I'm considering getting a steel frame to upgrade from my aluminum xc bike. As it will be my first steel frame I'd like to understand if there is more after ride care required than my current bike. Usually after rides now I generally just wipe off the staunchions and wash only on the weekends. If I had a steel frame that had been rust proofed would I have to do much different?
I ride a steel frame fixed gear nearly daily in tropical conditions, and near the sea. It really puts the frame through its paces. As far as my experience goes, there's nothing that can be totally rust proofed.
Using any sort of metal lubricant on the inside of the tubes will certainly help prolong the life of your steel frame. Some may insist on using the tried and proven J.P. Weigle's Frame Saver. The seat tube and bottom bracket are where rust forms the quickest, as moisture gets to them easily. Always remember to lube them, especially after wet rides, as the lubricants can be easily washed away by tire spray and water seeping between the crevices.
Apart from the inside of the frame, do note that the quality of the paint/clear coat has a great impact on how "rust-proof" the frame is. If the paintwork is chipped, which can easily happen if you ride often, there's a chance that the frame will start rusting from the chip.
Do care for your steel frame as you did with the aluminum frame. It may be prone to more visible wear and tear, but as long as you take care of it, it's bound to last a lifetime. Steel frames are durable and great to ride on. It's worth the time to take care and maintain them.
As an extra precaution, I remove almost all the components, except for the crankset/bottom bracket, and give them a thorough wipe down and re-lube once every two months.
If you're going to be riding in particularly corrosive environments (the beach, salt coverered winter roads, etc.) I recommend doing something to protect the inside of your frame. I spray some T-9 in the frame of my Surly every couple of rides in the winter. I've also heard good things about J.P. Weigle Frame Saver. http://www.bikeradar.com/gear/category/tools/cycling-tools/chain-lubricant/product/review-jp-weigle-frame-saver-10220
(I am not talking about the things you buy from department store with two wheels for $100.)
There is a mis-perception boarding on conspiracy that steel rusts and aluminum doesn't. Aluminum bikes rust about as much as steel. This is mostly propagated by people who have never owned a decent steel bike and don't know what they are talking about... Quality steel does not rust significantly, otherwise how do you think all those bridges and ships don't fall apart after a few years. Do you avoid buying a car made from steel because it rusts? When did you last see an aluminum car (Land Rover - but plenty of them rusted their way to the wreckers yard)
I have a 1992 steel MTB that lives outside. Apart from the old surface rust where the frame is scratched, there is no rust on it - except the chain, nut and bolts, cluster, seat rails..... i.e. all the accessories that an aluminum frame has that are made from steel - hence my assertion that Aluminum bikes rust about as much as steel... The accessories do on both, and the frame doesn't on both.
Have you seen what happens to aluminum when it corrodes, which it does.... I would rather ride a old rusty steel frame than an old, poorly maintained aluminum frame.....
I agree with Snikrs and also ride a steel fixed gear frame in often wet UK. I recently purchased my current frame (upgrade the old one didn't rust through) and before using it sprayed the inside of the frame with Waxoyl but if I had been able to find it in the UK would probably have used J.P. Weigle's Frame Saver which many people swear by.
What I don't like about Waxoyl is it remains quite slimy, I'm not sure if it would be good in a hot climate but it would be better than nothing. You have to be careful in the seat post area and clean it out to allow the frame to grip the seat post. But if done with care its not an issue. I usually just wipe the seat post with an old greasy rag to prevent it sticking in the frame. It is also important to move the seat post every now and again (3 months maybe) as a stuck seat post can be really hard to remove.
The other precautions I took before riding the frame were:
The one step I didn't follow in the Bike Radar article was drilling a hole in the bottom bracket shell. I couldn't bring myself to put a hole in my nice new frame even though its not a flash one. I suspect plugging all holes before ever ridding may negate the need for this but I will inspect the bottom bracket shell after a few very wet rides. If you do drill a hole remember this will open the frame up to rust so paint it or varnish it.
Finally keep on to of scratches. I usually apply clear nail varnish as you can never get a perfect colour matched paint.
I hope this helps.