FREE Suspension Data Acquisition (MTB Rear suspension Ep.6)

[@Piplodocus]

I don’t have a GoPro, but I’ve currently got 5 GoPotatos. Great series, just what I was after: the real physics/engineering I can understand and use the principles of, rather than wish-washy vibe words I can’t fully embed in my brain.

[@justsayin3600]

I've watched quite a few videos on suspension and I think your videos are the best explained so far.

[@andrextr]

Thank you my friend cheers 🍻

[@thisoldjeepcj5]

I listen closely and even turn on Closed Captioning for English which sometimes makes me laugh. But want to compliment you on an outstanding presentation your English is very good. Thank you for sharing your work.

[@andrextr]

Thanks my friend! Cheers

[@rogerunderhill4267]

Great information that will help me set up my electric unicycle. Thank you!

[@FlorianScheikl]

Awesome video, again. Very basic and/but good explanations. Keep up the good work.

[@rvpaiva7040]

Keep up the great work André! proud to have you on the Arrow Team (btw love the shirt!)

[@andrextr]

Oh yeah! Arrow team FTW ;)

[@jonathanlebon1366]

thanks for your dedication, great contents and informations !

[@andrextr]

+Jonathan Lebon You are welcome :) Stay tuned, I will do more episodes ;)

[@jonathanlebon1366]

+andrextr great, where can I place the Gopro on a 2014 devinci wilson frame ? (for a shock view)

[@andrextr]

+Jonathan Lebon Hi. In some bikes it's impossible to film the rear shock in a kind of perpendicular way. For the Devinci Wilson probably you can film from the back of the seat tube (pointing to the ground). And you can track the shock eye, or even the "mud guard" of the seat stay. For tracking you need a high-contrast point like the red knob of rebound that I used. If not, the software cannot track the object. You can use a sticker, or a piece of white paper glued to the object that you want to track. Then you need to calibrate the measurements and apply a correction factor. Don't worry I will show you how to do this in a futuro video. It's not that hard :)

[@andrextr]

+andrextr Nice bike BTW ;)

[@jonathanlebon1366]

+andrextr Thanks, I think that the seat tube is a good option, so I will wait the next video ;)

[@torabora851]

Great idea! I'm look forward to the tutorial about how to make such funcy graphs!

[@andrextr]

+Maxim Stepanov Hi! Yes, I will finish and upload the tutorial video in the next weeks... Bye :)

[@APEX.86]

Great video, but please make the follow up with the details of setting up Kinovea and Tracker! Even a quick write up on that would be great.

[@andrextr]

Hi thanks! Unfortunately I didn’t finished the follow up... anyway I received recently some reports of people playing with this, and there is even one guy that did an app to get similar graphs based on phone accelerometers (MTB shock tune app on playstore).

[@APEX.86]

@@andrextr I played with it over the weekend and got great results. Shooting footage at 2.7k 120fps was a good balance of resolution for accurate vision tracking and time interval (at least for slower speed events). I made a 50mm piece of white tape for length calibration and a triangle piece for tracking. Here is one of my tests: kzbin.info/www/bejne/eGauh4tojatqq7s

[@Skovhugger37]

Keep up the good work - These videos are absolutely brilliant!

[@andrextr]

+Skovhugger37 thank you my friend :)

[@Raumance]

Thank you for making these it's very nice to understand.

[@michaelsorley3107]

Really enjoying your videos learning a lot. Appreciate the effort thanks

[@oscar199768]

Greetings from Perú andrextr! I have recently seen your videos, and im impressed with the analysis you do; i am studying electronics engineering, and the fact of designing a "perfect"("" because there is no perfection) frame geometry for a type of shock and use (for example.... jumps and drops in trail) would be very interesting!

[@andrextr]

Thank you Oscar! Puedes hablar espanõl que yo lo entiendo también jejejej :D Stay tuned for more videos. Bye :)

[@oscar199768]

Genial! Saludos tambien!

