Cracked frame. How dangerous?

Correction:

The crack is where the top tube joins the seat tube, not the down tube.

--
Paul Turner

Paul Turner said:

I know that's the end of the line for the frame. Is is dangerous to ride it
gently for a few days while I shop for a new bike? I suspect that wouldn't
be a good idea, but I don't know anything about how aluminum tubing fails.

Consider your two options, toss the bike in the corner and save the gear
for spares or a better frame, or ride the bike. If you ride and the
frame fails it is, being aluminimum, likely to go very suddenly and
without any planning. If it doesn't happen while you are descending a
hill or being passed by a truck, and if the frame doesn't become a
jagged folder, or launch you face-first into the bitumen, so much the
luckier for you. If you avoid serious injury and also avoid damaging
some of those otherwise salvagable components of your bike then luckier
still. Always a better feeling than waking up in hospital to a long
recovery period, totalled bike and huge hospital bill. Do you feel lucky?

Paul Turner said:

Correction:

The crack is where the top tube joins the seat tube, not the down tube.

Is it the tube that is cracked or the weld, if it's the weld it could be
repairable, providing you know what aluminum alloy it's made from, and
there is a welding shop with the right equipment and welding rod in your
area.

W

On Sat, 12 Nov 2005 06:45:37 -0600, "Paul Turner" <[email hidden]>

Quoted message said:

I have an aluminum Cannondale touring frame (T800) about four years old. The
last couple of days there has been a great deal of clicking that I couldn't
localize. I finally found the source last night and it's obvious once you
see it. There is a crack in the top tube where it joins the down tube. It's
a little less than 180 degrees around the circumference at the top, very
straight and neat. The sides have not separated. I finally looked in the
right place after realizing that the sounds continued even when I wasn't
pedaling but stopped when I stood.

I know that's the end of the line for the frame. Is is dangerous to ride it
gently for a few days while I shop for a new bike? I suspect that wouldn't
be a good idea, but I don't know anything about how aluminum tubing fails.
When I try to imagine what would happen if the crack propegated all the way
around the tube, it doesn't seem like the frame would collapse spilling me
on the ground, but maybe I'm not thinking it through correctly. My only
prior experience with this kind of thing was a crank that snapped. The guy
at the shop made a convincing case, based on oxidation of the break, that
there had been a crack for a long time half way through and then it snapped
suddenly as I accelerated.

You may be facing another one of those boring "what bike should I get"
threads shortly.

Did you buy it new? What about a warranty?

I wouldn't ride it, or if it was necessary, I would duct tape it.

Life is Good!
Jeff

The Wogster wrote:
..

Quoted message said:

Paul Turner said:

Correction:

The crack is where the top tube joins the seat tube, not the down tube.

Is it the tube that is cracked or the weld, if it's the weld it could be
repairable, providing you know what aluminum alloy it's made from, and
there is a welding shop with the right equipment and welding rod in your
area.

I think it is the weld, as it is so close to the seat tube, but I don't know
enough to be sure. In any event, I'm not really considering repair. I was
just wondering about the risk posed by limping around on this for a few days
while I talk to the dealer about replacing the frame or look for a new bike.

--
Paul Turner

: Consider your two options, toss the bike in the corner and save the gear
: for spares or a better frame, or ride the bike. If you ride and the
: frame fails it is, being aluminimum, likely to go very suddenly and
: without any planning. If it doesn't happen while you are descending a
: hill or being passed by a truck, and if the frame doesn't become a
: jagged folder, or launch you face-first into the bitumen, so much the
: luckier for you. If you avoid serious injury and also avoid damaging
: some of those otherwise salvagable components of your bike then luckier
: still. Always a better feeling than waking up in hospital to a long
: recovery period, totalled bike and huge hospital bill. Do you feel lucky?

That kind of puts things into perspective, doesn't it now?

Pat in TX

Paul Turner said:

I have an aluminum Cannondale touring frame (T800) about four years old. The
last couple of days there has been a great deal of clicking that I couldn't
localize. I finally found the source last night and it's obvious once you
see it. There is a crack in the top tube where it joins the down tube. It's
a little less than 180 degrees around the circumference at the top, very
straight and neat. The sides have not separated. I finally looked in the
right place after realizing that the sounds continued even when I wasn't
pedaling but stopped when I stood.

