The 2nd Biggest Misunderstanding in RC Crawler Tuning

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  • Опубліковано 17 лис 2024

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  • @peterk7662
    @peterk7662 2 місяці тому +15

    I used to run a rubber band on my front end. Got laughed at until the haters watched my high side tire grab and pull the whole rig up and over the obstacle 😂. Love the content!

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +5

      Thank you! I like the mod but I didn't always. I don't see any other way to achieve what a simple negative springs does, unless you completely choke your shocks with too thick of oil (upcoming video) and make other compromises.

  • @watch-box
    @watch-box Місяць тому +2

    I started looking at RC as an 'inexpensive' hobby that I used to enjoy in my teens whilst Covid kept me at home with spare time.
    Forward a few years, my wife is now an RC widow! I have 4 cars (none of which are fully finished).
    This 'inexpensive' hobby has me relearning Math I haven't used for 30 years, eats a LOT of spare time, and oddly involves more 'tinkering' than driving (I'm sure this is different for some).
    Without these great, easy to follow experiments I'm not sure I would be enjoying myself half as much - having predicted incorrectly how springs would affect the performance of my cars.
    Thank you for taking the time to make these guides (and stop me pulling my hair out!) - subbed.

    • @BoomslangSuss
      @BoomslangSuss  Місяць тому

      It always seems inexpensive but adds up fast! Thanks for the kind words.

  • @vdel9036
    @vdel9036 2 місяці тому +4

    Funny : these equations are exactly the same as those for electrical capacitors, when they're connected in parallel or serie.
    Mechanic and electric sciences work the same : a spring stands for a capacitor, a flywheel stands for an inductance and friction of sliding surfaces stands for resistors.
    Nice video ! I really learn, watching this.👍

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +4

      The only way I could get through my electrical engineering classes was to visualize it as fluid dynamics! 🤣

  • @hairypaulmm7wab195
    @hairypaulmm7wab195 2 місяці тому +7

    Have been running matched sets of hairband negative springs on my LCG crawler for a while now with good results. I used a simple balance scale test fixture arrangement to test a whole bag of hairbands, This allowed me to make several sets of 6 bands that are very closely matched, 4 go on the crawler and the other 2 go in my race bag for when one on the vehicle gets damaged. After a few weeks of testing on specific obstacles in my local forest , a derelict coal mine spoil heap and a short course made with collected rocks and granite slabs The difference was clear that using the hairband negative springs improved climbing performance on all obstacles. One specific granite slab is an incline of 67 deg, With the bands fitted this climb is relatively easy to clear cleanly with careful throttle control. The same climb is not possible without the negative springs always resulting in the car tipping over backwards even with the slowest possible wheel rotation. Good to have a proper full explanation of the physics behind this. With a little thought and matching of hairbands as best you can it is a very cheap mod that works well. Have fun!

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +4

      I like your style. We should hang out. 🤓

  • @shafiqjan1474
    @shafiqjan1474 2 місяці тому +6

    I liked the break down, watching while ultrasonic cleaning some chains for a buddy and heating up my waxer. 👍🏻

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +3

      I can appreciate that. 🚴‍♂️

    • @shafiqjan1474
      @shafiqjan1474 2 місяці тому +3

      @@BoomslangSuss 1st chain is in the wax...

  • @Tyrells_Tiny_Trucks
    @Tyrells_Tiny_Trucks 2 місяці тому +4

    I think many folks run too strong of a "negative spring" setup. My main goal when setting them up is keeping them minimal enough to not be limiting downtravel for breakover or articulation on less extreme inclines.
    For an empirical test, I like to hold the front end up by the chassis, near the vehicle's tipping point, and have the negative springs hold the axle up a bit, or sucked down. As I lower it to be more level, and the weight force of the axle partially transfers from the links to the shocks, I want to see the suspension extend to full downtravel. If I can achieve this, it seems to be a good starting point, and I tune from there.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +2

      I agree completely and I like your test method. I think most people don’t know what spring rate they have up or down.
      I’m going to publish a video shortly with a test method that I like, which is along the same lines as yours.