[@rologti]

andrextr jajajaja...impresionante...estudias medicina, hablas por lo menos 3 idiomas y te manejas tanto o mas que yo en temas de diseño y fisica...y yo soy Ingeniero y con un par de postitulos. Mis respetos y saludos desde Chile!

[@andrextr]

Gracias! Recientemente he tenido mucha gente de Chile en lo canal gracias a Germán del MTB enduro chile :) Saludo

[@rologti]

andrextr I found your channel looking info about the Spz Enduro, German also make some references to your channel with one of his videos...he is a very good rider! Congratulations!!!! you have make some great and useful videos!...lot of knowledge application and communication skills!!!

[@SteveGraber]

Another excellent video! I'm interested in watching your next video in this series where you will explain how to set up the software, perform analysis, etc. Have you uploaded it yet?

[@andrextr]

Yes, I have the stuff more and less prepared, but I have being postponing this ... I will try to finish it one day! :D

[@francodelvalle9948]

Excellent, Amazing!!! worthy of an engineer. Saludos desde Argentina

[@andrextr]

Gracias!! I'm a biochemist, not an engineer, by the way. :) Salu2 desde Portugal

[@HannyDart]

just got a completely new suspension set (boxxer with fast co3 and solo-air/canecreek double barrel) since these are not that easy to setup i will just watch all your videos and try to do what i think is best haha :D

[@andrextr]

+BAEMERZ eheh that's the way! :) I will talk about compression in the future :)

[@HannyDart]

andrextr i just switched from demo8 to norco aurum and their kinematics feel completely different so i need to readjust my whole suspension

[@andrextr]

+BAEMERZ yes you have to adjust the damping amount to match a different kinematics. For rebound damping check my Ep.5 and you will have a good starting point. For compression you have to tune on the trail. If you are bottoming put more HSC (+), if not, remove HSC (-). If you are wallowing under rider inputs, berms, pedal bob, etc, put more LSC (+). Always use the lowest compression damping as possible (without sacrificing too much the wallowing and bottom-out of course).

[@HannyDart]

andrextr ive already seen all the episodes :D (Y) gonna do my best to follow these instructions...but currently the weather sucks here so ill just wait a few days/weeks

[@andrextr]

Eheh! If you want to ride, come visit us at Portugal with www.weride.pt :D Winter, what winter? :D Stay tunned, a new episode will come in the next 24 hours :)

[@theodounis272]

I think that your videos are very technical can you do one on the fox Dyad RT 2 rear shock cheers 👍

[@andrextr]

+Theo Dounis Hello, its a late response but in my last video (Ep.14) I built a simulator with Dyad RT2 data. Check it out. bye

[@jesuisFORTIO]

you sound just like engineering explained :D

[@andreano81]

This is great approach. very curious about software and how good it works at high speeds.

[@andrextr]

+Andriy Gavrylenko I will continue this video in the next few days. It works quite well, specially if you are filming at 120 or 240 fps, and have a good light conditions, low perspective distortion (perpendicular angle) and a good tracking point (you can use a paper sticker).

[@addiuseighter]

I defenetly love your videos! please continue with the second part and more explanation!!! SO NICE VIDEOS

[@andrextr]

+addiuseighter Thank you ! :) More videos coming in the future :) Stay tuned!

[@addiuseighter]

+andrextr I also got a few questions :) would you answer your email Adress down this comment? :)

[@andrextr]

[e-mail]

[@trailseeker3722]

Haha, nice Go-Potato. Is that the silver or black version :D

[@animenatsu999]

wow your videos are amazing!!!

[@SewerynZeman]

+andrextr can you show few charts for different trail situations on "how should they look like"?

[@andrextr]

+Seweryn Zeman Yes, I'm preparing that data for a future video with an excell file to share with everyone to analyse their own data. But I still have other ideias for the next episodes though. But I hope to get there one day :D Bye

[@chrisgall4664]

Was there ever a follow up video to this or one on the Kinovea? Great stuff!!

[@andrextr]

I dont think so. It was a crazy experiment 4 years ago :) eheh cheers

[@cryalowicki]

This is awesome... But I have some questions. Maybe you'll answer them in future videos so if so please disregard. Will you be showing us how to use the software? And wouldn't fisheye distortion from the lens affect the data?

