Crawler Canyon Tech Notes: the Anti-Dive Primer. Also, shock angles!

[@gypsytreasures7386]

I'm soon glad I found your channel! I needed this nerdy information. Great job explaining.

[@brianmassey7563]

Good stuff. I've always wondered why we angle shocks. The more you know (trigger rainbow).

[@BrandonMythigander]

Yeasssssss. Another vid to watch tonight. I dig the chassis work 😎

[@electronsmove]

It is useful to invert your reference in regards to the relationship of the frame and axle. Instead of thinking about the frame moving up , think in terms of the frame pushing the axle down. This can be seen when watching a drag car in slow motion as they leave the line. The rear bumper appears to rise but the car is pushing the rear axle down into the track to gain traction. It may seem counter intuitive but making the rear of the car compress under acceleration is actually lifting the rear axle at the point of launch. The same will happen with an RC but probably to a lessor degree as there is much less mass and inertia. So do you want to push the axle down or pull it up? I would think you would want to compress the front and extend the rear when going up a steep incline. If I made these chassis, I would fill the frame with holes so anything could be mounted anywhere. It would reduce weight as well as being easy to adjust everything. If strength is an issue, use steel or thicker material.

[@johnarcher9480]

More shock angle also allows for longer wheel travel for a given shock length. Even when elevated, the spring rate will be softer. The spring is resisting the arc of the suspension travel no matter the angle of the car.

[@jord001]

I need to angle my shocks, my rig is only 4.5lbs without a body (not got one yet) and i have the softest springs I could get in side the shocks (I have no budget and could only afford the Injora Mountains) That made sense to me so I must try it as there is no droop on my shocks the rig is too light. I have standard chassis but looking to fabricate one like you have. I have aluminium flat bar I can use but will probably have to use shock keys as its not wide enough to incorporate the towers.

[@timbertime738]

Coming from zero knowledge I definitely have a better understanding, thanks for your efforts, I'm new to rc rock crawling and have an scx24 and really wanting to climb steeper terrain but also descend them too

[@rccrawlingaddict207]

Great lesson.....THANK YOU!

[@user-6tfvk70k78]

Each chassis (whole vehicle with body & electronic) should be tuned. That's why in our world we have Car services. Keep doing it, Jack

[@kollinsendall1]

Do you have a dedicated shock tuning video? I’m looking for more detailed information on shocks specifically. Full droop, half droop, no droop. That kind of shock video. Thanks!

[@StopMotionJeff]

The angle of the shock should only matter in relation to the axle path. The angle of the chassis should have no effect on the axle path. I want to see some testing on the amount of force it takes to compress the shock at different chassis angles. Pretty please with a cherry on top.

[@covecityboys]

It’s confirmed the pressure needed at the contact patch changes with shock mount position. It changes the lever in the shock/link/chassis assembly.

[@CornholioMcGeeRC]

Awesome!!! Thanks a lot. That was I who asked about that and I had no idea . Very informative! Oh and have you tried vanquish’s new tires. I’m wheeling right now while I listen and they are very sticky. Surprisingly good especially compared to the garbage that came with the Phoenix Thanks again!!!

[@danweiss1371]

Again, what can I say but thank you thank you

[@Fantaman900]

Tilting the truck doesn't change shock angle, suspension moving up and down will change the shock angle and the more it's away from vertical the more it will move away from vertical during compression. Gravity pull straight down, your wheels give an equal force straight up. When you tilt the truck uphill the center of mass moves away from the front and towards the rear. As you tilt the link will also go from horizontal to vertical and as you do you take away load from the spring and on to the link. When you angle your shock you take away force from the suspension travel path and put it in the link.

