[Closed] Quick fork oil question

Don't think I'd use motor oil myself - is it fully synthetic? If you pushed I'd just use the 7wt.

Is the oli in the lowers just lube for the bushes? ie a small amount and no damping properties required? If so then any oil will do. However why do you want to mix it? Why not just use the fork oil?

yes just lowers, i know your meant to use 15wt, so thought id mix some , would just motor oil be okay for lowers and foam rings? Which would you use, 7wt fork oil or 15wt/50 motor oil?

i have some 15wt-40 thats semi-synthetic like the fork oil, should i mix with this?

I'd just use the 7 wt fork oil.

Edit - actually i'd buy some 15 wt fork oil

why would you not the the 15w40 with 7wt ? or just use the 15w40?

thanks,

Just use the motor oil (if it's synthetic).

That's what I do for lubrication purposes in all my forks.

its semi synthetic? is that okay

Just bear in mind that if it heats up signficantly (depends on your riding) it'll get closer to the 50 than the 15, which could get sticky. Or rather if it heats up it wont thin out like a single weight oil will.

Just try it & see what it's like

you can't hurt anything

so , should i mix it half and half with the fork oil? (both semi synthetic)

thanks for the replies

It's not that simple, IIRC viscosity doesnt "average" out - 100ml of 5 plus 100ml of 10 doesnt make 200ml of 7.5w. It's an experiment each time.

coffeeking - it won't get thicker as it heats up! It will still get thinner like any oil, just less so than a 'standard' type.

The 50 refers to the fact that it is the same viscosity as 50W oil at (I think) 100C. However, this is still thinner than 15W at 20C.

Synthetic oil is a lubricant consisting of chemical compounds which are artificially made (synthesized) from compounds other than crude oil (petroleum). Synthetic oil is used as a substitute for lubricant refined from petroleum when operating in extremes of temperature, because it generally provides superior mechanical and chemical properties than those found in traditional mineral oils.

Would mineral type oil (non-syntheic) rot your seals? Just a thought? Probably not.

glenh - yup, already covered, check the edit I made before you posted lol 🙂

foxyrider - non-synth and synth are pretty much universally swappable in automotive terms, but I'm not sure about fork seals and bushes. The only real benefit I could see from ester based synths in forks is to maintain better films when left un-used for ages.

I personally would put decent fork oil in and just get the right stuff esp if the fork is worth quite a bit - £10 for oil vs £500 for a fork?

Indeed, fork oil is approx £7 a litre from halfrauds.

i ended up putting a 70-30 mix of motor oil and fork oil in the lowers, and just used motor oil for foam rings, both semi synthetic so should be fine, it 's not for damping so i presume something designed to keep a car engine lubricated will be fine in a suspension fork keeping the stanchion lubricated.
dry as a bone in there, the foam rings had no oil on them! 2009 dual air rev's , put a bit of 7wt in each air chamber with the suspension pump too.