Which road bike is the fastest?

On the 100km Gran Fondo mountain route, which type of bike and equipment gives the greatest advantage? There's only one way to find out.

Aero gear works fastest on flat ground; the lung is fastest on steep climbs – we all know that. But what if you're doing a long ride like the Gran Fondo, with flat sections, uphills, downhills, all the way? Is the aero, lightweight or all-mountain configuration faster overall?

The answer isn't obvious, so to find out, we put together three bikes and three matching kits and tested them all on a 100-kilometre track in the French Pyrenees, including a climb up the majestic Col du Tourmalet. The entire route climbs 2000m in total and is dominated by this famous pass, but it's worth remembering that the Tourmalet is only a fifth of the distance and much of the remainder of the route looks like a good hunting ground for aeronautical equipment (see more about the route here at map below).

'Performance along the route should always be the focus, so this is a great test,' says Drag2Zero's Simon Smart, a consultant to several leading WorldTour brands and teams. 'It can be tempting for riders of all levels to focus their choices equipment on the obvious highlight of the route, the Tourmalet in this case.”

'For the last 14 years my work in bike and equipment design has been focused on finding the optimal balance between aerodynamics and weight.'

Bicycle and equipment

For our aero bike, we chose the BMC Timemachine Road 01, which isn't overly heavy at 7.9kg but is designed to be fully aerodynamic. The exception is its 50mm wheels, so we replaced them with a set of ultra high-profile 82mm Zipp 808 Firecrest wheels. They weigh 2015 grams, bringing the overall weight to 8.2kg, but should make the BMC a real rocket on smoother roads.

Additionally, the Giro Eclipse Spherical helmet and Suplest Aero shoes promise real aerodynamic gains in exchange for a few extra grams of weight. Castelli's Sanremo suit was the original one-piece racing suit, and version 4.1 is faster than ever. The Rule 28 socks, which complete the set, save a few watts with their ribbed fabric. The entire equipment package is designed for high speed and weighs only 9.46 kg.

For a lightweight bike, we chose the Specialized S-Works Aethos, weighing just 6.19kg. Its round tubes are completely devoid of aerodynamics as part of its extreme diet. The Poc Ventral Lite helmet and Giro Empire SLX II boots are the perfect complement to the lightweight, while the bib shorts and Assos Superleger socks are designed to tackle big climbs on hot days. A proper jersey only has one pocket for indoor training, so for this test we used the Dhb Aeron Lab Ultralight jersey, which is incredibly lightweight but still has three pockets to withstand longer rides. With a total weight of 7.16kg, this kit is a lifting enthusiast's dream.

Our all-round bike, the Factor Ostro VAM, which the company calls the “bike for everything”, combines low drag and light weight – 7.21 kg. The Met Trenta helmet and Lake CX302 boots, like the bike, split the weight difference between the lightweight and aero kits, and the helmet adds aerodynamics as well. The Sportful Bomber Jersey fits tightly to the body, but at the same time, like the Total Comfort bib shorts, is suitable for wearing all day long. The weight of the bike and gear is 8.4kg, which is almost exactly in the middle between the other two sets.

Test Method

Obviously it's very difficult to control such a long test with races on different days, there was still a lot we could do to make it fair and representative. I first rode with a focus on power, using identical Favero Assioma Duo pedals with a power meter on each bike. I set the pace for the first run, then repeated the same power for each section of the course on subsequent runs, with a list of sectors and power targets taped to the top tubes of the frame (see map for details of each sector).

Although this cannot be done blindly, by carefully monitoring the current power and average power per lap (segment) on the screen, both the overall average power over the course and the smooth distribution of power can be easily monitored. However, this requires a lot of concentration.

Second, I used the same aerial position on every section of the course—pistol grip on gentle climbs, top handlebar grip on steep climbs, bottom handlebar grip on descents and flats—and the bikes were set up identically. Thirdly, I took with me the same spare parts and tools, food and two liter flasks, so as not to stop and replenish supplies. I even ate at the same places on every trip.

Fourth, to eliminate any differences in rolling resistance, all bikes were fitted with 26mm Pirelli P-Zero Race tires with Maxxis Ultralight tubes, inflated to 6.2 bar at the front and 6.5 bar at the rear.

Of course, repeated tests are good, but for such a long trial it is not practical. It took a lot of planning and a lot of luck to get a week of stable high air pressure, calm and sunny weather in which all three races could be held alternately. I rode non-stop and did not wear a vest or jacket on the descents, which could have affected the aerodynamic comparison.

Even with all these efforts, there are still vulnerabilities in the method. The barometric pressure will not be the same, and there is no way to control the aerodynamic effect of passing traffic on the flats or the delays caused by having to pass cars on downhill slopes. If there is any delay – for example, sheep on the road – processing of data from Strava can be used to determine the loss of time. In addition, two towns on the route – Lourdes and Bagneres-de-Bigorre – were impossible to drive with constant pedal power, so they were neutralized and all three events were given the same average time on this section.

