Sito

Hi there, I have recently been looking at a set of relatively affordable carbon wheels that are available in both 45 and 55mm profiles. They would certainly both look nice on my bike but the 45 version weighs 1650 grams or so and the 55mm 100 grams more.

That’s not insanely heavy but I already have a set of decent aluminium wheels with a 32mm profile that weigh in at around 1450 grams. So I am in doubt if the carbon wheels would offer any advantage over the alu ones. Given that, at least in the case of the 45mm carbon rims, the profile isn’t that much deeper, would those wheels offer any significant advantages over the aluminium wheels I already have? Or would you, due to the heavier weight, even expect them to perform worse? Any insight will be much appreciated

rpenmanparker 

You are totally ignoring the aero benefits of the deeper wheels. If you want light, you go shallow. If you want aero you go deep. If you want the lightest approach to either, you go carbon instead of aluminum.

datlas 

Are you racing?? Or riding competitively?? If not, I suggest you not bother as the benefits are very modest.

dksix

This was posted in a recent thread where I posed a similar question. The aero advantage is more important that weight from these test.
FLO Cycling - The Great Debate - Aero vs. Weight

Sito

Sorry, just realizing I probably asked the question in the wrong way. This is probably better: If you have two wheels with the same rim profile and weight, one is carbon, the other aluminium, would the carbon wheel offer any advantage over the alu wheel? Would it be more comfortable, stiffer or somehow 'quicker' despite same weight/profile?

BengalCat

Sound advice unless money is not a factor. Performance enhancement is modest.

rpenmanparker 

Lighter weight of the carbon might be some advantage during climbing. Very marginal.

hooCycles

CFRP has a higher stiffness:weight ratio and thus with proper engineering should give a wheel with a higher stiffness:weight ratio. Keep in mind that geometry plays as important of a role in stiffness as material, though.

Lazyass

If you want a rougher riding poorer braking bike that gets blown around in crosswinds buy the carbon wheels.

hokie cycler

OP clarified the question to compare wheels that are the same weight and profile. In that case, the difference would be immeasurable to the average rider.

dksix

How would one know how aero a wheel is vs another one?

Homebrew01

By getting to the coffee shop 12 seconds faster or slower than before

Clipped_in

In a word, no. Stiffer (vertically) is largely a function of x-sectional depth. Quicker is a mostly a function of mass. Comfort is a pretty much irrelevant. If x-sectional depth and weight were equal, the disadvantages would be with carbon: increased cost, reduced braking quality, noisier in many cases, and requirement for premium brake pads. The functional benefits of carbon rims is reduced weight for a deep section, and the ability to really fine tune the aerodynamic profile due to manufacturing differences. Of course, the aesthetic benefits of carbon rims are that they do look really good.

Homebrew01

I use 50mm carbon tubulars for racing. I ride on basic aluminum rims the other 99.9 % of the time.
Don't ask me which aluminum rims, I have no idea.
Have not felt the need to spend big bucks on wheels. Good tires are worth it though.

cruiserhead

no, you would be wasting money on the carbon wheels.
You get carbon wheels for aero, lightweight or both.

If you are just as aero and same weight with alloy, than enjoy the better braking and durability of alloy without lightening your wallet by a K.

cruiserhead

LOL
Even if that coffee shop was 2 miles up a 10% grade, the difference would be less than that.

Sito

Thanks for your insight, guys! You've pretty much confirmed what I thought. Carbon for carbon's sake doesn't do it. I usually ride on hilly terrain and sometimes on proper mountain passes, so a lightweight wheelset with a bit of profile does make sense for me. A Carbon upgrade would only make sense if I get a deeper profile at the same weight or the same profile at a lower weight and that would cost me a lot of money, not worth it

colnago62

My question would be if the aluminum and carbon wheels are the same in every dimension, how did the carbon wheels get so heavy? ;-)

link0

I bet they are just alum rims with carbon fairings.

Fox Farm

To the OP, take a look at some Boyd carbon wheels. Well priced and also not nearly has heavy as you mentioned.

In my experience with carbon wheels (Boyd 44 carbon tubulars), they are very stiff and climb quite well, weighing in the 1400-something range - the clinchers are a little bit more heavy. The wide rim width is a benefit. Running 700 x 25 tubular tires at lower pressure (85psi) makes for a very compliant ride and lower rolling resistance than say 700 x 23 at 110psi. They do not get blown around in the wind, unless it is a very windy day and in that case, you are going to get blown around no matter what wheels you have on the bike. They climb really well, as good as my 1300 gram aluminum wheelset. They get up to speed very quickly and hold speed better than my Mavic Ksyrum wheels. The one draw back is that they do not brake as well as aluminum wheels. I will try some different pads and see how they do; Campy pads are reported to be very good. I have used Swisstop and they are average at best. See if you can go to a demo day and try some on your bike and then decide. Now, would I spend $2800 on Zipp, HED, Reynolds, or Enve carbon wheels? I would not but many others do. If this purchase will be your first foray into carbon wheels, and you are willing to shell out about $1300, the Boyd wheels are a good value. Write to them and you will likely get a response from Boyd Johnson, owner of the company, to guide you in your decision making process. Otherwise, look at some of the new wide profile aluminum wheels. If you ride with others who have the type of wheels you aspire, ask to try their bike and see how they feel. I would think that wide rims with 700 x 25 or greater tires at 85 psi will really get your attention for comfort and handling, be these carbon or aluminum.

bikebreak

I use both zipp 303 and various alloy rims. my 303s are tubular and 150g lighter than my lightest alloy wheels.
yes they are faster, but not a lot faster.

if most of your riding is on hilly terrain and your average speed is under 18mph don't bother. If you average 20mph+ you will see more benefit from deeper rims.

Drew Eckhardt 

They could use a power meter and Chung's virtual elevation model to estimate CdA riding outdoors, or accept a bike company's wind tunnel data.

rpenmanparker 

Do you really expect us to believe that you can sense a such a small difference in acceleration and deceleration. Ridiculous. Maybe the stopwatch could see it over 20 miles, but I don't believe you can feel it.

dksix

I can't remember the specific models but I once saw some research on the aerodynamics of cars. Just because something looks aero doesn't necessarily make it so, maybe @Jeff Wills can shed some light on what does and doesn't make a wheelset aero.

Doctor Morbius

Or the pub in my case.