock for weight of rider translated to sag when the rider was on the bike....

 

Or am I way of here..

 

[TitusTi]

Pretty good deductions there young man.

[KDEE]

Hell thanks TitusTi... ah if only the young man part was true... Over 40 now and all the what were gentle changes of elevation in the bush when I was young now feel like hills!

[Johan Bornman]

Thanks for the replies' date='

Fork was stored in the garage presumably.. very little dust on it.. Not sure if it was laid flat or stored upright.

Another question ( forgive the ignorance ). I am presuming the oil is for damping and the air for ride height? I played with the air last night and the height the shock ( unladen ) changes a lot when air is let out and vice versa. I then presumed that the air pressure as indicated on the shock for weight of rider translated to sag when the rider was on the bike....

Or am I way of here..
[/quote']

 

It's one of those Yes/No answers, so you decide if you're way out there or not.

 

Most high-end forks have more than one oilbath in there and they're separated.

 

The oil that we generally think of and replace from time to time - the oil that leaks out the top seals when they start to wear, is in there for lubrication of the seals. It sloshes around (about 10ml of it) inside the form and lubricate the various parts that slide over each other. You drain and refill that oil by unscrewing a sump bolt at the bottom of each stanchion. Don't do this on the carpet in your lounge.

 

This oil has nothing to do with damping or ride height. Inside that same chamber could be a pressuriseable air chamber and compressed air in here does change ride height. Spring pre-load also changes ride height as does different rubber bumpers/springs you can fit to the fork.

 

Inside one of the fork's legs is a cartridge damper that also contains oil. This oil is purely for damping and not for ride height. Note only one of the forks therefore has a shock absorber (damper is a better word) and that's why you adjust damping only on one of the legs.

 

Sometimes when the fork is stored upside down or horizontally, some of the lubrication oil will leak out. This is because the wiper seal between the stanchion and leg does not seal perfectly, nor should it seal perfectly.

 

If all the oil has run out, the fork will run dry and wear prematurely. However, you would have noticed this when you took the fork off its shelf or resting place. You'd also have seen evidence of oil on the fork itself.

 

To replace this oil you drain it and fill it with fresh oil in the upside down position. The type of oil is not critical, in spite of the dire warnings you get on forks to only use their approved oil. Even engine oil works, as long as you have a low enough viscocity such as the 10W40 oils used in today's turbodiesel engines.

 

Go ride it.

 

 

 

 

 

[GoLefty!!]

thats correct. I recommended some Helix Ultra 5W 40 to chum recently and he is happy as a pig in sh*t with the action of the fork. engine oil is perfect lube for the sliding bits.

You can also use industrial slideway oil if you like. Most hydraulic oils also have friction modifiers and anti wear agents so these are also suitable.

 

 

[KDEE]

Jeez, that was an answer to surpass all answers! Thanks Johan and GoLefty.. No oil leakage, so I will ride it for now.

[Mauritzvw]

I agree that most hydraulic oils will be fine for lubrication 5W to 15W, engine oil will also do the job and is normally safe for rubber seals as your crank seal contains rubber 

 

Put a bit of lube on the stanchions and ride it!