Aero Wheelsize Dilemma - Calling Aero Geeks

you are fast enough that a deep narrow wheel still has a good chance to be faster than a more modern "wide" rim.

I had thought about the narrower one. As for testing, the so variable, it would be kind of hard to tell. I can't do a redo during a race, just wrung what ya brung, so obviously it would be impossible to know. I guess that I might have to kiss up to wifey and ask for an early bday present, some wind tunnel time at Faster.

I like the feel of lighter wheels too, maybe b/c I'm only 146lbs, but I can feel the spinning weight of the wheels on accelerations and going uphills. At our tri course in Tempe, AZ... at least for the longer courses, like the SOMA HIM... there are 3 loops of the course, each loop has 4 or 5 u turns, and countless other 90 degree turns around street corners... and some of the turns feature going uphill right after them. I think that I estimated that those stops and starts and turns eats up about 2 to 3 minutes of time, assuming it takes about 20 seconds to slow down, turn and reaccelerate... there is that many turns, like a grand prix race track. So, at least, I feel the sluggishness of getting back up to speed and the energy required is higher. I did a course in Show Low... that had very few turns, no loops, just swinging around the countryside... it was awesome... just stay down on the bars and keep motoring... the very first bike leg that I've had like that. I got a PR too, even without shaved legs (first time ever for me, pure laziness)... LOL.

The only thing about the Flo that I could say, is that the mass seems to be more centered toward the outside edges, thus making them feel heavier, esp. the disc. I'd guess that a Zipp disc would feel lighter eventhough it's only 100gm or so lighter. I've considered replacing the 60 also with an all carbon with the similar shape... it would save 175 gm, or .35lbs, but besides the fact that aero trumps weight, it's the feel of the wheel, again esp. considering the race course at Tempe.... and also where I felt like I was dragging an anchor was at St. George going up the steeper parts of Snow Canyon. I would have loved to swap in a lighter wheelset right there..

But, mid Sept. is racing season again for us in AZ, so I need to dial in any equipment changes, esp. if I'm going deeper... need to order now.



Edited by tomspharmacy 2014-08-04 3:38 PM

Does the shape of the brake track make a difference... is there any info around... the straight edge vs. the slanted? It seems that Zipp and Flo have adopted the slanted, but HED still uses a straight edge aluminum... seems to work for them too.

I think that I'm looking for someone to tell me what to buy... Chris say narrow, so I can either give him all the praise or disdain, depending upon results..



Edited by tomspharmacy 2014-08-04 3:43 PM

HED H3 comes to mind. IIRC at low yaw it simply has the best numbers. Now for what tires to use with it....

I would think the 1st option which is the 3rd picture would most likely be best. You also have to look at spokes, spoke count, hubs, bearings. Your spitting hairs at this point but you are FOP so it's understandable. Also consider a 23mm on the front with a 25mm on the back.

If you have a nice consistent 10-15 mile coarse you can do twice a week, you may want to do trials to see which tires, tire sizes, and pressures work best for you. Try to minimize the variables and repeat each combination a couple times but not back to back. Ignore all the data until your done so as not to influence the results.

Most importantly if you do this, report back to BT your findings!

I will try to remember to do this.

The only thing is that I stopped going out on the open road where I would have consistant conditions. Where I live, we have one AZ state highway going into town and out of town... the speed limit is 65mph and there are no shoulders, just a white line along the edge... the shoulders are dirt, cactus, rocks and more dirt cactus and rocks. I stopped doing the road when a convoy of fricking snowbird RVer's almost killed me. It was like 10 in a row, I didn't know they were there, passed me with just inches and feet, They never moved off the edge,.. I got seriously buffetted and almost lost it. After that, it wasn't worth it anymore... I do all my interval training indoors and just do a 4.3 mile loop on a 25mph speed limit internal road in town. For long days, that means like 15 loops or more.

The only problem that I had in the past for consistant aero testing is that I'd make several changes at a time, then go out, so it would be difficult to pinpoint what affected what the most... fitness, equipment or position changes. Other than the race results, which show a positive change in the right direction.

Edited by tomspharmacy 2014-08-04 3:59 PM

Yaw, looked at those too... now, you're going to cause me another 2 weeks worth of headaches over tires...

