Why is the Gyraline Problematic? Debunking the Fanatics
- Roger Maeda
- 11 hours ago
- 12 min read
In the week since we published our 1-year review of the Gyraline G1 (AKA the Gyraline DIY), we have seen quite the reaction from the DIY alignment community. A number of customers and enthusiasts have come out to share their experiences with their Gyraline G1 and G2 devices, many of whom echoed our findings.
We have also seen a spike in site traffic from a few specific areas where we happen to know where Gyraline's founders reside. We also noticed two new, suspicious-looking anonymous posts on the Gyraline User Group that aggressively touted the accuracy and precision of the Gyraline G1 and G2 products to no one in particular. A quick look at our website analytics, Google search analytics, and a re-visit to the recently updated Gyraline website confirmed our suspicions. Our article has gained the attention of Gyraline's employees and its most fanatical fans.
So we thought we would take the opportunity to go into detail around how the Gyraline works, where the limit of accuracy and precision come into play, and why we recommend that you avoid the Gyraline G1 and use caution with the Gyraline G2.
Quick Access:
Why isn't the Gyraline G1 consistent or reliable?
We'll start with the big question - Why doesn't the Gyraline work as advertised?
Having worked on project that pushed the limits of the iPhone (and various Android phones') IMU packs, we are aware of several limitations.
Here are the top 4, from the author's perspective as a setup engineer with 20 years of experience with a variety of alignment tools:
iPhones rely heavily on the device's magnetometer to measure headings. But you can't use it for an alignment The big limitation of using an iPhone for these types of measurements is that the gyroscopes and accelerometers in these devices are budget-friendly consumer grade devices and rely on the magnetometer (compass) to maintain consistent heading measurements. The problem is, you can't rely on the magnetometer when using your phone to measure the toe on a car's wheels. Why? Modern cars have so much ferrous metal in them that they affect the magnetometer's readings.
This limits the Gyraline app to relying primarily on the phone's gyroscope and accelerometer, which affects its precision. Which leads to the second problem:
Without the magnetometer, the IMU pack in modern iPhones can only sustain a precision of ±0.5 deg to ±2 deg in yaw after the first few seconds All IMU packs, including those in iPhones, exhibit a phenomenon known as sensor drift. What this means is that the accuracy of the sensors decrease over time, as they lose their reference point. This sensor drift happens faster than you would expect. In fact, this drop in accuracy happens in seconds and only gets worse over time. This is why iPhones (and Android phones) seem to never live up to Gyraline G1's claims of ±0.05 degrees in yaw (rotating left and right, as if you were measuring toe on a car), even with algorithmic correction. Phones can only sustain that accuracy for a few seconds before the sensors in the IMU start to drift.
Without the magnetometer to help sustain its reference point, you should expect sensor precision in the range of ±0.5 deg to ±2 deg in yaw after 8 to 10 seconds of use. And that is with the help of software techniques to improve the accuracy of its results.
Due to gyro drift, that precision only gets worse over time. Expect accuracy to drop to ±1 deg to ±3 deg after just a few minutes This one is self-explanatory. Even with software correction techniques, the precision of phone gyros degrades to over 1 degree of yaw in minutes. While it is possible to extend the time by taking intermittent reference readings, this can be difficult depending on the application. This is why some of the most careful users of Gyraline have gotten some of the least consistent results. They take too long in moving between measurement points, inadvertently allowing the sensors to drift away from their reference point.
The iPhone gyroscope is very temperature-sensitive, and iPhones have no mechanism for correcting this This one is big, and there is very little you can do about it. Apple's official documentation specifies that iPhone's sensors are the most accurate when the ambient temperature is between 60 deg F and 72 deg F (or 16 deg C and 22 deg C). This temperature range is closest to factory calibration range. Outside of this range, the sensors become significantly less accurate. Too cold and the gyro drift will become worse. Too hot and the sensors will pick up noise that will affect the quality of the readings. Those of us who have experience with alignments already know why this is a problem: DIY alignments are rarely performed in perfect, climate-controlled conditions. The author has performed alignments in near-freezing temperatures and searing summer heat nearing 100 degrees Fahrenheit (37 deg C), both inside shop spaces and in the field. Many of our fellow racers work in much harsher conditions. The iPhone's built-in sensors, and therefore the Gyraline G1, will not produce reliable measurements in these "extreme" temperatures. And yes, this issue affects all IMU packs, including those built into the Gyraline G2 unit.
Can't you calibrate your phone to improve accuracy?
This question was posed from a user on the Gyraline User Group posting using an account with a pseudonym and a suspicious locked profile called "Need Speed."
Here's the screenshot of their post:
"Need Speed" recommends a series of AI-summarized calibration steps from an older version of iOS as a way to improve the accuracy of the Gyraline G1.
The problem?
The Figure 8 calibration procedure and Location Services toggle only affects the magnetometer (the magnetic compass), which does not help with the accuracy of the Gyraline.
