ajst2duk

Took my bike to Singapore with me, had a great time, got three rides in. Get home to find a big dent in my top tube about 1/2 way along.
Is there any way I can get this fixed, I don't think it weakens the bike but it did make my heart sink when I saw it.
Anyone else had this problem - **********??
Maybe it's time for a custom paint job ???
Looking for sympathy and advice????
AJ

roadwarrior

How big of a dent? A mechanic in our shop races a CAAD7 with a top tube dent, and based on his results, it is not bothering him in the least. Cosmetically, it's not great, but the frame was dented in a racing collision and the customer who had the frame got a CAAD8 and gave him this one. So, it's dented but not to the point where the tube's integrity is in question. This guy sprints this bike at 35mph+.

If it's small, it can be filled. I am talking more cosemetic, than structural. We use a paint shop that will fill small dents.

Big dent, where the tube is no longer straight, get a new frame.

merlinextraligh

Think crumpled beer can. You can't smash a beer can end to end. But dent it a bit and it smashes easily. The CAAD 5 frame is a little thicker, which works to your benefit. If its much of a dent though its likely to become a problem over time. If it's not a huge dent, the chance of a catstrophic failure is pretty low, but I'd keep a close eye on it, if you decide not to replace it.

My wife had a 2 week old CAAD 7 fall over in the garage, and hit a christmas tree stand. (just the bike fell, no one on it.) Dented the top tube to the point that the C Dale rep said shouldn't be ridden. the fact that tiny accident trashed the frame tells you something about the thickness of the material, and its suceptability to side impacts.)
2 weeks, trashed bike, no warranty replacement ( although they did cut a deal on a new frame.)

jimbud

Who shipped the bike? Can't you file a claim with your airline or UPS or who ever the shipper was?

sydney

Some dents are meaningless,some aren't.Since no one here can see it all you are going to get is guesses and BS.

gcasillo

Why is this parlor trick always dragged out whenever someone has a dented/dinged aluminum frame? If the top tube is dented, wouldn't he have to stand the bike on its rear wheel and push down on the head tube to recreate the trick?

SAB

Get it checked out by a local dealer - make sure they know what they're talking about, or have them send it to Cannondale for an inspection. If it's a big dent, it's not worth the risk to ride it. Although the chance of catostrophic failure is quite small, it can and does happen with these very stiff, very thin-walled aluminum frames.

TheKillerPenguin

like roadwarrior says, depends on the size of the dent. I raced and rode thousands of miles on my Caad7 that had a top tube dent, and it was fine. If you want to compare your top tube to it, I still have that frame hanging around and could take a picture.

Dwayne

I don't think you get it. By your reasoning, why have a top tube at all? You make it sound like it's just there for decoration.

Just because the tube isn't vertical doesn't mean there's no load on it. The soda/beer can example simply illustrates that a deformation in the tube will cause it to lose a large amount of structural integrity it had. Whether it's a great enough loss to stop riding the frame altogether... depends on the damage.

CAAD5AL

I actually bought mine with about a dime-sized dent in the top tube, brand new. Cannondale had strapped it too tightly in the shipping container and left the little ding - 12K miles later, it's still just a dime-sized dent, and hasn't "beer canned" on me. That's just funny . . .

daytonian

I think the difference in the can example is the can has no tension pulling it at either end. The top tube of a bike has tension from headset to seat tube giving it more strength than if it were simply a tube with nothing welded to it.

ajst2duk

Thanks team, I will post a pic of it tonight. I think it is more cosmetic than structural, but this bike was my perfect bike. I didn't unpack it for a week, I did have travel insurance, but didn't keep the box, so figure a claim would be fruitless. I was just a bit pissed, but I have a tough century in three weeks so I better just get on with it.

lotek 

well it all depends doesn't it?
if the tube is dented but not creased you should
be ok.
If the Tube is creased I wouldn't ride it.
Either way, have a Cannondale dealer check it out just to be sure.
Even if you don't have the box you may still be able to file a claim
against carrier. Given the cost of Frames I would be looking into that.

marty

merlinextraligh

how old's the bike. C Dale has had a generous frame replacement policy, at least in the past. You might be able to get C'Dale and your LBS to work a deal. $400-500 bucks to replace it with a CAAD 8 wouldn't be bad. I think C'Dale is sensitive to the arguments about thin AL tubing, and at least in the past would work with you.

Phantoj

sydney is the voice of reason here.

Personally, it would have to be a pretty gigantic dent before I'd be afraid to ride it. What, you think you're going to go over a pothole and your bike will turn into a pretzel? I just can't picture that, unless the dent is enormous. I wouldn't bother asking a Cannondale dealer because it will just be another opinion - an opinion from a salesman who would rather sell me a new frame than assume liability by OKing my bike. But if Cannondale said it was OK, then you'd know for sure it was okay.

I'd disagree with the poster who says buckling of the top tube is a nonissue because it's normally loaded in tension. I think the top tube is normally in compression.

1955

I could be wrong but isn't the top tube in compression and not in tension, giving the soda can theory some validity?

Avalanche325

The top tube is normally under compression, not tension. That is what makes a dent a potential problem.
I saw a bike on TV that had a thin cable for a downtube. You can do this because it is normally under tension. You can't do that with a top tube.

nova

When doing things like having it checked by a lbs make sure you take it to 3 of them and ask each. Just like buying a bike you want to shop around. Get all 3s advice on it and compare it. If all 3 say its toast your more than likly do for a new bike.

Phantoj

https://www.sheldonbrown.com/rinard/fea.htm

Damon Rinard's finite element analysis seems to be saying that the top tube is mostly loaded in torsion and out-of-plane bending..?

Ride it... just make sure your life insurance is paid up....