Author Topic: Magene P505 PES Base Spider Powermeter  (Read 26138 times)

Eddy_Twerckx

Re: Magene P505 PES Base Spider Powermeter
« Reply #45 on: December 29, 2023, 09:06:50 AM »
I've installed my power meter now, I used this bottom bracket: https://www.aliexpress.us/item/2251832835484740.html

and it worked well! The only thing I haven't diagnosed yet is that I have tried to use my Ultegra 11 speed chainrings with the crank, but the spacing between the two chainrings is wide enough that the chain can fall in the middle. I need to take it apart and see if I installed something incorrectly, or maybe the flanges that the chainrings mount to are thicker on the Magene vs. Shimano crank arms?

Mine were the same thickness (Shimano and Magene). Do you have any calipers you could measure with? Maybe bad QC?

00Garza

Re: Magene P505 PES Base Spider Powermeter
« Reply #46 on: December 29, 2023, 09:44:42 AM »
I got mine with the deckas chainring to replace the Senicx GR3 crank on my gravel bike. Haven't had time with holiday craziness, but should have it installed by next week.

eddietheengineer

Re: Magene P505 PES Base Spider Powermeter
« Reply #47 on: December 29, 2023, 01:05:33 PM »
Mine were the same thickness (Shimano and Magene). Do you have any calipers you could measure with? Maybe bad QC?

Thankfully it was a silly mistake on my part--I didn't realize the small chainring was directional--it has an ever so slight offset one direction. Flipping it around fixed it! Thanks

Gosy

Re: Magene P505 PES Base Spider Powermeter
« Reply #48 on: January 01, 2024, 02:19:27 PM »
so ordered mine today on pandapodium,

Avalius

Re: Magene P505 PES Base Spider Powermeter
« Reply #49 on: January 04, 2024, 02:16:28 AM »
Tested these units and well..

Spot on with my Kickr V5. Really within 1% on al my efforts ranging from 800w tot 20m 281w.
I'm impressed
"You can't be sad while riding a bicycle."

raisinberry777

Re: Magene P505 PES Base Spider Powermeter
« Reply #50 on: January 04, 2024, 03:16:18 AM »
One thing I've noticed with mine, set up with a Shimano 105 R7170 Di2 front derailleur, is that the gap between crank arm and outside of the front derailleur at the outer limit is quite tight - for me, looks like less than 1mm on my 2023 Merida Scultura. There's no scratches that would indicate that the two are touching at all - but it's probably something worth noting for those with a similar setup.

Greenred

Re: Magene P505 PES Base Spider Powermeter
« Reply #51 on: January 04, 2024, 12:13:22 PM »
Built it up yesterday, very easy.
It seems to consistently read around 5% lower than my Tacx Neo 2t.
So for the next ride I’ll be trying to adjust the Magenes power scaling and let’s see.
The weight penalty compared to the latest Ultegra 12s was 70g on 170mm cranks and 50/34 for the ww’s.
« Last Edit: January 04, 2024, 12:15:50 PM by Greenred »

toxin

Re: Magene P505 PES Base Spider Powermeter
« Reply #52 on: January 04, 2024, 04:10:28 PM »
Did you auto zero it?

Greenred

Re: Magene P505 PES Base Spider Powermeter
« Reply #53 on: January 05, 2024, 02:07:00 AM »
Did you auto zero it?

Yes, via the magene app and with the cranks being vertical.

toxin

Re: Magene P505 PES Base Spider Powermeter
« Reply #54 on: January 05, 2024, 05:22:24 AM »
You need to spin them back 5 revs to trigger auto zero

Greenred

Re: Magene P505 PES Base Spider Powermeter
« Reply #55 on: January 08, 2024, 05:27:26 PM »
You need to spin them back 5 revs to trigger auto zero

Isn't it the same outcome?
So far I did some indoor workouts and I'm now within <2% to the Tacx Neo 2t, still trying to optimize the exact powerslope.

Greenred

Re: Magene P505 PES Base Spider Powermeter
« Reply #56 on: January 14, 2024, 03:50:31 PM »
Built it up yesterday, very easy.
It seems to consistently read around 5% lower than my Tacx Neo 2t.
So for the next ride I’ll be trying to adjust the Magenes power scaling and let’s see.
The weight penalty compared to the latest Ultegra 12s was 70g on 170mm cranks and 50/34 for the ww’s.

Update on the accuracy: In short, I'm very happy about it.

After some test runs, average power and normalized power are on average only 0.4-0.6% (!) off from my Tacx Neo 2t wih a 104% power slope setting.
I found that the reason for the larger differences I previously experienced stem from the varying temperature in my workout room. The PM was always correctly zero'd. By having a +- constant room temperature the previous inaccuracies were greatly reduced as I found.

But that's not the full story, there's 2 more things to consider:

1. Eventhough the average power is basically identical to my indoor trainer, the actual power data is not always as close as the average would insinuate.
Actually, the Magene is often surprisingly above or below the tacx ("outliers"). The attached screenshot shows this nicely, where the blue line is the Magene and the purple line the Tacx.

2. The max power, is still off a bit, I think DCRainmaker noted the same thing. In my case it's still 6-7% in difference. Also, the 1s critical power is off by the same percentage, while all other CP value differences are negligible.

All in all a fantastic product and I'm wondering whether I can use it again for my upcoming gravel build. Maybe this time with a lighter 1by crankset as some have done here already.
« Last Edit: January 14, 2024, 03:54:37 PM by Greenred »

TidyDinosaur

Re: Magene P505 PES Base Spider Powermeter
« Reply #57 on: January 15, 2024, 02:27:11 AM »
All in all a fantastic product and I'm wondering whether I can use it again for my upcoming gravel build. Maybe this time with a lighter 1by crankset as some have done here already.

That will only be possible if you have bought the separate PM and not the PM + crank combo (505 base).
As I have stated before, you can not use that PM with another crank since they use a unique interface.

Greenred

Re: Magene P505 PES Base Spider Powermeter
« Reply #58 on: January 15, 2024, 01:33:58 PM »
That will only be possible if you have bought the separate PM and not the PM + crank combo (505 base).
As I have stated before, you can not use that PM with another crank since they use a unique interface.

Yes that was fully understood, already got the product saved. Thanks again

Greenred

Re: Magene P505 PES Base Spider Powermeter
« Reply #59 on: January 23, 2024, 04:08:12 PM »
That will only be possible if you have bought the separate PM and not the PM + crank combo (505 base).
As I have stated before, you can not use that PM with another crank since they use a unique interface.

Coming back on your builds @TinyDinosaur, does it also work with a 2by crankset, i.e. 2 chainrings?
I suppose they would need to be 3 bolt as well?
My idea was building a 46/30 crankset with the riro cranks.