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I live in Florida which is flat and often windy. I am a light rider, weighing about 125 pounds (57 kilograms).

How significant is the wind push around for someone my size?

My wheels are Reynolds Strike SLG carbon clinchers 622mm

There are lots of cross and head winds here, had me down to 13.6 mph today for a bit! I am a triathlete and have a big race coming up in Panama City, Florida, and ready for some aero benefits. I normally ride in the 18-20mph zone.

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  • I have added a stock image of a TT bike showing the wheels described. If these don't match your bike do feel free to add a better photo.
    – Criggie ♦
    Sep 24, 2017 at 18:08
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    Low rims would be a good start, at speeds of around 30km/h the benefit of having high rims is still negligible. Quintana, who is also very slight used a low front rim and a high rear in time trials where his heavier rivals had full disks rear and high front wheels to lessen the nasty effects of high side-winds.
    – Carel
    Sep 24, 2017 at 19:35
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    Weight alone has nothing to do with wind resistance. However, there is generally a relationship between weight and wind cross-section, and people with a larger cross-section presented to the wind will tend to experience more wind resistance. Your riding posture and the aero-ness of the bike are much more important factors. (And, as suggested, in crosswinds you want to avoid high rims, especially in front.)
    – Daniel R Hicks
    Sep 24, 2017 at 21:29
  • @DanielRHicks makes a good point, also winds are stronger further from the ground and light people tend to be short
    – Chris H
    Sep 26, 2017 at 9:03
  • Depending on the yaw angle and the deep section rim profile, cross winds can actually give a speed boost. Was it more of a head wind?
    – Rider_X
    Sep 26, 2017 at 23:31

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This is pretty simple. All things being equal, aerodynamic drag is a function of the relative wind velocity squared. Doubling the effective wind speed increases the drag force by a factor of four. Head winds could easily account for the loss in speed you are experiencing. Your body weight isn't a factor in dealing with head winds. Indeed if you are relative small, your drag will be lower than a larger rider. Weight is much more of a factor on hills, but in Florida that shouldn't be much of an issue.

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  • “Indeed if you are relative small, your drag will be lower than a larger rider.“ Yes, but due to the square-cube relationship of volume and size a larger rider will have more volume and output power relative to his/her surface area. This is similar to large animals having less skin surface compared to small animals, relative to their volume.
    – Michael
    Sep 26, 2017 at 16:47
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I depends on quite a lot of little things. First there is the weight repartition of your bike, think of it as a hammer : if the hammerhead is up high it will be difficult for you to vertically put it on a table in terme of stability but if the hammer upside is down it's not a problem. This is due to some lever phenomenon occuring and there is the same thing when you're on your bike.

It's mainly because even if you're light you're still the heavier part of it.

Now the thing with weight repartition is that's it's linked to efficiency because of the fact that it's your speed that makes the balance, the harder the balance to find the more energy you need.

This applies to every bike but the lighter you are the easier it is to have good weight repartition. (because 10kg+50kg is very not the same as 10kg + 80kg since you can't transfer your own weight)

So then again it's marginal but if your bike has good vertical weight repartition this should work for you and not against you and it's more easy to find.

Secondly there is the momentum issue, the higher you weight the less equilibrium you have but you get more momentum, that means that to a attain a good regime in some circumstances you will have to burn more energy under a certain weight. There also is an equilibrium to find because if you are too heavy it's the same thing, the momentum is harder to find.

So i'd say the lighter is not necessarily the absolute best, it depends on your general condition and gaining or losing weight depends on that. For the rest there still is some technical aerodynamics to do on you machine but I dout this alone would make you gain 10mph.

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