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Front wheels: 303 vs 404 vs 808
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I'm running an 808 depth rear. The question is what front wheel should I be running given I suck at handling my TT bike it seems (upgraded from road bike to TT bike this spring)? Has anyone seen any comparative aero data of running an 808 (82mm) vs 404 (58mm) vs 303 (45mm) front wheel? Or does anyone have a rough time estimate of the time delta over a 40k course between the three wheels? I realize there are a ton of variables at play, everything from wind speed/direction, tire choice, frame, etc. But even just ballpark would help.

My predicament:

I'm in the fortunate position of owning Zipp 303, 404, and 808 (all Zipp NSW) wheelsets, and trying to sort out how much time I should be spending trying to get comfortable in aero on the deeper front wheels. I'm a 155lb, 5'11", 3.25 watt/kg rider (unworthy of these wheels, I know.... but please help me anyhow.....)

I have no problems handling any of these wheelsets on my road bike except high speed descending in truly gale force winds, but on the TT bike, I just can't seem to get into the groove on anything but the 303 front wheel. I live in San Francisco, and pretty much every afternoon/evening this month I've been riding in 25mph+ winds. I've nearly lost control of the bike a couple times now, and it's starting to mess with my head as I head into my racing season (Santa Rosa 70.3 and Santa Cruz 70.3s, both which I understand can be quite windy).

At some point, with enough experience, I expect I'd eventually get comfortable riding the 808 pretty much all the time. But the problem is, during more intense workouts, I'm not pushing as hard on the pedals as I'd like to be due to temerity handling the bike thus leaving potential on the table. I'm gaining bike handling skills at the cost of increasing my power, but I know I have a LOT of headroom to increase my power on the bike (given bike time relative to swim and run times).

So what I'm trying to figure out is... how much am I playing for really, by continuing to train on the 404 and 808 wheels? Given it's already June, would my times this season likely even be faster on the 303 front wheel and just hanging up the 404/808 until this winter? Is the lower hanging fruit (in terms of getting faster) actually just training harder on a shallower wheel right now. I could use some advise prioritizing skill development vs raw power development right now.

Thanks.
Last edited by: wintershade: Jun 7, 19 15:15
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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You should be using a disc wheel on the rear.
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Re: Front wheels: 303 vs 404 vs 808 [jimatbeyond] [ In reply to ]
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jimatbeyond wrote:
You should be using a disc wheel on the rear.

Haha. Slowtwitch in one sentence.

But to answer your question, just based on my gut, go with the one that makes you feel most comfortable this season. But you do need to work up to the 808. Maybe by the end of the season you can get there. Maybe just the 404 and the 808 by next year. You can always bring them all and decide in transition that morning which one to race with based on conditions.
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Re: Front wheels: 303 vs 404 vs 808 [jimatbeyond] [ In reply to ]
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Lol, I was waiting for that. Jim, I'm starting to wonder if you had a bot running that immediately replies to any wheel aero question with "disc is always the answer" -- :0) I kid, and appreciate your input.

I forgot to mention, I ran a simulation of my expected finish time at Santa Rosa 70.3 in best bike split. I sort of fudged a bunch of numbers I wan't sure of at the moment like power targets, etc, but you'd think this would be pretty close. Here were the outcomes:
"shallow" front, "deep" rear: 2:44:20
"shallow" front, "disc" rear: 2:44:18 -- 2 sec faster than baseline
"deep" front, "deep rear: 2:43:51 -- 29 sec faster than baseline

If we're talking a <30 sec difference between a 303 and an 808 front, I kind of wonder if I'm just wasting my time riding anything but the 303 this season.
Last edited by: wintershade: Jun 7, 19 15:48
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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It depends on the course you're racing although I'd be picking only between 303 & 808. My favorite race which I do almost every year is the Hawai'i 70.3, where one can't have a disc rear anyway, and use my 45 front and 80 rear. In an A-race where cross winds aren't that much of an issue (almost any other race!), I'll cover the rear and swap a deep front on. Some races, like maybe IMAZ, could be windy, could be not, then I'l wait til the day of bike check-in to check the weather and make a decision there.

808 > NYC > PDX > YVR
2024 Races: Taupo
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Re: Front wheels: 303 vs 404 vs 808 [RichardL] [ In reply to ]
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I came across the chart but could use some help deciphering what it means. I’m not much of a physicist.

Assume I’m biking along at 21 mph (not 30, I wish!) on an out and back course like Santa Cruz. According to Best Bike Split my average yaw angle is 3 degrees. Looks like the difference is what, 5g? The curves don’t really seem to separate until 10-15 degrees of yaw. What does that translate into in real word conditions for a guy looking for a 2:35-2:45 bike split?
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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wintershade wrote:
I came across the chart but could use some help deciphering what it means. I’m not much of a physicist.

Assume I’m biking along at 21 mph (not 30, I wish!) on an out and back course like Santa Cruz. According to Best Bike Split my average yaw angle is 3 degrees. Looks like the difference is what, 5g? The curves don’t really seem to separate until 10-15 degrees of yaw. What does that translate into in real word conditions for a guy looking for a 2:35-2:45 bike split?