  • @Doorhinge64
    @Doorhinge64 2 місяці тому +2

    Thanks for sharing this! You really helped me in tuning my crawler and understanding these concepts. Especially with how much misinformation is out there.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +3

      You are very welcome! That’s exactly why I started the channel - to try and provide good info, backed up by demonstrations. Definitely a lack of correct info for this hobby.

    • @cameron6471
      @cameron6471 2 місяці тому +1

      @@BoomslangSuss As an avid mountain biker your effort is much appreciated. Nice to have a highly experienced engineer (with the credentials to back it up) making this info known. People will still disagree, but it is by their own ignorance, not for lack of math now!

  • @themountain59
    @themountain59 2 місяці тому +1

    This is the ultimate tuning guide....looking forward to the second part👍👌🏅

  • @TurtleMasterFlex
    @TurtleMasterFlex 2 місяці тому +1

    I absolutely love your content. Thank you for the work you put into each one, I am going to end up watching every video on your channel, both to expand my knowledge and to improve my RC! I got my first ever RC crawler about 2 months ago, and have fallen in love with the hobby. I have the SCX24 Deadbolt, my wife has the AX24. I have started to upload videos to my channel for fun and to receive input on improvements. I also enjoy mountain biking, but am on a long wait to ride again after fracturing C4 - C7, 4 vertebrae in an accident a year ago. I was getting home from work in the city, not even out on the trails!
    Ok ok sorry to ramble 😅 Thank you again for the great videos!

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      Please ramble on! I enjoy hearing people’s stories.
      Sorry to hear about your back. Good vibes for a continued, strong recovery.
      Crawling is a great hobby and so addictive. So niche and weird, but so fun. Thanks for watching! I have quite a few more planned.

  • @ericmyers1306
    @ericmyers1306 2 місяці тому +3

    great video. I run both compression and extensions springs on the same shock on all of my crawlers. no other setup works better based on my tuning experience. I only use an external rubber band (never internal extension springs) because they do not reduce the length of travel of the shock. If I want reduced travel, I use shorter shocks instead of internal springs. the main benefit is absolutely to eliminate weight unloading, but equally important is ensuring consistent ride height for precise and predictable transitions.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +2

      Agreed on all fronts. If you don’t have a good balance of the positive and negative you can get a weird balance point in the middle of your stroke which as you point out, you want consistency. I’m trying to figure out how to communicate that in a future video.

  • @Bradon881
    @Bradon881 2 місяці тому +3

    Can’t wait for your next video. I’m struggling to decide whether-to have droop or more articulation. Also I want to know how does it affect performance of puting two different length of shocks in the front and rear? (Eg 90mm front and 120mm rear)

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      You can have both droop and articulation if you do it right.
      No problem at all with different shock lengths. If you are running a forward bias skid, space gets tight in the front and you usually don't have enough room for long shocks and high articulation anyway.
      Also, your shock angle plays a huge role in the actual amount of axle travel, so you won't have the same wheel travel F&R if your shock angles are different.
      ua-cam.com/video/WHt5ONW3H7Q/v-deo.html

  • @robo6548
    @robo6548 2 місяці тому +2

    I've used droop (30% - 50%) on my latest crawler tune, its astounding how it now clings to rocks even up to 60 deg vertical.

  • @CrazyQuadBrothersP3
    @CrazyQuadBrothersP3 2 місяці тому +1

    This is actually really interesting.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      Thank you. I was worried it was too deep and uninteresting.

  • @curtkelsey2136
    @curtkelsey2136 2 місяці тому +1

    This is awesome, it has motivated me to get out and start experimenting with different setups. I have been running deez bands on my front shocks of my class 2 rig for a couple years now and I think that truck dose do better with them on.

  • @tjpighin
    @tjpighin 2 місяці тому +1

    This shows the issues of hairbands vs negative springs. Springs will give a more consistent result as they tend to hold their shape better. Elastics stretch and do all sorts or weird behaviors effecting the results each time. The desert lizard shocks or similar shock designs have been my best result and to further improve the performance, I use a suck down winch. Seems to be dialed now

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      For sure steel springs are more consistent than elastic bands, but elastic works decently if you replace them periodically.
      I like the Desert Lizard concept a lot, but they have a few shortcomings - no preload options, too long, springs too stiff, have to bleed everytime you change settings.

