John Cobb has discussed this before, the idea being that the center of pressure when you are hit with a crosswind is towards the rear wheel and further away from the steering axis when you run a deeper section or disc in the back which makes the bike easier to control.
Kevin
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for the front a HED 3 would probably be better than an 808, due to her being subject to more extreme yaw angles due to her slower speed…
I would stick with the 808 over any HED but especially the H3. H3 are bad in crosswinds plus they are just plain ugly.
According the HED website, if you run tubulars the 2009 808 is faster than the 404 out past 20 degrees, if you run clinchers the 808 is only faster out to 15 degrees of yaw.
The HED wheels show similar results, Jet 6 faster than 9 after 12.5 degrees and Stinger 6 faster than Stinger 9 after 17 degrees.
Kevin
The H3 may be “Bad in crosswinds” in that they are tough to handle.
But they are good in crosswinds in that they have less drag than the deep rims at very high yaw angles
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for the front a HED 3 would probably be better than an 808, due to her being subject to more extreme yaw angles due to her slower speed…
I would stick with the 808 over any HED but especially the H3. H3 are bad in crosswinds plus they are just plain ugly.
… Basically, in the simplest terms, the deeper rear wheel pushes you into the wind more than the deep front pushes you away from the wind, which is why it’s better to get a “mismatched” pair…
Will you discuss this concept a little more? Is a mismatched set faster in all conditions? Faster for all riders? Do the same rules apply that everyone is discussing here for going to deep wheels in general? I am saving my pennies for my first set of “race wheels” (planning on Hed Jet 60’s) and while I strongly prefer the balanced aesthetic of a matching set (I know, I know, but my mind just really likes symmetry) I do not want to let my personal idiosyncrasies lead me to make a sub-optimal decision. Is a 6/9 combo that much better than a set of 60’s?
A mis-matched pair is not necessarily faster, it makes the bike easier to handle. This can be counterintuitive to people that think, for example, that want to add a disc in the back, but think it will be “too much to handle.” So, for example, a 6/9 pair is going to be faster than a 6/6 pair AND easier to handle. However, a 6/9 pair will not be faster than a 9/9 pair, just easier to handle. So a mismatched pair is only faster if you end up with a deeper rear wheel that you originally planned for, not a shallower front. This totally ignores any speed gains/losses due to “fear” (or lack thereof), as in with a shallower front you actually feel like you can steer the bike and therefore stay in the aerobars.
Just out of curiosity, how much does she ride??
I recently interviewed top tech execs from both HED and Zipp for a little snippet we did on both company’s wheels. Both HED and Zipp told me that if a person isn;t consistently *over 25 M.P.H. *they should stick to 60 millimeter deep rims as opposed to deeper 80 and 90 millimeter rims.
The 60’s have a better, more efficient aspect ratio for lower speed regimes. Also, they are lighter and less affected by crosswind turbulence. For a rider between 10-17 M.P.H., especially on a rolling course, aerodynamics *do *still play a role, but a small(er) role relative to weight and stability. When it comes to rim depth slower (rider speed) equals lower rim profile. A lighter, more stable, slightly less turbulent shallower section wheels will both *feel *faster and actually be faster to a rider in the 15 M.P.H. regime than would a heavier, more turbulent 80 millimeter deep rim.
Right - Slightly worried now, having sold both my front H3 and 50mm wheel. I have a Planet X 101 on the front now, which is a basic V. What you, along with your contacts at Zipp and Hed, are saying is roughly this.
Since I average 24/25mph for a race, I’m a boarder line case. Keep the disc is the back, use the 101 for the flat stuff and the track, and get a 60mm front for those hilly races.
Is that it?
Hello Flying Wombat and All,
http://www.washingtonpost.com/wp-dyn/content/article/2009/03/03/AR2009030303618.html
I saw that too and it was a wake up call as I had previously ASSUMED the 808 clincher and tubular rims were almost the same aero wise. 
Bummer!
That could be a reason to go back to tubulars.
I am guessing it is the juncture of the metal rim and the carbon fiber rim that causes the premature stall in the clincher.
Looks like ‘Little things mean a lot’.
