I've been looking at expedition/touring bikes recently. One thing that doesn't make sense to me is that there are a lot of expedition bikes that have aluminum frames.

I understand that most tourists who buy these won't be in the second and third world where it's difficult to get aluminum repaired, but many of these expedition bikes, that are meant for world travel, have aluminum frames. Two that come to mind are the REI Safar and the Koga-Miyata WorldTraveler.

Is it better to have a steel frame on a bike meant for travel into the second and third world, or is it just me?

3.5lbs Al frame is worrisome, 4.5lbs Al frame won't break and is stronger than a 5.5lbs steel frame.

Cannondale CAAD touring frames have been all over the world.

It sometimes strikes me as worrysome, but we use 6061 T6 for all kinds of military parts and it seems to hold up "forever". The 7000 seires, which some bikes are made of is what is used in aircraft - think of the flexing and stressing that entails. If you get in an accident that mangles a frame will you still be able to ride it?

Joe

I broke my arm crashing an aluminium mountain bike, and rode it for a few thousand miles afterwards, over rocks and roots and small jumps. That frame (1999 Specialized Rockhopper A1) is perfectly ok.

I don't think the material matters so much as the way it is put together - but if you are planning on breaking a frame in a remote part of the world, steel is better because you'll be able to find someone who can weld it more or less anywhere.

American has 30 year old DC-9s. The wings are Al, they are holding up pretty well with over 50,000hrs on them. 50,000hrs on a bike takes 50 years at ~3hrs per day

It wouldn't worry me particularly. Frame failure is pretty rare (I've had two break, but that's over many years) and I'd expect that in most cases the best way to deal with it would be to have a replacement shipped out directly or buy a locally available bike to reach a place where one could get a shipment. And if I had to choose between two frames of similar weight but with one steel and the other aluminum I'd certainly put more faith in the aluminum one not to fail in the first place.

I know I've said this before but take an afternoon and attend some regional NORBA races and observe what those daredevils do with their aluminum mountain bike frames. When you witness what they put their bikes thru, you'll realize that your chances of breaking your frame while touring (although not impossible) is not very likely.

Although I still hold somewhat to the ol' "aluminum tends to be harsh" saw , I don't think it matters much. The chances that you will find an experienced welder who really knows how to repair a steel bike frame, and get it back to tour-worthy condition, is pretty small. The in-the-field welding jobs I've seen so far have not exactly been impressive.

I'd choose your bike based on comfort and specs, but do not see much reason to worry about frame material per se.

A related question: why not make touring frames of aluminum?

I was looking at Rocky Mountain's steel-framed Sherpa 30 tourer, and I noticed that, though it's obviously equipped differently, the frame geometry is extremely similar to that of my aluminum-framed commuter.

So given that so much else is equal, why the difference in frame materials? The [supposed] ride quality? The [supposed] weldable-in-rural-Africa factor?

And if you have a complete failure of your frame and are NOT in Africa, you can go to a nearby bike shop and buy a new bike. Of course, it's better if you don't have to do that, but few have needed to, so far.

I had done at least 50,000 miles of touring before I had an aluminum frame break in Australia in 2001 - so the overall incidence rate is fairly low. When that happened, I found the easiest way was to fly back to USA and pick up a spare bike.

While it wasn't third world, when I did a later expedition trip across Russia in 2007, I did do two things: (1) I left behind a spare Trek 520 in Russia on a pre-trip in 2006 and (2) I used a steel frame bike. So this way if a bike was broken or stolen, I could pick up my spare after a train ride within the same country.

So even though I did pick up a steel frame bike, I'd say risks of breaking a frame and not being able to repair it - would be pretty far down on the overall risk list for a third world tour and even lower on the list for a tour in the developed world.

It's not the hours in the air that fatigues the Al. it's the number of take-offs and landings.

It's not the number of takeoffs and landings that fatigues the Al. It's the number of pressurization cycles.

Never had a frame break on tour, course I've only done three so far. I have, however, had two other frames break. Both were steel, both cracked at the right dropout/chainstay interface. I don't own any aluminum bikes, but I wouldn't hesitate to ride one on a tour. Especially for heavy riders like myself, a good stiff Cannondale touring is probably a better bet than say a trek 520, which would be noodly under so much load. My touring bike is a trek 930 MTB, which with its oversized frame tubes has superlative frame stiffness as good as aluminum.

And worrying about frames breaking on tour is just one more way to express paranoia about embarking on an big adventure. Hell, if an aluminum frame breaks on tour, you could probably macguyver it with fiberglass to get you through.