[@andrextr]

+Cory Yalowicki Hi Cory! Yes I would address that issues in the next videos. I will show you how to work with the software, calibrate the software, and correct the distortions. The fisheye is not the most relevant problem. The problem is the distortion caused by the perspective. Due to frame constrains, I was not able to film the shock at a perpendicular angle. So I had to correct the data in MS Excel. Stay tuned :)

[@andrextr]

+andrextr But anyway, the distortion would not affect the "behavior" of the graph, it will only affect the magnitude of the values (the scale).

[@mpirretti]

Wow, this is really cool. Seems like it could be a scientific way to setup spring rate, rebound, and low speed compression damping. Or do you prefer some other method instead?

[@andrextr]

You can use the curb test to setup the rebound in a “scientific” way... see episode 5 of my series. The spring rate is adjusted using SAG. The low speed comp is the only variable that is more subjective and it depends on trail types (i also have a vid about that)

[@ovodo16]

Awesome, many thanks for sharing your knowledge. Are you an engineer?

[@andrextr]

Thank you! No, my background is on medical sciences, but I always liked physics and mountain bikes :)

[@ovodo16]

Thats great! An other question: does kinovea give you the option to plot the distance-time and velocity-time graphs or you used an other program?

[@andrextr]

Yes it does. And you can export to excel. When I did this video I also build an excel tool to calibrate the distortion of the camera, and to plot histogram graphs and so on...but I never published that, if you are interested tell me. Here's an example of an histogram analysis of a 3min descent on a flow trail ep1.pinkbike.org/p4pb14365161/p4pb14365161.jpg

[@ovodo16]

I own a norco aurum and looking at the frame design I think It will be pretty tricky to fit the camera in a good and precise position.. I may need some help once I have the videos, but I' ll let you know. Thank you again!

[@jamilabbas6384]

Thanks so much or this great method. I'm in the process of trying it out for motorcycle racing applications. What software did you use for the animated time based graphing in your video?

[@andrextr]

Hi! In this video I used the Tracker software, but I found out later that there is a better free software to track the suspension. It's the Kinovea. It is much faster to process the video. You can see the graphs on that software or export the data to excel and make the graphs (like I did). This method has some limitations but for a free method is pretty nice. My advise is to use a high-contrast circle sticker on the suspension in order to the software track better that point. The camera should be as perpendicular as possible to the suspension in order to reduce image distortion. Also, it should be tightly fixed to the frame in order to reduce vibrations (which can affect the result). Another advise is to start with small videos since a 2min video can take 5-15min to process depending on the PC specs, and sometimes you can run out of memory with bigger videos (with Tracker this happened to me, with Kinovea I dont remember). Filming with 120fps is ideal since you can see better the high-speed movements. Bye

[@guillechiappero651]

Hi Andre. Could you recomend me a support to mount the camera in the downtube? Kind Regards Guillermo

[@messiasbapbaptista353]

Excelente video! Parabens, pela dedicação! Um abraço

[@andrextr]

Obrigado!

[@massimomusso8863]

tnk Bro, amazing explanation ;)

[@VttattitudeNet]

Great job and great video, that system is very interesting. I didn't know that such software were free. The potato limitation acquisition rate of 60 (or 120) fps dosen't seem to be a problem.

[@andrextr]

+VTT Attitude Hi thank you! I'm testing a new free software (Kinovea) which seem to be better than Tracker. I will make a full tutorial video at the end of the week with the updated info. Although you can use 60Fps, with 120 or 240fps you get a better temporal resolution. That extra FPS can be important when tracking the front fork, since the forks can get velocities 3x times higher than shocks (you can reach compression velocities higher than 4 meters per second, or 150 IPS). With that velocity that means that if you film at 60 Fps, the suspension moves 64mm in each frame! So you get low resolution. Bye :)

[@Jukis82]

@@andrextr Hey. I guess you never made the tutorial? Cant find it. Anyways thank you for this video, I just started doing with my own setup for gopro-daq.

