According to these American users on bikeforums.net, mixing straight chainsaw oil (chain and bar lube) with mineral spirits 4 to 1 makes a great bike lube here:
Join Date: Dec 2005
Location: Sunny Tampa, Florida
Quoted: 54 Post(s)
Straight chainsaw oil (chain and bar lube) is very thick and sticky and tends to attract and hold dirt. Not a problem for its intended use but not so good for bike chains or other parts.
To use it on a bike chain mix it about 1 part oil to 4 parts mineral spirits in a small squirt bottle. Squirt the chain down and wipe off the excess with a rag. The spirits will evaporate leaving a very excellent lube on the inner parts of the chain where the lube needs to go. This will also remove the road grime from the outside of the chain. Use this mix to clean the glop off your chainwheels and cogs, leaving a light film of the oil to prevent rust. This has been my main lube on all my bikes for a few years now and it works great.
This is very inexpensive and I can't recommend it highly enough.
And another active user concurs:
Galveston County Texas
Quoted: 709 Post(s)
That is what i use. I ride with a Bike Mechanic. One Part chainsaw
Oil, Plus three parts Mineral Spirits. Put it in a spray bottle.
Another user has a slightly different take, mixing another cheaper oil with mineral spirits too here:
My bike's better than me!
Location: Northern Colorado..
Chain saw oil works. Almost any lubrication works. Keep your chain reasonably clean and lubricate it reasonably frequently.
You hit the Point of Diminishing Returns incredibly quickly on chain lube. If you value neither your time nor your money, you could certainly research the crap out of this, clean your chain with an ultrasonic cleaner every other day, and lube it with Dumond or Mobil1, straight, but ....why?
I apply a 50/50 mix of mineral spirits and Mobil1, with a toothbrush, AFTER every other ride or so, allowing the mineral spirits (that thin the Mobil1, allowing thorough penetration) to evaporate.
I get GREAT life out of chains, and that's with lots of hill climbing. I spend next to nothing on the mix.
If/where viscosity is a concern, you can thin it, but ... as Hobartlemagne said ... there is a point at which thick is too thick. You could probably follow the automotive manufacturers weight-vs.-temperature guidelines and not go too far wrong.