I know that's the end of the line for the frame. Is is dangerous to ride it
gently for a few days while I shop for a new bike? I suspect that wouldn't
be a good idea, but I don't know anything about how aluminum tubing fails.
When I try to imagine what would happen if the crack propegated all the way
around the tube, it doesn't seem like the frame would collapse spilling me
on the ground, but maybe I'm not thinking it through correctly. My only
prior experience with this kind of thing was a crank that snapped. The guy
at the shop made a convincing case, based on oxidation of the break, that
there had been a crack for a long time half way through and then it snapped
suddenly as I accelerated.

You may be facing another one of those boring "what bike should I get"
threads shortly.

--
Paul Turner

There are two choices, one of which may not be one for you...

1) Baby it along by not placing excessive stress on the frame and
rolling at speeds that won't inflict significant rider damage if it does
fail. This is risky since it may fail anyways at any time.

2) Roll with your 4-wheel vehicle until you've corrected the bike issue.

Pat said:

: Consider your two options, toss the bike in the corner and save the gear
: for spares or a better frame, or ride the bike. If you ride and the
: frame fails it is, being aluminimum, likely to go very suddenly and
: without any planning. If it doesn't happen while you are descending a
: hill or being passed by a truck, and if the frame doesn't become a
: jagged folder, or launch you face-first into the bitumen, so much the
: luckier for you. If you avoid serious injury and also avoid damaging
: some of those otherwise salvagable components of your bike then luckier
: still. Always a better feeling than waking up in hospital to a long
: recovery period, totalled bike and huge hospital bill. Do you feel
lucky?

That kind of puts things into perspective, doesn't it now?

Not really. I'd already figured a broken top tube MIGHT cause an accident,
that's why I asked. And I was already convinced I wouldn't like to be
speared by a jagged tube end or thrown under a truck. So what I was curious
about was whether those are likely consequences of a cracked top tube. After
all, some bikes don't even have top tubes. I thought maybe someone who
repairs bikes could say whether people come riding in all the time unhurt
seeking to have their broken top tubes fixed, or whether, on the other hand,
frames with broken top tubes are mostly brought to the shop by the widows of
cyclists who've perished under the wheels of a truck.

--
Paul Turner

Jeff Starr said:

I wouldn't ride it, or if it was necessary, I would duct tape it.

I second this. This joint is primarly in compression, so if you keep
the tubes aligned it should work. I'd use a lot of tape, around all
tubes in the area. If it doesn't look like [censored], you didn't use enough
tape. :-)

DD said:

Paul Turner said:

I know that's the end of the line for the frame. Is is dangerous to
ride it gently for a few days while I shop for a new bike? I suspect
that wouldn't be a good idea, but I don't know anything about how
aluminum tubing fails.

Consider your two options, toss the bike in the corner and save the
gear for spares or a better frame, or ride the bike. If you ride and
the frame fails it is, being aluminimum, likely to go very suddenly
and without any planning. If it doesn't happen while you are
descending a hill or being passed by a truck, and if the frame
doesn't become a jagged folder, or launch you face-first into the
bitumen, so much the luckier for you. If you avoid serious injury and
also avoid damaging some of those otherwise salvagable components of
your bike then luckier still. Always a better feeling than waking up
in hospital to a long recovery period, totalled bike and huge
hospital bill. Do you feel lucky?

Well, DO YA?!? (I left off the punk part because some people in here can't
recognize humor if it bites 'em in the tender bits.)

While it might be tempting to "ride it gently for a few days", the fact that
you said it was already making creaking or clicking sounds leads me to
conclude you'd better not. How fast do you want to be going when the frame
completely fails?!?

Find out if it's under warranty -- it's only 4 years old, right? -- and go
from there. If you need a bike for basic transpiration, then it's a good
time to learn a valuable lesson: ONE IS NOT ENOUGH!

Go buy a bargain beater backup bike (blue?),

Alliterative Bill

If I had that bike, I'd get out some epoxy resin, fiberglass cloth
and sandpaper. I'd fix it so it was stronger than before and it might
last for many more years. I've done this on several of my bikes and one
lasted for a dozen more years, before something else failed. Such
suggestions are heresy to metal-working purists.