[@CrawlerCanyon]

In a vacuum, sure. If a vehicle is climbing a perfectly smooth inclined plane, then what you're saying is true. Any, and by that I mean ANY change in directionality of that surface will change the direction of load on the suspension. Gravity is always straight down, but the direction of force returned by the tire depends on the attitude and loading of that tire. If gravity acted like air pressure, we'd never fall down. Gravity, straight down; everything else, "down" is relative to the surface. We're not in a vacuum. Tilting the truck DOES change the shock angle-- even if only a matter of a few degrees-- because the axle moves through an arc. The angle wouldn't change only if the links were so long as to make the axle travel completely linear. The same goes for change of shock angle through the arc of the axle-- it's only a few degrees, but it's there. It also doesn't necessarily mean that the shock shock/spring is softer at full compression-- because while the springs are linear, the oil inside the shock is not. Emulsion shocks are going to have some amount of pack in them no matter what, so a damper is going to behave differently at full compression compared to full extension. The link and the shock work together, ALWAYS. 3-link and 4-link suspensions are composite triangles, and every angle in that triangle has a certain resistance to all outside forces. We have some degree of control over that resistance, by altering the geometry of that triangle. Were this not the case, a 1lb/in spring and a 4lb/in spring would behave the same, and leaning the shock over would have no effect.

[@Fantaman900]

@@CrawlerCanyon Man if you bring "in a vacuum" and "gravity like a fluid" to the same table as shock angle talk. I think your understanding of physics is messed up. Fluids is another can of worms like suspension geometry is already very complicated. Crawlers are genuinely slow enough to not worry about pushing molecules out the way in air. Things in space don't have to push many molecules out the way but gravity is always pulling you toward another body of mass. Maybe I should have said that is always straight from and to the center of mass of the different body's.

[@CrawlerCanyon]

I don't mean "in an actual vacuum." I mean vacuum in the sense of cherrypicking one point to disagree with, ignoring everything else. I don't claim to be a physicist, and my math doesn't extend much past geometry-- but I am an empiricist, and I do take issue when someone argues a recorded result. Results for others may vary, as every rig is just a ball of variables, but a result is a result.

[@Fantaman900]

@@CrawlerCanyon Right reading text is mighty difficult because you miss a few cue's you can hear and see other wise. I'm not a physicist, I fall in the category of high functioning autism. My way of thinking is very literal. Jack of all trades, master of none. Meaning a at least have basic knowledge of many things. But I'm no expert in many things. The word of cars is my home. So I might know a thing or 2. You can call it a ball of variables but that makes it way more difficult to understand what is going on. So you take it 1 bite at a time ignore unimportant stuff so it's easy to understand. Let's go back to that cherry picking moment of holding a angle sensor against the (coil over) shock, moving the chassis so the shock is vertical you not only measured a shock angle but also chassis angle change. This is where you make it a difficult to understand a ball of variables. Sure a recorded result but here I am telling you keep the chassis angle constant and only move the axle up and down. Now you measure shock angle that is important and we ignore the arc it travels is for simplicity. And to be honest I don't want to be writing a wall of text to explain everything and people don't want to read a wall of text in comments. So I try to keep it short and simple, it's also fun to share a little knowledge.

[@aaronhouser3711]

Well Done!

[@gypsytreasures7386]

I have question. So on my 24th scale crawler, my front end rises considerably when I start to move forward (on a level surface). I've never had this issue with my 1/10 crawlers, so I'm in uncharted waters. Would this issue be caused by my shock position, or could my link geometry contribute to it as well? I'm trying to build my first 1/24 crawler and finding it to be more frustrating to dial it in. Any info or videos you can recommend would be much appreciated.

[@CrawlerCanyon]

It could be geometry, but the leading causes are: something is binding, causing the rear end to squat, or, the rear shocks are oversprung/underdamped so the rear collapses under acceleration. Always check for anything binding first.

[@snowking171]

This shock angle talk is incorrect. Even though your springs are at 90* when climbing a hill they won't compress more due to angle alone. They'll compress very slightly due to the body's weight in relation to your link travel but that's it. If you setup your coilovers at 90* to your links at full bump then your springs will be much more effective than the setup you currently have. Your axle moves directly along the travel of your links. How can the springs in the configuration you show compress any more than the linear travel of your axle?

[@electronsmove]

The angle of the car does not change the spring rate. The angle of the spring is relative from the axle to the frame. The spring is resisting the motion of the axle with respect to the frame not the horizon. If the car frame is standing straight up, the axle still moves in an arc toward the frame, not up and down in relation to the table. You can measure this if you have a spring scale. Pull the axle to the frame in all orientations. The force does not change. Mount your shock and spring in parallel with the frame, producing minimal spring rate, then stand the car up on its rear bumper and compress the suspension. You still will have minimal spring rate.

