It wouldn't be so bad -- really -- to come home one day and find that your wife ran off with an itinerant revival preacher, that your pickup truck was towed and impounded, and that your dawg was run over. At least they'd write a country/western sawng about you.
But who is going to give any sympathy to a mountain biker with a broken heart and a cracked frame? It cracked some time last week, just fore of the seat post/top tube weld.
Sigh. With a little bit of analysis I think I know who the culprit is. I had ridden with a rear rack that was cantilevered off of the seat post, because you can't mount a standard rack on a full suspension bike, which bends after all.
The rack warns people to put no more than 25 pounds on it. I put on less than half that. With 20/20 hindsight I suspect that their number was pulled out of thin air (or the next most imaginary source, computer modelling.) It would be too expensive for the rack manufacturer to do real-world, destructive testing on all the bicycles in the world.
The moral of the story is to avoid these cantilevered, seat-post-mounted racks, and find other places to mount your stuff.
A reader/commenter, Wayne, asked about mountain bikes the other day. Would this disappointment of mine also be a negative advertisement for full-suspension mountain bikes (i.e., those with shocks/flexure on the back as well as the front)? I was disgusted to learn what I should have paid attention to, earlier: that full suspension bicycle frames are only guaranteed for 5 years, unlike the lifetime guarantee on many of the "hardtail" bikes (i.e., those with shocks only on the front; the rear triangles are rigid.) But you need to check that for your bike -- the situation with warranties is degenerating.
Nobody bikes with two shocks instead of one, with all those extra pivot points, and expects it to have lower maintenance costs than a hardtail. But full-suspension mountain bikes are much more comfortable on washboard roads, let alone real trails. The case could be made that a hardtail with the bigger tires (29 inch) is the optimal middle ground. If so, then I have to admit that Box Canyon Blog was right and I was wrong. And I ain't prepared to take that step!
But who is going to give any sympathy to a mountain biker with a broken heart and a cracked frame? It cracked some time last week, just fore of the seat post/top tube weld.
Sigh. With a little bit of analysis I think I know who the culprit is. I had ridden with a rear rack that was cantilevered off of the seat post, because you can't mount a standard rack on a full suspension bike, which bends after all.
The rack warns people to put no more than 25 pounds on it. I put on less than half that. With 20/20 hindsight I suspect that their number was pulled out of thin air (or the next most imaginary source, computer modelling.) It would be too expensive for the rack manufacturer to do real-world, destructive testing on all the bicycles in the world.
The moral of the story is to avoid these cantilevered, seat-post-mounted racks, and find other places to mount your stuff.
A reader/commenter, Wayne, asked about mountain bikes the other day. Would this disappointment of mine also be a negative advertisement for full-suspension mountain bikes (i.e., those with shocks/flexure on the back as well as the front)? I was disgusted to learn what I should have paid attention to, earlier: that full suspension bicycle frames are only guaranteed for 5 years, unlike the lifetime guarantee on many of the "hardtail" bikes (i.e., those with shocks only on the front; the rear triangles are rigid.) But you need to check that for your bike -- the situation with warranties is degenerating.
Nobody bikes with two shocks instead of one, with all those extra pivot points, and expects it to have lower maintenance costs than a hardtail. But full-suspension mountain bikes are much more comfortable on washboard roads, let alone real trails. The case could be made that a hardtail with the bigger tires (29 inch) is the optimal middle ground. If so, then I have to admit that Box Canyon Blog was right and I was wrong. And I ain't prepared to take that step!
Comments
I've had stress fractures occur on 1/4 plate rigs and everything on down. The truth is likely that if that rack were on a rigid tail the failure would have occurred sooner as there would be no concussion absorption at all.
The real question is, and I think the most accurate; Did the rack make the seat fail... or was there 160 pounds or so sitting on the top of that seat that had a lot more impact on the frame than the 12 pounds you said you put on the rack?
Or, maybe even MORE likely, was there a fault in the tube/weld that led to the failure that had nothing to do with the rack?
I'm not sold that the rack was the problem. I also think it more likely the designers/engineers were more talking about the rack bending from weight than the bike frame failing. If your weight on the end of that tube isn't an issue, I can't believe a mere 12-25 pounds is going to be a problem.
Why a new bike? Get a good welder to seal up that crack and put a small gusset on the top while he's at it... maybe even another small gusset under the crack location as well. A couple of welds by a competent welder's a lot cheaper, and with gussets a whole lot stronger than a new bike that might just do the same thing.
You might be right that, all else being equal, a hardtail might crack before a full-suspension does. This would seem to belie the LIFETIME warranty for the hardtails versus the 5 year warranty for the full suspensions. But the difference might be the harsher use that the owners of full suspensions dish out.
Your advice about the welding is duly noted, and will be implemented soon. Actually, this is an interesting opportunity to see how much of the image and folklore of bicycle frame black art is just blarney. Every industry sees physical reality suborned by marketing psychology. More on that later, as the repair/replacement soap opera proceeds.