The Chainlink

Do Carbon Wheels Make a Difference?

By Brett Ratner

Pretty much any experienced rider will tell you that if you're gonna upgrade your bike, your money is best spent investing in the wheels.

More-so than that fancy new groupset, carbon cockpit, or even a new frame, quality wheels will net you actual advantages in aerodynamics, weight, and ultimately speed.

Despite hearing this for years, I've been resistant to the idea of fancy carbon fiber wheels...even when all the pros use them...even when at the local level, you'll see the fastest guys on bikes cobbled together from parts found on eBay, rolling on wheels that cost as much as a used car.

For me, a traditional aluminum box rim, hand-laced to the hub in a sturdy 3-cross spoke pattern was the way to go. My wheels rarely, if ever, went out of true. And if I were to wear out or damage a rim somehow, it would be relatively inexpensive to replace.

My personal bike sports a traditional-style wheel build, which has faithfully carried me through many an adventure. But I always wondered if they were the fastest option.

Particularly this past summer, however, I've been riding with exceptionally fast people on challenging, hilly terrain. I've generally been able to hang on (barely sometimes), but grew curious if I was working needlessly hard by sticking with my traditional road wheels.

Long story short, I'm now convinced carbon wheels absolutely do make you faster...and by a margin I can't believe. To learn how I arrived at this conclusion, read on.

The guys at Global Cycling Network recently conducted an eye-opening test, as seen in this video. While they achieved dramatic results, the problem in my opinion is that they were comparing a standard aluminum wheelset to a pair of the brand-new, redesigned Zipp 808s. Sure, the differences were massive, but the 808 is not a wheel that you'd be likely to use outside of a time trial, triathlon, velodrome, or perhaps a very flat criterium course on a calm day. Specifically, due to its extremely deep rim profile, the wheels are incredibly aerodynamic, but also heavier, and likely less stable in a strong cross wind than a shallower rim. As such, these would generally not be considered ideal for all-around road use, particularly on windy days, or in the mountains.

Fortunately, the folks at Rolf Prima were there to help answer my question. Rolf Prima is the preferred wheel brand of many of the fast guys I know around Lake Geneva, Wisconsin (whether they're on road bikes, cyclocross, or mountain bikes). In addition, the local shop is an authorized dealer, and one of my riding buddies participated in the Race Across America as a member of the 4-person Rolf Prima team.

Coincidentally, I met the Rolf Prima crew at last year's Interbike trade show, and was really impressed with their commitment to making quality, hand-built products in Eugene, Oregon.

Talking with them, I asked to try the road wheel they think would make the most noticeable improvement over my trusty and road-tested personal wheels...a set of Velocity A23 rims laced to 28-hole Shimano Dura Ace 7900 hubs in a 3-cross patter in back and a 2-cross pattern in front.

A week later, a set of Rolf Prima Ares4 Carbon Clincher road wheels showed up at my doorstep.

An Ares4 wheelset retails for $2,399 and features a full-carbon rim and brake track, with a wind tunnel-tested shape and a 42mm depth. Similar to competing products like the Zipp 303 and Enve SES 4.5, the "medium depth" configuration seems to really hit a sweet spot with the pros in terms of balancing aerodynamics, weight, and stability in cross winds. I base this observation on paying attention to what everyone was riding during this year's Tour de France, whether they be on flat "sprinter" stages, or mountain stages that favor climbers.

Anyway, pictures don't do these wheels justice. Between how they feel in your hand, to how they look, to the perfectly-applied Rolf-branded rim tape and decals, they are truly something to behold.

Right out of the box, you could tell the Rolf Prima Ares4 carbon clinchers means business.

And the Ares4 deliver the top-shelf goods, too. The custom, USA-made hubs are courtesy of White Industries, rolling on premium ceramic Enduro bearings. The bladed spokes are proven Sapim CX-Rays (a product of Belgium, where at least one or two decent cyclists came from). The rims are manufactured in Asia, but are not simply a generic "open mold" product with Rolf decals. Rather, they are built to Rolf Prima's proprietary designs. Finally, everything is assembled by hand at their Eugene facility.

The Ares4 came standard with carbon-specific brake pads, valve extenders, quick release skewers, and a spacer for using a 10-speed cassette on the wheel's 11-speed freehub.

Speaking of proprietary designs, Rolf Prima wheels offer a unique paired spoke technology, which the company says enables them to build an equally strong wheel to competitors, but using fewer spokes (to save weight and reduce wind drag). The wheels also offer a "differential flange diameter" design in the hub to enhance power transfer, as well as an unusual construction feature that hides the spoke nipples inside the rim to further reduce wind drag.

Rolf Prima's "differential flange diameter" design helps evenly distribute the force of your pedaling throughout the spokes.

Rolf Prima designs their wheels to hide the spoke nipples inside the rim, in an effort to further reduce wind drag.

From a weight perspective, they tip the scales at a claimed 1,365 grams (only about 3 pounds). For context, Velocity's featherweight A23 "Pro Build" aluminum wheelset weighs almost 1/4 pound more. My personal wheels are likely a full pound heavier than the Rolfs, due to the relatively high spoke count.

But all this techno-babble and weight weenie-ness is meaningless if it doesn't actually help you either go faster, or use less energy at the same speed.

