Keep these coming! As an engineer but not a hardcore 4x4 guy I’ve always understood what’s happening with these things but NEVER see any of the ‘reputable’ sources talk anything like this with detail and actual facts and proof on the vehicle. I LOVE IT!
Good info. I'm in the process of fitting 35's without adding any additional lift to what I already have. This video helps! I'm a firm believer of "Lift as much as needed but as little as possible" (~Roger Brown)
this is my thought process. i have a 2019 tundra with about a 2.75" preload collar lift and 285/75R18 tiree. just under 35" tires and didnt have to do any type of BMC or wheel spacers or anything. i can turn full lock and have no rub at all. no need to go any higher cuz its absolutely pointless!
Every couple years i want to lift my wife tacoma. Already at 31"s with stock ride height due to fab fours front bumper. Eventually i get to this dudes video and decide i'm not messing with IFS.
Well, like many of us I subscribed to some YT 4x4 or car addicted channels but I've never seen before such a technical complete explanation. Everything discussed with a cristal clear ease. Hope You'll find the time to propose further videos. You made my day!
I drive a solid axle chevy and I found this video very interesting to watch. Very well put together, no unnecessary bullshit or fucking around, just straight to the facts with "why and how" just like you said!
I love these videos.im no engineer.but im sure i understood this right.i own a prado 120 or in the states lc120.i put a 2inch dobinsons imf lift which has 150psi or 110 psi in the shocks downwood pressure stock i think 60 or 70, i had no draws in the back and i had a arb bullbar non winch. The ride was stiff and hitting bumps was more of a thud then the suspension taking the impact plus it was a little more lighter in the steering wheel. So the car wasnt traveling up and down much. I since added draws and changed the bullbar to a arb winch bar with winch. Since the upgrades the car has a softer ride and flexes better too. I put this down to the extra weight as the car was too light for the dobinson springs and shockers.i was going to go back to see if the car has lost ride height since the upgrades to reajust the front height.but the ride feels better. Is this about right with this video? Or am i way off? Cheers
What you're experiencing is probably not exactly what I described in the pre-load topic. For dynamic situation, it's all about matching of spring, mass and damper. This is much more complex and I didn't mention in this video. So I think your case is mostly a mismatch of the 3 parameters, but later fixed by added mass.
This clears so many misconceptions up. I feel kinda conned now about my ironman suspension being an "upgrade" even though I know it is on ride qualify. Seriously thought I was getting more articulation tho.
This video is really great, very clear. Your IM lift is fine (as are the competitors). You just want to make sure you have the proper spring (not too firm or soft, based on weight), and you don't preload the bejezus out of the front for more lift. 2" is a great compromise for toyota IFS -- the CVs will be at a comparable angle (except down instead of up -- if you look, you'll see the CVs aren't actually straight on stock either, at least mine wasn't). 3"+ limits more down travel, and creates more potential stress on the CVs. These lifts aren't really about articulation unless you start doing some serious fab work. They're just for adjusting down the relative range of travel to improve average ground clearance. Most IFS lifts are mostly limited by the IFS itself, not the lift hardware.
Good video, reality check for my 2000 lc 100 series. Can’t imagine I have more travel with torsion bars. Would be interested in a video on how much “long travel” gains you. Or if it just shifts the same ish travel down lower.
long-travel should move all of the suspension components away from the frame of the car and should allow for more articulation, hence why with long travel most people have to change out their fenders too.
@@Weegeegangstaz I could be wrong but it looks like just longer A arms and cvs. Like mind travel ish. So wheel is lowered from the frame but also wider, I’d assume it can go up to stock levels. Then yeah fenders will need to be changed. Haven’t seen one up close, but it looks like the only gain is the longer reach down. Personally when my upper A arms are at max droop they hit the mount. Only thing I can see would be longer arms and or adding a bend. Or altering the upper A arm mount which is possible
@@mondo_stunts27 What ones are you looking at? Opt offroad has some good pictures illustrating some pictures of the extended upper and lower control arms not sure on 100 series as I have a 3rd gen 4runner. So there's a travel increase with the further length you go away from the frame. Hence why in this video he was saying it was a 1/2" strut spacer equates to ~1" of wheel lift. throughout your wheel travel you want the wheel to stay as vertical as possible so when you extend this further away from the mounting point you get more vertical wheel travel. For example hold a pencil in the middle and move it up and down and watch the end as if it was a wheel traveling up and down, if you hold it at the other end and watch the other end you have more "travel"
That comparison video is in the making! Check out my Toyota Long Travel IFS video if you haven't already, where you'll see how the longer arms cycle and how much actual travel you get.
