What's more important - aero wheel up front or rear?
 

I already know the importance of aerodynamics, how an aero wheel can save you on the time and energy spent. But if I were to use just one aero wheel, where would it be more beneficial? In the front or the rear? Utilizing two aero wheels are not an option. I'm curious to hear everyone's opinion on this one. All other factors held constant (will not discuss the whole weight issue associated). Thanks!

Aero front wheel is more important over an aero rear wheel offering the greatest benefit of the two as it is hitting 'clean' air.

An old study but shows some interesting details. http://www.damonrinard.com/aero/aerodynamics.htm

Most important of all is for the rider to be in an optimal position which is comfortable enough to hold the whole race. There is no point having an aggressive position you can't hold for more than a few minutes...

That's a very interesting study. In the comparison study of a front disk vs a rear disk, you save 2x more time with a front aero disk wheel over a 40km distance.
Another figure that jumped out for me was the time saved with the removal of the water bottle and its cage.

Though without hydration for 40 km drop in performance will counteract the gains.

Another view on the bottle on the seat tube / down tube aerodynamics...

http://www.slowtwitch.com/mainheadin...erbottles.html

Whats a Shultang? And where can I get an inexpensive one?

Get an aero helmet instead.

Only if the objective is to save money rather than go fast.

Don't put a disk on the front - it'll seriously affect your handling.

Is pcad watching?

Smooth nylon socks: $8 0,4% 4 sec

That's 8 Deutchmarks, I think.


Who even sells a front disk anymore?

I assumed that since he only wants one aero wheel it was because of financial constraints.

That said though, i read an article a little while ago that basically concluded that an aero helmet has a benefit on par with a set of zipp 404s

That data was flawed and the conclusion incorrect. Search MIT hlemet aero wheel.

Aero helmet does more than a set of aero wheels.

You never run a disc on front, and in fact they arent allowed.

If you have to buy an aero wheel, buy a rear disc.

Repeating it doesn't make it true. The only data showing this (MIT) was shown to be erroneous.

Aren't allowed by whom? They're certainly legal for USCF racing, and there are enough pictures on cyclingnews with them to make me believe they're legal for UCI.

An aero helmet is waaaay cheaper than a Zipp 404.

It is obvious you arent a triathlete.

As far as the helmet goes, yes, it does make a bigger difference than the wheels. Repeating a fact doesn't make the fact true, but merely publicizes it. So thanks for finding one instance of a study..please talk to some triathletes and see what they say.

USAT governs most races of consequence and here is a quote from their rulebook "(g) Except as otherwise determined by the race director in the interest of safety, the front wheel may be of a
different diameter than the rear wheel, but the front wheel must be of spoke construction. The rear wheel may be either spoke or solid construction. Wheel covers shall only be permitted on the rear wheel."

So no... you can not use a disk on the rear. Next time, please know what you are talking about before you are so quick to criticize.

Actually ranger, you can use a disc on the rear under USAT rules, thats the 'solid construction' part. I know you can't use a full disc in WTC races though. Kona springs to mind.

As far as the helmet goes, there's been more than just the MIT study and the conclusions are all similar. They work, on par with a set of aero wheels.

I've seen plenty of data on wheels and helmets showing this is not so, but no data showing it is. With the only exception being those studies which considered only the unrealistic 0 yaw condition. Do you have a reference for a study showing data where aero helmets reduce drag more than a set of aero wheels over a range of yaw angles or even one realistic value?

No i don't. I'm not into the whole keyboard warrior thing where i feel i need to cite to win an e-argument.

I'm just regurgitating what i read. Take it or leave it - doesn't matter to me.

What I'm asking for is an end to that keyboard warrior thing you refer to. I'm not asking anyone to take my word for anything. There are discussions on slowtwitch regarding the change in drag with yaw angle for wheels and helmets. There is plenty of data on wheels and helmets at 0 yaw (from which the relative benefit at non-zero yaw can be inferred from the slowtwitch discussions. Though that isn't necessary as there is plenty of data for both at non-zero yaw out on the web. Anyone can take a look at the data and the results are clear.

On the other hand, we have you citing unnamed articles (not actual data) and not even a direct reference, but now we're supposed to take your regurgitation of facts at face value.

I think people can make up their own minds.

Great, noone else knows what this yet it could be saving us time accroding to that old study:eek:

You don't have to take anything i say as anything at all if you don't want. I'm just telling you what I've read in random articles online and in magazines, which is that helmets are just as good, or damn close to a 404 wheelset (no solids).

I'm neutral on the subject. I don't have aero anything ;)

Cmon guys, play nice!

Just to clarify a few points -

bvfrompc - Shultang directly translates to 'circuit' via babel fish translation from German. All I can gather is Shimano Sante (groupset back in the day) had either aero levers or brakes, though I have a set in the shed of both and don't appear more aero than usual unless they had another version.

ranger5oh -Front aero wheel has a greater time gain than the rear in every study I have seen, even if the rear wheel is a disk - as the front wheel faces clean air. The Aero helmet is definitely a worthy tool and valuable in the arsenal of go fast kit especially for the price but not as beneficial as wheels.

Disk on the front. Not legal for road as far as I am, aware and the uci rules (though I did recently see some pics from the Italian TT championships where a rider did have a front disk!?) or tri's (rules explained above by ranger5oh).

Aero Helmet better than aero wheels - Brief article was published in bicycling magazine with a comment about the value of aero helmets vs wheels from a guy from M.I.T.S. As asgelle has already said (though in a 'tone' which usual causes tension) the comment was based on 0 degrees yaw which isn't a realistic test given wind directions fluctuate considerably. So as soon as the wind starts to angle the aero benefits of the wheels improves considerably over the lid.

funny enough they actually have bikes these days with integrated bottle cages on the downtube that actually make the bike faster with than without. the cage basically just serves to extend the aeroblade

@Treefox you bring up the point I was going to make which is that you most often see TT athletes using a disc in the back and a trispoke or other slightly less aggressive wheel in the front.

This is because sidewinds hitting a front disc wheel can cause dramatic destabilization of the steering and make you crash. But as others have noted, if you want to take the risk and aren't limited by race rules, a front disc is more effective than a rear.