I agree totally that to change spring rate you need to change the spring however to my understanding if you add pre load this will reduce the travel in the spring therefore will reduce load/weight transfer which will affect the handling/braking/accelerating. I should also note changes to pre load only makes a small difference compared to installing the next size up spring rate (which would have a added bonus of no reduced travel). so preload to my understanding is basically used to fine tune the balance. at least this how I currently understand it. If this is not true can someone please explain why? just trying to get a better understanding cheers.
that might happen with progressive spring. If you have a linear spring which has the same spring constant through the whole spring, nothing will change. Nothing will change because if you start from higher position or lower, since constant is the same it will act as if nothing happened(because it didn't), it just got visually compressed. The ratio didn't change so the same amount of pressure will result in the same amount of travel no matter how compressed or relaxed the spring is. Unless the coils are so close to eachother that they start to sit on top of eachother haha Hope that helps.
When the spring is a little preloaded, doesn't the total amount of droop travel available reduce? If the spring rate is quite high, and there is only (say) 45mm droop travel available, wouldn't winding the perch up by 20mm, reduce the available droop travel to just 25mm? Couldn't that affect handling negatively if one of the wheels was to fall into a pothole deeper than 25mm?
yes, you're correct. This is a lot more complicated than "everyone else is doing it wrong you must use the spring perch to make adjustment." Preload the crap out of one corner more than another to get your corner weights in check and now you'll have one corner of the car contacting the bump stops way later than others = botched roll couple distribution. Especially important for cars utilizing bump stops as "spring supporters" that rely on 1-2" of bump stop compression to increase roll stiffness. I'd rather keep my bump/droop distribution even at all 4 corners. For this reason, I think the "height" adjustment of the coilover IS the best place to make these adjustments vs using the spring perch. Just don't adjust yourself into the wheel well liner...
So, how do you determine what the proper length of the shock stroke is? I need to put adjustable dampers on my car, I understand setting the shock base height so I'm not bottoming the shock after other contacts. But what about droop? Factory shocks have so much travel. Is it bad to be limiting the droop to a point that the car is at full extension at high g? Is this acceptable to control body roll?
No because the static deflection will be the same (sprung weight acting on the spring) , but if you add helper sprung that will increase your rebound stroke while decreasing your bump stroke , because helper spring fully collapses under weight
There's another critical problem with preload. As you come off the back side of a bump (with the chassis being bounced upwards), the spring is supposed to push the tire down onto the ground to keep it in contact. If it's overly preloaded, the spring instead hits the maximum length of the suspension and the wheel gets pulled up off the ground by the chassis. Very bad in a corner.
which is why when you buy a set of MCA shocks, they give you instructions to length the base height to compensate for excessive "preload", or more accurately known as raising the car via spring perches
Here’s a question, if I load up my UTV bed with weight and the result is the shocks compressing to near bottoming out, can I use preload to get some shock travel back?
There is a direct relationship between perch position and bump travel. If you move the perch 1 cm, bump travel will change 1 cm. So yes, if you can afford some reduction in droop and would like your vehicle to sit 1 cm higher, go ahead and add 1 cm of preload.
This is great stuff i wish there were more videos like this on setup, the hardest part of trying to understand how suspension works is being able to visualise it as most explanations become far too wordy and technical to follow. So am i correct in understanding that in this example you have corrected the restricted bump travel by lowering the base height? Then assuming the car had the desired fender gap would you then follow this and compensate for the ride height change by adjusting the spring preload accordingly? Just as you would have if you had adjusted the height by the spring preload then compensated by adjusting the base height?
The info on preload fails to discuss stored energy. Correct the rate will not change but the amount of stored energy does with a change in the amount of preload.