It means mostly in most cases you'll be negligible difference between the two wheels.

If there's some unusual condition with a strongish crosswind then the 808 could be significantly faster (with the tradeoff or more potential handling issues).

But in either case you can check the "got a fast front wheel" checkbox and move on to other things.
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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I don't have a model of your course, but using one of my local halves and inputting a 2.40 rider using some of my tunnel data (wheels in bike, no rider)
Profile Design 58f, 78r compared to Hed Jet 9f, Jet disc r - 16s advantage to the big kid wheels. That excludes watts to spin so add a few more seconds. Average yaw 5.4 in this scenario
There would be a few more seconds for dropping the front to a 40ish mm.
PD wheels usually test the same or better at low yaw than zipp and not quite as good at high yaw.
All the drama about wheels is rather overstated - except for always ride a disc...
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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wintershade wrote:
I came across the chart but could use some help deciphering what it means. I’m not much of a physicist.


That chart is meant for ordinary cyclists, so you don't need to be a physicist or a rocket scientist to decipher it. For example, at 15 degrees of yaw, the 808 FC has around 50 grams less drag than the 404 FC at 30 mph. Rule of thumb is 50 grams of drag at 30 mph is worth 5 watts. At 21 mph, 50 grams of drag is worth around 4.6 watts.

The equation is: 50 g of drag @ 30 mph = 0.5 s/km = 5 W = 0.005 m^2 CdA = 0.0005 Crr


So at 20 mph, you save 30 seconds over a 40K for 50 grams of drag reduction. Just learn how to handle your front Zipp 808. I'm 130 lbs, and I have zero issues doing a 40K TT using a front Zipp 808 FC, even in somewhat windy conditions.
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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I’d sell the 808 and 303 and get a disc for the rear as it will stabilise the front. This is not a myth it actually works
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Re: Front wheels: 303 vs 404 vs 808 [jimatbeyond] [ In reply to ]
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jimatbeyond wrote:
You should be using a disc wheel on the rear.


QFT - except if you're in the M45-49, then you should ride the shallowest, boxiest wheels w/gatorskins and a rudy wingspan.....trust me ;-)

With double deep dish wheels the reason you're having issues handling is the stall points on both wheels. Both wheels stall at somewhat different yaw angles. So your front stalls and the bike twitches, the rear stalls and you get more twitching.

You're the sail, the disc wheel is the keel.

Also 25mph winds are no joke. I've run a front Jet 90 & 808FC in those and your basically applying pressure to one extension and leaning into the wind to track straightish. I've done this w/ & without a disc. It's a lot easier to handle with a disc and one should never ride in near hurricane conditions with a set of H3's on....ask me how I know or would you like to see the scars?

If you're riding on heavily trafficked roads you're going to get some gusting from passing trucks/cars which won't help either.

Brian Stover USAT LII
Accelerate3 Coaching
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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ride a disc for stability... it helps with handling. The reason front wheels are twitchy is the size difference between the front and the rear. An 808 front will be much easier to handle with a disc rear than with an 808 rear.

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: Front wheels: 303 vs 404 vs 808 [hadukla] [ In reply to ]
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hadukla wrote:
It depends on the course you're racing although I'd be picking only between 303 & 808. My favorite race which I do almost every year is the Hawai'i 70.3, where one can't have a disc rear anyway, and use my 45 front and 80 rear. In an A-race where cross winds aren't that much of an issue (almost any other race!), I'll cover the rear and swap a deep front on. Some races, like maybe IMAZ, could be windy, could be not, then I'l wait til the day of bike check-in to check the weather and make a decision there.

Hi Hadukla -- This is interesting advice. Why do you say the choice is between the 303 and 808 and exclude the 404? Do you find that to really get the handling improvements of a shallower front wheel you have to go all the way down to a 303? (I think I do). So you decision is either 1) windless day and go all in on the 808 front, or some winds and you keep it super conservative with the 303?
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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wintershade wrote:
hadukla wrote:
It depends on the course you're racing although I'd be picking only between 303 & 808. My favorite race which I do almost every year is the Hawai'i 70.3, where one can't have a disc rear anyway, and use my 45 front and 80 rear. In an A-race where cross winds aren't that much of an issue (almost any other race!), I'll cover the rear and swap a deep front on. Some races, like maybe IMAZ, could be windy, could be not, then I'l wait til the day of bike check-in to check the weather and make a decision there.


Hi Hadukla -- This is interesting advice. Why do you say the choice is between the 303 and 808 and exclude the 404? Do you find that to really get the handling improvements of a shallower front wheel you have to go all the way down to a 303? (I think I do). So you decision is either 1) windless day and go all in on the 808 front, or some winds and you keep it super conservative with the 303?

My reality is that is the only choice available to me, haha but I think even if I could have it all, I would probably still decide between the 808 and 303. I feel if the winds are bad enough that I feel like i'm expending too much energy keeping the deep front stable, then I wouldn't feel enough of a difference going only one step down.

