ATF Lube for a 3 speed?
 

I dissasembled and regreased an old three speed bike the other day, and everything went fine until it came time lube the three speed hub. I checked around the garage, and the only oil I could find was Automatic transmission fluid. It was late at night, all the stores were closed, so I figured, what the heck, if cars love it, the bike may love it too. So, I loaded the hub up with ATF, let it soak an an hour, ran it through the gears, (unloaded), put a few more drops in there and away I went. This is the first three speed bike I've ever ridden, however, the hub sounds good, and it seems to shift fine. I've ridden this bike about 10 or 15 miles, and it still seems fine. Has anyone ever used ATF to lube a 3-speed before? If I keep it in there, do I run a chance of damaging anything down the future? Thanks

Well, when I was in the Navy, aboard an aircraft carrier, they told us that ATF was the only "all-purpose" oil. In the event of a shortage of hydraulic fluid for the F-14, FA-18, etc, we were authorized to use ATF as a substitute.

If it works in a fighter plane, it can't be that bad.

Sheldon says a medium weight oil is best, such as motor oil. I've never worked on a S-A hub, but I bought one recently and I'm going to use 30W motor oil when I add oil to it. Sheldon says a good way to tell how well the hub is lubed is by the sound of the pawls: too loud and it may be too light an oil or the hub is dry, and a very dull and quiet hub may mean it's gummed up. Here's a link to Sheldon's site, scroll down to the heading "oil lubrication."

http://www.sheldonbrown.com/english-3.html#sturmey

If it's working fine and sounding OK I wouldn't worry about it.

I was looking at a SA AW hub at the bike swap that had no fitting to add oil. It was one of the new ones. All the seller could tell me is that they don't need it. I'm not drawing any conclusions because I know nothing about SA hubs. I just thought it was interesting.

ATF should be ok, but you didn't say what ATF you used. Most modern automotive manual transmissions now specify a synthetic type of ATF for the fill and they see a lot more stress. We're not talking about Dexron, Mercon, or Type F, but ATF+4, Amsoil MTF, GM-SFM fluid: part #12377916, Royal Purple MTF, etc etc. The later fluids help in fuel mileage and allow tighter tolerances while providing protection and lubrication with a wider operating temp range and most have friction modifiers for really smooth shifts. But the cost is a lot higher than using a conventional or synthetic oil, so it isn't really worth it in a bicycle application unless you plan to race.

ATF is quite solvent...it might be better used for flushing out old crud from the hub than as a lubricant. Still, I can't see the harm.

That's what I thought, too. It has a lot of detergent, and being that my 3-speed hasn't been ridden in many years, I figured it would help clean it out. It has to have good lubrication because all of our automobile automatic transmissions use it. I used the two or three buck a quart dextron /mercron. I didn't use the high $$ fluid. I'll keep it in there until I hear otherwise. Thanks

After reading this, I am filling my AW hub with this also. How much should I use? What is the best method of filling it? I don't have a micro funnel.

My methods vary according to what's available. If my pump oil can is filled with something else, a squeeze bottle with small tip (like maybe the ones from saline solution used by contact wearers) might do the job.

You're not filling it right up, after all. A couple of teaspoons' worth is adequate.

If you have patience in abundance, you can bend a stiff wire to lead down to the oil port and drip ATF onto it. It works, but slowly.

I used a zip lock bag and just let it drip carefully into the filler. Worked great. The hub is so nice and smooth now! Only problem is that the hub is leaking it out. I am positive that I overfilled it, I just put tons of the stuff in there so that it would have plenty of lubrication. I over did it a little :o