Aero vs light wheels

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rustychain
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by rustychain

BmanX wrote:I think we need to clarify what someone would call an aero bike and the weight that goes with that and what a light bike is. I do not see why you can not have both.

A 900g aero frame will be faster than a 900g non aero frame.

A 1100g aero wheelset will be faster than a 1100g non aero wheelset.

So why would you not go aero and light?

With the 6.8 so easy to get to, why would you not design a super aero light bike to race.

If you can use less watts to go faster and further, why not.

If you look at the numbers we are talking very small advantages for a road bike if you look at weight or aero ( talking frame/ wheels not rider). Yes you can have a fairly light fairly aero road bike but I dislike it when we look at these factors in isolation. I would always put fit ahead of weight or aero. So how much farther can you ride on a somewhat aero and somewhat lighter roadbike ? Same question as to how much faster? Well in bike races I don't see any statistical advantage being shown. In RAAM I fail to see riders flocking to such bikes. Could it be that we analyze such minutiae to such extremes as to be of little practical value? Im not saying there is no advantages here, only that they are overstated. IMO it all becomes more a fashion statement then any performance gain. Aero and weight being a major advantage in the coffee shop ;)

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Zen Cyclery
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by Zen Cyclery

The aero vs. weight argument should be completely dependent on ones riding conditions. If you live in a place that is quite hilly, they you will definitely want to shave the weight a bit. However, if your doing rides where you have to sustain average speeds on the flats, then the more aero wheels will be a good call.
In the end, the most versatile setup I have found is to find a good balance. The low to mid 40mm range seems to be quite good for a daily driver depth, all though this is completely dependent on wether your running tubys or clinchers.

fdegrove
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by fdegrove

Hi,

It does not hurt to be light.
It does not hurt to be aero.

That said, I'd rather go uphill super light and when on flats I'd rather be as aero as can be. Don't much mind a bit of weight in the right place there either.....

Science does not ride a bike, is always right untill proven otherwise and never wins a race all by itself...

Ciao, ;)
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chrism
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by chrism

dcl10 wrote:Not to mention a lighter rim will allow you a smoother pedal stroke, which is more efficient as well.

You're going to have to explain to me why that is the case, when all logic suggests that a heavier rim with more inertia is actually better at smoothing out pedal strokes.
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elviento
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by elviento

What is aero is actually a much bigger question no one has discussed in this thread.

Aero wheels -- the advantage is fairly self evident.
Aero seatpost? Not sure, the pumping legs mean that the air around the seatpost/seattube will be dirty.
Seat tube cutout?
Narrow headtube? Probably not worth the sacrifice in stiffness.

Ironically, some so called aero bikes are solely for marketing and may not be that aero at all.
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fdegrove
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by fdegrove

Hi,

Ironically, some so called aero bikes are solely for marketing and may not be that aero at all.


Sure.

When it is stated that aero trumps weight it should be understood that an integrated system is viewed as aerodynamically optimized. Including the rider.
Obviously an aero seatpost is a bit hard to be viewed as beneficial in isolation....

Ciao, ;)
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BmanX
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by BmanX

Here you go. Exactly what I was discussing and not it just pops up into a bike. Build this up into a light bike. Not happy about the brake routing but at least them are making an attempt at something better.

Image
BIG DADDY B FLOW
AERO & LIGHT is RIGHT

Cervelo SLC 5960g/13.13 lbs

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prendrefeu
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by prendrefeu

elviento wrote:What is aero is actually a much bigger question no one has discussed in this thread.

Aero wheels -- the advantage is fairly self evident.
Aero seatpost? Not sure, the pumping legs mean that the air around the seatpost/seattube will be dirty.
Seat tube cutout?
Narrow headtube? Probably not worth the sacrifice in stiffness.

Ironically, some so called aero bikes are solely for marketing and may not be that aero at all.



viewtopic.php?f=14&t=89240 ??
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LouisN
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by LouisN

BmanX wrote:Here you go. Exactly what I was discussing and not it just pops up into a bike. Build this up into a light bike. Not happy about the brake routing but at least them are making an attempt at something better.

Image


That a battery or a spare tube box ? :lol:

Louis :)

cliplessnyc
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by cliplessnyc

Wow, great thread. Can anybody please look into following wheel "aero vs light" situation.
Stans ZTR340 wheel set - 20mm depth, 200 grams lighter.
Kinlin XR300 wheel set - 30mm depth, 200 grams heavier...

Is 10mm depth aero enough to justify 100 grams/per wheel weight increase?

fdegrove
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by fdegrove

Hi,

There's more to "aero" than rim depth. Think at least 38mm deep, spoke count, spoke shape, rim shape and so on.

I don't consider either rim particularly aero although 20mm is pretty useless aerowise...

Ciao, ;)
Last edited by fdegrove on Sun Aug 07, 2011 11:59 pm, edited 1 time in total.
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cliplessnyc
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by cliplessnyc

hmm ok, thanks!
so what about:
ZTR 340 20mm depth vs XR380 38mm depth?

The weight difference is now 400 gr per wheelset (XR380s are obviously heavier).

(Spokes Sapim CX-Ray, 24/24 & 20/24)

???

fdegrove
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by fdegrove

Hi,

Maybe you should ask your question in the "Wheelbuilding" thread. Those are the guys that know all the tricks.

Ciao, ;)
Being a snob is an expensive hobby.

drchull
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by drchull

Fit makes you more aero than everything else combined. Get fit in the most aero position you can get comfortable, in all the rest is secondary.
Like so many people above have stated so well, the rest depends on your build, riding syle and what you are doing.
I am a big clydesdale racer so my first consideration is sturdy. If it doesn't get through the last corner and ready for the sprint it is of no use to me. I have only ever won one race with brake pads rubbing and none with a flat or crash.
6.8 makes it easy though to do it all, sturdy aero wheels and aero frame if it fits and you are comfortable on it.
Oh yeah it has to look good, the new cervelo is just ugly (IMHO).

airwise
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by airwise

BmanX wrote:I think we need to clarify what someone would call an aero bike and the weight that goes with that and what a light bike is. I do not see why you can not have both.

A 900g aero frame will be faster than a 900g non aero frame.

A 1100g aero wheelset will be faster than a 1100g non aero wheelset.

So why would you not go aero and light?



Because a 900g "aero frameset" will be compromised in order to get the weight to that level.

Take the Foil. It weighs 940g. The fork 330g. That's around 240g more than the 2012 weenie framesets.

Now if you ride at 40 to 50kph for two hours you might still benefit. Otherwise it's pretty pointless really. Or so it seems. The trouble is no one has come up with a convincing demonstration of objective benefits for road riders when it comes to aero.

I for instance tend to average around 30kph on rolling terrain when not climbing mountains. At such slow speed ( although it's far more typical of all non racers ime) the so called benefits of aero are reduced to around 20% of those quoted as I understand it.

So taking a Cervelo S2 over an R5 would gain me something like twelve seconds in two hours of riding. I could stand up to fart and lose more than that.

by Weenie


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