Comparing Ergomos

[Due]

Hi

I finally did a comparison of my Ergomos.

Theres is a 40-50watt discrepancy between the BBs on my roadbike and
on my TT-bike.

I have done a comparison on my Tacx Fortius.

Can the wattage be adjusted so they match each other via K-factor? I
remember someone had a spreadsheet or something that could help with
this - i would like a copy of someone can help.

Thanking you all for a great forum!

[Paolo Tommasini]

1) you have to carefully run the offset procedure for both sensors

2) on the Fortius try to use the same wheel, with the same tyre, at the same pressure with the same number of turns of the screw that press the wheel on the roller

3) warm up at least 10 minutes the tyre for both bikes: Fortius is somewhat sensible to the temperature of the combination tyre/roller

 

After that procedure, run on each bike a ramp test (i.e. +20w/minute) and compare the two graphs.

If there is a reasonably correlation on the two graph (i.e. the values of the TT are 20% higher/lower compared to the road bike along the whole range of the values) you should adjust accordingly the k-factor.

 

Ex.: if TT is your reference and it is 20% higher than road bike (preset road k-factor=190) you should adjust his k-factor at 228 (190+20%of190=190+38=228)

 

Hope it helps

Paolo

 

2011/1/14 Due <duesoe...@gmail.com>

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[Due]

Thanks for the input.

Please let me describe the procedure i used

1) Offset/calibration of Ergomo
2) Tyre pressure 120 PSI
3) 3½ turns on the resistance knob
4) 5 minutes of warm up
5) calibration of Fortius brake
6) 60 minutes of varied cycling with VO2 max intervals
7) Ramp VO2 Max test

The only difference is that i used different wheels and the blue tacx
trainer tyre was not used on the TT bike. I dont know how much wattage
this can account for but all other things being equal i would say that
it would be max 10 watts which i will consider to be fairly ok.

Please comment on the above :-)

On 14 Jan., 12:19, Paolo Tommasini <paolo.tommas...@gmail.com> wrote:
> 1) you have to carefully run the offset procedure for both sensors
> 2) on the Fortius try to use the same wheel, with the same tyre, at the same
> pressure with the same number of turns of the screw that press the wheel on
> the roller
> 3) warm up at least 10 minutes the tyre for both bikes: Fortius is somewhat
> sensible to the temperature of the combination tyre/roller
>
> After that procedure, run on each bike a ramp test (i.e. +20w/minute) and
> compare the two graphs.
> If there is a reasonably correlation on the two graph (i.e. the values of
> the TT are 20% higher/lower compared to the road bike along the whole range
> of the values) you should adjust accordingly the k-factor.
>
> Ex.: if TT is your reference and it is 20% higher than road bike (preset
> road k-factor=190) you should adjust his k-factor at 228
> (190+20%of190=190+38=228)
>
> Hope it helps
> Paolo
>

> 2011/1/14 Due <duesoeren...@gmail.com>

>
>
>
> > Hi
>
> > I finally did a comparison of my Ergomos.
>
> > Theres is a 40-50watt discrepancy between the BBs on my roadbike and
> > on my TT-bike.
>
> > I have done a comparison on my Tacx Fortius.
>
> > Can the wattage be adjusted so they match each other via K-factor? I
> > remember someone had a spreadsheet or something that could help with
> > this - i would like a copy of someone can help.
>
> > Thanking you all for a great forum!
>
> > --
> > You received this message because you are subscribed to the Google Groups
> > "ergomo-users" group.
> > To post to this group, send email to ergomo...@googlegroups.com.
> > To unsubscribe from this group, send email to

> > ergomo-users...@googlegroups.com<ergomo-users%2Bunsubscribe@google­groups.com>
> > .

> > For more options, visit this group at

> >http://groups.google.com/group/ergomo-users?hl=en.- Skjul tekst i anførselstegn -
>
> - Vis tekst i anførselstegn -

[Paolo Tommasini]

Procedure OK
No idea of the impact of different tyres: blue tacx is softer so more
resistance but I think no more than 10w.
Try to adjust kfactor considering the difference between average watts
or (better) normalized watts

2011/1/14, Due <duesoe...@gmail.com>:

> ergomo-users...@googlegroups.com.

[Due]

Hi again

Adjusted the k-factor with the percentage i calculated during the
first test.

Adjusted from 183 to 231.

Forti road tt Diff
130 159 177 18
160 186 204 18
190 217 229 12
220 250 254 4
250 291 281 -10
280 324 296 -28

There is a larger discepancy in the higher wattages - during the test
on the TT the wattage raised a bit on that last interval so that might
also account for some of the discrepancy.
I am concerned if a sprint f.ex. would show very high wattagenumbers
with the new k-factor? i.e. wrong numbers

Any input on this?

Best regards

On 14 Jan., 15:01, Paolo Tommasini <paolo.tommas...@gmail.com> wrote:
> Procedure OK
> No idea of the impact of different tyres: blue tacx is softer so more
> resistance but I think no more than 10w.
> Try to adjust kfactor considering the difference between average watts
> or (better) normalized watts
>

> 2011/1/14, Due <duesoeren...@gmail.com>:

> >> >http://groups.google.com/group/ergomo-users?hl=en.-Skjul tekst i

[Paolo Tommasini]

Analizing data:

tacx	road	tt		step-tacx	step-road	step tt
130	159	177
160	186	204		30	27	27
190	217	229		30	31	25
220	250	254		30	33	25
250	291	281		30	41	27
280	324	296		30	33	15

It seems to me that there is something strange at 250w on the road sensor and at 280w on the tt sensor
Maybe another test could help
Anyway if I were you I'd adjust k-factor trying to match the "zone" where you'll mostly ride

Matching 2 sensors is always difficult, matching 3 values is difficult^2 !

2011/1/16 Due <duesoe...@gmail.com>

[Due]

Thanks for your input. Gave me a new view on things.

I will do some more testing in a week or so.

On 16 Jan., 18:12, Paolo Tommasini <paolo.tommas...@gmail.com> wrote:
> Analizing data:
>
>          tacx        road            tt
> step-tacx  step-road      step tt  130 159 177
>
>  160 186 204
> 30 27 27  190 217 229
> 30 31 25  220 250 254
> 30 33 25  250 291 281
> 30 41 27  280 324 296
> 30 33 15
> It seems to me that there is something strange at 250w on the road sensor
> and at 280w on the tt sensor
> Maybe another test could help
> Anyway if I were you I'd adjust k-factor trying to match the "zone" where
> you'll mostly ride
>
> Matching 2 sensors is always difficult, matching 3 values is difficult^2 !
>

> 2011/1/16 Due <duesoeren...@gmail.com>

> > > >> >http://groups.google.com/group/ergomo-users?hl=en.-Skjultekst i

> > > >> > anførselstegn -
>
> > > >> - Vis tekst i anførselstegn -
>
> > > > --
> > > > You received this message because you are subscribed to the Google
> > Groups
> > > > "ergomo-users" group.
> > > > To post to this group, send email to ergomo...@googlegroups.com.
> > > > To unsubscribe from this group, send email to

> > > > ergomo-users...@googlegroups.com<ergomo-users%2Bunsubscribe@google groups.com>
> > .
> > > > For more options, visit this group at

> > > >http://groups.google.com/group/ergomo-users?hl=en.
>
> > --
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