What's the Truth? Lubricant Sprays and Fork/Shock Seals

[Danger Dassie]

Silicone spray or a vinyl polish like Dash, also good for stopping fork seals from drying out.

[raptor-22]

That's not true. Both are harmful to rubber compound seals.

[droo]

I don't have a definitive answer for this one tbh. I know that some propellants and additives, chlorine being one of the more common ones, will swell the seals.

 

The other thing I know is that nothing you apply to the stanchions or seals will cause dirt to come out from under the seal lip - there are microscopic indentations in the stanchion coating that allow oil to flow past the seals, and what you're seeing is the dirt that's been flushed from these indentations by whatever lubricant you've applied.

 

I'd recommend using either a commercial stanchion lube - Fork Juice, Brunox Fork Deo and Finish Line Stanchion Lube are the 3 that I've seen locally - or fork oil.

 

Otherwise, as Capricorn says, test whatever you're going to use on an old seal and see what happens.

[brumby]

I sell an oil spray that we I have made up  for my customers. For every 1 can of normal penetrating oil / silicone or flon we sell 200 cans of this oil. On all our bicycles and motorcycles it's used on the suspension and on the chains. We have never blown a fork seal and due to its ability to penetrate the rollers the chains last much longer. My business services the transport and construction industry - so this products application is extremely broad based. If there is somebody in the Honeydew area (1 person only) - they can give me a call on 0828023997 and pick up a free can to try.

[JXV]

The other day I was reading an article on enduro-mtb.com (http://enduro-mtb.com/en/enduro-long-term-test-review-2015-fox-36-rc2/) on the new FOX 36 and came across this qoute:

 

"Also we never apply any oil out of spray cans onto the stanchion tube, as some lubricants can cause rubber to swell and reduce the performance of the seal."

 

What I want to know is the following:

• Is there any truth to this statement and if so, what causes the damage to the seals (the propellant, lube, etc.)?
• Is it necessary to lube fork/shock stanchions - I know many will argue that the dust wipers will simply wipe off any lube you apply, but the fact is that gunk still finds its way under the dust wiper.

Any thoughts?

Background : Many motor oils contain additives that act as "seal swelling" agents. These agents effectively "moisturise" rubber seals. They absorb into the rubber, soften it and improve its elasticity. This improves the sealing performance.

 

Rubber compounds used in seals may contain these or similar compounds at time of manufacture but due to exposure to heat and fuel (solvent) they leach out and the rubber seals harden over time.

 

The presence of such additives in engine oil, along wth acidity buffers and dispersants, is the major reason why you should change your car's oil regularly, because the additives get used up.

 

Now for MTB context : There is not much heat and no fuel exposure but there is dirt and a need to limit stiction. There is also exposure to UV light that may damage the exposed rubber. There is a trade-off in design - you want the wiper seal as tight as possible to prevent dirt ingress but you also want as little stiction as possible to ensure good "feel" and plushness.

 

So I can see how the seals might benefit from a coating of oil containing the right additives - but this should already be present in the lubricating oil that you add when doing a lowers service. This why you should use the manufacturer's approved oil, in the right quantity and at the scheduled times.....and soak the foam rings 'cos lubing the wiper seal is their job....

 

Spraying gunk on the outside may help but it will also attract dirt/dust and the quantity applied is very small compared to the volume of oil in your lowers, which is captive and can't evaporate or be washed off. Seal plasticisers need to absorb into the rubber, not sit on top of it.... for this they need time and contact.

 

Then there is the question of compatibility - I am getting good results with Fox 20wt Gold but Fox warns it is not compatible with seals on some of their older forks. The spray can - who knows what is in there and which types of rubber it is compatible with. In this regard please also be careful with solvents and degreasers used to wash your bike. The rubber and anodising on your fork stanchions can be affected by some household and motor cleaning products.

 

The convenience of spray cans helps to sell a lot stuff that is of dubious value and the results are subjective. Caveat Emptor.

Edited October 28, 2015 by JXV

[Martin PJ]

I used mineral oil in my disk brakes, they were supposed to have brake fluid. It wrecked the seals beyond repair in a few minutes. Even the agents could not fix them.

 

Get your old seals back when your shock is serviced, test them with some of your favourite oils and see what happens.

[BarHugger]

Finish Line Max Suspesion Spray:

Made with carefully chosen polysiloxane and advanced fluoropolymers, Max™ Suspension Spray is formulated to fight stiction, condition and protect seals, o-rings, and other rubber parts. Max improves the surface slip of any stanchion, even ones that are coated!

 

(http://www.finishlineusa.com/products/suspension-care/max-suspension-spray)

 

Siloxane:

Siloxanes also include branched compounds, the defining feature of which is that each pair of silicon centres is separated by one oxygen atom. The siloxane functional group forms the backbone of silicones, the premier example of which is polydimethylsiloxane.

