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Wheel configuration help

Looking for some help deciding on the optimal wheel set-up I should use for races this year.
I was not in the market for new race wheels, but basically stumbled into a dirt cheap deal for a set of HED H3 clinchers.
Right now I am racing on a set of chinese carbon clinchers that are about 60mm+ front and back.

I am guessing that my ideal set-up would be to pick up a disc cover for the rear 60mm and run the H3 in the front.
A couple questions that I wanted to pose to the forum:

- Despite the rear wheel being an open mold Chinese wheel, would slapping a cover on it still make it faster than just running the rear H3?
- I am set on running the front H3 all the time, but with those wheels being a bit narrow (19mm), am I best served picking up a Conti GPSII in a 20 instead of the typical 23 I run?

Thanks for any input in advance, and sorry to stoop to the low of posting an actual triathlon gear related post!
I am hoping to come to some conclusion where I can end up selling some combo of wheels if I determine I may not ride them much or ever.
Evansimonsen77
BSquad
Mid-Atlantic Captain

Comments

  • Options
    1) Yes
    2) No idea.
    3) What's your bike position look like? That will have a bigger effect than your tires.
    Kuch
  • Options
    Matt said:

    1) Yes
    2) No idea.
    3) What's your bike position look like? That will have a bigger effect than your tires.

    Thanks Matt, that was what I figured. H3 front and disc/cover in the rear
    I had read a bunch where the H3 had tested best with a more narrow tire due to its profile, so was just curious if anyone had experience with that.

    For sure, I actually just went back in and got my fit adjusted a bit on the Argon a few months ago, so I am feeling pretty solid in my position.
    I can poke around and see if I can find a decent photo. Being early in the season, I have only raced once but might have a side shot, or could pull the photo off my fit session report.
    BSquad
    Mid-Atlantic Captain
  • Options
    You want a narrow tire up front for sure with the old H3 clincher.
    KuchMatt
  • Options
    edited April 12
    @Matt how did you find 3 questions in there?

    Disc will be faster, aerodynamically, but if the hub is shit on either rear wheel, that could have a greater affect. H3 will be pretty damn close to a disc, especially in low wind/yaw situations.

    Get the narrower tire for the front. You'll lose a touch in Crr, but gain more aerodynamically. Remember that wider tires provide best rolling resistance on wider rims. Rule of thumb is to match tire size to rim width (or actually go a little smaller on the tire as they tend to be slightly larger than nominal). I'm assuming these are clinchers, where the tire shape is affected by the rim width.
    Kuch
  • Options

    You want a narrow tire up front for sure with the old H3 clincher.

    Thanks Zach!
    BSquad
    Mid-Atlantic Captain
  • Options

    @Matt how did you find 3 questions in there?

    Disc will be faster, aerodynamically, but if the hub is shit on either rear wheel, that could have a greater affect. H3 will be pretty damn close to a disc, especially in low wind/yaw situations.

    Get the narrower tire for the front. You'll lose a touch in Crr, but gain more aerodynamically. Remember that wider tires provide best rolling resistance on wider rims. Rule of thumb is to match tire size to rim width (or actually go a little smaller on the tire as they tend to be slightly larger than nominal). I'm assuming these are clinchers, where the tire shape is affected by the rim width.

    @KHilgendorf Thanks for the feedback!
    Perfect, that was what I was planning on with the tire choice. I typically run 23mms on my 23mm wide rims, so I will look to grab a 20mm for the front H3.

    Your point about the hub is a good one, and partially what I am curious about with the current rear wheel that's laced to a pretty basic novatec hub....where as, I would think the proprietary HED hub used on the H3 should be smoother.

    I guess I need to just keep all of these wheels!!
    BSquad
    Mid-Atlantic Captain
  • Options


    Get the narrower tire for the front. You'll lose a touch in Crr, but gain more aerodynamically. Remember that wider tires provide best rolling resistance on wider rims. Rule of thumb is to match tire size to rim width (or actually go a little smaller on the tire as they tend to be slightly larger than nominal). I'm assuming these are clinchers, where the tire shape is affected by the rim width.

    Source? Or any further reading? I had thought that the aerodynamic gain in the thinner tire would be negligable compared to a reduced rolling resistance?
    It's not that I don't believe you, I'm genuinely interested in diving deeper.
  • Options
    People tend to weight aerodynamics more heavily for the front tire and rolling resistance for the rear tire. This is mainly because there is more weight on the rear tire and the rear tire is shielded from the wind by the frame unless you ride a beam (and opposite for front tire - less weight and directly in the wind). I'm not sure I've ever seen any research directly on the subject though.
  • Options
    This looks like a good starting point for further reading:
    http://bikeblather.blogspot.com/2013/04/why-tire-crr-matters.html?m=1

    I'd summarize, but I'm so tired, I didn't read the whole thing yet. I'll be back tomorrow after some sleep.
    KuchAaronWebstey
  • Options
    @ellsworth53t I started writing all scholarly and shit, then deleted that because I didn't want to sound like an uppity asshole. People in the tri community are being persecuted for that today, I hear.
    Basically, you want a tire the same size as your rim or a mm smaller. This allows for the tire to be either perfectly round or slightly wider than tall, increasing the contact patch in the road. This increased contact area (where the tire deforms and loses energy through hysteresis) has less energy loss at a given pressure than a narrower tire because there is less deforming force acting on each unit surface area of the tire.

    Oh, fuck, I got all sciencey on you anyway.
    M WarekjrunninKuchellsworth53tTad_Machrowicz
  • Options
    @SeanH and @Nate_Mach take note...this is the kind of derailing/segues/asides we expect here at The Roost.

    @KHilgendorf thanks for that word, hysteresis, I love it! Tomorrow I will be dropping it into a random conversation that will make the engineers all go goggle-eyed. They still haven't recovered from the time I correctly suggested they could use a zero-crossing breaker in one of their substations.
    Matt
    Queen of All Pins
    Send your Pinterest suggestions to me at:
    QOAP@triroost.com
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  • Options
    edited April 13
    For further reading on all this: https://silca.cc/blogs/journal/118397252-tire-size-pressure-aero-comfort-rolling-resistance-and-more-part-1-how-we-got-to-now

    Keep in mind that even newer studies/articles are pointing back to narrow rims for aero due to most riding done at low yaw angles where frontal area is key.
    M WareKuchellsworth53t
  • Options
    So does that mean we went from the running shoe equivalent of Racing Flats to Minimalist to Hoka now back to Racing Flats?
    AaronWebsteyKuchsimonsen77KenElPescadoPelado
  • Options
    Matt said:

    So does that mean we went from the running shoe equivalent of Racing Flats to Minimalist to Hoka now back to Racing Flats?

    it means that nothing beats training hard and no one person or one wheel to frame set up is the same.
    train hard^3 + (buy gear + use gear)= success
    M WareKuchkjrunninMatt
  • Options
    Matt said:

    So does that mean we went from the running shoe equivalent of Racing Flats to Minimalist to Hoka now back to Racing Flats?

    Maybe? I dunno. I was too busy logging miles in DS trainers and lacing up spikes for races. I can actually understand the argument for super cushioned from an impact mitigation standpoint (though mostly for newer runners who are heavier than ideal).

    What the return to low yaw really means is that you shouldn't care about tire aerodynamics since the better performers only separate themselves at higher yaw angles. Go with the tire that matches your rim width and has the lowest Crr. Right now that's the vittoria cords speed for 23-25 mm rims. For the heds, I'd look for a 20 mm supersonic or older open corsa cx with the 320 tpi casing.
    MattKuch

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