Howdie! I loved this video and have referenced it a few times in forums in regards to spacer lifts... ot no avail. The common opinion amongst offroad enthusiasts is that spacer lifts (whether they are preload or top hat) should be avoided because they "cause damage to components" or "makes the ride stiffer due to the spring compression" without any explanation that makes sense. Occasionally i'll find somebody articulate enough in forums asking the right questions to which everybody responds with the same traditional answers. So my question for you is this: can you explain, either in video or comment, if and how ALL spacer lifts could be bad for IFS (i know you already said preload spacers are the best option, but for arguments sake and accuracy)? If so, what kind of damage would be done by wheeling a truck with spacers. Thank you! Edit: additionally, if IFS systems that utilize integrated bumpstops in the top hat would fair any better with spacer lifts?
Great explanations to a complex subject. I'd love to hear something similar about the suspension geometry on the new Land Rover Defender. How does it compare to up and down travel compared to Toyota IFS? Can you get more travel than factory? How do you get bigger wheels onto a new Defender?
Thank you for the excellent information! If I had known the information you provided when I purchased my 2018 4Runner, I would have NOT gone with the Readylift SST spacer lift. It includes the diff drop so the CV angles don’t look to bad. Correct me if I’m wrong, but isn’t the full droop supposed to be limited by the strut assembly? If that’s the case then I believe my droop is still limited by the strut, I just lost some down droop. Thanks
Thanks! Yes the droop supposed to be limited by the strut. But if you bolt a spacer on top of the strut, you make the strut longer by the spacer thickness. So the UCA ball joint is now limiting your droop before your strut fully extends. You don't lose down travel. You actually have too much down travel and is hurting other components.
Kai, why are bracket or knuckle lifts, such as a rough country frowned upon? They seem to move the top and bottom of the travel down, eliminating the rubbing issues at the top of the travel. Have you installed this style of lift, and compared it to a lift done with just coils and UCA’s
I guess the only thing not covered in this is how a rear lift (which does have a bigger overall effect on things as you discussed since it's a solid axle) interacts with the front lift when there's a high discrepancy with rake. Or are there also misconceptions with that? Seems like you debunk pretty much all of the "common knowledge" about Toyota IFS floating out there.
I have not tried it yet. But check out my KDSS video, in which i found the fixed swaybar link does not limit down travel during articulation (one wheel up, one wheel down). It only limits down travel when both front wheels are drooping at the same time, such as going air borne.
As a structural engineer, I am extremely impressed by the level of information and knowledge that is being passed along here. I am glad to have finally found someone that can logically explain why and how to lift our Toyota and Lexus vehicles. Amazing work, I look forward to your videos and the products you will be providing! ( just don't forget about us GX470 drivers)
I have a degree in Automotive engineering, I've worked for Aston Martin and McLaren racing as a design engineer. I also own a Toyota Hilux that I've modified and I want to congratulate your video. You make the points I've been trying to explain for years but you do so more eloquently than I usually do! Maybe I should carry a whiteboard with me... I upgraded my front suspension because the additional weight of a steel winch bumper and winch meant the OEM springs were struggling. I opted for Land Cruiser springs because they were available in the right rate but without lifting the front too much. Every other spring wanted a 2" lift which I didn't want because of driveline issues. It is very much worth mentioning that over lifting IFS usually gives the CV joints such a hard life at extreme angles then when a large torque spike is experienced (such as grabbing a rock off road after spinning in the air) that they usually fail way before a non lifted vehicle. Then whatever small advantage that clearance gave you is lost and more because you're now on a 3 wheel drive vehicle in a remote location! Hence why my ride height is back to near standard. 1“ higher than OEM. 1/2" from slightly larger tyres and 1/2" from the springs.... Its a close as I could get!
Really appreciate it and it's my honor to get validation from an actual automotive engineer! My career is mechanical engineering for product design, but I love to apply the fundamental principles to my passion in 4X4. Great point on CV angles. Now I want to ask you a technical question I've been pondering. It's regarding CV joint wear over highway driving (no off-road torque spikes). Generally, we relate bearing surfaces wear to pressure velocity (PV) limit. For a lifted full-time 4WD, highway driving will wear the CV because we have both pressure (torque) and velocity. However, what about part time 4WD cars which is only RWD on highway? The front CV joints still get the "velocity" but there is very minimum "pressure". Too much lift still have other concerns, but can part time 4WD owners be less worried about CV wear over highway driving?