What got me thinking about all these minute things are when you go to the cycling TT's, when the big dogs show up, esp. at the state championship. The top dogs in all classes are not only physically strong, but they're setups are amazing... at least a few of them, there are some screwy looking setups but results are results.

Edited by tomspharmacy 2014-08-04 4:05 PM

A little old, but worth a read

http://www.trainingandracingwithapowermeter.com/2010/11/aero-tires-...

Also

http://www.aeroweenie.com/assets/img/data/zipp808newvsold.gif

^ That is Zipps data on the older 808 (narrow rim) vs the FC design. Notice that at low yaw the old design is a good bit better


* always remember you can do a LOT of stuff wrong so long as you are strong enough to make up for it

Edited by Leegoocrap 2014-08-04 4:09 PM

RE: HED 3 wheels

There is the HED H3, HED 3 FR, HED 3D, HED GT3

The GT3 V2014 looks interesting.

Since they're narrower, except 2014 GT3, which tires, supersonic, GP TT, attack, Gp4000? all tubular I hope

I see a lot for sale all the time... first question, if they're good, why sell? and second, reliability, how crucial is it not to have scratches or dings?

This thread reminds me of the similar effort I went thru when putting my current Track bike together. I wanted to find the fastest front wheel as possible. In the end I found a NOS Zipp 1080 and called it a day. Seems like the faster you go the deeper the rim the better. In Track we'll have races at 30mph average and even in an out door velodrome very little side wind at that speed.

I have a Flo 60 I use on my Tri bike and find it gets blown all over the place. I'm 185lbs so not a light weight. I've tried that same wheel on different bikes and none of them get blown around as badly as my Tri bike does. That got me into looking into fork and frame interaction with front wheels and now my head really hurts I've tried the Flo 60 on the track and it feels heavy compared to the 1080 and I swapped it after one race.

Man, that's excellent real world stuff to ponder... now it's just to consider the fatter or narrower option.

As for the squiggly front end... I too had a problem when I put on the front Flo, but I swapped in a 100mm stem from a 90mm... I know that trick for calming the front ends... since longer stems slows down the handling... today's aerobars usually allow pad aft movement, so if you tested a longer stem, just move the pads and bar ends back the same amount, or keep them where they are, your body may not notice 1cm, but I could be wrong.

The only thing I'd be cautious about on the GT3 is that again... at lower YAW it's not as fast as the old H3.

The H3 FR is a little lighter
The H3D is a deeper wheel. It's a (very) small bit faster at 0-5°, but quite a bit slower anywhere else. It's also a bit squirrely in the wind. It's close enough at 0-5 and enough worse anywhere else that I'd suggest the regular h3.

the tire is the most important part of the H3. Run a thicker tire and it goes all to crap. You'll want a 20mm tire tops. In clinchers the best are the Bontrager Aerowings (you'll have to find some NOS ones.) but the 20mm Conti SuSo also fits well. I haven't had the tubulars personally, but I believe most people end up gluing a 20mm Vittoria CX to it, although I think the new GP4000sII comes in a 20mm.

Why are they for sale?
Not for everyone. They have a learning curve in the wind that is short but can be scary the first few times a gust gets you.
Narrow. It's not the trend currently.
Need specific (narrow) tires that can be a pain to source.
Not as "smooth" riding as some of the newer wider rims.

As far as reliability... they are notoriously bomb proof. I've got an old "specialized" (before hed bought the patent) trispoke from the early 90's and it's still reliable.

The only thing to watch out for when looking at them is whether or not it's an "A" or "B" wheel. None of the wheels come out of the mold 100% true or round. Usually they are VERY close (nothing you could ever tell) but once in a while one would be quite a bit warped. HED sold these as "B" wheels on ebay, they are still serviceable and usable, but generally enough out of true that brakes have to be adjusted for them and / or out of round enough that tire mounting becomes a hassle. At the prices the things sell for used nowadays there is no reason to get a B wheel.

Pretty much as usual, me and Chris are in agreement, so I'm not going to repeat what he already said.

To add to the discussion though, a heavier wheel is not always a negative… Yes, there's a penalty going uphill and accelerations will take longer, but once up to speed the inertia will gain a "flywheel effect", so it will be easier to maintain speed. In other words, if you ride lots of races with long climbs (short, power climbs, really won't make a difference) or technical courses with lots of sharp turns (where you can't hold the speed through the corners), then the weight of the wheel matters, if that doesn't describe the majority of your races, just skip the weight for now and get the most aerodynamic wheel you can find/afford.

