People use WD-40 for the darnedest things. I read an article awhile ago on people who suffer from arthritis. And they swore by rubbing WD-40 into the joints of their legs and/or arms.

I run some old bikes that use no grease except in the headset but rather, have oil ports in the hubs and bottom bracket.

It makes for an insanely smooth running bike but the oil does need to be topped up every 100 or so miles or after a long period of being idle.

Some of my bikes with non cartridge bottom brackets and no filler still get their bb's oiled via the seat post.

Using ATF (automatic transmission fluid) I found works great for those old rollers. There was the 6 ounce can of Sturmey Archer oil for $1.00. Or a quart of ATF - the "pink stuff" - for $1.00. I never did use up that quart - before some bald guy in a Porsche stole my bike from my garage at 3:00am.....GRRRRRRRR........

You can't trust bald guys who drive Porsches.

Once the thinner evaporates it does very little. After ~6 weeks you get a lot of chain noise regardless of how heavily the bike was ridden. That being said, there was a gentleman on here who was using WD40 on his winter bike, and simply applying every 2 days to combat the winter salt/grime. I suspect used in that particular, it probably does a far better job than a conventional chain lube would.

If you have a new bike, it should be pre lubed with propper greases and oils. No need for WD40 or any other oil for several hundred miles. Just assemble the bike per manufacturers instructions.

Let's leave bikes for a moment and look at cars. You use various oils for specific jobs in a car. The engine gets motor oil, the rear end gets a gear oil, and the transmission gets transmission fluid for automatics, or a different gear oil for standards. All of these come in various grades selected according to weather and operating conditions. Then there's grease for the hub bearings, a light spray oil for the door locks, and another for the throttle cable, and a few other places I haven't covered yet. So we have dozens and dozens of auto lubes.

Nobody questions the need for similar but uniquely different oils for various applications in a car, and there aren't car lube threads. One reason is that car makers, the SAE, and API are all very specific about what's used where, limiting debate to the confines of selecting according to weather. Another is that the consequences of using the wrong oil manifest rapidly and can be very expensive, so folks tend to toe the line.

But the bike world is very different, and there are no established rules, nor are the consequences of error obvious or expensive. But just like with cars, bikes have various specific lubricant needs, from the greases for ball bearings, to light oils for cables, to (I have to go there) what a chain calls for. Like with cars, the oil choices will also reflect operating conditions along with other factors.

So I don't debate whether WD-40 is a lubricant or not (it is) but whether it's an appropriate lubricant for specific applications on a bicycle. IMO - it can be fine for a chain that's not run at high tension loads such as for a small casual rider who doesn't climb hills often, but not for a heavier rider in hilly country, or a strong rider who cruises at 20mph or so. I use a product similar to WD-40 all over my bike, but not on the chain, or on loaded moving parts. Likewise I don't use chain oil where it isn't right for the job.

Now as for the best chain lube. That depends on all sorts of variables, starting with speed, slope, and rider weight. Then add weather conditions, and rider preferences, and it becomes obvious that we can debate forever because we're now comparing apples to oranges.

Might be that you could design a chain that used WD40 as lube :-).

The 91 Chevy S10 I had used ATF in the standard trans, and both of my current 2000+ model year Chevrolet use ATF in the transfer case. ATF is just an upscale 30 weight hydraulic oil actually. Many machine tools use AW32 for a lot of stuff and ATF has been used in a pinch. They also use a lighter oil in ring and pinion rear ends for stuff like qualifying for 3 laps under power. You could probably operate a vehicle strictly on ATF in a pinch, engine, trans, rear end and power steering as long as you did not run 70 mph for hours and hours.

That said as pure errata, I use WD40 as a cheep flushing agent when I'd rather leave a petro film for the next lube. Last winter I did use WD specialist silicone lubricant on FD and RD on my winter bike, just sprayed on and blew off all I could with compressed air, and will this winter too, they work sub freezing, if they wear out after another 1500+ this winter I will replace them. I put pro link on the chain after a wash out, but last winter was old wd40 every few days and a 100 psi blow dry.

Former pro, current GCN host Simon Richardson uses WD-40, both as degreaser and then lube. See video. I might just start using it myself just to wash all the oil debates permanently from my life.

You obviously don't hang out on car forums. There's endless debates on the "best" motor-oil for virtually every engine, and there's the entire Bob-is-the-oil-guy forums. An entire forum devoted to literally nothing other than engine oil.

Yes, but they're limited to the narrow scope of motor oils. No credible person proposes using gun, gear, or machine oil.

Let me tell you about motorcycle chains. You had wet and dry lubes.

The wet lube was meant for street bikes, and left a waxy residue. You needed to re-apply it after you rode in the rain.

The dry lube was meant for dirt bikes, and didn't leave any residue so you wouldn't catch the mud and sand on your chain. Normally you cleaned your chain after every ride and re-applied the dry lube.

Now for both types of motorcycles, some folks used WD-40 and it didn't seem to affect their chain life much. Since motorcycle chains are o-ringed, the main purpose of lube seemed to be to keep corrosion away. And WD-40 did that.

After that lengthy discussion, I think we're all going to be fine if we use WD-40. I personally am using the leftover motorcycle chain lube that I have in my garage.