This particular topic was discussed in another thread, but I can’t remember the title. It was recent though. The official response from AIM seemed odd to me, something along the lines of not compensating for the steering wheel motion. I think that’s bull because they have all the hardware to do standard compensation, but that’s the official answer.
@Spenny do you recall the thread?
Unipro were really straight-up with me about the limitations of GPS Vs wheel speed sensors. They said they are both wrong 
But, what they allowed for in their software was for you to switch between GPS and wheel speed sensors for the distance measuring.
That really impressed me, but I’m yet to try it.
So if your suspicions are raised, you can swap between wheel-speed and GPS, and seek some verification that way.
On the subject of GPS trustworthiness, I did once put two of the aim watches (mytach) on the same kart, and they both produced convincing but very different data.
But for sure, the GPS on the mychron 5 is way better now…
If anyone has 2 mychron 5 units, maybe throw them both on a kart and give it a whirl! That would be very interesting!
Funny enough, I have data with two different units at very different times. The accelerations were much higher on the 5 than 5S, so five minutes ago I was thinking of integrating those and seeing which one recreates the closer lap distance. I don’t have data of them both for a true apples to apples test though. That’d make it all too easy
It was this thread. TLDR - the Mychron does not compensate for steering wheel rotation. It can be zeroized to compensate for steering wheel mount angle though. It is just that while you are driving and turning the wheel left and right, those movements will impact the accelerometer data.
Mount the MyChron on a fixed part of the kart. The MyChron 4 inertial measurement package was mounted to the kart frame. There are some drivers who mount the My5 to the steering column support.
I have some fresh data from a mychron 5 mounted on Nassau panel uprights so stationary.
My concern is the difference between RS2 and RS3 time compare charts. RS2 makes sense, RS3 is way different and doesn’t make sense when looking at gps speed.
Same two laps, coloured the same.
Overall laptime difference is 3 tenths, so there’s a reasonable range in the laptime difference.
I must be getting something very wrong, or Race studio 3 is doing something really weird (latest version). The time compare charts are completely different between RS2 and RS3.
Also, the lap lengths are 1015m in RS2, and 1042m in RS3
Looking at the end of split 12 in RS3, the entry speed, apex speed are higher for the green lap, but the red lap on the time compare is a steep negative gradient indicating that it is making up time, for the corresponding position… Surely thats wrong?
Race studio 2 tells a different story, showing only a higher apex speed and no significant time gain, which seems to tally with the speed trace reasonably well
The split reports are wildly different, I don’t know where to start with those.
Hmmm, you’re right that something seems out of whack with RS3. The time compare graph not only behaves strangely, but it almost looks like its interpreting data at a different resolution than RS2, e.g. the steep erratic changes in the curve vs. more shallow and predictable in RS2.
For whatever reason I do not have this issue with mine. I’m using version 3.55.00. Maybe check the firmware version on the Mychron as well?
Here’s one of my time compares in RS3 for reference. Three laps from the same session with red being 49.83, blue 50.14, and Green 50.49. My time compare graph looks much more normal IMO:
yes, that certainly looks more like it, I might revert to an old version and see what I get. There’s a lot of release notes, maybe one will say ‘we changed the time compare calculation - it’s weird!’
Can you redo that laptime delta in RS3 but with a custom track that is only one split? There are some sharp changes in the delta plot that seem to correspond with a lap split:
For this one, you can see the delta drop after the end of 10 when the data looks like it should’ve held.
I agree with Caleb that the segmentation in RS3 is wacky. It does at all look like the track segments in the RS2 screen. I’m not familiar with RS3 but in RS2 when making a track map there are sliders that change the shape, number of segments of the track. Maybe some of the sliders are not set correctly in RS3. In this study I would think that the track maps and segments would have to be the same. I’m not sure that track maps can be shared by RS2 and RS3 but that would be best if they could.
Are you using a Mychron 5 or 5s? Curious if that could be the cause of the issues, due to hardware differences called out in another thread. I’m using a 5 fwiw.
