Crawler Canyon Tech Notes: the Anti-Squat Primer
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- เผยแพร่เมื่อ 6 มิ.ย. 2024
- I started with the best of intentions, and I did indeed make some low-rent graphics, but I feel like it started to get away from me toward the end. So this is the rambling primer on anti-squat, aka how a 4-link rear end behaves and sorta why.
IG: crawlercanyon - ภาพยนตร์และแอนิเมชัน
just wanted to let you know that these tech notes episodes are amazing. It opens up the understanding of this hobby to the next level😊
Well sometime before the halfway mark I ran out of enough IQ to really follow everything, but that's not for lack of effort on your part. Great illustrations. It's crazy how deep this rabbit hole goes.
Really diggin’ the tech notes, Doc. Your channel becoming well rounded in the way of education, entertaining contests, and the ongoing saga of Crawler Canyon. The builds are excellent, fabrication is innovative in practical applications and I really appreciate that I can watch your trials and tribulations.
I am fascinated about videos like this. It helps me understand my RC better.
I keep looking through your archives and I just find some amazing information. Thank you sir.
Technical Erotta. My new favorite term. Thank you for your continued efforts. Your devotion to this hobby is admirable. Crawler Canyon has quickly become favorite channel. Keep it up.
Yeah this link setup talk is definitely helpful because nobody really talks about it in detail like you've done so far. So expanding on this video would be awesome. Im definitely going to share this with my group.
I love this stuff. The more I understand about what I'm interested in the more I enjoy it, because for me the fun is in the improvements to anything, whether it's a real performer or not. And I love the customization aspect of configuring your own performance. Please do the anti-dive! I need to get a few rigs to descend better without just using weight. My next step is to build my small course so I have these repeatable obstacles to test on :)
Great stuff man, keep it coming. I do like your ramblings they are entertaining.
This is all new to me. Videos like this are few and far between but I am so glad I found it. I would like a video explaining ESCs/BECs. The in and outs of electronics.
Seriously though I’m glad I found your channel. I’ve learned some things I THOUGHT I knew
Very well done! Hopefully people will sit and watch. Lots of great info here!!
Thank you for all the good info good Sir! As a new subscriber and new to the Crawling hobby these are extremely helpful!
Mind…… blown……. Thank you for this video. I will have to watch it a few more times, but it’ll get my rig started off right.
- This is so exciting !!!! 😯 ...😁👌 -I dig all this technical stuff !!! 👍 - THX
well explained, correct terminology, and visual aids. It all really helps.
I'm less confused than I was.
Thanks. I needed that. I've poked around online recently to gain a better understanding of link geometry, and didn't really find anything straightforward in regard to RC crawlers. My Capra is on a Rouge chassis w/ tons of link adjustment options front/rear. I've kept upper links low and rear uppers high where they mount to chassis. So it sounds like I'm doing something right after absorbing the info in your video 🤣
Great video. Another good way to look at anti squat is relating to a dirt bike vs sport bike (crotch rocket) suspension and the way they behave though the setup is more in the chassis design vs link lengths and positions ... the principal is pretty similar though the suspension systems between motorcycles and trucks are completely different 🤷
Echoing other comments and I really love these. I have been a fan of the link riser for Element axles since trying one on my class1 truck. I got one for my class2 truck shortly after getting a feel for the behavior. There seems to be more grip on the front tires with the upper links running horizontal / flat, or angled slightly toward the ground in front. I wanted to use one on my 4ws build, but obviously that is tough with a SOA mount :)
Freaking love the technical stuff. 🤙
Very good video. Definitley a video I'm going to watch more than three times... 😁
man, one day with this guy on my rig and I'm certain I'd be driving in a whole new world.
Great explanation! You will find Jake Burey (busted knuckle offroad) explain anti squat as well. This topic is very important when you build cars that you want to preform in a certain way. Thanks for sharing ✨👍🏻
very good and technical information for me, but i understood almost the technique that i will apply from now on, on all of my rigs. Thanks
Mr. Canyon we need more
Great video!! I just subscribed. I've been trying to learn about my Khafra four wheel steer version I noticed on the two wheel drives they sell a link riser but the four wheel steer you get nothing I was wondering about that and then in your video you said you could compensate with that with weight. I am interested to learn more with your knowledge on crawler suspension tuning specifically and for the record you didn't ramble you delivered it like your buddy in the garage to where we can understand it. Thank you.
