I think you might be generalizing from the particular. For you, a TT guy the big ring is more specific. However, for me (a climber). I feel the small ring is more specific. I do use the big ring (53), to introduce variety and higher cadence work.
It has nothing to do with the individual pedaling the bike. It’s all about the physics.
Say more please. What else is to say besides torque and power?. Also, with the big ring, high cadence there’s this weird “help” you get from the wheel rotation.
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Could you go into that a bit more? What is the significance?
Copy that… I’m off to see what I can find & pull together. I will share a Google Sheet with everyone if/when I get something worthwhile.
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I envision a basic set of calculations for various rider/bike weights along with a few of the most common trainers for comparison.
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PS, anyone with the knowledge and willingness to pitch in here is very appreciate by me. I know the concepts at basic level, but getting the right calcs for this is out of my normal realm of expertise.
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Lower inertial resistance = easier to accelerate crank during downstroke = more pedals slow down when crank is near vertical. The result is altered muscular demands that makes training indoors even less like cycling outdoors.
The only way you’re getting “help” from wheel/flywheel rotation is if you’re using a fixed gear.
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Lots of interesting info here, much of which is over my head as far as me being able to participate intelligently. I completely follow what the argument is regarding: trainer vs real world. Pro’s and Con’s to wherever you’re training is taking place. The good thing with the trainer, for me, is the ability to ride when riding outdoors is not an option, i.e. 4am, it’s dark. 115*F during the summer.
I almost bought the Wahoo Roller for the specific reason of being able to use a fixed gear. I would love to have a track/fixed gear application avail on a trainer but in the Zwift VR world. I have a fixed I love riding on a straight and rolling path near the Y, fixed is such a great workout.
After my ride today, all in erg, I believe i’ll retake the Ramp Test this weekend. I do not feel I am being taxed nearly enough. I have never trained specifically for an event. I understand the training approach in levels, I guess I’d rather error on the side of I’m really prepared for the ride vs I think I’m prepared for the ride.
this is an interesting problem…
So first part is you have a cyclist traveling at a constant speed and you want to understand how much force that takes. At a constant speed you are at equilibrium so air drag equals the force you are applying to move forward. So that F = ma=0.5air densityfrontal areadrag coefficientvelocity squared. This is your linear inertia of a rider.
Now rotational flywheel is torque=rotational inertia of a disc* angular velocity.
And I have no idea what the dimensions and mass of a flywheel are on a trainer but generally you are at near constant angular velocity when at a specific power and rpm. Then you will relate that torque to the force and realize they are equal because you are at equilibrium.
At the end of the day the flywheel inertia is there to get you through the dead spots in your pedal stroke which gives you a realistic feeling. You just dont want your angular velocity of your flywheel to slow much at those dead spots. So yes more flywheel inertia is the answer. But I don’t think the relationship to linear inertia is appropriate. You fundamentally want a force profile that you apply to the pedals when riding outside to match riding the trainer. Im honestly not sure how different a modern trainer is from outside riding but you cant get there with your linear inertia comparison.
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There’s more than one solution to the problem of inertial simulation on indoor trainers. Indeed, trainers like the Kickr Bike and Tacx Neo claim to be able to take into account the rider’s weight and alter resistance during an individual pedal stroke to simulate a realistic force profile.
They may make that claim, but I doubt that they are capable of doing so. It takes some pretty pricey equipment/fancy electronics and programming to be able to precisely regulate the current flow with millisecond resolution. That’s why Tom Compton could never find a market for his Pedal Force Simulator:
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The answers are 1) yes, 2) a lot, and 3) it’s the simplest solution.
(Note that when cycling outdoors there is both linear and rotational inertia, The former almost always dominates, but the point is that the physics quickly become rather complicated, especially as you consider different speeds, etc. Adding additional mass to the flywheel obviously doesn’t replicate all possible scenarios, but at present they don’t even overlap.)
It’s worth mentioning again that we recommend using a lower gear (small ring & at least halfway up the cassette) for a better experience when using TrainerRoad. Keeping the flywheel speed low allows for smoother transitions between intervals, especially when there are large differences in power targets, such as in “on-off” style workouts. In my opinion, it also seems to require me to be more engaged in the entirety of the pedal stroke (I used the big ring for almost a year before switching to the small one).
The goal when using our product is not necessarily to simulate “real-world” riding, and personally, I don’t find it practical to attempt that sensation on a stationary bike of any sort anyways. If we were talking about Zwift or something more interactive, I could see why riding outside of ERG mode with a full range of gears would be beneficial, but we are recommending what we know works best with our product.
If you like the feel of more momentum behind your pedal stroke when riding in the big ring on TR, by all means, continue on that way, but just know that it’s not what we recommend to achieve the best results.
It looks like the OP has gotten what they needed here! 
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Not really, the kinetic energy of a moving object is it’s mass * speed squared, finally divided by 2.
Kinetic Energy of an object is different. Newtons second law is F=ma which is effectively linear inertia. If you want to change the velocity of an object you have to impart a force on that object. That’s inertia. If you want to know how much energy that requires then yes you would use kinetic energy. But if you want to compare a linear moving mass to the rotational inertia of a flywheel then you need to use F=ma and it’s partner in rotation Torque= Rotational Inertia * angular acceleration.
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