Roller with two different bikes

Discussion in 'Cycling Equipment' started by Christopher Mey, Mar 5, 2004.

  1. I recently bought rollers and am enjoying them...but here's the question

    When I ride with Bike A., my speed at the same exertion (measured by HRM)
    as when I ride Bike B is about 5mph slower. Bike A has Rolf Seistre wheels
    (with new and recently rebuilt freewheel) and Conti 3000 GP tires whereas
    Bike B has Mavic SSC SL wheels with Vittoria Corsa Evo tires. I switched
    the wheels and Bike gained a lot of the speed with the Mavic/Corsa combo.

    What fascinates me is why there would be such a large difference between the two wheel/tire
    combinations. Those of you with more experience, please enlighten me. Are there other factors?
     
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  2. "Christopher Meyer" <[email protected]> wrote in message
    news:[email protected]...
    > I recently bought rollers and am enjoying them...but here's the question
    >
    > When I ride with Bike A., my speed at the same exertion (measured by HRM) as when I ride Bike B
    > is about 5mph slower. Bike A has Rolf Seistre
    wheels
    > (with new and recently rebuilt freewheel) and Conti 3000 GP tires whereas Bike B has Mavic SSC SL
    > wheels with Vittoria Corsa Evo tires. I switched the wheels and Bike gained a lot of the speed
    > with the Mavic/Corsa combo.
    >
    > What fascinates me is why there would be such a large difference between
    the
    > two wheel/tire combinations. Those of you with more experience, please enlighten me. Are there
    > other factors?

    Are the freewheel's the same on both bikes? how 'bout the chainrings? Is the computer properly
    calibrated for each wheelset? are the tires pumped up to the same presure on both bikes? a
    combination of all these factors could make quite a big difference.
     
  3. B. Schneider

    B. Schneider Guest

    "Christopher Meyer" <[email protected]> wrote in message
    news:_b32[email protected]...
    > I recently bought rollers and am enjoying them...but here's the question
    >
    > When I ride with Bike A., my speed at the same exertion (measured by HRM) as when I ride Bike B
    > is about 5mph slower. Bike A has Rolf Seistre
    wheels
    > (with new and recently rebuilt freewheel) and Conti 3000 GP tires whereas Bike B has Mavic SSC SL
    > wheels with Vittoria Corsa Evo tires. I switched the wheels and Bike gained a lot of the speed
    > with the Mavic/Corsa combo.
    >
    > What fascinates me is why there would be such a large difference between
    the
    > two wheel/tire combinations. Those of you with more experience, please enlighten me. Are there
    > other factors?
    >
    >

    I noticed a similar effect when changing tires half-way through the winter - the roller just ate
    tires like there is no tomorrow.

    I switched from Bontrager Select 700Cx25 (relatively soft rubber) to Conti Gatorskin 700x23C (much
    harder rubber). With the Gatorskins I now have to use 2-steps lower gear than with the Bontragers.
    As a side-effect the noise level went down significantly, too.

    So the tires, width and rubber mix, make a significant difference.

    Enjoy the monotony of staring at the TV while on the rollers :)

    Bengt-Olaf.
     
  4. Greg Estep

    Greg Estep Guest

    "slartibartfast" <[email protected]> wrote in message
    news:[email protected]...
    >
    > "Christopher Meyer" <[email protected]> wrote in message
    > news:[email protected]...
    > > I recently bought rollers and am enjoying them...but here's the question
    > >
    > > When I ride with Bike A., my speed at the same exertion (measured by
    HRM)
    > > as when I ride Bike B is about 5mph slower. Bike A has Rolf Seistre
    > wheels
    > > (with new and recently rebuilt freewheel) and Conti 3000 GP tires
    whereas
    > > Bike B has Mavic SSC SL wheels with Vittoria Corsa Evo tires. I
    switched
    > > the wheels and Bike gained a lot of the speed with the Mavic/Corsa
    combo.
    > >
    > > What fascinates me is why there would be such a large difference between
    > the
    > > two wheel/tire combinations. Those of you with more experience, please enlighten me. Are there
    > > other factors?
    >
    > Are the freewheel's the same on both bikes? how 'bout the chainrings? Is
    the
    > computer properly calibrated for each wheelset? are the tires pumped up to the same presure on
    > both bikes? a combination of all these factors could make quite a big difference.

    Even if you have accounted for all the above variables (and I'm sure there are a few others) I would
    not be surprised to hear that the tire/wheel combination still makes an observable difference in
    your effort required. I'm guessing that it's the tire, not the wheel, that accounts for most of the
    difference. The deformation of the tires where they meet the drums is responsible for the resistance
    you experience while ridding rollers. Therefore, a change in the tire can be looked at as being
    similar to adjusting the resistance on a mag/fluid/air trainer. Of course, if you have an external
    resistance device on your rollers (Kreitler rollers with a Killer Headwind, for example) the
    relative effect of a tire change would be reduced.