One of the major advances in the last few years is the shape of the rims. Not too long ago, a deeper rim could be a handful to control in gusty conditions, now, not so much… My Jet9's are easier to control than my old Jet 50's, despite being much deeper. My wife (just over 100lbs) rides Zipp 808's even in the windiest conditions without any issues.

Personally, I prefer a spoked wheel vs. a tri-spoke, just a better (as in smoother) riding wheel. You can't go wrong with a HED Jet 9 (or HED Stringer 9 if you don't mind tubulars) or Zipp 808 Firecrest, both will offer an advantage over the Flo 60 (which is a pretty good wheel mind you).

+1

Worth mentioning that if a Spoked wheel is what you want to go with, the old 808 (pre-firecrest) was pretty much even with the H3 (biketechreview has an old article...think you have to pay... that tested them against each other)

As in the link above, if 0-5° is what you care most about, the old (toroidal) 808 is a little faster than the firecrest at those angles. You do need to run a narrow tire on it still, but it's a little less crucial than on the h3 due to the toroidal shape.

Not 100% sure about my zipp history, but I think the non-dimpled 808 is what you are looking for. Not sure if the dimpled ones were the narrow rim design or not.

Ah, I found and looked thru Zipp catalogs from 2007 to 2012, the 808 dating back to 07 had dimples... here's the link to the catalogs: http://www.zipp.com/_media/pdfs/catalogs/2011_catalog.pdf (for the years, just write over the year, goes up to 2012)... It seems that Zipp hasn't updated the 808 since firecrest in 2011.... I don't know about the new Firestorm??? or whatever.

So, Zipp is an early adoptor and one of the only ones using and angled brake track for the FC design... Flo, HED and maybe others still use a straight edge.

It seems that the 25mm flared track to the 27mm wide profile closely resembles the Firecrest design, and the 25mm straight to 27mm resembles a hybrid of the older 808 and Firecrest design. The 23 mimics the other but is just narrower... so if it would be my guess... the modern design would be the best performer in all around conditions, ie use for triathlons and TT... but the 23 maybe the fastest at the lowest yaw angles, but harsh at higher yaws.... the 25 straight, somewhere inbetween (I like that it has an 18mm wide bead, since I understand that the wider beads lower CRR for the same tire sizes).

Do I have this about right?



Edited by tomspharmacy 2014-08-05 10:07 AM

Yet another profile that I just got from another supplier.

OMG, is this wide!!

25mm flared to 28mm and 88mm deep... unless the 28mm is a statistical roundup







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25flared-28-88mm wheel.jpg (22KB - 2 downloads)

I can't believe I'm about to type it but...

you're overthinking it.

Deepest, narrow (narrow is aero, amirite?) rim = ideal for very low yaw. Not as comfortable, limited tire selection, possible issues in the wind, likely limited to aluminum braking surface.

"Modern" aero wheel. Wider, better in sweeps and/or higher yaw. More tires available, carbon braking surface, better ride in the wind.

How many hairs do you want to split? If you want the bar none fastest wheel at 0° get a 1080 or a H3D. If you expect low but not 0 get a narrow 808 or H3. If you expect varying conditions get an 808 FC.

Solved.

*also, understand that for the most part we are talking about minute differences at low yaw among all of the above. Enough to care about? Depends.

Edited by Leegoocrap 2014-08-05 12:05 PM

Well, I was a foreign language intelligence anal-yst for 15 years with the government, see where it got me?

ugh

:D

I lol'd, this is where I got to and why I picked up a 1080 front.

Well, thanks guys for forcing me to make a decision...

I went with the yoeleo design... it seems the closest to Flo or Hed. I was already in the process of ordering a road bike disc brake set from them, so I just added a front wheel, the 25 x 88... since I'll do TT's maybe 2 or 3 times a year max, I figured that you guys are right and focus on the maximum utility.... 88 is a split hair between the 808 and 1080 depths and a wink of an eyelash from the 90.

Edited by tomspharmacy 2014-08-05 2:29 PM

Look at that, Yoeleo had one piece stem/bar and seat posts in carbon that fit my MTB with free shipping.... Last metal bits on my MTB are about to be put in the spare parts container