As the link mounts on the axle tend to be directly below the servo, adding a link riser is certainly problematic. But tuning the link mounts at the chassis end, as well as link lengths and weight bias can help achieve similar results. The link riser is just easy-- I have an SOR riser on several of my Element-axled rigs-- but not on all of them, because sometimes it's not needed. In my tuning, my Capra-based/Capra-adjacent rigs (I'm assuming autocorrect turned Capra into Khafra, unless there's a pharaoh-themed crawler now) have responded to low link mount at the chassis, usually as low as possible, and as close to the lower link length as possible without binding or interference.
The stock Capra skid has quite a few mount points for the upper link, I would start at the OE position and move down, which will require lengthening the link, as the mount points are effectively getting further away from one another, and see how it responds. There are so many variables, there are no hard and fast rules-- literally everything on the rig will affect handling and balance, so a change made on Rig A with wheels this and tires that might not present the same result on Rig B with different stuff.
I wish I would have found your channel sooner. Great video and explication of anti squat. Subscribed 👍. Now I'm gonna have to do some tuning and probably move some traction to the rear.
I feel like TH-cam is hiding me, because I get a whole lot of people saying a very similar thing.
@@CrawlerCanyon
The crawler community is definitely missing out on your channel and awesome content.
great video keep them up thank you.
Incredible content
Busted knuckle films on TH-cam has some good videos explaining 4 link geometry, dumbed down a little for people like me.
What makes the contact point of the tire move slightly towards the center of the car and is there a way to adjust that? Is there an imaginary line you can draw through s pair of joints to see where it would land? Awesome video by they way I will keep watching for a more in depth explanation!
Great stuff!
Thank you so much Sir... Very informative...
Thank you for this fantastic and informative video. 👌🏻😊I have a question about the link lengths; the ratio that you mentioned; 87%; different skids have different lower link mounting points; I think this is the ratio if you were able to align the upper and the lower links screws mounting points vertically at the skid side, am I right?
It’s the physical link length itself, so if you had both upper and lower links removed and laying side by side on the table then the top would be 87% the length of the lowers.
The 87% is purely link length itself, completely independent of mounting points.
Hey mate I’m a bit lost rewatching this now and seeing the new builds like #27 etc. It 16:46 seems like you’re going for a higher mount position on the rear upper link skid side, is this just to compensate for a heavy forward weight bias of EoA or you’ve changed up the method? It seems like every axle has an axle side upper link riser available but there’s not many (any?) options for chassis side risers?
I’m trying to tune a 2.2 Wraith at the moment, I’m not getting enough down pressure on the front tyres despite a bit of brass and SoA. I’m running Deez bandz so it’s not pulling off the wall due to the shocks but I am finding that rear traction is causing it to pull away. Also despite 25% rear UD.
I’d read this as a rear upper rear link riser.
Also curious about the axle swing on build 27 with the upper links being so short compared to the lowers.
Raising the rear upper link point at the chassis effectively trades overall forward drive for what I guess I'd call "vertical stability." That is, the rig has a tendency to transfer less weight to the rear wheels when ascending, so the rig is less likely to flip backwards at the limit. Most people are questing for maximum forward drive, and usually maximum forward weight bias. I don't prefer that much front weight, as it descends poorly and doesn't sidehill as well as something more neutral.
I think in your situation you could benefit from more link separation at the chassis, as weight transfer is likely putting too much traction in the rear tires.
The rear links on #27 are not optimal, but they're what I'm working around at the moment. Big link disparity results in (at least) a bunch of caster change in the rear, which can help or hurt, usually a big pinion angle change through the swing, and as is true with most things, a loss of overall forward drive. I can't tell what has happened negatively because all I can see is that shudder brought about by the rear end dragging like an anchor.
Great knowledge and how can I get a chassis?
Yes sir awesome info!! What do you think about “high clearance” links? Do you think it really improves the clearance or is it just a money making maneuver? Thanks for your knowledge
Oh and if you could do a tech video about shock attachment points that you really be helpful. Like straight up compared to laid down pros and cons ect
In the application that marketers are pushing "high clearance" links, I don't get it at all. If they were really interested in more clearance, every ring would have a high pinion. I have a single instance where high-clearance link is called for: Rusty's front lowers are Element HC links turned on their sides, as straight links hit the chassis rails under compression.
But if a link is bent to "clear more," it just means that something lower, like the chassis or driveshafts, are gonna hit the ground first. I prefer to slide on the links rather than bang something else into a rock. To my knowledge, the bent links don't affect anti-squat/dive at all. I think they're most likely 70% buzzword, 30% useful.
Good job!