    • @tjpighin
      @tjpighin 2 місяці тому +1

      @BoomslangSuss but once they are dialed ooooeeeee hahah. I have the longest ones yo buy. I do wish they came with one softer than the softest for sure. The vrd is almost too light but it works just barely. You must be using on a 24th or something. Like they are down to 80mm I believe. And once ya set it, forget it. I do wish they had a bleed screw to top it up and make bleeding easier but value with all the tuning options is pretty dang sweet and for the 8.5 lbs ti buggy, they are sick. I do wish they had a threaded rod end on both ends as well

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      Now you got me thinking. Might try some SCX24 springs inside a Dravtech.

  • @KlimovIlya
    @KlimovIlya 2 місяці тому +1

    Great topic! Thank you for covering the theory behind the negative springs. In the next video could you please also talk a bit about how to tune the shocks with negative springs to help with flipping over when going downhill (you briefly mentioned it in the beginning of this video ) because this is exactly the problem that i am trying to solve on my mini at the moment. Thanks

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      For sure. I’ll definitely do a more practical follow up video soon. The easy answer is drive faster! 🤣

    • @KlimovIlya
      @KlimovIlya 2 місяці тому +1

      ​@@BoomslangSussdriving fast is not always an option due to the placement of the gates (i comp).😊

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      Very true.

  • @Gibsonlife573
    @Gibsonlife573 2 місяці тому +2

    Awesome video I always run rubber bands

  • @JacobScherer
    @JacobScherer 2 місяці тому +2

    I'd love to hear your take on running a single band/negative spring in the middle of the axle rather than a band at each shock.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +3

      I've run single bands in the middle and they work nicely IF you also have springs on the shocks to address body roll. Personally, I got rid of my positive coils altogether, though I know that's probably a mental leap for many. So I keep my neg bands at the shock to help keep the chassis level on sidehills.

    • @chris-q8v9u
      @chris-q8v9u Місяць тому

      @@BoomslangSuss I'm running the same setup on my Ascent fusion which has little to no travel in the front due to panhard bar. No external/positive springs. Hairbands, which I bought every pack at dollar store to find the right rate and 60 wt shock oil. Man what a difference crawling ! Thanks for your very helpful videos.

  • @archerash6695
    @archerash6695 18 днів тому +1

    I buy shocks 10mm longer and add pen springs on the front shocks shafts, inside the shock.
    Its a very careful balance of oil weight and axle weight.
    On an incline, your front end should stay down by the pen spring pressure.
    Once the axle is off the ground, the pen spring must be weak enough to let the axle fall to full extension.
    Oil weight effects this factor.. I use lighter oil in the front, lighter than normal.
    In the rear, I use a bit stiffer pen springs and thicker oil.
    If you want to trail ride, simply lowering your shock collars.
    This will override your pen springs giving you normal suspension for the trail.

    • @BoomslangSuss
      @BoomslangSuss  18 днів тому

      I like it. I run stiffer in the front because that one seems to need more help staying down.

  • @electronsmove
    @electronsmove Місяць тому +1

    The hair tie / rubber band in parallel with the extension spring as it would be installed on an actual truck acts as a preload to the extension spring and a limit strap. Both of which are used on 1 scale trucks.
    Your experiments are carefully arranged to support your hypothesis while purposefully obfuscating the actual use case.
    Mount the tie and spring on an actual truck and then measure how much force it takes to move the tire up and down. Do this with and without the band or tie.
    We can achieve the same result if we use a shorter extension spring with a preload, the end stop of the shock body can act as the limit with internal o rings to limit travel.
    It is possible to determine the spring rate and extension length desired and design a spring and shock to fill the requirement, without a hair tie / band. 1:1 Scale trucks use limit straps to avoid damaging other components due to over extension of the suspension, we only need worry about driveshafts coming apart, the shocks on RCs are strong enough not to be damaged by over extension.
    The use of a tie or band on an RC truck is quick fix / band aid to avoid addressing the root cause. It is quick and cheap and easy. But it is not necessary.