Instead, we recommend simply checking the health of the built-in sensors using an app (there are several free ones on the App Store) and restarting the iPhone prior to using it for any precision work.
As an aside, it is notable that "Need Speed" admits in this very same post that they have not compared the readings of their Gyraline G1 with any other alignment system. This is just another reason why you should ignore "Need Speed"'s advice.
Every tool has a learning curve. Don't you just need to learn how to use the Gyraline?
In the same Gyraline User Group, another anonymous participant accused critics of the tool of using the tool improperly. A sampling of his similarly aggressive posts and comments are listed in the gallery below:
There are three fundamental problems with this unnecessarily belligerent argument:
DIY alignment tools (and in fact, all commercial alignment tools) must be designed to be as easy as possible for an untrained user. This is a matter of catering to your customers. The average car enthusiast or novice alignment tech does not have the time to scale the steep learning curve of a new tool. That's why toe plates and camber gauges now come with such detailed instructions, and why we took the time to write an unofficial assembly manual for the promising B-G Racing string rack. Good alignment tools have a very shallow, or even a flat, learning curve. By admitting that its learning curve is steep, this Anonymous Participant is confirming that the Gyraline is not an appropriate tool for the average car enthusiast.
This Anonymous Participant is baselining his Gyraline to the notoriously imprecise Dunlop Optical Alignment gauge For those of us who are too young to remember, the Dunlop Optical Alignment gauge is a toe gauge that was popular in the 1960s. They look like this, work primarily based on a periscope and a set of mirrors, and are well-known for their ease of use:
A Vintage Dunlop Optical Gauge. They can still be found on eBay They are also known for having warped over time and are notorious for their poor precision. A well-respected vintage racer once shared that you should expect precision in the range of ±0.2 to ±0.3 deg from a well-preserved set. This is significantly worse than what you can expect from a set of brand-new toe plates or from a modern string alignment rack. In fact, an alignment on a toe gauge with a precision tolerance of ±0.3 degrees will return measurements that are outside of the tolerance range of the factory specs for most passenger cars. If you need to baseline your measurements on a DIY alignment tool, we recommend using a set of Longacre toe plates. They are checked for straightness at the factory and will offer substantially better precision than this vintage gauge.
This anonymous poster offers no helpful advice as to how one could tackle the learning curve of using a Gyraline G1/G2 This probably will not come as a surprise to anyone who spends a significant amount of time online: Scouring through this Anonymous Participant's contributions reveals that he gives no useful advice on how to get more reliable or precise measurements with a Gyraline G1 / G2. It is all too easy to assume that this post was submitted by a fanatical follower who is affiliated with Gyraline LLC, possibly an older friend or family member of one of the founders. Based on the wording of his posts and his misspelling "Dunlop" as "Dunllop" (a common misspelling from car enthusiasts of a certain vintage) and a bit of OSINT by yours truly, this assumption may very well be correct.
How CAN you improve the accuracy of the Gyraline G1 / G2?
Despite the fact that we were not able to get consistent results from our Gyraline G1 during our 1-year re-test, we can offer some advice to those of you who would like to try to use the device:
Work in a flat, level, and temperature-controlled environment When we first tested the Gyraline G1, we did it in a temperature controlled indoor environment which was kept at 65 degrees F (18 degrees C) and had a perfectly flat and level working surface for the car. We recommend working in similar conditions at all times. We also recommend finding a flat, level spot on the floor near the centerline of the car for the gyro calibration step (where you place the device on the ground for a few seconds prior to using your Gyraline). *And yes, we used similar conditions for our 1-year retest.
Work quickly. Move from wheel to wheel in less than 10 seconds The accuracy of IMU sensor packs degrade rapidly after the first 8 to 10 seconds. In order to ensure accuracy, we recommend that you take each toe measurement within 10 seconds of each other. This means moving from wheel to wheel in under 10 seconds, while keeping the Gyraline frame straight, level, and pointed in the same direction. This means working very quickly, faster than you typically would with other alignment tools. We recommend clearing your work area as much as possible and mark the measurement points on each wheel with a marker beforehand to ensure that you are measuring on the same spots every single time.
Keep the device flat, LEVEL, and pointed in the same direction when moving around the car The Gyraline manual recommends that you keep the device flat and pointed in the same general direction as you move around the car. We also recommend that you keep the device level on the long end, to reduce sensor drift.
Bend your knees slightly, walk carefully, and keep your device pointed in the same direction at all times.
Why wouldn't the G2 be accurate to 0.01 degrees of precision?
In the past few days, the Gyraline G2 page on the official website has been updated to remove any mention of the G1 or G2's precision. Here are the before and after screenshots, comparing early January to early February. Note the claim of "Up to 0.01 deg Ultra-High Precision" on the top left of the first screenshot, which has been replaced with a generic claim of "Reference-Grade Repeatability" just a few weeks later:
Although the average consumer may see this as a bait and switch marketing tactic, they would be absolutely correct.
