Background: Have a Quarq DZero/SRAM Red22 crankset
Towards the latter part of my ride this morning, my chain dropped as I was shifting from small to big ring and got stuck between the small ring and the frame. Fortunately, I was going slow and managed to pull over and fix it.
After a mile or two, I noticed the power reading (3 sec avg) displayed on my Garmin 830 was way off. It was reading very low power for a mid to high effort, ranging from 0 to 50W.
I pulled over again to recalibrate it through the Garmin. Got an offset of ~450. Rode again for another few miles and the same issue. Pulled over, took out the battery and put it back in, then recalibrated. This time, an offset of ~570. Went a few miles again and had the same issue. Cadence reads perfectly fine.
Did some quick research and it seems this is a relatively common issue based on some SlowTwitch and TR threads. But others have been getting really high (or low) offsets of -32000 and even some have their max power measurement pegged at 2400W.
To further diagnose, I’m going to try the following in order: Calibrate using SRAM AXS app (seems to have replaced the Qalvin app), reinstall and retorque all the fasteners holding the spider to the crank, contact SRAM/Quarq. Unfortunately for the last one, I purchased my unit secondhand and warranty has likely expired at this point.
Anyone else have the following issues and have found or can suggest a fix?
Weird! I remember the Quarq I had years ago did this. Would register 2000-3000 watts when chain dropped. But it never went dead. It would go back to normal once the chain was back on.
I set my current Quarq so that I don’t ever drop chain so not sure if it’s still the case. Hope it gets resolved!
I had the same thing happen to me. The chain dropped into the BB. Stopped, reset the chain, and kept riding. My Quarq DZero first started showing absurd numbers (around 2-3kw), and after a while, it would just show zero. Unfortunately, I bought my PM second hand and it was out of warranty, so Quarq could not do anything for me
Got another one though because I really like the PM, as long as it worked it was really reliable but I did install a chain catcher to avoid that issue in the future - I’m sorry but I think this can not be fixed.
I reached out to Quarq support and they were helpful. Basically nothing could be done since it’s out of warranty and I’m not the original owner. However, they offered great deals on a crank + power meter packages. I ended up just buying another Quarq DZero Dub spider from a separate dealer anyways since they were running a sale, so all is well now! I heard this failure mode is now fixed on newer Quarq DZero spiders?
2023, did anyone find a fix for this? I had a chain drop in January and my Quarq stopped working. I can’t believe this can completely break it. Is there something I can do a part from buying a new one?
The fix is replacing it. To confirm, what are the reasons you state it is not working? Usually it is a super high zero that demonstrates it is bricked.
It’s toast as far as I know. Frustrating for sure. Quarq has special pricing on out of warranty units if you reach out to customer support.
There was a Slowtwitch thread on this that I can’t be bothered to search for. Basically, strain gauges are delicate instruments. If knocked, they can be put of whack. The fix is … I’m not sure if Quarq could fix a damaged PM in principle, but it might not be economical. Anyway, as far as I know, they have redesigned their PMs to be not vulnerable to chain drops. I dropped a chain on one of those newer Quarqs (a warranty replacement for one that died to a chain drop), and it was fine.
Sorry, but the fix is buy a new PM. Quarq should have had the foresight that chain drops are a thing that can happen, but engineering is complex, and they did at least correct the issue.