I thought the same thing, conceptually, but,"stored energy" has no affect at all on the return rate of the spring. The suspension will droop at exactly the same rate as it compressed, regardless of preload. There will still be "stored energy" in the spring, true, but, that will only come into play when the tire is completely in droop (catches air). When the tire re-makes contact with the ground that preload will make the car effectively stiffer until the initial preload amount has been overcome. Not too sure if there are any handling implications of this. I thought there was but now that I think about it more I don't think it will have any effect. You can prove to yourself the above by plotting an example. Corner weight = 700lb. 700lb/350lb spring = 2" of rebound travel. preload that 350lb spring by 1in. Now you have (700-350)/350 = 1in rebound. You've changed your bump/droop distribution, and the "stored energy" in the spring, but, so long as the tire is on the groudn the spring loads/unloads along the exact same slope (y=mx+B).
Erm not entirely true. Increasing preload can raise the ride height of the car and reduce droop, which will have an effect on the ride comfort as well as handling due to a higher cog.
Bullshit. Base height adjustment does not affect bump travel if you're not hitting the chassis. The amount of preload will affect the sag and thus how much compression stroke you have available from static height. Too much preload (to achieve desired ride height) means not enough droop travel.
In reply to the first part of your statement, I think what you’re trying to say is that it’s ok to use base height adjustment as long as there are no major contact issues? Whilst it could be argued that this is true if there are no safety concerns, the fact is that most people will not know if the shocks are currently setup in a way that could potentially cause these safety concerns, because it wasn’t setup correctly by the manufacturer in the first place. The other potential issue is who is to say the amount of bump travel you have is enough? One issue is too much travel, but a separate issue is not enough to function/perform properly. It’s about having the correct amount of bump travel, which in most cases is as much as possible before any contact issues. Even in cases where there is room for more bump travel than will be practically used or be able to be used, it’s still good to know this and know that your suspension is still setup appropriately. One of the major issues with base height adjustment is the lack of knowledge as to how it’s actually setup and what’s really happening and able to happen. In reply to the second part of your statement which is primarily about the potential for insufficient droop travel, yes it’s possible that if you raise the vehicle too much by the spring seat it could result in insufficient droop travel. However, this is only possible if the amount of droop travel is ignored by both the designer/manufacturer as well as the installer. When we design our suspension products we build them in a way that provides sufficient droop within a large range of height adjustment. Having more droop is no problem so for lower ride heights it will have more than it needs, but at higher ride heights it will still have enough. On our install instructions, we also specify a certain amount of droop as being a minimum required amount. If the customer requires a ride height that will mean this minimum droop is not achievable, then it tells the installer to use the spring seat until the minimum droop is achieved and then do the rest using the bottom mount. However, this is not a normal situation for installers of our products to find themselves in as we design our shocks to be able to achieve factory ride height or close to factory ride height without the need for bottom mount adjustment. The reasons that it’s ok for the bottom mount to be used in this scenario is because a) the amount of bump travel is known to be plentiful and more than enough for the desired application and b) the amount of bump travel is known to not be too much and so no contact issues can arise. My answers are based around normal passenger vehicles such as sedans, coupes, wagons, etc. Not 4x4 utes or offroad vehicles. Whilst the principles are essentially no different, some of my comments that relate to our products might differ if we were referring to offroad vehicles, such as instead of aiming for factory ride heights as an upper limit, we’d be designing them for a certain amount of lift.
Thanks a lot MCA, we support 2 cars in rally gravel and always make podium with your suspension product..🙏🏻
The loose connector at 4:20 is brilliant
I really enjoyed the wheel position demonstrator 9000, and the CGI. I also learned something. Bravo.
The spring preload myth used to get me, until I recalled Hooke's Law from high school physics.
this music!!!! plz keep it and make a whole series on this!!! its really informative and interesting
I agree totally that to change spring rate you need to change the spring however to my understanding if you add pre load this will reduce the travel in the spring therefore will reduce load/weight transfer which will affect the handling/braking/accelerating. I should also note changes to pre load only makes a small difference compared to installing the next size up spring rate (which would have a added bonus of no reduced travel). so preload to my understanding is basically used to fine tune the balance. at least this how I currently understand it. If this is not true can someone please explain why? just trying to get a better understanding cheers.
that might happen with progressive spring. If you have a linear spring which has the same spring constant through the whole spring, nothing will change. Nothing will change because if you start from higher position or lower, since constant is the same it will act as if nothing happened(because it didn't), it just got visually compressed.
