NEO better control at lower speed

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Michael RSA
Posts: 1
Joined: Tue Mar 13, 2018 11:46 am

NEO better control at lower speed

Post by Michael RSA » Tue Mar 13, 2018 12:13 pm

Hi All

I have a Neo, for about a month now.
some background... I previously had a homemade IDT with a double reduction gearing, I guess similar to the Flux or Kikr. I always rode in a big gear 54x15 or thereabouts to ensure the flywheel at the back was spinning really fast to ensure enough inertia.

I then used the same gear combo on the Neo, figuring higher speed from the flywheel will make it operate better/smoother/quicker
when riding 2 x 20 min @ 280w @ 95 cadence the graph was very ragged in terms of holding the power at 280w fluctuating from 260 to 300 depending on how I hold the cadence

I then decided to experiment and rode in 39x17 or there abouts ( just to get a straight chain line) Same interval 2 x 20 min @ 280w @ 95 cadence the graph was a lot smoother I would go as far as saying easier to hold the W. fluctuating from about 275w to 285w
This is all in Power mode, using the Tacx App

try it and see the difference

M

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ms6073
Posts: 1808
Joined: Sat Oct 07, 2006 9:06 pm
Location: USA, Houston, TX

Re: NEO better control at lower speed

Post by ms6073 » Wed Mar 14, 2018 3:40 pm

Michael RSA wrote:
Tue Mar 13, 2018 12:13 pm
( just to get a straight chain line) Same interval 2 x 20 min @ 280w @ 95 cadence the graph was a lot smoother
My thinking is that while the improved chainline helps reduce impediments to a smooth cadence, I am really thinking it suggests you need a new/better chain. :D
Power is essentially torque * angular velocity (cadence) so to achieve higher power outputs, we can either increase/decrease torque or angular velocity. An SRM powermeter has 8 strain gauges to measure torque each revolution of the crank and power output tends to be very stochastic. The Neo uses 48 or so magnets to measure and update power and cadence output with each revolution of the drum, so while the app displays an average 95 rpm cadence, I would expect the raw power output to be much more stochastic than an SRM. If you have a cycle computer that displays power metrics, my advice is to pair the Neo with the cycle computer and set the power output to display 3-second and 10-second data to eliminate the constant spikes in power that are characteristic of every powermeter and smart trainer on the market.

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Rugnravee
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Re: NEO better control at lower speed

Post by Rugnravee » Fri Jul 06, 2018 7:07 am

I'm looking for information about this is offline.

EHB
Posts: 43
Joined: Tue Dec 01, 2015 3:43 am

Re: NEO better control at lower speed

Post by EHB » Sun Sep 09, 2018 9:19 pm

I think it’s just basic maths. There are a set number of magnets and each can probably just be on or off. By reducing wheel speed you reduce the maximum power but also shrink the difference between x and x+1 magnets on.

You’ve got a good trainer so the shrinking maximum isn’t a problem. I used to have a flow and you could max it out in that gear quite easily.

Another possibility is that it is something dodo with your virtual flywheel size changing, but I am guessing you are in erg mode so that doesn’t matter. It might be something todo with how the Tacx Firmware creates the flywheel effect though.

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