The reality is that the makers of the Gyraline G2 should have never promised ±0.01 degrees of precision, even under ideal conditions. This is because there are no industrial-grade or DIY MEMS packs that can promise ±0.01 degrees of precision at the price point of the Gyraline G2.
For reference, a Movella MTi-3 AHRS Dev kit (a commercially available industrial-grade MEMS pack) has a retail price of $469 US and can get to a precision of 0.2 deg of precision in Yaw with GNSS Satellite assistance. This can be further refined down using software algorithms, but not to the ±0.01 degrees of yaw precision that the original Gyraline G2 product page promised.
Hardware-level precision of ±0.01 degrees in yaw typically requires a fiber-optic gyroscope, in units such as the SBG Apogee-D. For those of us who may not be familiar, the SBG Apogee-D is a military grade component that is typically used for UAVs and marine navigation. Needless to say, products like this are out of reach of the average commercial electronics provider, and cost significantly more than the Gyraline G2's unit cost (and not by a small margin either).
So what kind of MEMS pack IS in the Gyraline G2?
Given the price point and the work required to integrate and calibrate the units, a more realistic option for a product like the Gyraline G2 is something like this Witmotion Shenzen WT901, an affordable IMU that can be purchased for under $35 US:
Under perfect conditions, with proper calibration, and on a single spot measurement, units like the Witmotion WT901 can theoretically claim up to ±0.05 degrees of precision in yaw. As we mentioned earlier, however, Gyraline alignments require the user to take 4 to 6 spot measurements in different places. Each additional measurement reduces the precision of the overall measurement, and the time needed to move between points causes sensor drift. Given this reality, a realistic precision figure for an alignment performed with the Gyraline G2, with its external MEMS pack, would be ±0.1 to ±0.2 degrees in yaw, which is closer to the precision claims for the original Gyraline DIY than for the G2.
What about Gyraline's Accuracy Study?
Gyraline has reformatted and updated their accuracy study of the Gyraline G1 several times since the inception of the site.
Here is the study in its current form, captured as a screenshot in case it is edited again:
Any of us who have any experience reading academic studies will immediately notice the following textbook issues:
Sample size of 1 car
Limited testing conditions
Selective framing of results
Critical details omitted (e.g. what does "2023 model car" mean?)
No peer review / independent verification
But the biggest problem - The premise of Gyraline's Accuracy Test is fundamentally flawed. A relevant accuracy study of a new tool would not revolve around performing 10 measurements on 1 car. A more relevant study would involve 10 different cars, with 1 measurement taken on each using the Gyraline, and each car baselined against a reliable, well-known alignment system.
Because of these issues, we recommend that you ignore the results of Gyraline's accuracy study.
Is Gyraline a scam?
Not quite, but it is safe to say that their marketing claims do not reflect the reality of their products and that their pricing and products change with unusually high frequency.
And seeing how a brand-new version of the G2 was announced as we wrote this article, it's hard to say whether this will change any time soon.
Those of us who have tracked the product since inception remember that the original Gyraline was $79.99, and that it was the entry-level companion to a pro-focused Gyraline Quick Check that had a planned price tag of $1299.00 as well as a monthly fee of $99.
In just over a year, this price dropped to $39.98 with a subscription, then bounced back up to a $159.98 one-time fee, then up to $499 and $739 for the Founder's Edition Gyraline G2 models, and has now transformed into single G2 model with a $599.00 price tag as of February 9th, 2026. This wild fluctuation in price and product is, at best, opportunistic marketing, and at worst, repeated cases of bait-and-switch sales tactics. Meanwhile, feedback from other customers of the G1 indicate that support for the older Gyraline devices has degraded noticeably, with some users reporting that they are now receiving unhelpful (and sometimes dismissive) responses to their inquiries. This is unusual for a hardware-dependent product that is less than 2 years old.
It is only fair to assume that customers of the Gyraline G2 could face a similar degradation of support for their devices over time.
Gyraline's actions seem to reflect those of a tech startup with an ambitious product that is trying to reach solvency rather than an outright scam. That said, customers should be aware that either one can take your money without delivering on their promises.
In short: Proceed with caution.
Have any other questions?
The above analysis was written by an author who has over two decades of software development experience, hands-on experience with mobile phone development and IMU hardware, hands-on training with both DIY and professional level alignment tools and has raced at the club and pro level in various capacities.
If you have any other questions, feel free to write to us via our Contact Us form. We will be happy to respond to any questions to the best of our ability. We may even add to this article if we think your question might help others.
In the meantime, see you at the track.
~R
Disclosure Section:
StudioVRM and Roger Maeda are not affiliated with Gyraline or any of the other vendors mentioned here. Any of the parts purchased and reviewed for this article have been purchased at full price from our team's car development budget and Roger's own pocket.