what is the _training_ benefit if a super-heavy flywheel on a trainer's resistance unit?

[W.A. Manning]

i understand the benefits of a flywheel, but i'm having trouble envisioning how a _super-heavy_
flywheel has any benefit to training. after a certain point, it seems the returns diminish
significantly as to be non-existent.

perhaps a super-heavy flywheel would be good when training for standing-start events, like the kilo
or even TTs in general. i suppose they may provide additional training resistance when doing sprints
or intervals during the initial fraction of the interval when the flywheel is spooling-up.

anything else?

 

[Andy Coggan]

"w.a. manning" <[email protected]> wrote in message
news:[email protected]...
> i understand the benefits of a flywheel, but i'm having trouble envisioning how a _super-heavy_
> flywheel has any benefit to training. after a certain point, it seems the returns diminish
> significantly as to be non-existent.
>
> perhaps a super-heavy flywheel would be good when training for standing-start events, like the
> kilo or even TTs in general. i suppose they may provide additional training resistance when doing
> sprints or intervals during the initial fraction of the interval when the flywheel is spooling-up.
>
> anything else?

A greater inertial load better simulates cycling outdoors - see http://www.ncbi.nlm.nih.gov/entrez/-
query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11036570&dopt=Abstract. Training exclusively on a low
inertia trainer (which describes just about everything except perhaps a Velodyne) therefore isn't
the most specific way of preparing for competition in the real world.

Andy Coggan

 

[Scott Hendricks]

[email protected] (w.a. manning) wrote in message news:<[email protected]>...
> i understand the benefits of a flywheel, but i'm having trouble envisioning how a _super-heavy_
> flywheel has any benefit to training. after a certain point, it seems the returns diminish
> significantly as to be non-existent.
>
> perhaps a super-heavy flywheel would be good when training for standing-start events, like the
> kilo or even TTs in general. i suppose they may provide additional training resistance when doing
> sprints or intervals during the initial fraction of the interval when the flywheel is spooling-up.
>
> anything else?

the real benefit to the super-heavy flywheel (how heavy is 'super-heavy', btw?) is that it creates a
better sense of 'road feel'. Your bike doesn't accelerate/decelerate rapidly on the road, and
shouldn't do so on your trainer, either.

'Road feel' seems more natural, and while it isn't necessarily a motivating factor, at least it's
not a 'de-motivator'. Try riding on what feels like a poorly designed trainer and you'll understand
how it just seems like you're wasting your time on it.

 

[jlscott3]

Originally posted by Scott Hendricks

> the real benefit to the super-heavy flywheel (how heavy
> is 'super-heavy', btw?) is that it creates a
> better sense of 'road feel'. Your bike doesn't
> accelerate/decelerate rapidly on the road, and
> shouldn't do so on your trainer, either.

This makes sense to me based on how I *think* the fluid trainers work, and AFAIK it's only fluid trainers that have flywheels. When I upshift or pick up the tempo, I've felt a bit of resistance lag on my Cycleops Fluid2, which has a fairly low rotating mass. A few seconds after I accelerate, I feel the resistance increase. I assume that lag is the time it takes the viscous coupler to increase viscosity based on the increased power input. A higher-mass flywheel would provide more inertia to counteract that initial jump. Of course, if the fluid trainer is actually something more complex than a viscous coupler, then I'm all wet.

IMHO, the value of the higher-fidelity "road feel" depends on how much interval/power training you plan to do on the trainer. If you use the trainer mostly for constant-effort sessions, as I do, it probably isn't worth a whole lot.

JLS

 

[John Forrest To]

On 26 Jan 2004 06:30:41 -0800, [email protected] (w.a. manning)
wrote:

>i understand the benefits of a flywheel, but i'm having trouble envisioning how a _super-heavy_
>flywheel has any benefit to training. after a certain point, it seems the returns diminish
>significantly as to be non-existent.
>
>perhaps a super-heavy flywheel would be good when training for standing-start events, like the kilo
>or even TTs in general. i suppose they may provide additional training resistance when doing
>sprints or intervals during the initial fraction of the interval when the flywheel is spooling-up.

Right -- a super heavy flywheel is useful if you are training to start fast or accellerate fast.
Beyond that -- that is beyond the first ten or 15 seconds of effort, it is not useful.

