Recomending settings for 29er MTB

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scomtb
Posts: 4
Joined: Wed Mar 04, 2020 8:47 am

Recomending settings for 29er MTB

Post by scomtb »

I'm looking for recommendation on tuning the settings on my PowerPod v3 to better match with the bike, as my attempts so far to adjust the settings produce wind scaling values between 8 and 20 which won't then upload.

I had various had resets ( 10+ second press ) and pairing attempts ( 4+ second ) before I could get my speed and cadence sensors seen by the PowerPod, I've since replaced the batteries in both as I was seeing drops in power readings rather than a relatively steady reading.
- I've not yet attempted another short out and back calibration as the winds over the last 2 weeks is generally around the 20+ mph.

The short out and back that produce the current settings was done in winds from 10 to 15 mpg, with gusts up to 25 mph, but this was done before replacing the batteries in the speed and cadence sensors.

The attached ride file would have had winds between around 20 mph, with gusts up to 35 mph, this was an out and back over the same route, with a tail wind / cross wind on the outbound and a cross / head wind on inbound.

Readings on oubound looked a little high ( 20 to 40 watts ) with the tail wind, but low by a similar amount when heading back into the head wind. At times it dropped down to 20 to 50 watts total while heading into some of the gusts, rather than going the other way.

Winds are likely to be like this for the next few weeks or more, so getting a near windless calibration run in will be a problem.

I'd looked at using the values from https://www.bicyclerollingresistance.com/ for the CRR values however they seem much two low, so I'm not sure how to use these values or not.

Bike: Giant AnthemX 29er
Handle bars: Wide straight riser bar.
Position on the bike is upright, saddle position is slightly below tops of handle bars.
Tyres: Schwalbe Racing Ralph 29x2.25 at 25psi
https://www.bicyclerollingresistance.co ... eskin-2015
Rider Height: 172cm
Rider and Kit Weight: 180lbs
Bike Weight: 30 lbs

I'm also looking to setup the PowerPod on a Giant Toughroad ASR 2 Gravel bike, but have yet to fit the PowerPod and setup on this, so looking for recommendations for initial settings.

Bike: Giant Toughroad ASR 2
Handle bars: Wide straight riser bar.
Position on the bike is upright, saddle position level with handle bars.
Tyres: Schwalbe G-One Speed 29x2.3 generally at 25psi to 30psi
https://www.bicyclerollingresistance.co ... g-one-2016
Bike Weight: 27 lbs

Thanks.
Attachments
iBike_03_07_2020_1224_14_Miles.ibr
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Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Recomending settings for 29er MTB

Post by Velocomp »

Your wind readings are very low. Please post front and side images of your PP mounted on your bike.
John Hamann
scomtb
Posts: 4
Joined: Wed Mar 04, 2020 8:47 am

Re: Recomending settings for 29er MTB

Post by scomtb »

See photos of PowerPod v3 mounting on Giant Anthem X 29er
- Mount was originally used with a PowerPod v2 unit and its position is unchanged from that usage.
PowerPod v3 mounted on Giant Anthem X 29er - Front view
PowerPod v3 mounted on Giant Anthem X 29er - Front view
PowerPod_v3_Ax29_Front.jpg (77.46 KiB) Viewed 3950 times
PowerPod v3 mounted on Giant Anthem X 29er - Right-hand side view
PowerPod v3 mounted on Giant Anthem X 29er - Right-hand side view
PowerPod_v3_Ax29_Right_Side.jpg (119.79 KiB) Viewed 3950 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Recomending settings for 29er MTB

Post by Velocomp »

Please email technicalsupport@velocomp.com with a copy of your ride file. Tom will give you next steps.
John Hamann
scomtb
Posts: 4
Joined: Wed Mar 04, 2020 8:47 am

Re: Recomending settings for 29er MTB

Post by scomtb »

A replacement PowerPod v3 is now on its way from my local supplier and should be delivered in the next 2 to 3 days.

Can you recommend some initial values to use for the two bikes detailed above ( Giant AnthemX 29er & Giant Toughroad ASR 2 ) so I have a better starting point out the box for the initial calibration runs ?

I was thinking the best approach would be to use the "Power House" application on my Android phone to make the initial setup as it does have a "Bike Type" of "29er Mountain Bike" so should be closer to my 29er MTB and Gravel bikes than any of the options available in the profile setup available in "Isaac for Windows".

Only issue I had setup using Power House" app was setting the tyre size, as there is no custom option that I could find. Best I could do was to use the largest available which was 2180mm 700x38c, this is a bit short of my actual 700x57c (29x2.25) or 700x60c (29x2.3) tyre sizes, so I would then look to use "Isaac for Windows" to adjust this and any other settings that need tweaked.
- Is this the best approach or would I be better doing the initial setup in some other way before the out and back calibration run ?