The ratio didn't change so the same amount of pressure will result in the same amount of travel no matter how compressed or relaxed the spring is. Unless the coils are so close to eachother that they start to sit on top of eachother haha
Hope that helps.
@@Saugusari11 The same force causes the same travel, but there is less of that travel.
When the spring is a little preloaded, doesn't the total amount of droop travel available reduce? If the spring rate is quite high, and there is only (say) 45mm droop travel available, wouldn't winding the perch up by 20mm, reduce the available droop travel to just 25mm? Couldn't that affect handling negatively if one of the wheels was to fall into a pothole deeper than 25mm?
yes, you're correct. This is a lot more complicated than "everyone else is doing it wrong you must use the spring perch to make adjustment." Preload the crap out of one corner more than another to get your corner weights in check and now you'll have one corner of the car contacting the bump stops way later than others = botched roll couple distribution. Especially important for cars utilizing bump stops as "spring supporters" that rely on 1-2" of bump stop compression to increase roll stiffness. I'd rather keep my bump/droop distribution even at all 4 corners. For this reason, I think the "height" adjustment of the coilover IS the best place to make these adjustments vs using the spring perch. Just don't adjust yourself into the wheel well liner...
Yes, that's why you adjust the bottom collar to add more droop. MCA states to have a minimum droop of 50mm.
"DANGER TO MANIFOLD!!!" had me in stitches :D:D
Excellent work!
So, how do you determine what the proper length of the shock stroke is? I need to put adjustable dampers on my car, I understand setting the shock base height so I'm not bottoming the shock after other contacts. But what about droop? Factory shocks have so much travel. Is it bad to be limiting the droop to a point that the car is at full extension at high g? Is this acceptable to control body roll?
plz keep these coming!
This is surprisingly informative and hilarious :D, please make more.
Will the spring concept in this video change if the spring was replaced with a longer spring? Thank you
A longer spring with the same diameter and coil pitch will be softer.
No because the static deflection will be the same (sprung weight acting on the spring) , but if you add helper sprung that will increase your rebound stroke while decreasing your bump stroke , because helper spring fully collapses under weight
There's another critical problem with preload. As you come off the back side of a bump (with the chassis being bounced upwards), the spring is supposed to push the tire down onto the ground to keep it in contact. If it's overly preloaded, the spring instead hits the maximum length of the suspension and the wheel gets pulled up off the ground by the chassis. Very bad in a corner.
which is why when you buy a set of MCA shocks, they give you instructions to length the base height to compensate for excessive "preload", or more accurately known as raising the car via spring perches
If everyone read the instructions, this video wouldn't exist in the first place though :P
Here’s a question, if I load up my UTV bed with weight and the result is the shocks compressing to near bottoming out, can I use preload to get some shock travel back?
unlikely. increasing preload only makes a small difference. you will need stiffer springs
There is a direct relationship between perch position and bump travel. If you move the perch 1 cm, bump travel will change 1 cm. So yes, if you can afford some reduction in droop and would like your vehicle to sit 1 cm higher, go ahead and add 1 cm of preload.
This is great stuff i wish there were more videos like this on setup, the hardest part of trying to understand how suspension works is being able to visualise it as most explanations become far too wordy and technical to follow.
So am i correct in understanding that in this example you have corrected the restricted bump travel by lowering the base height? Then assuming the car had the desired fender gap would you then follow this and compensate for the ride height change by adjusting the spring preload accordingly? Just as you would have if you had adjusted the height by the spring preload then compensated by adjusting the base height?
This is how I understood it. Use the base height to set maximum travel (so full bump clears the frame) and set height using the spring.