In fact, I think in general less of flywheel is better as the rider will get more feedback on the
smoothness of the pedal stroke.

JT

 

[Tom Compton]

"jlscott3" <[email protected]> wrote in message
news:[email protected]...
> Originally posted by Scott Hendricks
>
> > the real benefit to the super-heavy flywheel (how heavy is 'super- heavy', btw?) is that it
> > creates a better sense of 'road feel'. Your bike doesn't accelerate/decelerate rapidly on the
> > road, and shouldn't do so on your trainer, either.
>
> This makes sense to me based on how I *think* the fluid trainers work, and AFAIK it's only fluid
> trainers that have flywheels. When I upshift or pick up the tempo, I've felt a bit of resistance
> lag on my Cycleops Fluid2, which has a fairly low rotating mass. A few seconds after I accelerate,
> I feel the resistance increase. I assume that lag is the time it takes the viscous coupler to
> increase viscosity based on the increased power input. A higher-mass flywheel would provide more
> inertia to counteract that initial jump. Of course, if the fluid trainer is actually something
> more complex than a viscous coupler, then I'm all wet.
>
> IMHO, the value of the higher-fidelity "road feel" depends on how much interval/power training you
> plan to do on the trainer. If you use the trainer mostly for constant-effort sessions, as I do, it
> probably isn't worth a whole lot.
>
Another way of saying what you describe is that resistive power is proportional to speed. So an
increase in resistive power requires an increase in speed, which is what is required if one wants
trainer resistive power to mimic road resistive power.

Pedaling speed, although nominally constant at some cadence, is not really constant. There are
accelerations within the pedal stroke. Accelerations within a pedal stroke are very small on the
road compared to typical trainers which are very large. A heavy flywheel reduces the magnitude of
the accelerations.

Regards,

Tom Compton www.AnalyticCycling.com

 

[Per ElmsäTer]

Tom Compton wrote:
> "jlscott3" <[email protected]> wrote in message
> news:[email protected]...
>> Originally posted by Scott Hendricks
>>
>>> the real benefit to the super-heavy flywheel (how heavy is 'super- heavy', btw?) is that it
>>> creates a better sense of 'road feel'. Your bike doesn't accelerate/decelerate rapidly on the
>>> road, and shouldn't do so on your trainer, either.
>>
>> This makes sense to me based on how I *think* the fluid trainers work, and AFAIK it's only fluid
>> trainers that have flywheels. When I upshift or pick up the tempo, I've felt a bit of resistance
>> lag on my Cycleops Fluid2, which has a fairly low rotating mass. A few seconds after I
>> accelerate, I feel the resistance increase. I assume that lag is the time it takes the viscous
>> coupler to increase viscosity based on the increased power input. A higher-mass flywheel would
>> provide more inertia to counteract that initial jump. Of course, if the fluid trainer is actually
>> something more complex than a viscous coupler, then I'm all wet.
>>
>> IMHO, the value of the higher-fidelity "road feel" depends on how much interval/power training
>> you plan to do on the trainer. If you use the trainer mostly for constant-effort sessions, as I
>> do, it probably isn't worth a whole lot.
>>
> Another way of saying what you describe is that resistive power is proportional to speed. So an
> increase in resistive power requires an increase in speed, which is what is required if one wants
> trainer resistive power to mimic road resistive power.
>
> Pedaling speed, although nominally constant at some cadence, is not really constant. There are
> accelerations within the pedal stroke. Accelerations within a pedal stroke are very small on the
> road compared to typical trainers which are very large. A heavy flywheel reduces the magnitude of
> the accelerations.
>

Very interesting Tom and it sounds logical enough. This brings another question to my mind. I
recently aquired a Polar Watt meter and am starting to get into Power measured intervals. I've heard
that *everybody* does the 2*20 and this is one of the things I started looking at of course. I just
did a set today where I added resistance on my trainer ( Tacx Swing) so that I was working just
under my LT for 2*20. The gearing turned out to be 39-17 at 85 rpm. According then to your reasoning
above would it be smoother to lower the resistance of the trainer and move on up to my big ring to
find the same workout level? Ie the same amount of Watts. Or did I misunderstand you?

--
Perre

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