Carbon vs aluminium - just what is the difference...?

Superbalicious

I own a Trek 1.9 with an aluminium frame and carbon forks. I'm quite happy with the bike overall, including the Ultegra group set, even down to the colour. I do wonder though, what difference would I feel if the whole frame was carbon?

I appreciate there are different grades of carbon, probably the same with aluminium too, but would the riding experience be different, would one transmit more or less 'feel' and would that be a good thing, or a bad thing (in terms of vibrations)? Would one material be more flexible, or more vague? Would a full carbon frame be that much lighter that I'd actually be able to tell the difference, given other factors such as wind, road surface and gradient?

Enlighten me with your knowledge if you will

simona75

It depends on the quality of the actual frames rather than purely the materials used. I own both aluminium (allez) and carbon (orca) bikes and the difference in ride is noticeable (mainly comfort and reduced road buzz) but I would dare say that this is because one bike cost three times more than the other

hipshot

I agree with Simona75. It's a bit reductionist to judge on frame material alone; each bike is an individual case and carbon does not necessarily translate as stiffer/ smoother etc.

At a push I would say carbon has an edge in terms of performance although I personally ride an aluminium frame used by pro teams not that long ago. It easily competes with lower end carbon and is more crash resistant IMO.

lef

Ive ridden a few aluminium and carbon frames and I havent yet come across a aluminium frame that is as comfortable (road buzz) not saying that aluminium frames can't be as comfortable but I just havent ridden one. however from experience wheels can really help with ride comfort on ali. For example c24s / rs80s on an ali frame can really help smooth the ride out compared to say ksyriums.

lc1981

hipshot wrote:

...I personally ride an aluminium frame which pro teams used not that long ago. It easily competes with lower end carbon and is more crash resistant.

I agee with what's been said above about it all depending on the particular frame (give me a Cannondale CAAD over a cheap carbon bike), but not sure about aluminium being more crash resistant after having seen this.

hipshot

lc1981 wrote:

hipshot wrote:

...I personally ride an aluminium frame which pro teams used not that long ago. It easily competes with lower end carbon and is more crash resistant.

I agee with what's been said above about it all depending on the particular frame (give me a Cannondale CAAD over a cheap carbon bike), but not sure about aluminium being more crash resistant after having seen this.

Interesting. Nice to see some science for once.

I'd like to see something like this for typical road bike impacts.

thescouselander

Interesting video but I'm not sure what it what it proves. Did the aluminium frame fail earlier because of the material it was made of or because of the design?

thebadgerboy1982

The frame and in particular the geometry was the control. Meaning the biggest variation was the material. Looks like carbon won!

thescouselander

thebadgerboy1982 wrote:

The frame and in particular the geometry was the control. Meaning the biggest variation was the material. Looks like carbon won!

Not quite. No doubt an aluminium frame could have been engineered to the same strength as the carbon one if a different thickness of tubing was selected. Of course this would have added to the weight so at some point somebody made a conscious decision to design the frame as it was to optimise the weight/strength balance in a certain way. It could be that a different approach to design would have yielded different results. The test in the video will apply to those frames only.

Trev The Rev

Steel is best. More comfortable and more robust.

http://www.youtube.com/watch?v=nvk63bmVpck

Anonymous

At a given price point, I think you'll find the carbon frame is just a bit less fatiguing (due to elimination of buzz) and a bit more responsive. The bike in my sig is admittedly quite old, but a friend of mine also has a ribble sportive racing and we are the same size so swap over every now and then.
He loves the geo of mine (its quite pointy and racy) and I'm not such a fan of his geo (feels like im sitting right back).

That aside, his is FAR more comfortable, noticably so when you hit something in the road (in RP there are strips of cobbles here and there) which the bike just soaks up. On mine it gives you a kick in the crotch but his you can barely feel it. I found that VERY odd as I was waiting for a kicking!
Also, it is much stiffer in the BB area. I know mine is a very old alu frame, but when you stand up and pedal hard, you can feel there is a noticeable difference that the frame isn't flexing and the power goes straight forward.