Suppose some silicone sealant applied in that area would improve those flow characteristics? Vortex generators? Trip wires?
Maybe I shouldn’t have cut off the tire mold nipples - maybe they energize the air flow over that area.
Just more training needed to improve my 60MP.
Cheers,
Neal
not enough…100-150 a week she rides
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Who am I to deny this economy 2g’s of “stimulus” - but why not just go to Raceday Wheels and spend $150 on a great set up for the day?
Not worth it. At 15 mph she’s not generating a lot of aero drag. As such, aero wheels would only gain at most a couple of watts.
Who am I to deny this economy 2g’s of “stimulus” - but why not just go to Raceday Wheels and spend $150 on a great set up for the day?
well i get the 1080s for life and i suppose she will always have a nice set of wheels for racing…were in this for the long haul…i think
I have the perfect solution for ya… buy the 1080s, your wife can keep her current wheels and then you can give me a smoking deal on your 808s… everyone wins! 
Must resist. Must resist. Must resist. Hell, can’t resist!
Buy yourself the 1080s and enjoy them! Give your wife the 808s because you can. But, you’re still giving her used wheels while you’re getting new ones.
The only equitable solution is to also buy her either the P4 or a P3C. That’s the only way to guarantee she makes the cut off time.
After all, this is Slowtwitch, so Cervelo is always the right answer!
Training Neal!? Shhhhhhhh we dont want people to know about that, its all about the gear…
I though about going back too, if I was road racing/TT only I would, but I know with a good glue job there is no way I can get that tire off easily and I like to corner hard and worry free.
Kevin
Buy a 404 front and a 1080 rear. Give your wife the old 808 rear and the new 404 front. Then you have an 808 front and a 1080 rear.
As the Hed site says relative to apparent wind - the slower you go the more apparent the effective crosswind and the more you need a wheel that stalls at greater yaw angles.
Deeper rims stall at larger yaw angles … hence the deeper rims are more useful to slower riders than fast ones, as long as you are not on hills over 6% to 8% and you do not have control problems in the wind.
Sorry, but this couldn’t be more wrong. It is completely opposite reality. Yes, the slower you go the more apparent the effective crosswind. At that point it becomes more critical to find a wheel that doesn’t stall at greater yaw angles. Stalling is a bad thing because the air flow is disrupted and your fancy aero shape isn’t doing you any good. From Hed’s own site:
“When a wheel stalls out, drag increases, because the wind no longer “sees” an aero shape that it can flow over smoothly; instead the wheel looks more like a flat surface. Instead of flowing over, the wind pushes on the rim. Turbulence as airflow leaves the wheel creates constantly changing pressure gradient on the downwind side and starts to buffet the wheel. A wheel that is hard to handle is a wheel that has stalled. The deeper the rim, the higher the drag when it stalls.”
I’d have her test ride your 808s on a windier hilly route. I’m a strong- but lighter weight rider- 150 lbs- and I’ve had a hard time handling 808s before on speeds north of 35 mph on windy descents over open road areas- like a descent leading to a bridge crossing a lake. I seem to be able to handle an H3 easier in the front- in the same conditions. My wife- 103 lbs- has a hard time handling a 303 front on windier days. I’ve since sold my 808 and her 303s… Positioning would probably be much more helpful for her, along with an aero helmet- than the several watts a front wheel would get you. You might want to consider HED’s shallow JET 4, a clincher- which is much more aero then BOTH: Zipp’s deeper 404 and slightly more aero than the much deeper than the 808 clincher, esp when you get out to higher yaws (more likely for her at her slower speeds).
Buy a 404 front and a 1080 rear. Give your wife the old 808 rear and the new 404 front. Then you have an 808 front and a 1080 rear.
that could work…but then ive missed kona cutoff by 15 mins the last 3 yrs…i mite need a further edge w full 1080 attack
You want the 1080’s for the same reason I do-they look cool but NOT noticeably faster than 808’s.On zipp’s site they claim that a pair of 1080’s are TWELVE SECONDS faster than a pair of 808’s over 40 km.So for an ironman you are looking to save 54 seconds. Not much of a bite in that 15 minutes you need for KONA.