After two years of winter commuting using my old Bianchi Nyala, last year I decided to buy a dedicated winter commuter. I picked up a Rockhopper A1 comp, aluminum frame, in great shape. My first aluminum frame - figured I wouldn't have to worry about rust, etc.

Edit: Rode it all last winter, during the extended polar vortex, aka the Winter from Hell. Worked great, got me home almost every time!

Two weeks ago, with the impending polar vortex, I tuned up the Rockhopper, and put on the studs, to prepare for my first real winter commute of the year. I finished my tuneup, drive-train sparkling like new, and was taking the bike out of the repair stand, when I notice THE CRACK. My head tube had about a 1" crack starting at the top cup.

So much for my first winter commute. I didn't have time to switch my studs to my "summer" bike; there went my 8 week unbroken streak of bike commutes.

Just tonight I disassembled the Rockhopper. A buddy of mine is a welder - I was going to let him try to fix the crack. Then I notice the SECOND CRACK on the bottom of the bottom bracket.

So I guess this frame is now going to recycling.

I kind of wondered how aluminum would hold up to Minnesota sub-zero winters. Now I know!

How's YOUR winter commuter running?!

Wow! Sorry that happened to you but I've been using an aluminum bike for a few winters now without any problem. Even my 10 year old aluminum/carbon road bike has seen some pretty cold temps.

I'm confused. Reading your post, it sounds like the bike hasn't been out in th cold yet. If that's correct, why are you blaming the cold for the problem?

While it's true that aluminum expands/contracts at almost twice the rate that steel does, I don't believe the difference (even in a Minnesota winter) would be enough to stress crack it. Plus, it looks like an aluminum headset, in which case, differential contraction wouldn't be an issue at all.

If you bought it used, odd are that something else happened, possibly beginning with galvanic corrosion which stressed the frame causing cracks.

I commuted a full winter on it last year - the winter from hell. Multiple, extended subzero days. My coldest commute was -23° F.

The bike is probably about a 1995 vintage. The guy I bought it from was the original owner, and the bike appeared to be relatively lightly used. He said he was a Pastor, for christsakes, so I have no reason to think this bike was abused.

It is the "A1" comp, so probably Specialized first generation aluminum. I'm thinking the subsequent generations were better quality.

I'm not really ripping aluminum bikes. It is just kind of funny that the first one I bought cracked.

Hey, I'm glad you responded! I know you're riding a Nashbar aluminum frame - how long have you used that? That is definitely one option I'm thinking of. A guy has a Nashbar frame on CL right now - if only he'd respond to me.

I was tuning up the "summer" bike today, and there is LOTS of rust on the frame. The problem isn't even so much that there is salt on the roads. The issue is that I'm a one way commuter, and the bike gets thrown on the front of the bus every morning, where it gets blasted with road salt at 60MPH.

My steel frames could probably handle getting blasted at 15 MPH .

My point was that you need to look elsewhere for the problem. A temp of -14°F is nothing. Consider jet aircraft that see swings down to -40 to -60°F twice daily and are made of (guess).

As I posted, I suspect the issue was corrosion not temperature swings.

I got it from Nashbar during one of their frame clearance sales, but it's not a Nashbar frame, it's a Mongoose similar to this except that I put drops on mine. At $25 it seemed like it was a steel (tee hee) but it was missing the EBB core which proved to be very hard to find.



This is an older picture. Now it has a fork that's similar to what it's supposed to have.



The model is called "Sabrosa" and it's kind of a jack of all trades. It could be fitted with a derailleur or an IGH. It has an EBB but newer models had sliding dropouts which would be better.

I can only speculate on the cause. If it had only been the head tube crack, I could have chalked it up to a number of reasons - corrosion, improperly seated cup, random stress. But when I found the second crack, I've got to believe there is an issue with this particular set of tubing itself. The bottom bracket cup is aluminum as well; there's no exceptional corrosion there, and as much as I'd like to think differently, I'm just not strong enough to create exceptional stress!

I'm pretty sure the guy I bought it from didn't use it in the winter; it was way too clean. So it only has one winter commuting to contribute to the corrosion issue.

It's funny . .. when you look at that picture long enough, the snow starts to look like beach sand. And you can almost imagine the frozen lake as bright blue water.

That was lake Nokimis.

This one is from its maiden commute by the Mississippi. I hadn't even gotten the bar tape or fenders on it yet. I do like to ride it in the summer too but this year it seemed like I had barely got around to getting the studded tires off and I had to put them back on again.



Don't really have a good recent picture.

That is the proper way to break in a bike in MN!

Has this bike seen salted roads? If so, galvanic corrosion might be the problem. Have you seen any white powder coming from or near the cracks? (Probably visible only if you take the HS and BB off.)

Ben

Heavily salted.