Unless I’m missing something the problem is the segmentation of the track likely in RS3.
These are the segments in RS2
These are the segments in RS3
The segment should look the same.
A track map from RS2 and RS3 might help.
My concern is they may have changed their logic on how to normalize lap distance. If, for example, they don’t normalize each segment in RS2 but they do in RS3, then even having the same track and segments might show different results. I think the best way to rule out that possibility is to first create a map that is just all one single segment and then compare the deltas. If they match better, I might be right.
This what i get between RS2 and RS3. Didn’t make the lap one segment but used most recent data. The difference can be as large as 40 ft, which could be caused by my line and GPS errors but the average difference is pretty good about 3 feet.
What is more disturbing is the acceleration data is off by 20% between RS2 and RS3 but it looks as if this might be related to how the RS filters the data. Acceleration data is not so important in karts and I use it only for relative measure of driving performance. But anomalies at times point to a bigger problems. Regardless, RS2 and RS3 should match.
Oh, I’m not using My4 or 5(S). I use an EVO4 (for cars). Maybe it’s more accurate.
I might have to take back my criticism of RS3. I got it running last night, the most recent version Nov 2023. You all should make sure that the most recent version is being used.
Yes, the splits it creates automatically are definitely strange.
I merged them down to one sector, which you do in the time distance chart (I couldn’t figure out the map system for the life of me )
The time difference chart hasn’t changed.
The lap length is significantly different between rs2 and rs3. Rs3 has another 27metres which is a long way.
I asked Robinson Shay @ AiM USA about this thread and he said:
The discussion is interesting, but there’s a lot of missing information that I would ask for, before being able to provide any good context to his posts. I myself would first have the question of the Software version for RS3 the user is operating with, the firmware version of the device, and a shared data set to compare.
I read that someone would be surprised that RS2 Analysis and RaceStudio3 Analysis would operate differently, which surprised me.
RaceStudio2 Analysis basis was built prior to GPS even being in the AiM Sportline hardware capability in the early 2000’s?.. GPS was introduced at a later time to the hardware ability, and then analysis features for GPS were built in along the way, and in use for 15+ years.
RaceStudio3 was introduced in the last couple of years with GPS data at the core of the functionality, and the version can make a difference. I will say it is not immune to bugs, and new features are still being added regularly.If it is a Mychron5S the RS2 Analysis does not handle the 25Hz GPS frequency the same as RS3 Analysis will. RS2 Analysis forces the data to 10Hz and that has some play into an immediate difference in data comparisons between the two.
I asked him to join the thread if he has the bandwidth.
Interesting. Not sure if I was clear but my data is from the EVO4 and not MyChrons. Maybe that is why RS2 and RS3 analysis look very similar.
I’ve been using RS3 and it much much better than RS2.
So, if I’m to understand this correctly, if I use RS3 “version” Data or data from a MyChron 5 or 5s in RS2 I’ll get different data than if I upload it in RS3?
I think I understand the way each software was built, but I guess my question is in regards to backwards compatibility….
Certainly I get a totally different time-compare chart between Rs2 and RS3
I just downloaded the November 30th RS3, and that gives a slightly different time compare graph to the RS3 from November 28th for the same data.
So I guess there is still some tweaking going on.
My guess is that RS3 is taking into account the line you take, because I’m seeing time gains where speed is slower. Maybe RS3 is doing something very clever that RS2 wasn’t doing.
Speed on top, time compare below.
Time compare shows a 2 tenth gain despite having lower speed at that point time. But the higher speed might also be running wide and giving away distance. This is conceivable for that corner.
If thats the case then RS3 is way superior…
Robinson Shay @ AiM USA I was running standard mychron 5. November 28th release of RS3
The release notes also say this:
Hmmm, seems like an interesting coincidence that I wrote in this thread they should be normalizing throughout a lap and then they release a new version… Good news is they might actually be reading this thread, haha