[@AdamJohnSwenson]

Thanks. Liked and subscribed. I like knowing the rationale behind this stuff. I have a Corrupt Carbon Reaper Chassis I'm trying to wrap my head around at the moment. :)

[@rybuds47]

I'm doing the same thing right now! 😄 that chassis makes me need to get smarter.

[@AdamJohnSwenson]

@@rybuds47 - right? I have a guy who knows a lot who is helping me out. I think it's going to be a lot of trial and error and incremental improvements

[@iamnoone6607]

makes sense

[@covecityboys]

If the distance from fwd link mount to upper and lower shock mounts is equal that is “90°” essentially. Move upper forward leverage makes shock essentially weaker. Move it aft and it becomes essentially stronger. Nothing changes spring rate or shock strength except changing springs.

[@CrawlerCanyon]

There’s a difference between the rate of the spring and the effective rate when the spring is installed on the shock. There are charts to compute the effective spring rate depending on the angle of the damper. If the effective rate didn’t change, we would all run ours at a 90° angle, perfectly perpendicular to the ground.

[@covecityboys]

@@CrawlerCanyon agreed. The video sounded like you were saying it differently either I missed it or you were keeping it simple for some. Always love your videos!

[@CrawlerCanyon]

@@covecityboys oh, there’s every chance that the words that came out of my head aren’t the same words that were inside my head. My mouth outruns my brain every day, often to my own dismay.

[@covecityboys]

@@CrawlerCanyon same here. ADHD, OCD and 136 IQ don’t seem to mix…..

[@covecityboys]

@@CrawlerCanyon I have seen a ton of your videos. Haven’t seen this truck with this chassis run. Do you have any of those videos?

[@Andrew_Red]

won't angled shocks also increase flex?

[@CrawlerCanyon]

Possibly-- it depends on where the shock "bottoms out" on a given rig. Some builds will reach the physical limit of flex before the shock bottoms out, even with the shocks at 90º. A rig is going to have a maximum amount of flex determined by it's suspension geometry, whether that be 4-link or something else. There is such a thing as too much flex, so the shock can in some cases be serving a better purpose by limiting flex. I've never leaned a shock over purely for flex purposes myself. It's always been to soften the rate-- as many times, even a 2lb/in spring is too stiff.

[@johnarcher9480]

Yes, you would get more travel vs being inline with the travel of the axle.

[@ka4172]

Does a lean over shock get more friction on one side of his shockrod?

[@CrawlerCanyon]

So long as tolerances are correct, the shock shouldn't care what orientation it's in.

[@Bandoe72]

And ppl think this is playing with toys😂😂well it is,but there sure is a bunch of math homework🤯🧠 to get your rig runN how you like it Gr8 video

[@user-6tfvk70k78]

he told us how it is in theory. to see the full picture, we need practice tests. most theories, when faced with reality, they fail, they fail the test.

[@CrawlerCanyon]

I call it suspension theory because... well, that's what I call it. Suspension design would perhaps be more pedantically accurate. Anti-dive and anti-squat are definitely things, and a working knowledge of them can absolutely help to get a rid to handle if not better, then at the very least more predictably. I stick to theory because there are a nearly infinite number of variables-- so knowing the potential outcome of changing a link length or mounting position is helpful, but won't necessarily point to an absolute outcome. We've all got different tires, different foams, different bodies, different everything. All that aside, the effects of +100%/-100% anti-dive all hold absolutely true. It's in the math.

[@user-6tfvk70k78]

@@CrawlerCanyon yes, exactly. There are a lot of variables in our business. and each variable affects the result

[@CrawlerCanyon]

And I cannot isolate those variables. Any change made to one of my rigs is not guaranteed to have the same end result on someone else's-- but the fundamentals don't change, no matter what other variables are present. Raising the chassis mounting point for an upper link does the same thing to every vehicle with a multi-link suspension. Anything beyond that is determined by the choices of whoever engineered and/or built it. And let's be completely honest while we're at it: the lion's share of people have no idea what moving that link mount will do. They chose a mounting point to set the pinion angle (if they even look that far into it) and call it a day. I would reckon most people are still wheeling on however the RTR came from the factory.

[@SlavaRC]

🥰🤩💥💯👍👏