I can most certainly tell you Al bikes do just fine in much colder temperatures, for much longer than you see in Minnesota. You have something else going on here.

Whatever the cause is, that's a real shame. I don't see that happen much. Might it be covered under warranty? I don't remember if bike companies honor warranties for second owners.

You misunderstood me. I'm not talking about external surface corrosion. The issue (I suspect) is INTERNAL corrosion between the frame and head and BB cups. Aluminum "swells" as it corrodes, greatly increasing then internal pressure stretching the thin "rings" of the head tube and BB shell.

I'll net a few beers that if you knock out the head cup you'll find plenty of whitish powdery material there, likewise at the BB shell - if you can get the BB out.

If riding bikes in wet weather, especially in salty wet weather, it's absolutely critical that all cups, BB, and seatposts are greased well enough not only to prevent galvanic corrosion, but to fill any crevices that water might otherwise wick into.

As I said from the beginning, I don't believe this was a failure of the material. Instead it was a failure of the maintenance protocol.

A "premature" failure, as you seem to have experienced, usually results from circumstances not in accordance with the design intent. Fatigue cracks result from what is known as "cumulative damage". In the normal range of loading, this cumulative damage takes a long time to generate a macroscopic crack. If, for instance, the frame had been subjected to many cycles of abnormal loading prior to your acquisition, a large amount of cumulative damage may have been pre-existing.
Another possibility is a quality defect or perhaps an artifact of accidental damage during maintenance, resulting in a stress riser (notch, scratch, or nick in the material) in a highly stressed area, in other words a ready-made crack initiation site, which equates to a large amount of cumulative damage. Since your frame has two cracks, it would be quite a concidence for this to be the root cause in both cases.
It also occurs to me that simple overtightening of the threads (at least in the case of the bottom bracket) can cause an immediate or incipient crack.
On the other hand, some metal alloys are known to go through a brittle transformation below a certain temperature. This is certainly true of some grades of stainless steel, but I don't know if any aluminum alloys/heat treatments are subject to this phenomenon. Again, there could be a quality issue, not in terms of a physical defect, but rather alloy composition or heat treatment (though both of these seem quite unlikely to me). You might check with the manufacturer to find out if there are any known issues with the frame or its material, and whether or not the material has a brittle transformation temperature in the range you have ridden it.

I doubt that cold temps and salt had anything to do with the head tube cracking. I have an aluminium MTB frame which is 7 years old and has been exposed to a lot of salt, there are a lot of dings and scratches on my frame which means that bare aluminium is being exposed to a lot of salt, I don't even wash that bike, no cracks yet.
Since you bought the bike used, maybe the previous owner was doing a lot of jumps and drops to flat and not landing properly which put a lot of stress on the head tube and bottom bracket area. Or maybe it's just a quality control issue, something was done wrong at the factory where it was welded.

Probably a bad alloy mix or something. I rode my 12 year old cruiser in the polar vortex, and it too was completely fine. I would grab the serial number & contact manufacturer. Alu does not, in my experience, just crack. Something must be wrong with the alloy mixture or was not aneeled properly or something. Even expanding corrosion shouldn't do that to one of the thickest pieces on the frame.

My old cruiser did have one crack in it, however that was definitely from crashes, and NOT from cold.

- Andy

Yeah, pastors *never* lie, or bend the truth a bit.

Sometimes you just get a lemon, dude. Or the bike was stressed in tough ways and the guy never realized it.

Out of curiosity was that their "m2" aluminum? I have a '95 road bike of theirs and it has always impressed me for its age. Granted its been a California bike, so slightly different...

Just to further the point.......





- Andy

bummer, but on the bright side, there might be a new bike in your future!?

I think this is pre 'metal matrix', not sure when they started using it on the stumpjumpers.

I just realized, this is the second aluminum Specialized where I've found a head tube crack during a tuneup. I was tunin up a friend of mine.s hybrid about four years ago. That bike I know had less than 200 miles on it. But she was the original owner,so she got a new bike out of the deal.

That is the silver lining. In fact, I aready picked up another bike. A guy had a Diamond back Sorrento on CL for $15. Apparently it wasn't selling at such an outrageously high price - a couple days later I saw he cut the price to $8. I figured I could find a use for it so I picked it up. The seller had used it as a winter bike and put it away w/o washing off the salt, so the chain was a solid chunk of rust - which is why he was asking so little. Its cleaning up nicely,!

The types of forces generated through expansion, dwarf what frames are designed to withstand. Freezing water routinely bursts the thickest, strongest steel pipes, and shatters the stronger rock formations, so why should anyone be surprised that corrosive expansion can crack an aluminum tube.

Of course, that's just a theory, but it can be confirmed easily enough simply by removing either the head cup or the BB and examining the inside surface of the damaged tubes.