 

(https://en.wikipedia.org/wiki/Siloxane)

 

Silicone:

Silicones are polymers that include any inert, synthetic compound made up of repeating units of siloxane, which is a functional group of two silicon atoms and one oxygen atom frequently combined with carbon and/ or hydrogen. They are typically heat-resistant and rubber-like, and are used in sealants, adhesives, lubricants, medicine, cooking utensils, and thermal and electrical insulation. Some common forms include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk.

 

(https://en.wikipedia.org/wiki/Silicone)

 

Q8 (silicone spray)

Q8 is a unique silicone spray which repels moisture and waterproofs all surfaces. Q8 is a non-staining lubricant for clips, hinges, rubber bushes and plastic fittings making it ideal for use on cars. Q8’s unique difference to other silicone sprays is that it has a 60% silicone oil content, making it one of the highest quality silicone sprays you’ll find on the market. It consists of an organic mixture of polydimethylsiloxanic fluids which repels moisture, waterproofs surfaces, lubricates and prevents arcing and spatter.

 

(http://qoilseurope.ie/portfolio-item/q8-silicone-lubricant/)

(a.tritonleo.co.za/docs/Q8_MSDS.doc)

First to admit that I am no chemical engineer.............am I missing something, or is both the Finish Line and Q8 product silicone based? 

[rouxtjie]

if the fork is running dry surely its time for a lower service....as an emergency maybe use a little of the oil you use to service.

[raptor-22]

Finish Line Max Suspesion Spray:

Made with carefully chosen polysiloxane and advanced fluoropolymers, Max™ Suspension Spray is formulated to fight stiction, condition and protect seals, o-rings, and other rubber parts. Max improves the surface slip of any stanchion, even ones that are coated!

 

(http://www.finishlineusa.com/products/suspension-care/max-suspension-spray)

 

Siloxane:

Siloxanes also include branched compounds, the defining feature of which is that each pair of silicon centres is separated by one oxygen atom. The siloxane functional group forms the backbone of silicones, the premier example of which is polydimethylsiloxane.

 

(https://en.wikipedia.org/wiki/Siloxane)

 

Silicone:

Silicones are polymers that include any inert, synthetic compound made up of repeating units of siloxane, which is a functional group of two silicon atoms and one oxygen atom frequently combined with carbon and/ or hydrogen. They are typically heat-resistant and rubber-like, and are used in sealants, adhesives, lubricants, medicine, cooking utensils, and thermal and electrical insulation. Some common forms include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk.

 

(https://en.wikipedia.org/wiki/Silicone)

 

Q8 (silicone spray)

Q8 is a unique silicone spray which repels moisture and waterproofs all surfaces. Q8 is a non-staining lubricant for clips, hinges, rubber bushes and plastic fittings making it ideal for use on cars. Q8’s unique difference to other silicone sprays is that it has a 60% silicone oil content, making it one of the highest quality silicone sprays you’ll find on the market. It consists of an organic mixture of polydimethylsiloxanic fluids which repels moisture, waterproofs surfaces, lubricates and prevents arcing and spatter.

 

(http://qoilseurope.ie/portfolio-item/q8-silicone-lubricant/)

(a.tritonleo.co.za/docs/Q8_MSDS.doc)

First to admit that I am no chemical engineer.............am I missing something, or is both the Finish Line and Q8 product silicone based? 

 

 

 

being silicone based does not make them even broadly similar in behaviour

[droo]

if the fork is running dry surely its time for a lower service....as an emergency maybe use a little of the oil you use to service.

 

This is true. However, when you wash your bike you remove the oil that sits on the surface of the stanchions, so the for the first few cycles they run unlubricated through the seals. Using a stanchion lube after washing sorts this out.

 

Using stanchion lube to avoid servicing your fork is just a waste of time.

[droo]

being silicone based does not make them even broadly similar in behaviour

 

Sand is also made of silicone, and its lubricating properties are well documented...

Edited October 28, 2015 by droo

[raptor-22]

silicon and silicone are not the same thing

 

 

sand is aluminium silica. again Silica is more closely related to silicon than silicone.

 

sometimes English is just Sili

Edited October 28, 2015 by raptor-22

[BarHugger]

being silicone based does not make them even broadly similar in behaviour

That is why I am asking. Please explain the difference in behaviour.

[droo]

silicon and silicone are not the same thing

 

 

sand is aluminium silica. again Silica is more closely related to silicon than silicone.

 

sometimes English is just Sili

 

http://1funny.com/wp-content/uploads/2012/02/silly-cone.jpg

[Capricorn]

Sand is also made of silicone, and its lubricating properties are well documented...

 

*points and giggles*

[raptor-22]

That is why I am asking. Please explain the difference in behaviour.

 

 

Key is in what you posted earlier about the molecular make up and the length of that chain.

Longer chains are less susceptible to polymerization whereas shorter chains are. then is its state a solid, semi-solid or liquid at room temperature.

So the solid can be used as additive to a lubricant, the liquids can be used as a lubricant and high temperature hydraulic oil (DoT 5 Brake Fluid : Note not DoT 5.1)