Spring Stiffness

How do car manufacturers decide how stiff to make the springs in their cars? This video will explain the process and the math behind the choices OEM's have to make when deciding what springs to use.
Chapters:
Introduction 0:00
Ride Frequency 0:56
Measuring Ride Frequency 2:15
New Car Designs 3:06
Spring Motion Ratio 3:58
Using the Spring Motion Ratio 5:11
The Effect of Bushings 7:17
Calculating Spring Stiffness 8:05
One More Check 10:20
Effects of Increased Ride Frequency 12:03
Other Spring Types 15:03
Impact of Air Springs 15:51
Suspensions Explained
Huibert Mees

Пікірлер: 45

  • @SylvesterOziomek
    @SylvesterOziomek2 ай бұрын

    I am impressed with the quality of the information in this video, I've seen a lot of those but this one is the best. Variations, typical values, presentation and especially example calculations makes the topic easy to digest. This is how every video explaining car topic should look.

  • @BimmerDrives
    @BimmerDrives4 ай бұрын

    Amazing video! Please target adaptive damping next, and talk about how quickly it works when you hit an undulation in the road. Also how much better it really is vs a well-tuned passive setup.

  • @JoeGezahegn
    @JoeGezahegn4 ай бұрын

    Excellent video! Could you make a video on chassis torsional stiffness? If the spring rate is affected by the stiffness, how OEM improve stiffness in a unibody, what is the target stiffness in Nm/degree, etc.

  • @suspensionsexplained

    @suspensionsexplained

    4 ай бұрын

    I'm glad you enjoyed it. Chassis stiffness is on the list of topics I will cover in the future.

  • @JoeGezahegn

    @JoeGezahegn

    4 ай бұрын

    @@suspensionsexplained thank you sir! You are doing the lords work with these videos

  • @confuzionn4843
    @confuzionn48434 ай бұрын

    thank you so much for making these videos. I have struggled to find someone who adequately breaks down the math and the concepts in a video without either being fully conceptual, or fully mathematical. as a student engineer, this makes understanding suspension design so much better.

  • @IgnitionP
    @IgnitionP12 күн бұрын

    Really useful, the explaination is brilliant. Ps. I love the GT40 in the back

  • @audaxrallymedia
    @audaxrallymedia4 ай бұрын

    I don't know how this world was made. But now i am a Suspension Engineer. And i realize how it's advisable could for me years ago. Brief Strait and Easy to get. Keep Going with your channel!

  • @mampe4122
    @mampe41224 ай бұрын

    I'd always wondered about the squared component of the motion ratio, but never quite enough to understand. thank you for clearly stating why this is.

  • @leandrolefa
    @leandrolefa4 ай бұрын

    Your videos are amazing! I don't know how much time it takes you to prep, record and edit... But the resulting video is packed with clear information. Thank you so much for making these!

  • @thatopendiffdude9109
    @thatopendiffdude91092 ай бұрын

    Fantastic channel!!! Youre doing a great job, dont stop making videos

  • @claykossmeyer3868
    @claykossmeyer38684 ай бұрын

    Very good explanation, really enjoyed the examples. A topic for another day, but would love to see you go over the Jaguar E-type IRS and what made it so great.

  • @suspensionsexplained

    @suspensionsexplained

    4 ай бұрын

    A friend of mine just got finished restoring a series 2 E-Type so the idea of doing a post on that IRS is already there. But thank you asking for it. The design was revolutionary for its time, but we've learned a lot since then.

  • @marcos1669
    @marcos16694 ай бұрын

    Awesome video, can you do a video talking about mechanichal grip?

  • @user-rd5nc1nb9f
    @user-rd5nc1nb9f4 ай бұрын

    amazing videos honestly. i hope you can make a video about dampers too. am trying to make my car ride waaaay better through stuff like chassis modification tire selection and suspension redesign but its all very confusing and its hard to get real data and formulas or even ways to quantify subjective stuff like you did in this video

  • @spiky29
    @spiky293 ай бұрын

    Great explanation. But i have 2 points for improvement: 1. When calculating mass on specific corner...you forgot to substract unsprung mass..it changes final spring stiffnes quite a bit. 2. Rebound/full extention can also be solved with helper springs.

  • @suspensionsexplained

    @suspensionsexplained

    3 ай бұрын

    You are right on both counts. In trying to keep things a bit simple, I didn't include unsprung mass but I think I went too far.

  • @spiky29

    @spiky29

    3 ай бұрын

    @@suspensionsexplained yt has a lot of amater videos. It's hard to find really in-depth explanations of things on varoius topics. I know it has to be adjusted for viewers..to still be understandable & interesting. But i would rather watch super indepth video..even if i have to watch it 5x to understand, rather than something i already heard. But thats just me.

  • @wordsshackles441
    @wordsshackles4415 күн бұрын

    Fantastic, thank you.

  • @VolumetrikHD
    @VolumetrikHD4 ай бұрын

    Thank you! Clearly presented with concrete examples.

  • @artempavliuchenko1815
    @artempavliuchenko18154 ай бұрын

    Outstanding video! It deserves thousands of views

  • @maksimd6033
    @maksimd60334 ай бұрын

    Thanks! Could you please make special video about: 1. Rubber bushings stiffness; 2. Arms, subframes, knuckles stiffness; 3. Hydrobushings in suspension; 4. Ball joints stiffness, torques, design?

  • @leandrolefa

    @leandrolefa

    4 ай бұрын

    Do you want fries with your order?

  • @suspensionsexplained

    @suspensionsexplained

    4 ай бұрын

    Thank you. Most of the topics on your list are on my list for future videos.