@@TinkerersAdventure Hi there. Yes indeed there is less abuse on the front diff when it's free wheeling. It's under load that problems will occur. The only issue I can think of with prolonged high speed running with high CV angles is that grease will tend to be shoved to one extreme of the tripod slider rather than being more evenly spread. I can't see that causing many issues as the first time you hit decent compression it'll get relocated pretty fast. In a perfectly designed system all the driveline components should be in line or within the angles specified. Another issue is tail shaft angles round the centre bearing when the rear is lifted. You'll usually feel this, usually around a certain resonance period and particularly when lifting off as the driveline will react to make the tailshaft angle more severe. I've not known any to break because of this but my mechanical sympathy kicks in... Things aren't meant to vibrate like that!
@@daveg4963 Baja trucks and Humvees are all IFS. They're pretty handy off road. But I agree with Matt here... What's the point in the comment? Edit: I've owned a Jeep and two Defenders and managed to break suspension and steering components off road. Solid axle is cheap, easier to lift and gives great articulation hence rock crawlers use it. Doesn't make it indestructible.
What an awesome video. Had to subscribe after watching. As a solid axle guy I think there’s a lot to be learned in this video not only for IFS guys but for solid axle guys too, I wish half the guys in the Jeep groups I’m in would watch this video and learn something from it. A really cool and controversial topic that this reminds me of is whether or not wheel spacers alone add stability, after watching this video I think you could do a great job at proving or disproving this theory in a way that guys would understand. Another idea is the benefits of running an offroad swaybar as apposed to no swaybar and how the presence of a swaybar improves not only stability but traction as well.
Thank you and I really appreciate those technical topics. I had actually reasoned through the effect of wheel spacers and swaybars in my mind before. I can see where you're going and I think we share similar ideas. I will definitely try to get something together in an easy to digest presentation. The bottle neck of most internet discussions is that many think only the first layer and isolate a single component. It is also common to have black & white binary reasoning (this is good, that is bad). The reality often has more nuances and requires looking at the system as a whole.
Please make more content like this regarding suspension geometry and limits. This single video cleared up nearly a year’s worth of misconceptions I’ve accumulated on the forums while deciding on a lift kit. Thank you so much for making this.
Amazing to see the effort and detail in all of your videos. Great job my friend. As a FJ owner myself, seeking knowledge in all set ups off road, finding factual data is even harder to find. You have a fulltime subscriber in me. Cheers!
Much appreciate it! Yeah I am very much a data driven person. Opinions are only opinions. I always like to strive for quantitative fact based information.
@@TinkerersAdventure What do you think of the wescott designs pre load collar lift kit for the trd pro 4Runner. Says it maintains factory ride. I want lift my pro but don't want to sacrifice my factory fox shocks for newer ones.
VERY nicely done! Refreshing to see actual technical content in the off road community, backed up by science. Too many channels focus on what "looks sick", which unfortunately is what most bros are capable of digesting...
As a female, I was never taught about cars/trucks and basic information one should know about them, let alone anything beyond the basics. Anything related to vehicle modifications is intimidating to me, but as a 3rd Gen Tacoma owner, I’m trying to learn how to give my truck its best life, and to do the work on my own as often as I can. THANK YOU, so much for your videos. I feel like you break everything down in a way I can easily comprehend (even though I may need to rewind and listen again haha). I appreciate you and your videos so much!! 🙌🏼
I’ve never seen this explained! Excellent! I have lived and 4 wheeled the Rocky Mountains for nearly 50 years. I’ve only been doing it in Toyotas with IFS for the last 20 using skinny 235/85R16s. No more than a 1.6” lift. It has worked well for my purposes.
Can you do a thing on how air suspension +I4S figures in all this? Given that even vehicles like the new LR "Defender" has that, LR3/LR4 have it, my Gen 1 Cayenne has it (along with a center & rear locker, low range and a 6MT mind you!), etc. One thought is changing the air suspension ride height is kinda like changing the preload, since what's actually changing is the air spring height/"thickness"? But I guess as opposed to a coil spring, increasing an air spring's preload involves raising the ride height not lowering it as in a compressed coil spring...so that's why raising air suspension means increased harshness, because the spring compression isn't taking up as much force upon maxing out downtravel, then hitting the next bump. What about when you then do a body lift? In this case, you're not actually increasing the pressure inside the air spring (preloading) to raise the car. It also doesn't seem like you are pre-extending the shock either- you're just adding material above or below it to compensate for the body lift. However you are still trading down travel for up- because the various joints on the suspension are already closer to maximum droop (unless you do a subframe drop as well?)- but this wouldn't affect ride quality per se right?
Great video. I wish the ARB USA customer service would watch this. They told me I can make my BP-51 coil overs softer by reducing preload. That’s one of the reasons I ditched them and went to King coilovers. Easy to modify, tune, and rebuild at home. But then I switched entirely to a Jeep and can lift 6” and fit 42” tires and retain my full travel.