Steve McDonald

Paul Turner said:

I have an aluminum Cannondale touring frame (T800) about four years old.
........ There is a crack in the top tube where it joins the down tube. It's
a little less than 180 degrees around the circumference at the top, very
straight and neat. The sides have not separated.

I understand that in "industry", aluminum is welded (for repair) on a regular
basis. I had a welder at Manitoba Hydro do a "government-job" for me when I
lived in a Northern Manitoba near a hydro-electric dam site. The aluminum piece
he welded (it was part of a radio antenna) in about 1980 is still holding.

You might want to check with a welding shop that specializes in doing aluminum
before you replace the bicycle....... In the mean time, don't ride the bicycle -
your health/safety is more important.

Ken
Winnipeg, Manitoba.

Paul Turner said:

The Wogster wrote:
.

Quoted message said:

Paul Turner said:

Correction:

The crack is where the top tube joins the seat tube, not the down tube.

Is it the tube that is cracked or the weld, if it's the weld it could be
repairable, providing you know what aluminum alloy it's made from, and
there is a welding shop with the right equipment and welding rod in your
area.

I think it is the weld, as it is so close to the seat tube, but I don't know
enough to be sure. In any event, I'm not really considering repair. I was
just wondering about the risk posed by limping around on this for a few days
while I talk to the dealer about replacing the frame or look for a new bike.

While it's true the frame should be replaced, a decent welding job,
could be a good stopgap until you can get it replaced. You might also
be able to get a metal shop to build a piece that would go over the
joint to hold it together, until you can get a new frame.

W

"Paul Turner" (clip) After all, some bikes don't even have top tubes.
(clip)
^^^^^^^^^^^^^^^^^^^
So, Paul, why don't you take a hack saw and cut off the top tube, and then
go ahead and ride it? <BG>

The fact that that weld has developed a crack means that it has been flexing
under load. Every cycle of flexure makes the crack grow a little. At some
point the remaining metal will be unable to carry the load, and the joint
will fail SUDDENLY. That could be on your next ride!

If you're going to try for a warranty replacement, I wouldn't do any
welding--Cannondale will want to get the frame back for inspection. I am
confident that a welder could fix it, so that you don't have to buy a new
bike right away--maybe never. Laying a plate over it and welding would make
it better than new, but uglier.

:
: Find out if it's under warranty -- it's only 4 years old, right? -- and go
: from there. If you need a bike for basic transpiration, then it's a good
: time to learn a valuable lesson: ONE IS NOT ENOUGH!
:
: Alliterative Bill

My bikes don't transpirate. Only my plants do. You have a one of a kind
bike, Bill!

Pat in TX
:
:

Leo Lichtman said:

The fact that that weld has developed a crack means that it has been flexing
under load. Every cycle of flexure makes the crack grow a little. At some
point the remaining metal will be unable to carry the load, and the joint
will fail SUDDENLY. That could be on your next ride!

If you're going to try for a warranty replacement, I wouldn't do any
welding--Cannondale will want to get the frame back for inspection. I am
confident that a welder could fix it, so that you don't have to buy a new
bike right away--maybe never. Laying a plate over it and welding would make
it better than new, but uglier.

Call Cannondale before doing any welding because Leo makes a very good
point about such a repair negating any warranty replacement. I
understand that you want to ride but consider the forces that will be
exerted if that top tube separates. Your diamond frame will immediately
become a vee frame. The head tube and seat tube will migrate (or
collapse) toward each other. Your rear brake cable will be pulled tight
by the changing angle and your rear brake will be applied. If you
happen to be exerting more than JRA force on the pedals when that
happens, the torque will try to pull the head and seat tubes even
closer together. In the best case scenario an unintended dismount will
occur and in the worst case, you'll crash. What you need to decide is
just how badly do you need to ride. Are one or two days on the bike
worth the risk?

Regards,
Bob Hunt

Leo Lichtman said:

The fact that that weld has developed a crack means that it has been flexing
under load. Every cycle of flexure makes the crack grow a little. At some
point the remaining metal will be unable to carry the load, and the joint
will fail SUDDENLY. That could be on your next ride!