  • @davepax982
    @davepax9824 ай бұрын

    Thanks for posting this. It's clarified many things. Can i be bold and ask if you can cover the topic of damper valving and its effect on ride quality and handling?

  • @nostamine2567
    @nostamine25674 ай бұрын

    Incredible video content sir , but it would be great for future videos to make some Lego equivalent structures to better show the concepts . Usually people tend to understand things better when they see stuff moving around , especially in mechanical engineering and suspension design, i myself learned a lot of simple concepts like KPI , caster , camber gain , multilink steering , motion ratios and lots more just by putting together a bunch of plastic parts ! Other than that its great , love from Romania !

  • @suspensionsexplained

    @suspensionsexplained

    4 ай бұрын

    I've thought about this as well but I find Lego or even RC car suspensions to be too limiting in what I can achieve in terms of geometry. I hoep the computer models are clear enough to illustrate what I am talking about.

  • @mry82
    @mry823 ай бұрын

    👍😀

  • @samcastevens8044
    @samcastevens80444 ай бұрын

    Great video as always! Just to be sure, the Mass in the ride frequency formula represents only the fraction of the car's total unsprung mass that is supported by one spring?

  • @suspensionsexplained

    @suspensionsexplained

    4 ай бұрын

    Yes, that is correct.

  • @samcastevens8044

    @samcastevens8044

    4 ай бұрын

    Thanks!

  • @cam3002
    @cam30024 ай бұрын

    Assuming an equal distribution of weight front to rear (50/50) and similar motion ratios, should the front and rear have the same (or at least similar) spring rates? My observation is that all front engine, rear wheel drive cars I've see have significantly softer springs in the rear. To be more specific, the various generations of Mazda MX5 have near 50/50 weight distribution.

  • @WCHADWICK

    @WCHADWICK

    4 ай бұрын

    I too wondered this as my NB’s current springs are 33% stiffer on the front axle. EDIT: Having looked at the front and rear suspension arms, I’m fairly confident that this difference in spring rate is due to the different lower suspension arm geometry between the front and rear. I say this as between the inner and outer bushes (the dimension that is 100mm in this video) the measurement is 336mm with a motion ratio of 0.71 for the front suspension, whilst the rear suspension is 393mm (also with a motion ratio of ~0.7). However, as 393mm is only 17% larger than 336mm I’m not entirely convinced this is the whole picture… Potentially wheel offset (which I’ve not accounted for) could make up some of the remaining difference?

  • @suspensionsexplained

    @suspensionsexplained

    4 ай бұрын

    I didn't get into this in the video but generally speaking, most cars will have a rear ride frequency that is about 20% higher than the front. That is not a hard and fast rule but in general you will find this to be true, especially in sedans or other passenger cars. The reason is that since the front wheels hit a bump first and start moving up and down first, the rear needs to be a little stiffer so that once the rear hits the bump, the rear oscillations "catch up" with the front and even out so that car moves more or less up and down vertically and not like a porpoise. The NB may not follow this general rule for reasons only Mazda knows.

  • @WCHADWICK

    @WCHADWICK

    4 ай бұрын

    @@suspensionsexplained interesting, thanks!

  • @shootinbruin3614
    @shootinbruin36144 ай бұрын

    Fantastic explanation! If I may ask, what are the effects of preload on ride quality? Please correct me if I'm wrong, but from my understanding, preload isn't a factor unless the suspension is almost completely unloaded. But in the case of a deep pothole--or in a more extreme example, a jump--how does preload affect harshness when forces begin to compress the suspension? I ask this because from what I understand the suspension does not begin to articulate upwards until preload is overcome. Does this mean that until the force compressing the suspension is sufficient to begin upward travel, the impact of the tire with the road isn't mitigated by the spring? If so, how would one minimize the harshness of this impact within the limited suspension travel of a typical car?

  • @suspensionsexplained

    @suspensionsexplained

    4 ай бұрын

    The preload in the spring is only just enough to hold up the weight of the car. Any additional weight, be it in the form of added weight in the car like passengers or added force coming up from the road, will cause the spring to deflect. The force doesn't have to overcome the preload. If that were the case, you would not be able to move a car up and down simply by pushing on it with your hands. It is a simple spring/mass system and any force applied to the mass will cause deflection in the spring, no matter how small the force.

  • @shootinbruin3614

    @shootinbruin3614

    4 ай бұрын

    @@suspensionsexplained I appreciate the answer. Thank you for taking the time

  • @bobbyalley86
    @bobbyalley863 ай бұрын

    Great video! What the highest ride frequency you've seen on a street car? I know some racecars can be well over 2hz, but how crazy is that to run for a street setup?

  • @suspensionsexplained

    @suspensionsexplained

    3 ай бұрын

    I really haven't seen much beyond 1.7-1.8 Hz in a street car although if memory serves, I think the Honda S2000 may have been at 2 Hz.

  • @bobbyalley86

    @bobbyalley86

    3 ай бұрын

    @@suspensionsexplained Thanks for the info! What was the Ford GT?

  • @TranceFur

    @TranceFur

    2 ай бұрын

    Looks like the Ford GT’s is around 1.75 hz.

  • @JoJoDo
    @JoJoDo4 ай бұрын

    12:22 Oops!

  • @chithraiselvan7755
    @chithraiselvan77552 ай бұрын

    if you increase the speed of your push there is a chance the no of cycle would go up isnt it ?

  • @TranceFur

    @TranceFur

    2 ай бұрын

    Yes, but that would be due to an outside force. It would take a great deal of outside force (and be very difficult by hand) to make a car oscillate at a frequency other than its springs natural frequency. This would never happen in a driving scenario.