[@andrextr]

@@Jukis82 Never finished it... :) Good luck :) Use Kinevoa software instead (in description). Its much faster. Cheers

[@premiumboard21]

Hy, Andre what do you thought about "missmatching" front travel by 40mm would it potentially broke the frame? I'm really wondering about that and i believe you are right person to ask.

[@andrextr]

Its a bit too much... it would make the bike a bit unbalanced imo.

[@premiumboard21]

@@andrextr so, would i potentially damaging the frame?

[@andrextr]

I dont know which frame do you have, but yes, a much longer fork can cause more stress in the frame... if it breaks or not it’s impossible to know... that depends on the impact, your weight etc...

[@valentincunchon6385]

incredible work !!

[@flyingchic3n]

buying a full sus just so i have a reason to collect the shock data

[@godtux]

This is a very nice idea. I will put it to use for sure. did you tried the kinovea free software ?

[@andrextr]

+godtux Hi! Thank you! No, I didn't know that software! Does it offer an auto-tracking feature? I can test that in the future :)

[@godtux]

+andrextr Yes it does. Open source also.

[@andrextr]

+godtux Wow! I'm trying the Kinovea software, and it seems better than the "Tracker". I'm still testing. If Kinovea is better I will share you suggestion in the next video for sure. Thank you! :)

[@AltPrizm]

EPIC work !!!!! ;0 :)

[@goncaloareias98]

Muito bom Sr Engenheiro :D

[@stoenchu122]

Do you have any master degree in something or you just read stuff about bike`s mechanics? Great video, again.

[@andrextr]

+stoenchu122 Hi again! Yes, actually I have a PhD in biology... lol... But it's not related with this... I like physics, and bikes are my passion. I always wanted to demystify and understand how suspension works. I had the ideia of this video 2 weeks ago just by chance... Then I found the Tracker software and it worked like a charm! :D It was a nice "Eureka" moment for sure :)

[@Carecovzki]

I like that go potato, does it shoot in 4K? :p

[@andrextr]

+Carecovzki No, it's a Silver potato, only 1080p :D

[@Carecovzki]

+andrextr you should try the new small potato session, hahahaha

[@wlt3r]

Very cool.

[@andrextr]

+Walter Sorenson Thank you! :)

[@architf1]

Does this method work with smartphone cameras with stabilisation?

[@andrextr]

It works with any type of video but the results are better with good quality videos with low distortion good ligth and a tracking point of high contrast in order to software make a good motion tracking

[@Nickporter17]

andrextr I wish you were still making videos. They are great!

[@Nickporter17]

andrextr it seems like bike tech has taken off over the last few years, curious what your thought are on all the changes.

[@maqusss]

Would you do video on high pivot vs low pivot?

[@andrextr]

+maqusss Sorry, I didn't understand the question... Is it related to this video, or do you want me to compare some particular bike? Bye

[@maqusss]

andrextr It would be great to see your comparition of bikes with high pivot frames to low pivot bikes. High pivot like Peregrine DH www.pinkbike.com/photo/12910081/ or Zerode G2, to low pivot like Orange 322, or basicly every thing else because almost every other frame is low pivot.

[@andrextr]

+maqusss yes, already did for commencal DH v4. And i will do it for zerode soon. And I will do a episode about brake squat where I will talk about high pivots. Basically high pivot tipically have an higher brake squat and they have a lot of chain growth unless they use a idler pulley. The best thing is the rearward axle path.

[@andrextr]

+maqusss Zerode G2 here: kzbin.info/www/bejne/bHepp2imrpqih6c

[@maqusss]

yupi, thx :)

[@unpocodetodofuerzayhonor6061]

🙌🙌🙌🙌🙌🙌🙌🙌🙌🙌👏🏼👌

[@andrextr]

UnPocoDeTodo Fuerza y honor 👍👍👍👍👍👍👍👍👍👍😂

[@Jwachter146]

It’s not really free if you need to use a $300 camera to acquire footage.

[@SuperSSystem]

a face that want to be punched