    • @BoomslangSuss
      @BoomslangSuss  Місяць тому

      A hairband does not act as a limit strap.
      I think we’re the saying the same thing. You can replicate two springs with one spring, though it’s not the same as a shorter preloaded spring as you suggest.

    • @electronsmove
      @electronsmove Місяць тому +1

      @@BoomslangSuss My point is, it is possible to replicate the same result using one compression spring which is properly designed. And any extension spring or hair tie becomes a limit strap when it reaches the end of travel, or it breaks.
      I like the channel and respect what you are doing. I think it could have been demonstrated more directly and simpler.
      I'm a big fan of simple. We definitely agree on the core issue.

  • @khimbittle7705
    @khimbittle7705 28 днів тому +1

    Great content

  • @jeffnewhart491
    @jeffnewhart491 2 місяці тому +1

    Bamf tire inserts makes suspension bands. They work great!

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      I know there are a couple brands that make nice ones. I haven't used them but I am sure they git 'er done nicely.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      Those BAMF ones are 3D printed? That's not generally a durable, long term material. I like the concept but would prefer injection molded polymers, but that requires a tooling investment.

    • @jeffnewhart491
      @jeffnewhart491 2 місяці тому +1

      @@BoomslangSuss I've been running mine for about a year now on 2 of my rigs. Hair bands actually stretched out way faster than these. They have a tiny bit of slack in them since they were new.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      That is true. Good to know.

  • @xjtorc
    @xjtorc 2 місяці тому +1

    That AG jersey is sick!!

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      Thanks! I designed his winning bikes for a couple years. The jersey was worn in practice too.

    • @xjtorc
      @xjtorc 2 місяці тому +1

      @@BoomslangSuss wow, that’s awesome!!

  • @CAPRAQUEENRC
    @CAPRAQUEENRC 2 місяці тому +1

    I use a which to pull down my RYFT and it works amazingly after so many people laughed at me!

  • @meirdeaph
    @meirdeaph 2 місяці тому +2

    That's awesome ❤

  • @Jsfea01
    @Jsfea01 2 місяці тому +1

    I really appreciate the science/math behind why things work or don’t work. Is there a “best place” to locate the band? Should you use one band centered over the front axle or use 2 with each one being located further out to the side?

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      I depends. Center mount is a nice idea IF you also have positive springs on the shocks. Personally, I don't run positive coil springs, and this is what I will recommend for most people. Then the issue becomes body roll. You need some force (pos OR neg) out to the sides to keep the chassis level when side hilling. So I keep my negs near the shock since I don't have posis.

  • @whitsrcleftovers2707
    @whitsrcleftovers2707 2 місяці тому +1

    I use a rubber hold down in the rear. It goes around the chassis, but to a single anchor point on the rear axle/diff housing. So the rear doesn't unload, but I still get the articulation.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      I have played with that as well. I found that when I removed my positive springs, the body would roll under side hilling, so I keep my negs at the shocks for some side stability. Center is great if you have springs on the shocks or a sway bar.

  • @Team_ReVolt
    @Team_ReVolt 2 місяці тому +2

    Man I love your videos. it's all becomming clear to me now.
    Already looking forward to that next video!
    And I ordered that tool on AE (27€).
    You can't ever have enough tools 😁
    Do you have a link to those 2mm & 3mm hairbands?

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +2

      Thanks! I just added some links to bands - good idea. They have colors too. You can use the thin ones and wrap one end around the mounting bolt a couple times for preload. I'll demonstrate this in an upcoming vid.

