The faster you go, the more you should be concerned about drag, because its effects are going to be felt more substantially. To illustrate, compare the wind resistance you feel when you're struggling up a mountain pass (not much), to the wind resistance you feel when you're careening down the other side (quite a bit). Equipment that provides an aerodynamic advantage would be superior in events such as a 40 km time-trial, where your speeds might approach 30 mph (and the overall effects of air drag will be much greater). What about ultra events, where speeds are more going to be about half that much? Do aerodynamic wheels really provide a significant advantage at those speeds, or should we be more concerned with the weight of our wheels?

At moderate speeds, over relatively flat surfaces, aero wheels (e.g., tri-spokes) provide only a slight advantage over lightweight, spoked wheels (e.g., Mavic Heliums). At 16 mph, for example, with all other aspects of the bike and rider being equal, you would be about 1 second faster for every mile traveled. This converts into being 0.07 mph faster. For a 500-mile RAAM qualifier, this translates into being about eight minutes (or a little over two miles) ahead if you ride aero wheels as opposed to lightweight wheels. Of course, the greater your speed, or the longer the distance of the event, the more this advantage will become apparent. In RAAM, for example, this becomes a 50-minute (or 13 mile) difference.

Aero Wheels and Climbing
But these figures apply only to relatively flat surfaces. What happens when the road begins to rise? Aero wheels continue to maintain their advantage until the incline reaches a grade of about 4%. At that point, and on any steeper grades, lightweight wheels gain the advantage. And the more steep the grade, the greater the advantage. On a 9-mile climb up an 8% grade, for example, lightweight wheels that are each about 200 grams lighter than aero wheels will provide you with a 30-yard advantage by the time you reach the top.

"What if you had to do a mountainous course like the Furnace Creek 508 on only one set of wheels?"

But what if you have to make a choice? What if you're in an event where you don't have a support crew that can give you a lightweight bike with lightweight wheels every time a major climb emerges? What if you had to do a mountainous course like the Furnace Creek 508 on only one set of wheels? Would lightweight wheels or aero wheels be better? All else being equal, aerodynamic wheels would provide you with about a six minute (or 1.5 mile) advantage by the end of the race. All in all, then, it would seem that aerodynamic wheels are indeed the way to go for ultra events. The advantages that they provide are clearly slim (they make you about 0.03% faster than conventional wheels), but if you're looking for a time-saving edge in wheels, they will provide it best.

RAAM Riders Experiences
"Most RAAM racers seem to be riding Spinergy wheels as their primary wheelset, with reduced-spoke wheels of lighter weight as their climbing option. "

RAAM riders are clearly aware of the advantages of different wheels for different terrain. Almost all RAAM riders who responded to the poll mentioned that they have a number of different types of wheels with them, and will change wheels as the terrain dictates. As one rider put it, "aerodynamic wheels are excellent if you ride very fast; a light wheel is perfect always". Clearly, the best option is to be using aerodynamic wheels that are also very light. The next best option is to be riding aero wheels that are relatively light. With this in mind, most RAAM racers seem to be riding Spinergy wheels as their primary wheelset, with reduced-spoke wheels of lighter weight as their climbing option. Spinergys were the wheel of choice because they were regarded as durable and relatively light, while still being considerably aerodynamic. Conversely, no particular brand emerged as the favourite with respect to lightweight wheels. Some were riding Shimano 16-spoke superlight, others were riding Mavic Helium, others were riding Zipp. Many of these choices were made because the wheels, in addition to being light, had less drag than conventional wheels. It was, then, an attempt to get the best of both worlds while climbing, but with the emphasis still being on lighter weight.

