Tire Width and Speed

Discussion in 'Cycling Equipment' started by smyrna45, Jul 27, 2004.

  1. smyrna45

    smyrna45 Guest

    I am sure this has probably been answered here numerous times,
    although I can't seem to find a definitive answer by googling the
    newsgroups. I also find "Bicycling Science" to be lacking on the
    subject, although its great on most other topics such as tire pressure
    and diamter.

    On my recently acquired Miele I have 700 x 32c tires. I am sure its an
    improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
    I do most of my riding on a relatively flat paved muliti-use trail. I
    am trying to decide whether it would make sense for me to get some
    skinnier tires, such as 25c's. Most of what I read seems a bit vague,
    using such terms as it will only make a minor difference in speed. I
    don't know how much "minor" is. I do know skinnier tires are more flat
    prone and not as easy to handle on the occasional sand or mud patches.

    Is there a source on the net that shows any scientific data on speed
    vs tire width, or failing that rolling resistance vs tire width?
     
    Tags:


  2. Terry Morse

    Terry Morse Guest

  3. smyrna45 wrote:

    > I am sure this has probably been answered here numerous times,
    > although I can't seem to find a definitive answer by googling the
    > newsgroups. I also find "Bicycling Science" to be lacking on the
    > subject, although its great on most other topics such as tire pressure
    > and diamter.
    >
    > On my recently acquired Miele I have 700 x 32c tires. I am sure its an
    > improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
    > I do most of my riding on a relatively flat paved muliti-use trail. I
    > am trying to decide whether it would make sense for me to get some
    > skinnier tires, such as 25c's. Most of what I read seems a bit vague,
    > using such terms as it will only make a minor difference in speed. I
    > don't know how much "minor" is. I do know skinnier tires are more flat
    > prone and not as easy to handle on the occasional sand or mud patches.
    >
    > Is there a source on the net that shows any scientific data on speed
    > vs tire width, or failing that rolling resistance vs tire width?


    Depends how fast you go. For riding over 20mph, narrow tyres will win
    out because air resistance is far more significant than rolling
    resistance. If you pootle, use the wider ones.
     
  4. Werehatrack

    Werehatrack Guest

    On Tue, 27 Jul 2004 09:31:18 -0400, smyrna45 <[email protected]>
    wrote:

    >On my recently acquired Miele I have 700 x 32c tires. I am sure its an
    >improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
    >I do most of my riding on a relatively flat paved muliti-use trail. I
    >am trying to decide whether it would make sense for me to get some
    >skinnier tires, such as 25c's. Most of what I read seems a bit vague,
    >using such terms as it will only make a minor difference in speed. I
    >don't know how much "minor" is. I do know skinnier tires are more flat
    >prone and not as easy to handle on the occasional sand or mud patches.
    >
    >Is there a source on the net that shows any scientific data on speed
    >vs tire width, or failing that rolling resistance vs tire width?


    Speed is a function of power input vs. power loss; tires contribute
    only one part of the loss.

    Tire construction and inflation pressure has more of a bearing on
    rolling resistance than width; testing has shown that there is no
    direct correlation between width and rolling resistance within the
    range of road tires tested. There is no extensive database to consult
    for information on the rolling resistance of tires currently on the
    market, so it is difficult to state whether any given tire has high,
    moderate or low resistance. The aerodynamic drag of the tire is
    unlikely to be a significant factor for the casual rider.

    One thing that is frequently reported, however, is that narrower tires
    ride rougher than wider ones (which is most likely due to higher
    inflation pressures being used in the narrower tires), and often are
    reported to have a higher rate of punctures.

    All things considered, given where you ride, I'd advise staying with
    the 700x32.
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.
     
  5. "smyrna45" wrote:

    > Is there a source on the net that shows any scientific data on
    > speed vs tire width, or failing that rolling resistance vs
    > tire width?


    Schwalbe has a little info on rolling resistance at
    http://www.schwalbe.com/index.pl?punkt=265

    John
     
  6. smyrna45 wrote in message ...
    >
    >On my recently acquired Miele I have 700 x 32c tires. I am sure its an
    >improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
    >I do most of my riding on a relatively flat paved muliti-use trail. I
    >am trying to decide whether it would make sense for me to get some
    >skinnier tires, such as 25c's. Most of what I read seems a bit vague,
    >using such terms as it will only make a minor difference in speed. I
    >don't know how much "minor" is. I do know skinnier tires are more flat
    >prone and not as easy to handle on the occasional sand or mud patches.
    >
    >Is there a source on the net that shows any scientific data on speed
    >vs tire width, or failing that rolling resistance vs tire width?


    Road grip, rolling resistance and handling is all improved by a more
    flexible casing.
    If you can feel the difference manipulating the tyres with your hands,
    there will also be a noticable difference on the road. Some tyres use a
    low thread count, these would be expected to puncture more frequently and
    wear out more quickly as the rubber has to do more work. A highly flexible
    casing with fine thread laid flat, not woven, and a thin covering of rubber
    is approaching the ideal of a pneumatic tyre.
    I feel it is always best to go for the thin tyre, dependant on frequency
    of debris, but not necessarily a narrow tyre. A narrow tyre, especially of
    the wired-on type, requires extreme high pressure to avoid pinch punctures.
    A consequence of this is a shortening of the tyre contact patch which makes
    a bike skittish through corners in the dry and liable to side slip when the
    road is wet.
    Narrow tyres are not difficult to handle, they are different. Narrow
    tyres with low pressure or excessively high pressure are compromised.
    If you really want narrow tyres, you need to try tubular tyres which come
    with a collection of perceived problems.
    Recommendations are difficult. Testing is needed upon the roads that
    you use, with pressures that give an acceptable level of comfort and grip
    without compromising puncture risk.
    TJ
     
  7. Gary Young

    Gary Young Guest

    smyrna45 <[email protected]> wrote in message news:<[email protected]>...
    > I am sure this has probably been answered here numerous times,
    > although I can't seem to find a definitive answer by googling the
    > newsgroups. I also find "Bicycling Science" to be lacking on the
    > subject, although its great on most other topics such as tire pressure
    > and diamter.
    >
    > On my recently acquired Miele I have 700 x 32c tires. I am sure its an
    > improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
    > I do most of my riding on a relatively flat paved muliti-use trail. I
    > am trying to decide whether it would make sense for me to get some
    > skinnier tires, such as 25c's. Most of what I read seems a bit vague,
    > using such terms as it will only make a minor difference in speed. I
    > don't know how much "minor" is. I do know skinnier tires are more flat
    > prone and not as easy to handle on the occasional sand or mud patches.
    >
    > Is there a source on the net that shows any scientific data on speed
    > vs tire width, or failing that rolling resistance vs tire width?


    If you want to compare tires of different widths, make sure you pick
    tires of comparable quality. Your chances of getting a high quality
    tire (i.e., fairly lightweight and supple) are probably better in the
    25mm width (since many wider tires seem aimed at people who won't
    tolerate flats).

    I once had a pair of Specialized Armadillo tires in a wider size
    (either 28mm or 32mm) and found them to be terrible -- heavy and
    harsh-riding. For a while I stayed away from all wide tires because I
    thought that was the nature of the beast. But then I discovered tires
    like the Avocet FasGrip and the Panaracer Pasela (both available in
    sizes bigger than 25mm).
     
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