Anti-squat only comes in to play when there is acceleration. You said that forward motion is acceleration, which is not correct. You can be moving forward at a constant rate, which defies the very definition of acceleration. Also, I’d love to see a drawing of this tractional wheelbase that you referred to.
I needed this information. I’m curious of finding your CGH and the rotation of the rear axle versus your contact patch on your tire to the ground.
Rear caster isn't a thing in the real world, but it does work for us. We're pretty limited by driveshaft angle, but I like some negative caster on the back axle-- IME it lessens the tendency to flip the nose when getting to more extreme angles. Not as impactful as raising the chassis side upper link mount upward, but certainly beneficial. Side note, if you're 4WS, you have to address other concerns.
@@CrawlerCanyon I’m fairly new to this hobby, about 2 years in and I learn somthing new every single day. Being a mechanic by trade helps to fuel my interest, and quest for constant improvement. I appreciate what you’re doing here sir. Thank you for sharing that information.
What if your antisquat instant center is above 100%, but in front of the center of gravity?
H awesome video my crawling budy has similar background as you his rigs handle awesome he is always talking about exactly what you are describing i dont quite get it but you are making it more understandable to me i so setting the rear dif output angle is not necessarily parallel to the ground you want it more pointed up towards the trany ? 1st of many questions tx
If we're talking about a rig with conventional 2WS, so the rear axle is fixed, rear caster angle isn't super impactful, so in my experience, it's best to set the rear driveshaft not parallel to the ground, but in such a way as to try to keep the universal joints as straight as possible. Now if the driveshaft is level at ride height (which often happens with the TRX-4 gearbox, as the outputs are so low) then that's great.
@Crawler Canyon thanks I'm going to have to rap my head around that if you get a chance ck out my videos on the PBX XTREEM and the Reaper on TH-cam at dubbleportion see what you think if it looks like any suggestions I have got them to do very well so i think thanks
I am currently trying to set up a custom buggy. My chassis connections are at the same level vertically. The upper links are shorter than my lowers and I am getting A LOT of pinion angle change. What can I do to change this to keep my pinion angle stay consistent?
Thank you but also hard to understand, i wish you would have given some simple advice like link riser and or front higher does what, what angle of the diff to look for, not sure if i have found the information i would need to decide that.
I'm just wondering about that you refer with the squat value just with above and below the CG plane. Is there an explanation why you don't use the traction line? With taking only the CG plane into account that will create some weird link constructions.
That's where you choose your compromise. Take this as a prime example: th-cam.com/video/Y_dWay74o_4/w-d-xo.html
So essentially the triangle points to where it’s sending the traction?
How do you apply this theory to portal axles? Does the opposite rotation of ring and pinion affect this at all.
I've tried to apply my knowledge from setting up drag racing suspension and my rigs with portal axles fight me all the time. Now for my straight axle suspension I cold set those up in my sleep, using my knowledge from drag racing.
Can't wait until you start the talk on antidive.
I hadn't really considered it, oddly. I make geometry changes without thinking about the portals, working with the rig in a static position, then keep/revert based on how it translates to the rocks. I'm an empiricist, and went years making changes pretty much at random, until I decided to start learning the theory to frankly save myself some time. I was independent suspension for so long that suddenly adding a fleet of live axle rigs basically started me over.
My fleet is becoming gradually less "portal heavy," and come to think of it, the straight axles seem easier to tune from scratch, but it seems like my portal-equipped rigs are less fussy. So just as how portals trade CG for GC, tem likewise seem to trade some "fine tunability" for being easier to "get going." Everything is a compromise.
Does this same concept apply with side hill crawling? I used your video to rid my self of shock bands for unloading while climbing and now I’m curious. Will this also allow for decreased side hill unloading, or would using shock bands to prevent the shocks from unloading from sprung weight be the better solution? Do you have a video regarding side hill capability?
End of the day, the only thing that genuinely improves sidehilling is decreasing sprung weight-- or at the very least, improving the ratio or unsprung weight to sprung weight. You either add what's on the axles, or decrease what's on the chassis. In my admittedly non-expert opinion, when folks start fiddling with springs and oil the battle is already lost.
So the anti-squat angle does impact sidehilling, but where link angle determines front bite and fore-aft transfer, I don't think I'm qualified to say how it directly affects sidehill performance. What I do now for a fact is that removing sprung weight IMMEDIATELY improves sidehill. Look at the best sidehillers-- MOAs-- and they have next to no sprung weight at all. Meanwhile, I'm over here with multiple D110 Defenders and a van. Sometimes we sacrifice performance for vanity.