  • @snörre23
    @snörre23 2 місяці тому +3

    Looking forward to part two, this was a bit too theoretical for me.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      I agree. After I finished it I realized it’s not that useful yet. 🤣

  • @jerryvolpini7987
    @jerryvolpini7987 2 місяці тому +1

    My head hurts (I knew I should have paid more attention in math class), lol! Seriously though, complex idea but math rarely lies and I thought you explained it well. I still firmly believe that real world analysis is vital and getting out and testing is the only measure that matters! I must add that I'm really looking forward to the segment when you discuss how to use this knowledge to set up your rig.
    For me, I generally have found that light oils, all-around, work best. I like to use a hair band on the front shocks so, that it is slightly preloaded at ride height (near full droop, typically). Testing on a variety of terrain, I have found this greatly improves handling and climbing ability is drastically increased (much more than I thought). In the rear shocks, I'll use super soft springs to transfer some weight up front with a slight sacrifice when descending. Interested to see what you think about running hair bands at both ends as I have not tested this out yet but I know this is your preferred setup.
    Quick question - not taking cost into consideration, is there any advantage/disadvantage to using a shock band over hair ties? The ties are probably more versatile and easier to use but I really like that the bands have a secure mounting point. Thoughts? (sorry for the long post)

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      Thanks Jerry. Part 2 will be a lot more practical.
      Light oil - YES! I run 15WT and this topic definitely needs more science. I don't understand the LCG trend to run 60WT+
      If you are talking about Deez Bandz they seem nice but I have not tried them. I think the key seed I want to start planting is KNOWING what negative spring rate you are applying and then tuning the preload. I foresee good opportunities for better commercial solutions once we all start on the same page.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      I took off my coils springs front and rear and ever went back. That might be a stretch for most people (pun intended) but there was only 1 downside to it. I did add a light band to the rear to help stabilize body roll. If you have no springs whatsoever, nothing keeps your body level side to side, so I use negs front and rear for that duty as well shock droop management.

  • @brianmorrison2846
    @brianmorrison2846 2 місяці тому +4

    Since you mentioned it I kinda feel like I’m in an algebra class

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +4

      Hopefully it's not giving you PTSD

  • @pocketfuloducks1062
    @pocketfuloducks1062 2 місяці тому +1

    I love when math is mathing.

  • @NovemberFoxtrotRC
    @NovemberFoxtrotRC 2 місяці тому +2

    Wait you must be local with that Rock City clip 🤔

  • @a36538
    @a36538 Місяць тому +1

    Is this akin to limit straps?

    • @BoomslangSuss
      @BoomslangSuss  Місяць тому

      No. Limit straps create a hard down stop and don’t affect the springs. The negative spring concept actually adds an opposing spring that is active across the full wheel travel.

  • @thindigital
    @thindigital 2 місяці тому +2

    But wait, those hairbands cost $1 so they can't give better performance than my $160 shock setup!

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      Maybe????

    • @thindigital
      @thindigital 2 місяці тому +2

      @@BoomslangSuss lol, after I'd been in the hobby a while I realised a.lot of money is being made selling folks 'upgrades' they don't need or understand. Simple steps like venting tires, hair bands and weight distribution yield actual results, for little money.
      This kind of info will save the new guys lots of money, thanks for the video!

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      I don’t know if many people are actually making a LOT of money in RC, but I agree with the sentiment for sure. Link risers are well intentioned but completely bogus upgrade among others.

  • @cybron7089
    @cybron7089 2 місяці тому +6

    Dont talk about this in public. You are ruining my advantage...
    🤪🎉

  • @DHFHades
    @DHFHades 2 місяці тому +3

    well done with the "hater" comment. now anyone who disagrees is clearly a hater...lol

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому

      That’s a fair point. I probably could have characterized that differently.

  • @inspireonex
    @inspireonex 2 місяці тому +2

    Big science bro. I prefer just being shown this on a rig but, you do you. Guess that wouldn't make a 30 min. vid.

    • @BoomslangSuss
      @BoomslangSuss  2 місяці тому +1

      For sure. This background version is not for everyone. I will definitely do a follow up that shows it on a rig.

    • @inspireonex
      @inspireonex 2 місяці тому +1

      @@BoomslangSuss cool. I'll check it out

  • @lgrc6120
    @lgrc6120 Місяць тому +1

    Crickets 😂