Gravel bike power readings too high

Post Reply
BevOutside
Posts: 4
Joined: Wed Sep 04, 2019 8:32 am

Gravel bike power readings too high

Post by BevOutside » Thu Sep 05, 2019 4:18 pm

Hi, I've been riding with my PowerPod V3 on my road bike and I think the power readings are quite accurate. They are very much in line with 2 different trainers that I ride. Recently, I added a second profile for my gravel bike, did a calibration then rode a 52 km out and bike ride solo, and the power readings were higher than would be possible for me, given my heart rate and perceived effort. I was on some pavement and gravel, though the readings seemed high on both surfaces.

I guess I need to modify the profile somewhat, though I don't know what to change to improve the accuracy. If it makes any difference, the pod is mounted upside down on my handlebars to avoid cables. I'm running 700x38 tires with a semi-slick tread pattern. I noticed that if I played with the Crr, I can alter the power readings pretty significantly, but how would I know which value to use, if that is indeed what needs to be done?

Any advice would be appreciated. Thanks.

Velocomp
Velocomp CEO
Posts: 6133
Joined: Fri Jan 11, 2008 8:43 am

Re: Gravel bike power readings too high

Post by Velocomp » Fri Sep 06, 2019 12:46 am

Please post a .ibr ride file and I'll take a look at your settings.
John Hamann

BevOutside
Posts: 4
Joined: Wed Sep 04, 2019 8:32 am

Re: Gravel bike power readings too high

Post by BevOutside » Fri Sep 06, 2019 8:30 am

Here it is:
Attachments
iBike_09_03_2019_1337_52_km.ibr
(618.91 KiB) Downloaded 3 times

Velocomp
Velocomp CEO
Posts: 6133
Joined: Fri Jan 11, 2008 8:43 am

Re: Gravel bike power readings too high

Post by Velocomp » Sat Sep 07, 2019 5:55 am

Your Crr is quite high. I set it to 0.008, a much more reasonable value for gravel riding.

Modified profile and ride file attached.
Attachments
Bev.ibp
(637 Bytes) Downloaded 2 times
Bev_008_09_03_2019_1337_52_km.ibr
(618.61 KiB) Downloaded 2 times
John Hamann

BevOutside
Posts: 4
Joined: Wed Sep 04, 2019 8:32 am

Re: Gravel bike power readings too high

Post by BevOutside » Sat Sep 07, 2019 6:04 pm

Thank you. I'll give this a try. I assume that having now sent this profile to my pod, it will automatically detect when I am riding my gravel bike and use the correct profile?

Velocomp
Velocomp CEO
Posts: 6133
Joined: Fri Jan 11, 2008 8:43 am

Re: Gravel bike power readings too high

Post by Velocomp » Sun Sep 08, 2019 12:07 am

BevOutside wrote:
Sat Sep 07, 2019 6:04 pm
Thank you. I'll give this a try. I assume that having now sent this profile to my pod, it will automatically detect when I am riding my gravel bike and use the correct profile?
Yes
John Hamann

BevOutside
Posts: 4
Joined: Wed Sep 04, 2019 8:32 am

Re: Gravel bike power readings too high

Post by BevOutside » Sun Sep 08, 2019 8:05 pm

I did 83 km with my gravel bike today, the vast majority on a basically straight and flat gravel rail trail. We had a strong headwind going out and corresponding tailwind on the way back.

The pod gave an extremely high reading right at the beginning of the ride, while I was still in my driveway, so obviously not correct. The rest of the ride's power readings seemed quite a bit too low. I noticed that the wind graph doesn't appear to reflect the strong headwind we experienced. It did seem to capture the tail wind on the way back. If anything, it felt like the headwind was stronger, but then it always does, doesn't it? :lol:

Is the pod just not that great at calculating power on gravel, or is it a matter of fine tuning the profile a bit more?
Attachments
iBike_09_08_2019_1222_83_km.ibr
(846.67 KiB) Downloaded 1 time

Post Reply