For me it isn't about control, I am about 175 lbs and quite confident of a handler, I just do feel that keeping a line in crosswinds with a deep front is more energy expenditure than it's worth.

808 > NYC > PDX > YVR
2024 Races: Taupo
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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Ride what you're comfortable on. The mental energy expended on keeping the bike upright totally negates the aero benefit if you're racing/riding in heavy crosswinds.

I don't really notice a difference between 303 and 404 personally. 808 took a bit of getting used to but now only bothers me on the gustiest of days. Had a 1080 for a bit and I thought I was gonna die at least twice every time I rode that damn thing.
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Re: Front wheels: 303 vs 404 vs 808 [indianacyclist] [ In reply to ]
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"Had a 1080 for a bit and I thought I was gonna die at least twice every time I rode that damn thing."

I ride a 1080 front sometimes. Rode it at IMTX this year, and had a few sketchy moments of crosswinds, but I will say that when the wind was favorable.....holy crap that wheel was fast!

Team Zoot-Texas, and Pickle Juice
Last edited by: Taugen: Jun 12, 19 10:26
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Re: Front wheels: 303 vs 404 vs 808 [indianacyclist] [ In reply to ]
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Thanks. That's pretty much how I feel riding the 808.

Lacking a disc wheel (with no plans to buy one until Zipp comes out with an NSW Tubeless Ready disc wheel with the Cognitiion hub and Showstopper brake track), should I run the 808 rear or the 404. I assume the deepest wheel possible so it is the "keel"
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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You’ve got most your weight over the rear wheel, so deeper shouldn’t be an issue (unless you’re a 105lb flyweight)
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Re: Front wheels: 303 vs 404 vs 808 [ericMPro] [ In reply to ]
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Eric -- How big is the handling benefit of a disc on the rear? Are we talking night and day (like 303 vs 808 front wheel) or splitting hairs (404 vs 808 front on a windy day). I'm contemplating whether it's worth it to sell some of these wheels for a Super-9. My dealer would allow me to return one of the wheels sets for store credit, which would get me 80% of the way to a disc wheel.

I guess the simplest answer is get a disc cover and decide for myself what the handling benefit is worth, if I'd rather have variety of the disc. But my hunch is the answer is to trade the 404 NSWs for a Super 9. Keep the 303 for truly gale-force wind days and work up to the 808 front, keeping the 808 rear for non-disc legal races.

One downside to this though is I've switch to running tubeless and really like it, and Zipp hasn't yet released a tubeless-ready NSW disc. So if I switch between the 808 and the Super-9 I'll also have to adjust brakes, etc. Just more headaches....
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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I suppose one other option, if I want to stay tubeless and narrow wheel choice even further would be to just sell the whole arsenal of Zipps for a set of Enve 5.6 + Enve Disc. Use the 55mm front for everything and the disc vs 6 rear depending on disc-legality of course. Then it's only 3 wheels to maintain vs 4-5 and fewer decisions to make (with respect to front wheel) on race day. But then again, that's a lot more change I'm introducing into the system (new wheels, new brake surface) just a month or so out from my key races.

Thoughts?
Last edited by: wintershade: Jun 13, 19 14:17
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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the disc acts like the keel of a sailboat. You should definitely dump one of the shorter wheelsets and get the disc.

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: Front wheels: 303 vs 404 vs 808 [desert dude] [ In reply to ]
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Thanks for the advice.

I just ordered an ENVE SES Disc and 5.6 set. Plan is to train + race on the 5 front so I'm comfortable with how it handles in all conditions -- none of this constantly wondering what front wheel to choose. My understanding is the 5 handles almost as good as a 303 NSW but significantly better than a 404, which sounds just about right for my abilities. Race the disc 100% of the time unless the course doesn't permit it. And do most of my training on the 6 rear to keep the disc in good shape.

I feel good about this choice. I get bizarrely indecisive with equipment selection, so this will be one less source of stress on race day.
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Re: Front wheels: 303 vs 404 vs 808 [wintershade] [ In reply to ]
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wintershade wrote:
Thanks for the advice.

I just ordered an ENVE SES Disc and 5.6 set. Plan is to train + race on the 5 front so I'm comfortable with how it handles in all conditions -- none of this constantly wondering what front wheel to choose. My understanding is the 5 handles almost as good as a 303 NSW but significantly better than a 404, which sounds just about right for my abilities. Race the disc 100% of the time unless the course doesn't permit it. And do most of my training on the 6 rear to keep the disc in good shape.

I feel good about this choice. I get bizarrely indecisive with equipment selection, so this will be one less source of stress on race day.

Roadie here so this is somewhat constrained to road racing and TT's but the 303 is the best front wheel hands down. Zero issues in even the strongest crosswinds. If you can ride a 404 you can typically ride an 808. That is why i have a set of 303's as my primary race wheels and then a set of Enve 7.8's for zero wind days. Since you went disc Enve is a great option. I think for rim brakes the Zipps are better but disc eliminates that variable.
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