Size: 650c vs. 700c
How much should the size of the wheels be a consideration when choosing the wheels you ride? What are the advantages of each? The most obvious difference is that 650c wheels, by virtue of their being smaller, are also lighter. By simply switching from 700c to 650c wheels, you can reduce the weight of the wheel by about 200 grams. Such a savings in weight, as noted above, translates into better acceleration capabilities, and (what we're more concerned with for ultras) better climbing. In other respects, though, such as riding at constant speeds, the true performance difference between the two wheel sizes is negligible. In fact, 700c wheels, because they are larger, have a greater stabilizing effect than 650c wheels.

Given that there really isn't much performance difference between 700c and 650c wheels, the rule of thumb for wheel size is based largely upon rider height. A shorter rider (under 5'7") is encouraged to ride 650c wheels, because a bike frame with 700c wheels might not allow you to get the front of your body low enough to be fully efficient or fully relaxed. Conversely, taller riders (over six feet) should ride 700c wheels, because the 650c wheels displace body weight over the bike in ways that are not the most efficient or comfortable in the long term. Only riders between 5'7" and 6'0" have a real choice between the two wheel sizes. One possible option in these cases is to go with a 650c front wheel (thus trimming some weight), and a 700c rear wheel (for increased stability, and somewhat better body-position dynamics).

Almost all the RAAM riders that responded were using 700c wheels in both the front and back. This was particularly the case with their primary racing bikes. Undoubtedly, rider height is a factor here. Most RAAM riders tend to be relatively tall, and for most it was the case that 700c wheels just "felt better". This consideration is especially important for ultra events, where you need to maintain a position for long periods of time. Clearly, the more comfortable your riding position is, the more efficient you're going to be in the long run. Many RAAM riders (who were taller) noted that they simply felt "too cramped" on a 650c wheel bike after hundreds of miles. A couple riders, though, were using 650c wheels with their climbing bikes, in order to decrease the weight.

Tires: Clincher vs. Tubular
"Accomplished RAAM riders are almost all riding clincher tires."

More Information    UltraCycling Magazine Authoritative information for endurance cyclists. Each issue contains articles by experts on: training nutrition equipment event preparation rider profiles race results Join the UMCA and receive six issues a year.

Order back issues

There are clear advantages to both types of tire here, and whichever you use is mostly a matter of personal preference. Tubular tires, overall, provide a better ride (there's a reason that more pros use tubulars!). Quite simply, tubular tires have higher tire pressures, and therefore, lower rolling resistance. This also provides them with a more comfortable ride. Additionally, tubular rims are on average about 100 grams lighter than clincher rims, and tubular tires are about 30-50 grams lighter than the clincher tire/tube combination. So you will also gain a weight advantage by riding tubulars. Practically speaking, they also tend to be more puncture resistant, and pinch-flats are non-existent with tubulars because of the very nature of their construction.

The main advantages of clincher tires is that they are less expensive overall than tubulars, and they are somewhat easier to change (particularly on the fly). The performance gap between clinchers and tubulars has decreased in recent years. A good clincher tire performs almost as well as a tubular these days. So what you choose to ride, in the end, really is a matter of personal preference with respect to juggling these pros and cons.

Accomplished RAAM riders are almost all riding clincher tires. Though most riders recognized that tubular tires provide a better performance, they also noted that the difference between the two types of tires has lessened over the past number of years. Thus they chose to ride clinchers primarily because of their increased convenience, both for training and for racing. There were a couple of tubular tire hold-outs, but they were clearly in the minority among RAAM riders.

The most common brand of tire among those who rode clinchers was Continental. It was the clear favourite, with the Grand Prix series being the preferred model. With respect to tubulars, Vittoria was clearly the company of choice.

There are a number of choices to consider when choosing a wheelset for your bike. In the end, much of it seems to come down to personal preference, based on a finite number of variables, such as weight and aerodynamics. As with your frame selection, the wheels you select for your bike should be chosen with your particular events and goals firmly in mind.

[ To Top of Page  | Home   | Calendar  | Current Results  | Standings  | Year-Rounder  | Records  | Training  | Equipment  | Nutrition  | About the UMCA  | Site Index ]