Fortunately, I've spent a lot of time riding the picturesque, winding farm roads around my Lake Geneva home. And they offer a little of everything, from rolling hills, to flat stretches, to a couple of 14% grade "stingers" that are almost 1/2 mile long.

The carbon rims definitely lent a more aggressive look to the bike, a lightened it up by a pound, too.

And you can make fun of Strava, as well as power meters, but to me they've been useful tools in terms of gauging my personal progress over the course of the summer. 

And, what I lack in talent and outright speed, I seem to make up for with laser-like precision and consistency. In other words, I can ride the same 10-mile section of pavement on five different occasions and finish within seconds of my best time. As such, performing personal "time trials" on my favorite stretches of road offered a really good basis to compare the carbon Rolfs to my aluminum wheels.

A particular 10-mile loop I like to ride features lots of rolling hills, a few short/steep climbs, and a three-mile, slightly uphill "false flat." The loop mostly makes a square, which helps to negate any wind advantage from one day to the next. That said, the wind always seems to be coming out of the west when I ride it, meaning I start the loop with the wind at my back, and ride into the wind on the false flat section.

Long story short, I generally finish in slightly under 30 minutes, with an average speed of 20.9mph. First time out with the Rolfs, I averaged 22.5mph, nearly 2mph faster!

Thinking the wind conditions that day gave me an advantage, I checked my speed on the 3 mile uphill section (which is a Strava segment). Despite going into a headwind and slightly uphill, I averaged 20.3mph, significantly faster than normal.

Next, I wondered if I was simply having a good day and was especially strong. Turns out my average power was 8 watts LOWER than normal.

The carbon brake track and specialty pads provided surprisingly nice stopping power and feel.

And that ride turned out to be no fluke. I've been breaking Strava "PRs" (personal records) left and right with these wheels, and even nabbed a Strava "KOM" (King of the Mountain) or two. And while I'm still one of the slower guys on my group ride, I'm having an easier time keeping up.

While I wasn't completely surprised that the wheels made me faster, what did surprise me was the way in which they did.

Specifically, I don't notice much of a difference going uphill, particularly steep hills. Granted the wheels are very stiff and responsive, but neither in feel or evidence on Strava do they seem to offer a significant climbing advantage. Same holds true at cruising speeds at or below, say, 20mph.

Where the difference IS very apparent to me is on the downhills. The Rolfs spin up crazy quick and seem to be good for an extra 2mph in top speed. This is important because more speed on the downhills means more momentum to carry you up the next hill. That extra 2mph also seems to be true when sprinting against your riding buddies toward that sign by the county line. Another thing I notice, when riding in a fast paceline (+/- 25mph), is the wheels help you accelerate faster, and you don't slow down as quickly when you stop pedaling. Both of these qualities have really helped me keep up.

To put it another way, the faster you're going, the more advantage the carbon wheels seem to offer.

Do the Ares4s have any flaws? Well, I used them on a 200-kilometer brevet, and maybe over long distances they seem a little less comfortable due to their stiffness...but barely. Also, hiding the spoke nipples in the rim presumably means the tire, tube, and rim tape needs to be removed to adjust the spoke tension. That's not a service-friendly design in my opinion. And perhaps most importantly, the carbon rims would be much more expensive to repair if damaged.

On the other hand, the folks at Rolf Prima say that thanks to their paired spoke design, it takes a strong impact to knock the wheels out of true, so they are not wheels that will frequently need to be adjusted. They added that they have customers who've ridden up to 30,000 miles on their wheels and not needed truing.

On addition, the Ares4s were a snap to mount up (the tire bead slides right over the carbon brake track with zero effort). And there is no "deflection" (flex to one side) under hard pedaling. In contrast, if I'm climbing a steep hill out of the saddle, my rear aluminum rim can rub up against one of the brake pads if the pads are set too close. And yes, these test wheels have thus far stayed perfectly true, despite having HALF the spokes of a traditional road wheel.

So do you NEED fancy carbon wheels? Of course you don't. You especially don't if most of your riding is below 20mph. At normal, everyday speeds, carbon wheels seem to offer practically no performance advantage, but a serious disadvantage in terms of expense.

But if you like to ride fast, and aspire to ride faster, and are willing to spend the money, aerodynamically-tuned carbon wheels really are the best equipment purchase you can make...and they really do make a difference.

A huge thanks to Rolf Prima for lending a set of wheels for this experiment. Visit http://www.rolfprima.com/#built for more information on their handbuilt wheel products, which include both aluminum and carbon offerings for every style of bike.

About the author:

Brett Ratner (brett@thechainlink.org) has been a professional journalist for more than 25 years. He has contributed to dozens of publications, including The Chicago Tribune, The Nashville Tennessean, The Nashville Scene, Guitar Player and Musician. Brett began commuting by bike in 2005. Shortly thereafter, his interest in cycling expanded to century rides, bike camping, and trail riding. The competition bug bit in 2012 and nowadays he also occasionally races cyclocross, track, mountain bikes, criteriums and gravel for The Bonebell.

Comment

You need to be a member of The Chainlink to add comments!

Join The Chainlink

Groups

© 2008-2016   The Chainlink Community, L.L.C.   Powered by

Disclaimer  |  Report an Issue  |  Terms of Service