Quarq / Qalvin calibration?

Triathlon Forum
1

I have SRAM Red Quarq power meter and swopped the 53t outer ring with a 55t.

I knew I had to re-calibrate so I bought the Qalvin app for my iPhone and the Wahoo dongle. I watched the YouTube clip and zero’d the calibration and then went into ‘Calibrate Slope’, I used my certificated calibrated weight and went through the app process to change the slope.

I now seem to be 30w less power output on both average and normalised but I’m going faster? Have I done something wrong, anyone else come across this?

2

You do not have to re-calibrate. The new Quarqs have a feature which means swapping chainrings will not affect calibration.

3

You do not have to re-calibrate. The new Quarqs have a feature which means swapping chainrings will not affect calibration.

Really??? That’s the first time I’ve heard that?

4

Funny I just posted a similar issue except I don’t have the weight. Did you buy one? Where’d you get one and was it like $200?
I’m pretty sure recalibration is required as I swapped my 53 for a 54 and power readings are off.

5

Funny I just posted a similar issue except I don’t have the weight. Did you buy one? Where’d you get one and was it like $200?
I’m pretty sure recalibration is required as I swapped my 53 for a 54 and power readings are off.

Yes that’s what I thought, you can do a manual or auto calibration but I thought that was minor check against atmospheric pressure or whatever, but the slope has to be recalibrated if you change the ring size, or so I thought, the Qalvin youtube clip seems to suggest that to.

http://www.youtube.com/watch?v=4IZL3QXtYv0

I didn’t but the weight, I had a weight calibrated by a calibration company weighing in at 25.33kg, only cost £25.00

6

but the slope has to be recalibrated if you change the ring size, or so I thought, the Qalvin youtube clip seems to suggest that to.

http://www.youtube.com/watch?v=4IZL3QXtYv0

I didn’t but the weight, I had a weight calibrated by a calibration company weighing in at 25.33kg, only cost £25.00

Do you have a Cinqo or a Red/Riken/Elsa? If its the former you absolutely have to change the slope with Qalvin. Iits a newer Quarq with omnical its not necessary.

Have you looked at Quarq ring calibration table? See if your rings are posted and check what Quarq recommends.
http://www.quarq.com/ring-difference

7

but the slope has to be recalibrated if you change the ring size, or so I thought, the Qalvin youtube clip seems to suggest that to.

http://www.youtube.com/watch?v=4IZL3QXtYv0

I didn’t but the weight, I had a weight calibrated by a calibration company weighing in at 25.33kg, only cost £25.00

Do you have a Cinqo or a Red/Riken/Elsa? If its the former you absolutely have to change the slope with Qalvin. Iits a newer Quarq with omnical its not necessary.

Have you looked at Quarq ring calibration table? See if your rings are posted and check what Quarq recommends.
http://www.quarq.com/ring-difference]

I have SRAM Red Quarq, I can’t find the rings in the table which is why I went ahead and calibrated them.

8

I have a SRAM Red Quarq 172.5mm crankset.

Current slope 9.23
Factory slope 9.43

Last data sent after calibrating again…

Old Slope:9.254974

Local Gravity:9.812859

Length:0.172500

Weight:25.340000

Torque Left Small:42.750000

Torque Right Small:43.062500

Torque Left Big:43.843750

Torque Right Big:44.000000

Torque No Weight:0.421875

New Slope:9.233726

Direction:forward

GAM:disabled

Qalvin Version:1.3.1

Dongle Version:1.16.0

9

I’m still surprised you “re-calibrated” it in the first place. You didn’t have to. As mentioned, “omnical” is a feature that means you can swap chainrings and not worry about it. (assuming they’re installed correctly, obviously)

10

yeah, but mine still seems to very even with omnical. slope does not equal factory slope currently

he can always reset to factory settings with the tap of a button.

hopefully he is on firmware 19 as well, if not might be good to update

yes his watts will read lower now, he lowered his slope

11

yeah, but mine still seems to very even with omnical. slope does not equal factory slope currently

he can always reset to factory settings with the tap of a button.

hopefully he is on firmware 19 as well, if not might be good to update

yes his watts will read lower now, he lowered his slope

But, only about 2% lower…so, if his readings are 30W lower, that means he must be looking at an interval where he put out 1500W??

12

he’s pow-ful
.

13

Actually I’ve made a mistake, its a SRAM Quarq not SRAM Red, does it still have the omnical feature?

14

Actually I’ve made a mistake, its a SRAM Quarq not SRAM Red, does it still have the omnical feature?

No. But it doesn’t appear that your slope changed much anyway.

15

Would it be right that the slope reduces when the ring size increases?

16

Would it be right that the slope reduces when the ring size increases?

It could…perhaps the ring is stiffer tangentially? Again, though…you’re talking about just a 2% difference.

BTW, you don’t happen to be changing from a non-round ring to a round one by any chance, right? :wink:

17

Would it be right that the slope reduces when the ring size increases?

It could…perhaps the ring is stiffer tangentially? Again, though…you’re talking about just a 2% difference.

BTW, you don’t happen to be changing from a non-round ring to a round one by any chance, right? :wink:

No they’re both round, but you’re right the new 55t ring is the solid TT one so probably stiffer.

18

be sure to check all the chainring bolts are tightened to 10Nm. a loose bolt can contribute to low readings.