How off could it be? (Quarq question)

[Nooch]

I’ve got an older quarq cinqo power meter that I wanted to throw on my cx bike with a single ring. However, I’m impatient and don’t much feel like sending it in for calibration at this point.

So, how messed up is it really likely to be? 1% or like 20%? I can deal with a small amount of inaccuracy if it means no interruption.

[Nooch]

Anyone?

[simonov]

Are you worried that it needs calibration because it's old or because of the single ring? I've never used a quarq as a single ring, but even my old one that's had multiple ring swaps has never been off by more than a couple percentage points.

[Bentley]

Electronic measuring devices calibration drifts over time as do mechanical devices. How much is a guess. But unless it's been damaged likely 10 to 15 percent depending on things like the condition of the battery and electronics.

I would suggest that you could eyeball by using relative effort from one bike to another (with a power meter on both) at the same speed, road conditions for a estimate of difference.

I really don't understand why the cal would be affected by one of two chain rings? The measurement (realtime) is only on one ring.

Ray

[AngryScientist]

find someone with a smart trainer, hook the bike up and spin - that should be a quick, free check to see where you're at?

if you dont have someone closer, you can throw your bike on mine anytime.

[Nooch]

Originally Posted by simonov

Are you worried that it needs calibration because it's old or because of the single ring? I've never used a quarq as a single ring, but even my old one that's had multiple ring swaps has never been off by more than a couple percentage points.

This gen of quarq lacks omniCal, so the calibration needs to be set manually when changing chainrings.

Nick, I’d not thought about comparing numbers on the kickr versus the quarq — I may move ahead and see how far off it is

[kppolich]

So quarq has a nice computer program that you can use to analyze the sensor and give you a better understanding of what is working and what is not. It just requires the ant+ stick to talk to the quarq. It's free, try it out. I believe this is also a tab or setting in that app to reset slope if you have a weight or something to hang from the crank arm.

[Nooch]

Originally Posted by kppolich

So quarq has a nice computer program that you can use to analyze the sensor and give you a better understanding of what is working and what is not. It just requires the ant+ stick to talk to the quarq. It's free, try it out. I believe this is also a tab or setting in that app to reset slope if you have a weight or something to hang from the crank arm.

I’m familiar with Qalvin but lack the calibrated weight

[loxx0050]

Originally Posted by Nooch

I’m familiar with Qalvin but lack the calibrated weight

You can ask the post office to weigh things for you. They are as close to a place that has certified scales as you can get without going to a measurement lab that specializes in that stuff. I've seen others suggest that on other forums.

Or you could do the hill test with total weights. See this for an example https://youtu.be/sqb-WhzCAgw

[simonov]

Originally Posted by Nooch

This gen of quarq lacks omniCal, so the calibration needs to be set manually when changing chainrings.

Nick, I’d not thought about comparing numbers on the kickr versus the quarq — I may move ahead and see how far off it is

Ah...forgot about OmniCal. Mine both have that so my comment above isn't relevant. Thanks for the tip.

[kramnnim]

I used a small 5 pound scale to weigh multiple ~2 pound objects I had around and put them all in a bucket and used that total weight to calibrate my old Cinqo.

[kgreene10]

In addition to calibration for the new chainring, check offset numbers before and after rides. More than 50 points of drift implies that the electronics aren’t working as well as they once were.