Can the PowerPod v3 auto switch to a different profile where the only difference is the id of the wireless speed sensor, cadence would be same on two profiles, HRM would be same across all four profiles ?
- I have a 2nd set of wheels for each bike with a different set of tyres, typically with a different tyre size and likely different rolling resistance, I've fitted these spare wheels with a separate Garmin Wireless Speed sensor ( magnetic less version 1, not new version 2 sensor).
- If I set this up on a different profile will the PowerPod be able to select the correct profile or will it get confused ?

Can I use the values for specific tyres / pressures from https://www.bicyclerollingresistance.com/, if so how should I be using them as the values there seem seems to differ greatly from the Crr values I've been seeing in "Isaac for Windows" ?

Is there any advantages to using the new Garmin Wireless Speed and Cadence Sensor 2 over the version 1 units, or should they give similar results ?

I have noticed that PowerPod v3 ( in Isaac for Windows ) shows a different ANT+ sensor id for my speed sensor compared with what my Garmin Edge 1000 is showing, however both cadence and HRM sensor have matching ANT+ ids on Edge 1000 and PowerPod, is this normal ?
- A comparison of the speed graph between PowerPod v3 recording and Garmin Edge show a fairly close match so it does not look like I picked up some other wireless speed sensor during sensor pairing, which was my initial thought.

Thanks.
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Recomending settings for 29er MTB

Post by Velocomp »

Lots of questions!

1) OK to use PH app for initial setup, but for most precise setup Isaac is a bit better.

2) Yes, V3 will auto-switch across profiles when the speed sensor is different. You'll need to do a sensor pairing and cal ride for each profile

3) If you use Isaac to set rolling resistance for your different tires and profiles PP will not get confused, but if you're using the same bike speed sensor you will have to manually switch profiles

4) You can use tire/rolling resistance from your website. The most thing here is consistency, not absolute accuracy of Crr

5) We have not tried the Garmin 2 sensors. I suspect they give identical results.

6) Isaac truncates the sensor ID. This is completely normal but it means that you have to do a sensor scan from your PP, not enter sensor IDs from Isaac.
John Hamann
scomtb
Posts: 4
Joined: Wed Mar 04, 2020 8:47 am

Re: Recomending settings for 29er MTB

Post by scomtb »

I'm considering mounting the PowerPod v3 under a K-Edge out front mount in line with the stem, so sitting in front of the handle bars rather than underneath them to and to the right of the stem, which is hides the status LED making it difficult to see if everything is ok, especially during initial setup.
- Is this out front position better or worse mount point than where I have it currently, am I better leaving it where it is ?
- I'm thinking there may be a little more flex, but probably not much, in the out front mount than the carbon handle bar.

I'm still confused about setting a CRR value, as I'd tried using a value of 0.00719 for CRR which resulted in friction half the original ( around 13 rather than 26 ) and this dropped the average power from just over 100w ( which was already rather low ) to an average of 59 when the modified profile was applied to the existing 14 mile out and back run attached to the initial post.

So using the values from https://www.bicyclerollingresistance.com/ seem to make thinks worse not better, so I'm still unsure how I should be using these values or not, is this due to the low wind scaling or am I messing up settings in some way by attempting to make adjustments.

I'm currently seeing a value of 0.0211 for CRR on my initial profile setup, not quite sure where this came from, but suspect this was either from Isaac or more likely form the last 10s hard reset as I struggled to get sensors to pair initially, so probably wiped out any initial setup attempts via the Android or Windows apps and went back to unit in built defaults.

This is what I'm finding on https://www.bicyclerollingresistance.com/ for the tyres I'm trying to setup ..

Rolling Resistance: Schwalbe Racing Ralph
35 PSI / 2.4 Bar 20.8 Watts CRR: 0.00624
25 PSI / 1.7 Bar 24.0 Watts CRR: 0.00719
- These values were for a tyre fitted with a 225g inner tube, I'm using Schwalbe SV19A which should be around the 140g, so not sure how to adjust for this, or if it makes are real sense to do so.

Rolling Resistance: Schwalbe G One Speed
35 PSI / 2.4 Bar 13.6 Watts CRR: 0.00408
25 PSI / 1.7 Bar 15.8 Watts CRR: 0.00474
- This also was for a tyre fitted with a 225g inner tube, I'm running tubeless with these, and its suggested this would make a 2.5w to 5w reduction, so I'm thinking using the 35psi value would probably be a bit closer to my tyre setup.

Thanks.
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