Hi Do you need some great lighting for your car to help you better driving, off-road? We're the pro auto lighting manufacturer for nearly 20 year and we're looking for sponsorship!
This is my first TA video. Stumbled here looking for answers about lift vs down travel for my IFS Frontier/Navara. Absolutely top shelf, gold plated, twin-locked, perfectly tuned content! From one engineer to another, I love it when the guy that paid attention in school starts playing with cars! 😀 Subscribed.
When adding a steel front bumper and winch to a 2.5” lift, it will obviously lose some lift. Would you recommend adding more preload or change the springs to a “heavier” load springs?
a definite answer would require looking at some numbers and your preference on ride characteristics. But on a high level, with enough weight you'll NEED a higher spring rate for a few reasons. Possibly heavier valved shocks too. The dynamic ride characteristics depend on the combination of spring, mass and damper.
When he said, “Don’t worry if you haven’t viewed part 1.” I thought he was going to say , “Click on the link to view part 2” next. Instead he summarised and integrated part 1 into the video. Great job!
I had a 2012 4Runner that my parents gave me when i was 16 years old.. Now I own a 2019 5th gen 4Runner TRD Off Road, with KDSS option.. The difference, off road, is night and day.. The 2012 use to wheel lift a lot more and was a bit scary.. My current 4Runner (with the KDSS) articulates like a sick Giraffe's neck, and suspension is stock as a rock lol.
sounds like a 2" lift os the Goldilock lift . As far as spacers, Toyota land cruisers come with a small spacer on top of the front coilovers from the factory everywhere except the US market...not sure why, but the point is that Toyota understands the benefit of this small spacer in the geometry. ( look for part 43136-60020 Toyota)
So taking this all into account, in your opinion, what setup and lift height would be the sweet spot for most people who drive on road most of the time and then do trails and light rock crawling?
Great question. I should've included some personal recommendations in the video. I think extended travel coilovers are the bare minimum because simply how precious every bit of travel is for IFS. 2" lift to me is a sweet spot between clearance and flex. Also lower CG for road manner. I personally like the idea of using larger tires and less lift to gain clearance. I have 2" lift on my FJ. With long travel IFS I have 5 inches of down travel. With taller fender flares and 315 tires, it looks tall. But once parked next to most other lifted Toyotas on 33s, mine is almost lower on the roof line.
@@TinkerersAdventure Awesome response! Thank you! When I set up my truck in the beginning I definitely believed in some of these myths. I have 3 inches up front with 33s and have noticed I basically have 0 down travel from ride height. I also have OEM size coilovers so looks like I need to find some decent extended and lower it an inch. I think a cool video idea for you would be your top 3 or top 5 setups. Best weekend warrior setup, rock crawling set up, full time overlander set up, and etc etc. Just a thought :)
Another (former) automotive engineer here. You nailed it. Nice job. I've seen even some of the prominent/respected off-road guys get a lot of these details wrong. To your question about the effect of lift on the CV's on the highway, since they're not under load, a couple considerations (I'm not sure the answer). The higher angle means the CV balls are sliding back and forth in the cup splines a further distance with every revolution. From essentially nothing if the CV is straight, to quite a lot at high displacements. This leads to more shearing of the grease, which will break it down faster. Also, I would wager that even though the shafts have no torsional load, there's quite a lot of force required to rotate the joint. ie: Take a CV, hold it straight, how much torque does it take to rotate? Now bend the joint 30 degress and rotate it. It should take a lot more force to rotate. And at high speed, keep in mind the balls are oscillating very fast, which is also doing work. Which requires force, that is not required when the joint is straight. Does it really matter? I don't know for sure, but it's something.
Keep making these. Your hit count WILL go up. These are some of the best technical videos on the subject out there. Don't stop! Thank you for these. If you did 4Runner and Tacoma videos I promise you. Views will SOAR!!!!!
This is excellent and well done, thanks for putting this out there! I think suspension is the most misunderstood part of autos much less 4x4s. I see so many people only look at $$ => inches of lift without considering quality.
I think the most important measurement of articulation here is YOUR ability to articulate these tests and measurements. So great! Thanks for all your work.
Well done. Two notes. 1) Wheel rate is the spring rate times the motion ratio squared. kwheel=kspring*(mr^2) mr=xspring/xwheel 2) Suspension does necessarily rebound past ride height into droop after bump travel. It can but doesn't have to. A lot of the harshness comes from the lift causing steeper control arm angles resulting in wheel loads being transferred directly into the chassis through the control arms.
You are the suspension professor! I'm very impressed with your practical (physical), and graphic depictions of these suspension scenarios! Brilliant and very helpful!