    --
    Greg Estep
     
  5. Kinky Cowboy

    Kinky Cowboy Guest

    On Fri, 05 Mar 2004 20:28:05 GMT, "Greg Estep"
    <[email protected]> wrote:

    >
    >"slartibartfast" <[email protected]> wrote in message news:[email protected]...
    >>
    >> "Christopher Meyer" <[email protected]> wrote in message
    >> news:[email protected]...
    >> > I recently bought rollers and am enjoying them...but here's the question
    >> >
    >> > When I ride with Bike A., my speed at the same exertion (measured by
    >HRM)
    >> > as when I ride Bike B is about 5mph slower. Bike A has Rolf Seistre
    >> wheels
    >> > (with new and recently rebuilt freewheel) and Conti 3000 GP tires
    >whereas
    >> > Bike B has Mavic SSC SL wheels with Vittoria Corsa Evo tires. I
    >switched
    >> > the wheels and Bike gained a lot of the speed with the Mavic/Corsa
    >combo.
    >> >
    >> > What fascinates me is why there would be such a large difference between
    >> the
    >> > two wheel/tire combinations. Those of you with more experience, please enlighten me. Are there
    >> > other factors?
    >>
    >> Are the freewheel's the same on both bikes? how 'bout the chainrings? Is
    >the
    >> computer properly calibrated for each wheelset? are the tires pumped up to the same presure on
    >> both bikes? a combination of all these factors could make quite a big difference.
    >
    >Even if you have accounted for all the above variables (and I'm sure there are a few others) I
    >would not be surprised to hear that the tire/wheel combination still makes an observable difference
    >in your effort required. I'm guessing that it's the tire, not the wheel, that accounts for most of
    >the difference. The deformation of the tires where they meet the drums is responsible for the
    >resistance you experience while ridding rollers. Therefore, a change in the tire can be looked at
    >as being similar to adjusting the resistance on a mag/fluid/air trainer. Of course, if you have an
    >external resistance device on your rollers (Kreitler rollers with a Killer Headwind, for example)
    >the relative effect of a tire change would be reduced.

    The aerodynamic drag from the spokes is quite large when on the rollers, probably about 25% of what
    you get at the same speed on the road, somebody else can do the math if they want to. Given that
    you'll probably be going faster on the rollers than on the road, spoke drag will become
    increasingly significant. Rolling resistance is much higher on rollers than on the road, for
    obvious reasons. If you want to experiment, swap the tyres from one set of wheels to the other so
    that you can isolate these two effects. Also check your position on the two bikes, as postural
    effects can have consequences on the rollers which are often cancelled or overridden by aerodynamic
    effects on the road.

    Kinky Cowboy*

    *Batteries not included May contain traces of nuts Your milage may vary
     
  6. Thanks all....I'll try the tire swap this weekend. The Mavic spokes are bladed vs the Rolf's round
    ones so that's probably in there two.

    "Christopher Meyer" <[email protected]> wrote in message
    news:[email protected]...
    > I recently bought rollers and am enjoying them...but here's the question
    >
    > When I ride with Bike A., my speed at the same exertion (measured by HRM) as when I ride Bike B
    > is about 5mph slower. Bike A has Rolf Seistre
    wheels
    > (with new and recently rebuilt freewheel) and Conti 3000 GP tires whereas Bike B has Mavic SSC SL
    > wheels with Vittoria Corsa Evo tires. I switched the wheels and Bike gained a lot of the speed
    > with the Mavic/Corsa combo.
    >
    > What fascinates me is why there would be such a large difference between
    the
    > two wheel/tire combinations. Those of you with more experience, please enlighten me. Are there
    > other factors?
     
  7. "B. Schneider" <[email protected]> wrote in message
    news:[email protected]...
    > "Christopher Meyer" <[email protected]> wrote in message
    > news:[email protected]...
    > > I recently bought rollers and am enjoying them...but here's the question
    > >
    > > When I ride with Bike A., my speed at the same exertion (measured by
    HRM)
    > > as when I ride Bike B is about 5mph slower. Bike A has Rolf Seistre
    > wheels
    > > (with new and recently rebuilt freewheel) and Conti 3000 GP tires
    whereas
    > > Bike B has Mavic SSC SL wheels with Vittoria Corsa Evo tires. I
    switched
    > > the wheels and Bike gained a lot of the speed with the Mavic/Corsa
    combo.
    > >
    > > What fascinates me is why there would be such a large difference between
    > the
    > > two wheel/tire combinations. Those of you with more experience, please
    > > enlighten me. Are there other factors?
    > >
    > >
    >
    > I noticed a similar effect when changing tires half-way through the
    winter -
    > the roller just ate tires like there is no tomorrow.
    >
    > I switched from Bontrager Select 700Cx25 (relatively soft rubber) to Conti
    > Gatorskin 700x23C (much harder rubber). With the Gatorskins I now have to use
    > 2-steps lower gear than with the Bontragers. As a side-effect the noise level
    > went down significantly, too.
    >
    > So the tires, width and rubber mix, make a significant difference.
    >
    > Enjoy the monotony of staring at the TV while on the rollers :)
    >
    > Bengt-Olaf.
    >

    Effect of computer calibration should be looked at, but aside from that, I also
    vote for tires. Back when my six-small-drum American Classic rollers were fresh,
    I used to marvel at how much easier it was to spin my tubular wheels with 22mm
    Conti Sprinters than my clinchers with the 20mm tires that were in vogue those
    days. On a lark I put some Avocet 28's on (which measured about 25mm in those
    days) and the clinchers became about as easy to spin as the tubies, in spite of
    being much heavier. Took them out on the road and found the same to be true
    there. Haven't had skinny tires on my bike ever since. These days anything
    smaller than a true 23 doesn't even get considered, and I'm only 140lbs and have
    mostly smooth roads where I
    live.
     
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