DFour DUB Power Meter Spider
You've been running with power in your cranks for a bit, but craving a drivetrain change. This can be a little tough to stomach, especially when you've been rolling with an expensive power meter that limits compatibility. If your setup involves a Quarq DZero DUB crankset, and Shimano's newest Dura Ace is catching your eye, don't worry, you don't need to lose out on your whole crankset, or compromise your drivetrain desires, with the Quarq DFour DUB Power Meter Spider you can bridge the gap. This spider enables you to keep running your DUB cranks with Shimano's Dura Ace 9100 drivetrains, so you don't have to make concessions anywhere.
The spider features Quarq's new design, which requires less correction in order to maintain accuracy in drastic temperature changes. Fewer corrections mean the DFour also better rations battery life than Quarq's previous power meter models, though when the battery does go out, you can still change it without tools or having to ship the whole thing to the manufacturer. It still incorporates five strain gauges strategically placed throughout the spider, and it's also still got the same claimed accuracy of +/- 1.5%, so its numbers are 0.5% more accurate than most meters.
DFour's accuracy is further boosted by the return of Quarq's 10k dynamic temperature compensation technology, which alleviates the need for constant, mid-race zeroings in variable conditions. Even if it's just coasting for a few seconds or toggling through your head unit to the proper option, it can still be the difference between winning and losing. It's also obnoxious as hell. The DFour is equipped with an auto-adjust schedule based on a constellation of around 10,000 data points that chart how the unit responds to temperatures ranging from zero to 130 degrees Fahrenheit. This lets the power meter figure out the atmospheric details for you with minimal drift, so you can focus on turning the crank, not babysitting it.
Power Balance and Omnical are two additional returning features that record total output and output for either leg individually (Power Balance) and let you swap rings without recalibrating or negatively impacting accuracy (Omnical). As with previous Quarq models, the DFour communicates to your head unit via ANT+ wireless, but Quarq also adds Bluetooth to this generation. Up till now, we've always tempered the obligatory head unit-compatibility statement by writing that your current computer is likely already compatible with the power meter; now, we can just state outright that it is compatible.
We recognize that there is value in cycling components that can stand up to the elements we often encounter throughout the course of a year of training, but Quarq demonstrates its penchant for being overly thorough by ensuring that the unit's internals can handle comically extreme conditions. The system is waterproof for 30 minutes while submerged under one meter of water, a feature that will come in handy on days you take your bike on the swim leg, too.
As the above implies, the DFour is effectively a catch-all for almost every bit of tech Quarq has thrown at the power meter problem over the past decade. This includes the AxCad accelerometer, which provides cadence information without the need of an additional sensor or magnet. The DFour is also compatible with various training software such as Training Peaks WKO+, Training Peaks, Golden Cheetah, and Strava. Unlike previous Quarq power meters, the DFour's Bluetooth compatibility lets it sync with the Qalvin BLE app to easily tune, tweak, and set zero offsets. That alone might be reason enough to upgrade.
- Stretch compatibility from your cranks with this Dura-Ace ready spider
- Built to pair with Quarq DZero DUB cranks, and Shimano Dura Ace 9100
- Redesigned strain gauge system is even more precise
- Broadcasts via ANT+ and Bluetooth protocols
- Requires less correction for better data and longer battery life
- Battery can be changed without tools by home mechanics
- Includes tool to simplify installation
- Please see chart below to ensure compatibility
- Item #QRQ802J
- Bolt Circle Diameter
- 110mm asymmetric
- Compatible Components
- Quarq DZero DUB cranks, SRAM DUB bottom bracket
- Claimed Weight
- 5.8oz (165g)
- Manufacturer Warranty
- 2 years
3.5 based on 2 ratings
What do you think about this product?
ViewSelecting an option will reload the available reviews on the page
April 24, 2022
Second one has failed in a year
I'm now on my second one of these failing. They start reading bad then just stopped transmitting power data. Beware.
Originally reviewed on Backcountry.com
November 24, 2020
Great alternative to Shimano based PM
- I've put it through the wringer
I built up a new Tarmac SL7 frameset this summer and wanted a good, accurate PM. I'm partial to Di2 and Shimano, but I read about accuracy issues with dual sided PM's using the latest Ultegra/Dura-Ace crankset. This Quarq PM fit the bill perfectly to pair together with Dura-Ace Di2 and chainrings. Looks fantastic and provides reliable power numbers. I'm also loving the MagicZero automatic zero offset that doesn't require you to zero offset before every ride. Just hop on the bike and start riding. I'm not a weight weenie but I did compare total weight of PM/crankset/BB to a comparable Shimano based setup. Weight is within 10-15g. Price is also competitive with the alternatives. Very happy with my purchase and 10/10 would buy again.
Need Expert Advice?
Our Gearheads Can Help
December 5, 2021