I'm not saying one is faster (his is marginally lighter) than the other, but for two bikes who are perceived to be the 'cheap' end of the respective market, you can definitely tell the difference, and he also says his bike is incredible for super long rides (although mine is also fine for 180miles non stop, too)

random man

simona75 wrote:

It depends on the quality of the actual frames rather than purely the materials used. I own both aluminium (allez) and carbon (orca) bikes and the difference in ride is noticeable (mainly comfort and reduced road buzz) but I would dare say that this is because one bike cost three times more than the other

^^^^ This. I 've now got an aluminium road bike, carbon road bike and steel tourer. The bike I enjoy riding most is the carbon - it surprised me just how much more comfortable it was than the alu bike, it's less rigid and you don't get anywhere near the same amount of vibration.
Even putting a carbon seat post on my alu bike has made a difference to the ride quality.

simon_masterson

Carbon fibre is a very good material to make performance bicycles out of because it can be made into a structure that befits the application, and the overall integrity of a monocoque is not dependent on the structure in the same way as a frame of metal tubes joined together; and I'm a steel bike devotee, incidentally.

I haven't ridden any carbon fibre bicycles myself, but it would seem that there is a certain distinctive character to a carbon fibre frame (identifying such characteristics is often misguided, as the construction of the frame has a lot to do with the ride quality), however I would identify the above as more crucial, as carbon fibre bikes are engineered to perform optimally by being strengthened in key areas; and conversely material is removed from areas it is not needed to save weight.

Trev The Rev

Simon Masterson wrote:

Carbon fibre is a very good material to make performance bicycles out of because it can be made into a structure that befits the application, and the overall integrity of a monocoque is not dependent on the structure in the same way as a frame of metal tubes joined together; and I'm a steel bike devotee, incidentally.

I haven't ridden any carbon fibre bicycles myself, but it would seem that there is a certain distinctive character to a carbon fibre frame (identifying such characteristics is often misguided, as the construction of the frame has a lot to do with the ride quality), however I would identify the above as more crucial, as carbon fibre bikes are engineered to perform optimally by being strengthened in key areas; and conversely material is removed from areas it is not needed to save weight.

I have had 2 carbon frames. They both broke.

Anonymous

random man wrote:

Even putting a carbon seat post on my alu bike has made a difference to the ride quality.

Now why did you have to go and say that! I was hoping it would make no difference at all! Looks like I may have to 'try' one out.

thescouselander

Not sure I get the whole thing about "road buzz". Carbon forks definitely work but then you can actually see them flex as you go over bumps. On the other hand the back of a bike (even a carbon one) is extremely rigid and will have minimal vibration absorbing properties - the tyres will absorb more since they flex a lot more. If there's a lot of road buzz on a bike it could just be that the tyres are pumped up too hard.

rando

coriordan wrote:

random man wrote:

Even putting a carbon seat post on my alu bike has made a difference to the ride quality.

Now why did you have to go and say that! I was hoping it would make no difference at all! Looks like I may have to 'try' one out.

So by bringing seatposts into the equation of ride quality do different posts make a difference.
Is the Syntace P6 Carbon Hiflex (http://www.syntace.com/index.cfm?pid=3&pk=2033) any better at smoothing out a ride than a standard carbon post ?

Anonymous

Too late. Bought the USE Alien Carbon one....half price for my bike at Witstanleys. 40 down from 80, postage incl (only 27.2/270mm)

Now, will this increase my average speeds?

Nik Cube

I've got both they feel the same just ride and enjoy

simon_masterson

Trev The Rev wrote:

Simon Masterson wrote:

Carbon fibre is a very good material to make performance bicycles out of because it can be made into a structure that befits the application, and the overall integrity of a monocoque is not dependent on the structure in the same way as a frame of metal tubes joined together; and I'm a steel bike devotee, incidentally.

I haven't ridden any carbon fibre bicycles myself, but it would seem that there is a certain distinctive character to a carbon fibre frame (identifying such characteristics is often misguided, as the construction of the frame has a lot to do with the ride quality), however I would identify the above as more crucial, as carbon fibre bikes are engineered to perform optimally by being strengthened in key areas; and conversely material is removed from areas it is not needed to save weight.

I have had 2 carbon frames. They both broke.

But at what end of the quality spectrum were these? Frames are not made equal... You may have broken two; some break none.

Carbon fibre can be very strong under a 'design load'. Its relative fragility is a drawback, but then again if you crash an aluminium framed bike that will be a write-off as well, and that may fatigue. With consideration to the considerable performance advantages of carbon fibre, unless you're going to go with steel (the best material to make a bike from) or titanium I think a carbon bike is a great choice; particularly as the wheels (some considerably more so than others) are generally pretty fragile as well...

Superbalicious

Thanks for all the replies, I should've realised that there wasn't a simple answer :oops: