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Discussion Starter #1
I'm thinking about getting a deep aero wheelset but I have a few questions about their effectiveness for my usage. I tried seaching thru the web but can't seems to find any good data. Need you guys to help me out.
Most of the aero reviews provide by manufacturer show significant improvements of their aero wheelset compare with standard 32 spokes wheelset @ ~50kph. This is pro level and I can never maintain riding at that speed. I can probably do 35kph for 60km. And I'm thinking of doing ironman where my speed will probably be 30+kph for 180km. Does aero wheelset still make a difference at that speed?
Also, another thing to consider is that although manufacturer claimed significant aero improvements (in terms of lower power to turn their wheels at certain conditions), how much is it affecting the overall speed. For example, it may requires 100w (i have no idea what this number is and i just made it up) to turn a standard wheel compare with 50w for aero wheel. That is 2 time higher!! But if the rider require 1000w to keep the bike moving considering the aero impact of the rider body (which is significantly higher compare with the wheels), the advantage of wheelset is now ~5% when you look at the overall package, instead of 100% if you just compare the wheels. Suddenly the advantage by the wheel is no longer as attractive as before.
 

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Help is help. It's true that the aid is non-linear with respect to speed, so you won't see as big a percentage gain (in terms of kph) as a faster rider. Curiously enough though, you may see a greater overall time savings than the faster rider. Just an oddity of the way the math works out. Check out analytic cycling for more info.

Given that it will help, is it 'worth it?' Financially, that's a question only you can answer. Functionally, there is another bit to consider. In the extreme, suppose a wheelset would make you a minutes faster, but because of sidewind handling would put you at greater risk of finding a ditch? Would that be worth it? The answer there too is individual, based on your wind conditions, bike handling skills, and so on. Typically, moderately deep sections don't provide much handling problems, so this is a minor consideration. On the other hand, if you are contemplating very deep rims and/or ride in coastal or plains areas, it's worth at least some thought.

If I'm spending your money, I say go for it. Spending mine, I'm not so sure. Good wheels will make you faster than 'ordinary' ones, but the percentage is relatively small, since (as you noted) wheels are only a minority portion of aerodynamic resistance. I'd spend it if I realistically thought I was competing for the podium, or if there was someone in particular I just had to beat. But simply for the sake of seeing what time I could put in? A good time with crappy equipment is at least as impressive as a (slightly better) time with (much better) equipment.
 

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" I'd spend it if I realistically thought I was competing for the podium, or if there was someone in particular I just had to beat"

There is always someone you have to beat on a club ride :) If you got the cash to burn then why not, you only live once and aero wheels look cool as heck.
 

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You don't need to spend a lot

If you haven't seen Zipp's website you should give that a look... compare data on their 202 (25mm deep) rim to the others, and look at the Tour test posted on the first page. Also see this thread:
http://forums.roadbikereview.com/showthread.php?p=550582#poststop

You can get most of the aero benefit with 25-30mm Al rims and aero spokes... unless you are really a contender or wealthy, I wouldn't do the deep carbon thing. In the old Tour test linked above, the Alex wheels (like Neuvations, Korsos) performed very well. Personally, I'd rather go with a custom build with CX-rays or AE15s, a 30mm rim and whatever hubs you like.
 

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teocl said:
I'm thinking about getting a deep aero wheelset but I have a few questions about their effectiveness for my usage. I tried seaching thru the web but can't seems to find any good data. Need you guys to help me out.
Most of the aero reviews provide by manufacturer show significant improvements of their aero wheelset compare with standard 32 spokes wheelset @ ~50kph. This is pro level and I can never maintain riding at that speed. I can probably do 35kph for 60km. And I'm thinking of doing ironman where my speed will probably be 30+kph for 180km. Does aero wheelset still make a difference at that speed?
Also, another thing to consider is that although manufacturer claimed significant aero improvements (in terms of lower power to turn their wheels at certain conditions), how much is it affecting the overall speed. For example, it may requires 100w (i have no idea what this number is and i just made it up) to turn a standard wheel compare with 50w for aero wheel. That is 2 time higher!! But if the rider require 1000w to keep the bike moving considering the aero impact of the rider body (which is significantly higher compare with the wheels), the advantage of wheelset is now ~5% when you look at the overall package, instead of 100% if you just compare the wheels. Suddenly the advantage by the wheel is no longer as attractive as before.
People will argue over this for all time but let me say that I have a new set of Borras and regardless of all testing and predictions the one thing nobody told me is how fun they are to ride. The acceleration is addictive, swooping down a mtn pass is awsome. I have had them out on some very windy days and it not so bad as people say in cross winds (not like getting bumped like I was in last weeks crit). It is the best money I have spent on a bike. Did I say they are fun?
 

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rruff said:
If you haven't seen Zipp's website you should give that a look... compare data on their 202 (25mm deep) rim to the others, and look at the Tour test posted on the first page. Also see this thread:
http://forums.roadbikereview.com/showthread.php?p=550582#poststop

You can get most of the aero benefit with 25-30mm Al rims and aero spokes... unless you are really a contender or wealthy, I wouldn't do the deep carbon thing. In the old Tour test linked above, the Alex wheels (like Neuvations, Korsos) performed very well. Personally, I'd rather go with a custom build with CX-rays or AE15s, a 30mm rim and whatever hubs you like.
I can vouch for the fact that a pair of Velocity Deep V 24/24 wheels feels pretty quick. Built a pair for a buddy that wanted to retire the CXP30 tubies that I'd sold him the year before. :dunno

Deep Vs aren't THAT expensive...

Neither are Zipp 440s. Chances are the 440s are still in fantastic shape 'cause they're 'race wheels.' No, they're not the latest and greatest, but they're still better'n nothing.

M
 

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danl1 said:
Help is help. It's true that the aid is non-linear with respect to speed, so you won't see as big a percentage gain (in terms of kph) as a faster rider. Curiously enough though, you may see a greater overall time savings than the faster rider. Just an oddity of the way the math works out. Check out analytic cycling for more info.

Given that it will help, is it 'worth it?' Financially, that's a question only you can answer. Functionally, there is another bit to consider. In the extreme, suppose a wheelset would make you a minutes faster, but because of sidewind handling would put you at greater risk of finding a ditch? Would that be worth it? The answer there too is individual, based on your wind conditions, bike handling skills, and so on. Typically, moderately deep sections don't provide much handling problems, so this is a minor consideration. On the other hand, if you are contemplating very deep rims and/or ride in coastal or plains areas, it's worth at least some thought.

If I'm spending your money, I say go for it. Spending mine, I'm not so sure. Good wheels will make you faster than 'ordinary' ones, but the percentage is relatively small, since (as you noted) wheels are only a minority portion of aerodynamic resistance. I'd spend it if I realistically thought I was competing for the podium, or if there was someone in particular I just had to beat. But simply for the sake of seeing what time I could put in? A good time with crappy equipment is at least as impressive as a (slightly better) time with (much better) equipment.
Causing the religious argument: my pair of Cosmics let me ride ~1 gear bigger (faster) in the pack with the same (relative) perceived level of effort vs my 'regular' wheels.

My 404 track wheels did slightly better 'cause they were lighter.

Having said that: it ain't the wheels, its the rider.

M
 

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Discussion Starter #9
Thanks guys. Played around with the Analytic Cycling calculation table and worked out that if wheels aero drag is halved, the power required to move the rider (for my size) is about ~5% lower for @30 and 35kph. Quite significant I think. Now let me see how can i translate that into speed.....
 

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Faster in the pack?

MShaw said:
Causing the religious argument: my pair of Cosmics let me ride ~1 gear bigger (faster) in the pack with the same (relative) perceived level of effort vs my 'regular' wheels.
Sorry, this statement makes no sense. To ride in a pack, you must ride at the same speed as the pack. In order for the Cosmics to make you faster in the pack, they would have to make the entire pack go faster. Is that what you are claiming?

Maybe the reason your perceived level of effort in the pack is the same, is because your wheels had no affect on how fast the pack was moving.
 

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Numbers

teocl said:
Thanks guys. Played around with the Analytic Cycling calculation table and worked out that if wheels aero drag is halved, the power required to move the rider (for my size) is about ~5% lower for @30 and 35kph. Quite significant I think. Now let me see how can i translate that into speed.....
5% of power is quite significant, and it would take some very aerodynamic wheels to achieve that, but it is within the realm of possibility. Also keep in mind that aerodynamic drag power increases with the cube of velocity, so you won't get a 5% increase in speed. Instead, you'll only end up with 1.7% increase in speed. So if you were going 30kph or 35kph with your "standard" wheels, you'd be going 30.5kph or 35.6kph with the aerowheels (at the same power).
 

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Relative numbers

teocl said:
Thanks guys. Played around with the Analytic Cycling calculation table and worked out that if wheels aero drag is halved, the power required to move the rider (for my size) is about ~5% lower for @30 and 35kph. Quite significant I think. Now let me see how can i translate that into speed.....
The very best aero wheels are worth about 0.6 kph at 40 kph, or 0.5 kph at 32 kph. That works out to a 2.4% power savings at 32 kph. You cannot halve the aero drag of a set of wheels.
 
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