Just noticed this the other day! It’s an AL frame, made by Javelin. It’s roughly 8 years old and has never given me a problem until now. The warranty is voided b/c the Co. went bankrupt/got bought a few years ago. Bike shop said cutting it at the bottom of the crack and putting a seat collar on won’t work b/c of the design of the bike. Flares and not completely round. I am attempting to attach a pic.
another pic to show the collar
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If it was me, I’d say 8 years is a pretty good lifespan for a bike.
I would pull the seatpost out, drill a small hole at the base of the crack to relieve the stress, reinsert the post and tighten it up and put the bike on the trainer (so in case anything bad happens, I won’t take anyone, including myself, out).
Probably not worth the cost of any other repairs.
Are you a light rider? It is not your fork, so I doubt that the frame is going to just snap along the seat tube all of a sudden. Ride it and review it daily. If you get two more seasons out of it, you have had your bike for 10 years. 
If it was me, I’d say 8 years is a pretty good lifespan for a bike.
I would pull the seatpost out, drill a small hole at the base of the crack to relieve the stress, reinsert the post and tighten it up and put the bike on the trainer (so in case anything bad happens, I won’t take anyone, including myself, out).
Probably not worth the cost of any other repairs.
This is what you need to do.
I do agree that you should retire it to the trainer. I’m not so worried about the crack spreading once it’s drilled as I am about other pieces being close to their fatigue life and ready to fail.
I have that exact same bike, and coincidentally just had to make a repair on the seatpost, though mine was because the threads on the seat-bolt stripped out. Although you face a potentially difficult repair, I disagree that the bike is ready for the trainer, this bike has a good dose of “ugly fast” - i.e., it’s not nearly as slick looking (nor nearly as comfortable) as the latest aero bikes, but it’s stiff, light, good geometry, and reasonably aero by aluminum frame standards. I pass a reasonable number of $4k carbon bikes on my 8 y.o. javelin, and I’m by no means a beast on two wheels.
A couple thoughts:
(1) Ignore the post about fatigue life. Fatigue life applies to parts that are subject to >thousands of stress cycles (push-pull) during their life. Unless you adjust your seat height every minute or two while riding, this particular crack has nothing to do with fatigue.
(2) Have you verified that the collar is cracked through? If your bike is like mine, the powdercoat paint is pretty thick in this spot. Since the powdercoat is much more brittle than the aluminum underneath, It’s possible that the crack is only “paint deep”. Easily checked by removing the seatpost and inspecting the inside of the seat tube with a bright light. If the aluminum is cracked on it’s surface, but not all the way through, you may be able to save it by grinding away only the cracked portion but leaving, say, at least 1/16th of an inch of material there.
(3) If the aluminum is indeed cracked through, you MUST drill out the end of the crack as the previous poster said - otherwise the crack will propagate rapidly
(4) It’s possible, even after drilling out the crack, that the seat-tube may securely hold the seat post just fine. This can be tested easily enough using tape/marker on the seat-post a bumpy patch of road
(5) Barring all of that, I still think you could put a normal seat-collar on that seat-tube easily enough. This is what I was considering when I stripped the threads on mine (found an easier fix for mine). The “flare” on the back of the top couple inches is just a thin sheet of aluminum on each side that are added on the a mostly round cross section of tube. By hacking off the current collar and then removing the top half-inch or so of the rear-ward “flare” sheet portions, you would be left with about 3/4 of a circle of round aluminum tube (with a bare spot in the back). This should be plenty of territory for a seat collar to securely grab the seat tube and clamp down on the seat post, making a solid connection.
If you do decide to retire the bike - let me know, I want to buy a back-up derailleur hanger and can’t find the one that came with this frame anywhere.
How about this…
Drill a small hole at the end of the crack.
Drill a bigger hole through the frame, through the seat post, out the other side, and then run a bolt through there.
This way you would stop the cracking and relieve the pressure on the collar.
drill a small hole at the base of the crack to relieve the stress, reinsert the post and tighten it up and put the bike on the trainer (so in case anything bad happens, I won’t take anyone, including myself, out).
I literally shart my pants as I took my first flight getting my private pilot’s license. The instructor was going over the pre-flight and he said ‘notice the cracks here, start keeping a mental note of which ones are new and old so you can inspect the ones we have drilled to relieve pressure’. Uh hem. Gulp. I learned that little 182 inside and out!
i removed the seatpost, inspected the inside and It doesn’t look like it is cracked all the way through. So what do I do to grind down the aluminum? Also , your seat collar option sounds doable? The LBS probably didn’t want to mess with it. What would I use to cut the aluminum? Also, is welding an option? Thanks for your help.
