# soloist "aero" advantage



## AZroad (Aug 21, 2004)

I am one who agrees that aero will ultimately make more differance than weight. (I love my 22lb bike) I do however have one question about the aero benefits of the soloist family of bikes. I like to go for long rides (60 miles+) and need at least two waterbottles. Now tell me if I am wrong, but won't the waterbottles negate the aero benefits of the frame. Isn't that why tt/tri bikes have aero waterbottles and strategice waterbottle placement. If someone can intelligently explain how the bike is still aero, than you may have converted me to a future cervelo owner.


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## z ken (Dec 30, 2006)

i think you can put an aero bottle on your Aero Soloist bike and not loosing an aero benefit. or you can put a bottle on your back jersey.


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## stevesbike (Jun 3, 2002)

first off, the advantages of an aero frame are subtle. According to Cervelo's website the soloist reduces drag by 1.5% over a non-aero frame. At 25 mph on flats that amounts to a difference of about 0.1mph. Adding water bottles would disrupt the airflow, create turbulence etc., so you'd have to run a model to quanitfy or put in a wind tunnel, but as a general rule of thumb you would just ignore this in a comparison of two frames both with bottles.

You're also wrong about that 22lb bike. If you ride in hills, there's no comparison between the savings of a lighter bike and a heavier one versus aero advantages. Check out the cervelo site again for their tech presentation on this. They compare 150grams difference (between the soloist sl and the r3), which is a tiny weight difference. A 22lb bike versus a 16-17 pound bike is far less efficient as soon as a few hills are considered than any aero savings.

ALso, consider that rider frontal area is the major producer of drag. Improving rider position will have a much bigger effect on drag than aero shaped tubes.


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## gradosu (May 17, 2007)

to maintain any sort of aero advantage wouldn't one have to ride in the drops the entire ride? Also, isn't there a minimum speed that must be maintained in order to gain any advantage whatsoever? a bike that weights 5 pounds less, I would assume would be more efficient even on flat ground due to the lower rolling resistance.


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## Mark McM (Jun 18, 2005)

*Aero drag, weight and power*



gradosu said:


> to maintain any sort of aero advantage wouldn't one have to ride in the drops the entire ride?


No. Every component adds to aerodynamic drag, and any drag savings in any component will decrease power to maintain speed (or increase speed at a given power). It is true that the rider's body creates the majority of the aerodynamic drag, but if you compared two identical riders in two identical riding positions, the one on the more aerodynamic bike will be (slightly) faster.



gradosu said:


> Also, isn't there a minimum speed that must be maintained in order to gain any advantage whatsoever?


No. Some people like to talk about aerodynamics and speed as if there is some magical speed below which there is no aerodynamic drag, but the reality is that there is aero drag at all speeds (and even at zero speed, if there is a headwind). However, since aerodynamic drag increases with the square of speed, the aero drag is very small at low speeds, and therefore the gains in with aerodynamic equipment become much smaller at lower speeds.



gradosu said:


> a bike that weights 5 pounds less, I would assume would be more efficient even on flat ground due to the lower rolling resistance.


Yes, but not by as much as you might think. As you know, rolling resistance is roughly proportional to the load on the tires. If the total load (bike plus rider) on the tires is 180 lb. then a reduction in weight of 5 lb. is only 2.8% of the total load, so rolling resistance would be reduced by that amount. However, at racing speeds (25 mph) rolling resistance is about 10-15% of total drag - the largest part of the drag (85+%) is air resistance. So that 2.8% reduction in rolling resistance is only reduction of 0.28% - 0.42% of the total drag. But even then, since the power to overcome air resistance is proportional to the cube of speed, when available power is increased speed will only increase by roughly the cubed root of the power increase - so that decrease in rolling resistance will only increase speed by about 0.13%.


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