If you're going to try for a warranty replacement, I wouldn't do any
welding--Cannondale will want to get the frame back for inspection. I am
confident that a welder could fix it, so that you don't have to buy a new
bike right away--maybe never. Laying a plate over it and welding would make
it better than new, but uglier.

Call Cannondale before doing any welding because Leo makes a very good
point about such a repair negating any warranty replacement. I
understand that you want to ride but consider the forces that will be
exerted if that top tube separates. Your diamond frame will immediately
become a vee frame. The head tube and seat tube will migrate (or
collapse) toward each other. Your rear brake cable will be pulled tight
by the changing angle and your rear brake will be applied. If you
happen to be exerting more than JRA force on the pedals when that
happens, the torque will try to pull the head and seat tubes even
closer together. In the best case scenario an unintended dismount will
occur and in the worst case, you'll crash. What you need to decide is
just how badly do you need to ride. Are one or two days on the bike
worth the risk?

Regards,
Bob Hunt

Paul Turner said:

I have an aluminum Cannondale touring frame (T800) about four years old. The
last couple of days there has been a great deal of clicking that I couldn't
localize. I finally found the source last night and it's obvious once you
see it. There is a crack in the top tube where it joins the down tube. It's
a little less than 180 degrees around the circumference at the top, very
straight and neat. The sides have not separated. I finally looked in the
right place after realizing that the sounds continued even when I wasn't
pedaling but stopped when I stood.

I know that's the end of the line for the frame. Is is dangerous to ride it
gently for a few days while I shop for a new bike? I suspect that wouldn't
be a good idea, but I don't know anything about how aluminum tubing fails.
When I try to imagine what would happen if the crack propegated all the way
around the tube, it doesn't seem like the frame would collapse spilling me
on the ground, but maybe I'm not thinking it through correctly. My only
prior experience with this kind of thing was a crank that snapped. The guy
at the shop made a convincing case, based on oxidation of the break, that
there had been a crack for a long time half way through and then it snapped
suddenly as I accelerated.

You may be facing another one of those boring "what bike should I get"
threads shortly.

--
Paul Turner

IANAE (I Am Not An Engineer), so I cannot comment on the nature of Al
tubing failure.

IAAP (I Am A Pragmatist). Do you ***need*** to ride the damaged bike?
Can you survive the "few days" without a bike? If so, remember the
adage "discretion is the better part of valour" and do without a bike
for a few days. Even an engineer cannot guarantee when/where/how the
bike will fail. A failure at the wrong time, in the wrong way, could be
fatal.

Around here (Winnipeg), this is a great time to be buying a bike as the
shops are trying to clear out their inventory before winter takes hold.
Since you didn't mention anything about winter, I'm assuming that you
may not get the same benefit.

Jeff

In article <[email hidden]>, Ken Pisichko <[email hidden]>

Quoted message said:

Paul Turner said:

I have an aluminum Cannondale touring frame (T800) about four years old.
........ There is a crack in the top tube where it joins the down tube.
It's
a little less than 180 degrees around the circumference at the top, very
straight and neat. The sides have not separated.

I understand that in "industry", aluminum is welded (for repair) on a regular
basis. I had a welder at Manitoba Hydro do a "government-job" for me when I
lived in a Northern Manitoba near a hydro-electric dam site. The aluminum
piece
he welded (it was part of a radio antenna) in about 1980 is still holding.

You might want to check with a welding shop that specializes in doing
aluminum
before you replace the bicycle....... In the mean time, don't ride the
bicycle -
your health/safety is more important.

Ken
Winnipeg, Manitoba.

Ken: bad advice!

I'm no metallurgist, but many Al bike frames are made of aluminum
designed to be heat-treated after welding.

If that is the case, then repair is tricky, mainly because few people
have both the facilities for heat-treating a bike-sized object, and few
of those people are interested in fixing bikes.

http://www.eastonbike.com/downloadable_files/fab_instr/fab_instructions-7
005_6061.pdf

There was a local shop, Pyrotek (aka Pyrobike) that advertised aluminum
frame repair, but a quick search shows their website no longer exists
except as a Google cache.

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos