Hi Everybody,

I was at a bike expo today in my local area and took a look at the Cannondale booth where they had a Cannondale R3000 bike on display. The bike was extremely light (15.6lbs for a 54cm I believe) but when I touched the frame, more specifically, squeezed the top tube in the center, it felt almost "soft" to the touch. I swear that I was able to squeeze it and feel the frame squeeze under my pressure (maybe that was in my head, but I have to say it took me by surprise). The rep pulled out a frame that was cut in half and showed me the cross section. I couldn't believe how thin the tubing was and that led me to wonder about how durable the CAAD7/Optimo frame is in the real world.

My question is...does anybody have any experience with the durability of these CAAD7/Optimo frames? How do they hold up in the real world for an average joe who trains and probably won't really race too much? Do you who do have experience with them feel they are prone to denting? Do you feel they are more/less durable than the CAAD5 frames? Would you recommend a CAAD7 for average/every day use or the CAAD5?

Any comments would be much appreicated as I was considering purchasing one at the end of the year, but now I'm not so sure.

Thanks in advance.

I'll probably get flamed for saying so - but I don't think alum is the way to go when you're trying to get ultralight weight...

1) Alum is not as stiff as steel
2) Thus you need to use oversized tubing to make the frame stiff
3) oversized tubing and light weight = thin tubing
4) thin tubing = ?

there is a point where material qualities become the limit - is alum at the limit? I dunno - but I'm fairly certain at the same weight, there are some quite reliable crashable composites.

Alu is great it is (along with CF) deposing steel in most industries where weight really counts. Al may not be as stiff as steel but my cdale is a hell of a lot stiffer than all the steel bikes I have ridden (all under $1500 so that might be a factor).

yah - that is because of the diameter of the tubing. They could make a steel bike like alum (wide diameter) .. but it'll be so stiff you'll shatter your teeth (exaggeration)

My concern is not so much the light-weight issue, it is more with the durability. Personally, I do like Aluminum bikes and I find that the stiff ride and the relatively low pricepoint work well for me. I asked the question regarding Cannondale's because I currently own one (CAAD3) and have been extremely happy with it. That being said, the bike is aging and I'm at a point where I can upgrade parts or buy a new bike. The CAAD7 frame trickles all the way down to their entry-level road bike point, where is the price range I'm looking at. However, the thin-walled tubing issue as mentioned by ShinyBaldy (extremely thin walled) has me concerned. Seems like it would dent very easily, maybe even if a rock came up and hit the frame (makes me question CAAD7 for mountain bikes). I don't want to spend $1800 CAD on a bike and have it dent more easily than other bikes in this price range.

Saw exactly the same specimen at a bike shop. Like you, I got a bit scared.

Yet, there most be thousands of similar thin-tubed frames on the road. Most of them never fail (and, fortunately, we haven't seen those from the inside), even if ridden hard and long.

Can't reassure you personally about the CAAD7 (but I am sure that many BikeForumers can). I have only ridden a CAAD2, which served me well.

Dipper, if your current CAAD3 frame is okay for you (I assume that it's the components that are 'ageing'), why spend money on a new frame with entry-level components? You might as well upgrade your current bike where necessary. That could be cheaper than buying everything new (and replacing those parts a few years later...). Plus, you can choose exactly the parts you like.

Just an idea...

It was in your head...I put several thousand miles on one without trouble

7 is a light frame...I have a 4 with a ton of miles on it as well, very nice. Same frame Cippollini won all those tour stages for Saeco.

You can't squeeze it...if you go to the Cannondale website, you'll see a piece on frame deflection. That frame is stiffer than titanium...

You don't really think that thousands of bike shops would sell a product that customers would be bringing back due to failure, do you?

Buy what you are comfortable with...

aluminum is very comfortable to ride....

I wouldnt worry, I have a CAAD 4 with no problems yet. It is vaguely possible that you can feel give in the tubes, but understanding the dynamic properties of tubular structures is a different matter all together. As an example if you do the same pressure test on a steel shafted golf club you get the same feeling of compression (almost is if you could dent it with your thumb), however a golf club shaft is less than 1/2" diameter at its narrowest and up to 43" long and is regularly smashed into the ground at swing speeds of up to 110 mph without breaking. It is truly amazing when you try and comprehend it. but as a crap golfer myself trust me it does work.

You are misunderstanding. Go drink a can of beer, or a can of coke. just make sure its a can, not a bottle.






















is the can empty yet? good. now, try and bend it. take the top and the bottom in your hands, and try to bring the top to the bottom by bending the can into an "L" shape. I'll be you $20 you can't do it. That is frame deflection. In a frame like the caad7, it is a similar thing, it resists frame deflection really well, better even than titanium.

now, take that can and squeeze it. RAH! you crushed it, didn't you?! You're an animal! the caad7 frame again has the same properties. since the walls are so thin, they don't resist forces from the side very well. that is what the original poster was feeling, and thats why an aluminum can crushes so easily.

in short, deflection is a whole different animal from the "crushing" that you feel.

I think you are right. Having used alu for the last 10 years I can say that the current frames do not resist dings as well as the old ones. While thiese dings will not affect the durability or performance of the frame who wants needs to worry about the cosmetic appearance of the frame every time it is mishandled, whether it is during riding or just getting the bike in and out of the house.

It bothered me when I would look down and see a new frame with dings in the tubes so I gave up and switched to carbon. Now i can abuse the bike and not worry about putting dings in it. I guess every one will write about carbons propensity for failure but I don't buy it. I think my carbon monocoque frame will outlast a similarly priced aluminum or carbon/aluminum frame.

I've ridden steel for 13 yrs with the exception of one of my mtn bikes Cannondale M400 and I just purchased an R3000. I weigh 180 lbs and plan to train and race the bike. It's stiff as can be and I am confident it will hold up to my power. Just a note get the blue.

Exactly. I don't want to spend cash on a new bike and worry that when I put it in my garage, it may dent if I lean it against something a bit too hard.

To be clear, I don't believe this frame will ever fail. I'm a Cannondale owner myself and do believe in their product--hence why I would like to buy another one, but the physics behind the technology (i.e. what Phatman said about frame deflection) and the fact that the frame cutout I saw showed my how thin the walls actually are make me wonder about its resistance. I believe even the Cannondale warranty speaks to handing the bike with care as the top tube is prone to dents.

Anyways, thanks all for your input.

Your assumption is correct. My idea was that I would either upgrade my components and use my CAAD3 frame or buy an entirely new bike--not just buy the CAAD7 and use my current components. I was thinking of the C'dale R800 or R1000. If I go the upgrade route, I will have to upgrade almost everything as I'm riding a mix of Shimano 105 and 600 from 1990 (I got the CAAD3 in 1997 when my previous Cannondale SR500 rear dropout snapped off) and I think it is time for a change. I really don't need a new frame, but seeing that the upgrades will result in practically a completely new bike, I thought I would look at maybe just buying one. But I do agree, choosing exactly the parts I want would be pretty cool.

Two seperate issues here: fatigue life and denting. Any sub 2.5 lb frame is going to have a limited fatigue life and won't last forever if used hard for many miles.

CAAD7 is a very strong frame, according to the limited fatigue test data I've seen. And, Cannondale should be applauded for being very up front about the issue:

https://www.cannondale.com/bikes/tech/pdfs/115622.pdf

Of course, if a frame is good for say 30-40K miles of hard racing/training, I figure it will last me about forever doing club rides, centuries, tours for 3-5K per year.

Denting is certainly an issue on this super thinwall tubing. I really don't want a bike that's prone to damage just in normal handling, or if someone else leans their bike on mine at a rest stop.

Still, have to question why CAAD 7 lightness is appropriate for the consumer market. I think C'dale and the other major brands are in a tough spot here, since so many buyers just want the lightest thing they can afford, and don't even think about life/durability.

Nothing wrong with CAAD7 tubing! It doesn't dent any easier than any other frame I have ever owned.
Unless you are going to kick or abuse your frame, it won't dent.
I sit on the top tube all the time, I use it just like any other bike I have ever had and it looks just like new after 12,000miles.

To say a carbon frame is more resistant to impacts is wrong. Carbon is brittle so maybe on a CAAD7, you will have a dent. On a Carbon, you may have internal stress cracks.
Unless you have a Coke can 57cm long, welded to other Coke cans in the shape of a bike frame, THEY WON'T ACT THE SAME WAY! Sorry, it's not a Coke can. It's bike frame. A bike frame that does not dent with normal use.
I have seen dozens on dozens of CAAD7's (Including T-Mobile's, Maxxis-7UP, Wheelworks and many club racers) and NONE of them were dented-except one that was involved in a crash. And that dent did not even chip the paint or affect the performance of the frame.

I remember reading off a frame builders site that Al, especially the new super light stuff, is good for about 10,000 'high-fatigue' (racing) miles

I should have expected as much. People are always so defensive about negative comments to their chosen frame material. If carbon is so brittle why do I never hear about carbon fork failures or seatpost failure. Next time that you cut the steerer off of a carbon fork take some time to try and break the tube. Use a hammer!

The stuff is not brittle. Also. sitting on the top tube disperses the load over a large surface area. Of course it won't dent. Apply the same forces over a smaller area and it will.

I am not saying carbon is perfect, all I am saying is that lightweight thinwall aluminum has drawbacks and one of them is its suscepibilty to dings.

Hmmm, I think that's about right. 10-15,000miles and it's done. But that's misleading because just about any bike (no matter what material it's made of) is done after a long season of racing.

That statement in itself is also misleading because you can still ride a race bike after 10-15,000 miles. It won't break.

Also, for non-professional riders, normal use of a aluminum or any bike is in the years. I know someone who trains and races on a Cannondale that is a good 5-6 years old. It still looks great and he likes it alot. Absolutely nothing wrong with it and it's a big frame- something like a 63cm.

I would have absolutely no problem recommending a CAAD7 to anyone and would be sure it would last them for many years.
I don't know about other bikes but the Cannondales are great bikes, plain and simple.

btw, Cannondale is coming out with the Carbon soon. I would take C'dale's aluminum lugs over Look's anyday.

Uh, I ride a Ti bike. I used to have a CAAD7. Aluminum isn't my "chosen material".

I've never heard of alloy fork or seatpost failures either. So what?

Carbon is brittle. Do you know what makes carbon stiff? Resin. Resin is brittle. Carbon fiber itself is a cloth.

Uh yeah, what else do you do to a top tube that is going to dent it under normal use?? "easily denting" just isn't an issue. Sorry, it isn't. Sure it will dent easier than something thicker (maybe, depending on the circumstances) but how could you ever predict that? What sharp impact would you get on a regular basis or is controllable? If you crashed and dented a aluminum tube, who is to say the impact would not have dented a steel tube too?

Since taking a hammer to a top tube isn't a normal function of riding, WHO CARES.

You may have already seen this regarding the Carbon Cannondale...
https://www.cyclingnews.com/tech.php?...004/news/feb11

Avg joe shouldnt have to worry about frame failure.

Are you an engineer?



































I didn't think so.


Ever spoken with an engineer who develops this stuff?



























I didn't think so.

Ever seen the inside of this frame? Ever ridden it? Ever crashed it?


I didn't think so.

Now...here is some information...

Frame info

Engineering data, no coke or beer cans used

Still no beer or coke cans...
Thanks.

What newer roadbike thats under 20 pounds doesnt have thin tubing. They all have thin tubing,well atleast alum,steel and ti and most likly carbon.Its the only way to get the frames snd the whole bike light like so many are crazy about.So which thin tubing will be the most dependable?

Hello everyone....

I've been reading all these posts and I have to say, there is some right in all of your posts, but I can't remember anyone getting it completely right. I own a bike shop in Indiana and do a lot of repairs. I've seen both Carbon and Aluminum frames come in after wrecks.....here is what I have to say.

Yes the tubing in the Cannondale frames is very light but as said above, so is the tubing in most lightweight bikes. However, once again as said above, they are safe. They would not allow an unsafe bicycle to be sold to the public. Now I do know that alot of you are talking about cosmetic appearances. I will admit that Aluminum will dent easier than carbon fiber. As for the comparison with steel, I have seen steel bikes come in that are just as easily damaged as the aluminum frames. Yes steel can be stiffer, but it is also heavier. Therefore, to make the steel frame comparable to the aluminum frame in weight, they sometimes make the steel frames even THINNER on the tubes. This makes them just as vulnerable as the aluminum ones. Now for the Carbon fiber........as stated above, Carbon fiber IS in fact brittle. If any of you remember your Chemistry lessons from highschool or College, you'll remember that Carbon is a nonmetallic element and one of the properties of a nonmetallic element is brittleness. This is not to say Carbon isn't strong, but it does break easier rather than bend when compared to the aluminum or steel. When it comes down to it, it really depends on your preference. If you want a frame that is light, and resists breaks yet MAY dent, get an Aluminum frame. If you want one that is light, will not dent, and will retain its overall appearance better yet in a reck has more potential to snap, get carbon fiber.

I myself have one of each. I have a Cervelo carbon soloist frame and I have a Cannondale R700 Caad7 Aluminum frame. Neither has given ME any trouble. What I've seen come in for repairs, the Aluminum has more of a potential to dent if you ARE NOT CAREFUL WITH IT. If you take care of your bike though, ordinary rocks or normal use shouldn't hurt it. I've used aluminum for years and no dents. As for the carbon, it really really really looks the same after a while. It doesn't dent very easily and resists harder use than does the Aluminum. However, I've seen many bikes come in the shop that have wrecked and the carbon doesn't have dents, but it has made hairline cracks in the material. Overall, Carbon will resist more abuses up to a certain point, but once you get PAST that point, the carbon fiber isn't as safe as the Aluminum. No bike material is perfect, because they all have problems in one way or another. You just have to choose which problems you care less about when you choose between them.


In answer to the original question, yes the material is very thin, but no thinner than other bike manufacturers products either. The special treatments and processes of the metals make them stronger than they look. Cannondale would be a wise choice for one looking for an aluminum bike, because that is their specialty. No-one makes Aluminum frames better than Cannondale. If your own bike has held up this long, I'm sure the new one will too. If its only parts you want to replace though, I'd go for replacement of them only unless you're a really avid biker or racer.

Thats what I have to say.