If none of the solutions work in regards to securing your seatpost there is another option. If you are not a weight weenie you could take a wooden dowel (or any piece of wood/lumber that would fit inside) and place it inside your seat tube and seat post so that your seatpost sits atop the dowel. You’d have to cut to length and carve/whittle/grind the bottom of the dowel so that it sits squarely atop the bottom bracket shell inside the bottom of your seatpost. I have a prototype bike and the seat post clamp/collar doesn’t hold the seatpost no matter how much friction paste or torque you put on it.
Disagreed on the part about fatigue life. The load cycle on that part is not limited to tightening and loosening the collar. The collar of the bike ( along with the other areas of the seat tube that are essentially working in an interference fit with the seat post) transfer the vertical load that is your body weight, along with any eccentric loads caused by pedalling, into the frame. I would say that part gets cycled with almost every pedal stroke and especially with every bump in the road.
i removed the seatpost, inspected the inside and It doesn’t look like it is cracked all the way through. So what do I do to grind down the aluminum? Also , your seat collar option sounds doable? The LBS probably didn’t want to mess with it. What would I use to cut the aluminum? Also, is welding an option? Thanks for your help.
First, using some medium grit sandpaper sand the paint off of the top part of the front of the seat collar - to get a cross-sectional view of the crack. Once you get through the paint inspect this cross-section with a magnifying glass (or at least an extra pair of reading glasses held up-close) and a bright light. If it appears only the paint layer is cracked, stop right there, your seat tube is sound (you may want to add a dab of epoxy or the like to keep the paint from flaking off in the future).
If the crack penetrates the surface of the aluminum, but not all the way - this is likely due to a welding error that made the outermost portion of the collar excessively brittle. Assuming you have a drill (or even better a dremel), use a grinding bit like the one linked to below, or maybe a spherical version of a similar bit, to sort of “dig out” the cracked portion of the aluminum, making sure not to leave sharp edges or corners. If you find yourself having to dig past about halfway through the collar, you’re better off going with the new-collar approach instead.
For the new-collar approach: To cut the aluminum, a carefully wielded hacksaw should be fine to remove the collar. Cut about 1/4 to 1/2 inch below the existing collar (making sure you’re past the crack) and make sure to cut perpendicular to the seat tube, rather than parallel to the ground like the current top of the seat tube (otherwise you’d need an oval seat clamp). Then you could get a small 1 1/2 inch side-cutting drill/dremel bit, instead of the grinding bit shown above, to remove the flanges from the circular portion of the seat tube. Such a bit would look similar to that bit linked-to above but thinner as to have a sharp edge.
Also, welding is definitely an option, if you are able to do it cheaply. You may even be able to get a replacement collar through the existing javelin company, since I know they are still in contact with the person that made these bikes and were extremely helpful when I called them. This could be welded on where the existing collar is/was and then you’re good as new (minus some yellow paint). If you don’t have an “in” with a good aluminum welder (or are one yourself) I suspect this would be a significantly more expensive route, though.
Let me know if you have any other questions.
Disagreed on the part about fatigue life. The load cycle on that part is not limited to tightening and loosening the collar. The collar of the bike ( along with the other areas of the seat tube that are essentially working in an interference fit with the seat post) transfer the vertical load that is your body weight, along with any eccentric loads caused by pedalling, into the frame. I would say that part gets cycled with almost every pedal stroke and especially with every bump in the road.
ZackC I can see what you’re getting at, but by far the primary load on an part of the seat collar is the constant tensile force created by the seat bolt pulling the collar tight around the seat post.
I could write ad nauseam about why the rider’s weight, being a relatively constant force, does not cause cyclical stress on this collar, or why the pedaling and road forces, which do cause cyclical bending moments and shear stresses in the frame, do not create any stress along the center-line of the seat tube. However it’s a beautiful day in south florida and I would rather spend my next couple hours creating eccentric loading on the frame of my own javelin. More to the point is that the original “fatigue” comment implied that the existence of this crack meant that other parts of the bike may soon fail by fatigue. Anybody who has studied the subject knows that fatigue life of parts varies widely (many orders of magnitude) based on the amount and direction of the cyclical force, specific geometry of the part, and other factors. The time of fatigue failure of one part on the bike therefore gives absolutely no indication as to where other parts may be in their fatigue lifetimes - so in any case it’s a moot argument. In other words, pjmlsu and the riders around him should feel just as safe riding today as they did any other day, regardless of whether fatigue caused the crack in his seat tube collar or not.
BTW an “interference fit” implies that the seat post would be larger, at least in one dimension, than the inner diameter of the seat tube it’s meant to fit in - something that conjures up images of giant hydraulic presses needed overcome the enormous forces that would be required to adjust seat height (then “your seat is too high”, may mean having the shell out $$ to the LBS for their hypothetical “seat height press” for an adjustment). The relationship between the seat tube and seat post would ideally be a transition fit, possibly a clearance fit, thus necessitating the additional fastener on the collar to, well, make it fast
Trevor? Give me a call,
Rich 954-242-0163