The info on preload fails to discuss stored energy. Correct the rate will not change but the amount of stored energy does with a change in the amount of preload.
I thought the same thing, conceptually, but,"stored energy" has no affect at all on the return rate of the spring. The suspension will droop at exactly the same rate as it compressed, regardless of preload. There will still be "stored energy" in the spring, true, but, that will only come into play when the tire is completely in droop (catches air). When the tire re-makes contact with the ground that preload will make the car effectively stiffer until the initial preload amount has been overcome. Not too sure if there are any handling implications of this. I thought there was but now that I think about it more I don't think it will have any effect.
You can prove to yourself the above by plotting an example. Corner weight = 700lb. 700lb/350lb spring = 2" of rebound travel. preload that 350lb spring by 1in. Now you have (700-350)/350 = 1in rebound. You've changed your bump/droop distribution, and the "stored energy" in the spring, but, so long as the tire is on the groudn the spring loads/unloads along the exact same slope (y=mx+B).
That music! :P
What about style vs bump travel/reserve? :)
As i would understand this, then ride height adjustment is very limited
Can u make a video i dont have to watch I want to listen in the back round 😅
Erm not entirely true. Increasing preload can raise the ride height of the car and reduce droop, which will have an effect on the ride comfort as well as handling due to a higher cog.
Bullshit. Base height adjustment does not affect bump travel if you're not hitting the chassis. The amount of preload will affect the sag and thus how much compression stroke you have available from static height. Too much preload (to achieve desired ride height) means not enough droop travel.
In reply to the first part of your statement, I think what you’re trying to say is that it’s ok to use base height adjustment as long as there are no major contact issues? Whilst it could be argued that this is true if there are no safety concerns, the fact is that most people will not know if the shocks are currently setup in a way that could potentially cause these safety concerns, because it wasn’t setup correctly by the manufacturer in the first place. The other potential issue is who is to say the amount of bump travel you have is enough? One issue is too much travel, but a separate issue is not enough to function/perform properly. It’s about having the correct amount of bump travel, which in most cases is as much as possible before any contact issues. Even in cases where there is room for more bump travel than will be practically used or be able to be used, it’s still good to know this and know that your suspension is still setup appropriately. One of the major issues with base height adjustment is the lack of knowledge as to how it’s actually setup and what’s really happening and able to happen.
In reply to the second part of your statement which is primarily about the potential for insufficient droop travel, yes it’s possible that if you raise the vehicle too much by the spring seat it could result in insufficient droop travel. However, this is only possible if the amount of droop travel is ignored by both the designer/manufacturer as well as the installer. When we design our suspension products we build them in a way that provides sufficient droop within a large range of height adjustment. Having more droop is no problem so for lower ride heights it will have more than it needs, but at higher ride heights it will still have enough. On our install instructions, we also specify a certain amount of droop as being a minimum required amount. If the customer requires a ride height that will mean this minimum droop is not achievable, then it tells the installer to use the spring seat until the minimum droop is achieved and then do the rest using the bottom mount. However, this is not a normal situation for installers of our products to find themselves in as we design our shocks to be able to achieve factory ride height or close to factory ride height without the need for bottom mount adjustment. The reasons that it’s ok for the bottom mount to be used in this scenario is because a) the amount of bump travel is known to be plentiful and more than enough for the desired application and b) the amount of bump travel is known to not be too much and so no contact issues can arise.
My answers are based around normal passenger vehicles such as sedans, coupes, wagons, etc. Not 4x4 utes or offroad vehicles. Whilst the principles are essentially no different, some of my comments that relate to our products might differ if we were referring to offroad vehicles, such as instead of aiming for factory ride heights as an upper limit, we’d be designing them for a certain amount of lift.
Please loose the music and just talk about what is going on.!
we will keep this in mind for the next video, thank you for the feedback.
@@mcasuspension3976 thanks for considering this
@@mcasuspension3976 No, it was pure perfection! This is the video that saves us :D