How did it go

All three runs went well, with much the same weather and no delays or glitches, meaning the power readings in each section were pretty much the same. In some places, such as uphill during the first 11km, it was difficult to feel the difference between the bikes in terms of speed. Surprisingly, the same thing happened when climbing the Tourmalet, although to a lesser extent. The difference in weight was noticeable, but it definitely didn't feel like one of the bikes felt like it was anchored while the other seemed to float.

Downhill it was different, but it was the handling that set them apart, not the aerodynamics or weight. The Specialized felt flimsy and almost too light, jumping off bumps and sapping confidence. The BMC on Zipp 808s was even more problematic. Such high wheels really have no place in the highlands, where the wind blows from everywhere.

The Zipps wheels are very stable for their profile in crosswinds on flat terrain, but on the upper slopes of the Tourmalet they were hit hard by crosswinds. Factor showed how it should be done: stable, clear, precise, confident… and it was faster.

The long, false flat descent that followed was accompanied by a slight headwind each day, and here the aerodynamic configuration was in its element, while the Specialized felt limited in these conditions. The universal Factor, as expected, was somewhere in the middle.

Results

And the winner is… the universal configuration with a result of 3 hours 19 minutes 37 seconds. In second place, with a lag of 2 minutes 46 seconds, is the lightweight configuration with a result of 3 hours 22 minutes 23 seconds. In third place is the aero highway, with a time of 3 hours 24 minutes 41 seconds, which is a full 5 minutes 4 seconds slower than the station wagon.

The all-round road bike won four of the seven segments and was second in the remaining segments. Of particular note is that he lost only 15 seconds to the lightweight version on the Tourmalet climb. Perhaps most impressively, he recorded the fastest times on various sections of the track: difficult climbs, difficult descents and flat sections.

The light configuration finished second, winning at the Tourmalet but failing to exploit its advantage enough to remain in the lead. In short, it's only most effective on steep climbs and comes at a cost on faster sections.

The Aero configuration took third place with completely opposite results: it won two stages that suited it, and was last in the rest. On the Tourmalet, the weight took almost two and a half minutes longer to climb, and then poor handling made the descent cost another 43 seconds.

'These results are impressive,' says Smart. 'The all-mount configuration loses some aerodynamics and weight, but it does the job best and was the most stable and confidence-inspiring bike. The overall time difference is enormous.”

You can view all metrics on Strava

1st place – All-rounder: Factor Ostro VAM, 3 hours 19 minutes 37 seconds, 237 W average power | Watch on Strava

2nd Place – Light Configuration: Specialized S-Works Aethos, 3h 22m 23s (-2m 46s), 236W Avg | View in Strava

3rd place – Aerochosser: BMC Timemachine 01 Two, 3 hours 24 minutes 41 seconds (-5 minutes 04 seconds), 235 W average power | View in Strava

Conclusions

ero is everything, and weight is… in most cases too. Combining these features into versatile products provides the best of both worlds, outperforming specialized lightweight or aero gear.

So the next time I sign up for Gran Fondo, will I just use the more versatile kit featured here? Not really. I would have preferred the more versatile Factor Ostro model, but I would have paired it with a Giro aero helmet, Castelli Sanremo aero suit and Rule 28 socks combined with Giro ultralight shoes. It would be 44 grams lighter and more aerodynamic. I think it would be worth another minute of gain.

Test route

Lots of ups, lots of downs and everything in between.

Rivals

Aerokit

BMC Timemachine 01 Two 8.18 kg (7.9 kg stock)

Wheels Zipp 808 Firecrest (our addition, model year 2021)

Helmet Giro Eclipse Spherical: 308 g

Glasses SunGod Airas: 33 g

Sports suit Castelli Sanremo Speedsuit: 256 g

Socks Rule 28: 56 g

Shoes Suplest Aero: 626 g

Equipment set weight 1279 g

Total equipment weight 9.46 kg

Lightweight kit

Specialized S-Works Aethos 6.19 kg

Helmet Poc Ventral Lite: 210 g

Glasses Poc Elicit: 23 g

Jersey Dhb Aeron Lab Ultralight: 83 g

Overalls shorts Assos Equipe RSR Superleger S9: 129 g

Socks Assos RS Superleger: 30 g

Shoes Giro Empire SLX II: 498 g

Equipment weight 973 g

Total equipment weight 7.16 kg

Universal kit

Factor Ostro VAM 7.21 kg

Helmet Met Trenta Mips: 287 g

Glasses Rudy Project Spinshield: 28 g

Jersey Sportful Bomber: 111 g

Overalls shorts Sportful Total Comfort: 168 g Rule 28 socks: 56 g

Shoes Lake CX302: 540 g

Equipment weight 1190 g

Total equipment weight 8.40 kg

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Photo: Chris Storrar (Chris Storrar)