Look up ‘roll centre’ it’s the side to side version of anti squat and anti dive etc.
It’s super critical for side hilling, it gets the links to help out instead of just shocks and weight etc
What all have you done to the Element Enduro SE Trail Truck, Sendero that you have been testing tires with to make it crawl so good and turn so sharp
Caster flip in the front, and it has the 12% UD out of the Stealth X. That's it. Geo and suspension are stock.
@@CrawlerCanyon thank you sir I am fairly new to RC trucks and I was going to buy a Redcat Ascent but after watching you Enduro SE Trail Truck I am having second thoughts on the Redcat. I would like to know more about the Sendero it seems to be a great little truck
Good vid
what is the specs on the servo you have for the dig i have a simalar setup im thinking i need a 120* to cut flex on the mount down what servo is that
With one exception, I'm running the JX 4409MG for all of my dig servos: amzn.to/40zkPWE
Rted for 6V, but I run mine at 7.4V with no issues. I don't see the throw listed anywhere, but I don't think I have a single dig running more than 50/50 on EPA. Many are 30% each direction.
Another question: How did you identify that upper horizontal line? and the intersection vertical that points the CGH? what's the way to find those lines?
To find your CGH, you're going to need 4 scales-- I use cheap kitchen scales, one for each wheel. This, combined with an online calculator (I have a video about it) will allow you to find out all sorts of useful information, like F/R weight distribution, cross weight (which can potentially show any issues with suspension setup,) and perhaps most important for this discussion, your rig's CGH. Had to dig through my own videos to find it: th-cam.com/video/6vz8nU4mxX4/w-d-xo.html
@@CrawlerCanyon Thank you!
are you everyday driver youtube as well?
Very informative video. Can you explain how I can achieve this if I have high clearance links?
The suspension can't tell that the links are bent so long as nothing is hitting anything else. The eye-to-eye measurement is what's important, so just ignore the fact that the links are slightly bent. I think I might only have four or five rigs that actually need an HC link, usually because I'm putting an axle in a chassis it wasn't designed for. I honestly don't see the utility of HC links in most applications-- I want the link to be the lowest thing, certainly below the pinion output on the axle. I'd rather slide a metal link than whang a driveshaft into a rock.
@@CrawlerCanyon thank you!
With a pan hard set up does it matter what side your single upper link is on?
I don't think so. I have rigs with links on different sides, doesn't seem to matter. I do know that on say the TRX-4, the front upper is on the right because it wouldn't clear the driveshaft were it on the left. Similarly, I've alway wondered why the Panhard mounts to the left side of the chassis and the right side of the axle. Like... always. Why not the other way around?
You sound like David Freiburger from Roadkill. It’s awesome
So, I’m following what you are saying…. mostly.
I think there may be a missed definition of terms.
I dont see the angles giving one axle or the other more traction by default.
I think you are talking about weight transfer and how that affects the balance of a rig, not quite so much the traction.
Basically, on the gas, you want the back end to rise going up a hill, and on the brakes you sant it to droop.
Both keeping the vehicle more level.
I would suggest doing before and after tests on something like a 1/2 pipe at a skate park.
There you can take measurable readings and compare numbers rather than feelings.
What effect does equal length rear links have?
Equal length links won't change caster or pinion angle through the suspension sweep. So if your driveshaft is level at ride height, it will stay level a full compression and full droop. Sometimes, depending on the build or layout, this might not be desirable. In a perfect world, we would want the pinion to point directly at the output on the gearbox throughout suspension travel. A level pinion at full droop is often a driveshaft asking to get stabbed into a rock. So I shoot for upper links in that "somewhere around 80%" of lower link length, and get the RH pinion angle set by mounting hole selection.
good!!!
The wheel contact point will always be directly beneath the axle. Physics of a round wheel means it can be nothing else
I guess if we only drove on flat surfaces that would be true.
@@CrawlerCanyon Indeed.
I was responding to your suggestion that twisting the axle somehow changed the contact point.... It won't.
🥰🤩💥💯👍👏
Because the metric system just works better 😊
i applaud your circle track time, but ima let you know you need to try radio or sports announcer, you have that kinda voice man.
I am the kinda guy with the voice for radio (and the face for radio) to figure it out after radio has kinda... expired as a form of media. So what I'm trying instead is "rock crawling podcast with moving pictures." I hope to be that overnight success that only takes 5-7 years to break through. A real Cinderella story. 🤗
Wait, I understood there would be no math…….
OMG ! What a way to waste my time 😂
No good .. too slow