The Most Asked Question in RC Crawling: What Weight Oil should I Run?

[@jerryvolpini7987]

I couldnt have said it better myself, lol 😂 I like that you take the time to explain why something happens and try to break it down into simpler terms (sometimes hard to achieve). You and I have always agreed on this - softer springs and oil to improve articulation. That quicker reaction can sometimes bite you in the ass but that's the nature of tuning. Agree or disagree, it always brings me back to the overriding priciple of tuning - test, test, test! I mean, how else can yoy truly understand if your RC vehicle is handling at its best!

[@BoomslangSuss]

Proving it in the field is absolutely essential to complement your theories. I’m gonna do a video on confirmation bias because a lot of people don’t approach their testing correctly and simply confirm what they THINK should happen without really confirming what’s happening.

[@a36538]

@@BoomslangSuss the abundance of confirmation bias, and the lack of critical thinking is so rife here on YT. Love this science based channel!

[@Violetlunar666]

I love these videos so far! I work in motorsports manufactuing and have ASD so getting a wall full of knowladge is awesome

[@BoomslangSuss]

So glad you like it. More to come.

[@Violetlunar666]

Would this be relevant to a trail truck aswell? ​@@BoomslangSuss

[@BoomslangSuss]

This particular video only discusses slow speed damping and how it applies to a slow moving vehicle, so it kind of depends on how you drive your trail truck. I’m working on a second video that discusses high speed damping on faster moving vehicles. I would say that low speed damping on solid axle high articulation vehicles should be set up differently than faster moving vehicles that need to absorb bumps and control chassis pitch and roll.

[@yodecaf]

I found your scenarios at the end while talking thru what you saw very insightful. It showed me how to evaluate my own rigs.

[@BoomslangSuss]

Nice! So happy it helped. 👊

[@hairypaulmm7wab195]

Marvelous explanation. Took me about a month of testing with different spring rates and oil weights to get my 1:10 scale crawler to 'stay planted' properly , ended up using much lighter oil, opening out the piston holes by 0.2mm and using slightly stiffer springs than I expected to stabilize the chassis/body. I guessed it was due to the rig being lighter than others but there are slight differences in the suspension and link geometry that must play a bigger part than I thought. Many of my riding buddies thought I was nuts for using 'light weight' shock oil in the forks on my downhill bike and fatbike because they would bottom out occasionally on hefty landings, I did fit elastomer end-stops (another thing we dont have on RCs) but they were the ones who were fighting for grip everywhere due to their 'never bottoms out' over-stiff shock setups. Funny how a few of them kept asking how I could run the same line they did with ''better flow'. No matter how I tried to explain they just would not believe it was almost entirely due to my suspension setup being more responsive so I wasn't always on the edge of losing grip. Has taken a while to get used to crawler setup as it is so different from MTB, go carts, quad bikes and rally cross. Keep up the good work Sir.

[@BoomslangSuss]

Thanks for sharing. Great stories. Lighter is smoother and faster.

[@kangme8680]

I believe you’re doing good things for the hobby and really like how you show practical demonstrations and examples for your topics. I have a 5.7lbs Comp C2 rig and I run between 10-15 weight oil and this has greatly improved my transition speeds from gate to gate on uneven or rough terrain in addition to keeping my rig planted on various inclines, side hilling, or descending. Thanks for reinforcing what I already believed 😄👍🏽

[@BoomslangSuss]

Thanks for the kind words. I run 15wt too. I found that 40 was unusable. I don’t see how guys are running 60+ 😂

[@danweiss1371]

I just love any information about suspension tuning. And I am not afraid to play with it/try different things. Thank you for the information.

[@BoomslangSuss]

Thanks for checking out the channel!

[@jamescox1896]

I'm slowly coming to this conclusion myself. nice to know there is some theory behind my guesswork 😂

[@antoineozaneaux6881]

good stuff , just starting to mess with my axial shocks . i did compete in high end mogul skiing for 20 years . with many separate circuits to manage . good channel thank you .

[@BoomslangSuss]

How is skiing related? You threw me off here, lol.

[@antoineozaneaux6881]

@@BoomslangSuss look for world cup MOGULS. i would post a video but i wouldnt want the mods to spill they their LATTES .

[@jasonbuxton3358]

Thanks for the videos dude. Your content is so comprehensive I always learn so much

[@BoomslangSuss]

Much appreciated!

[@jonk8916]

This is amazing. I'm really glad I found your channel and I look forward to watching the other videos. I ride mountain bikes (well, rode, quit recently due to medical issues) and have been a huge suspension nerd, as much as someone without taking fluid dynamics can be anyway :) I have had the chance to use several telemetry systems, a lot of different mtb suspension tech, and work with some really great tuners over the years. It's always been remarkable to me how few riders understand how to even get their stuff in the ballpark of where it should be, rebound damping being the largest culprit, I've been on folks bikes you could compress the linkage and count a second or two before it returned to full stroke! Anyway it was nice seeing the comparisons to RC crawlers. I listened to Wyatt Mellon talk about this briefly when he was discussing the SCX10 Pro design. He mentioned using lighter fluid than a lot of drivers. I watched his footage at nationals that year over and over, then compared it to other drivers, when the footage was slowed down there was a clear difference in how planted his truck stayed, how much more control he had, and how he was able to tackle sections others had issues with. That helped it click with me how to apply what I learned from setting up mtb suspension to setting up these cars, but I always had this hesitation because I'd often be running 30-40% the weight of most other competitors. Folks would tell me I'm wrong, I should run shocks upside down (where the piston would be out of the oil in some cases!), etc but it never really added up to me, this video helps me feel more confident that I was in the ballpark at least, so thanks for that.

[@BoomslangSuss]

I think you’re on the right track? Thanks for sharing. At the end of this video, I talk about running your shocks upside down. kzbin.info/www/bejne/fJeyqICam9-pe9ksi=Jo5kBEMUh1400mpZ

[@SOBRRC]

Love your channel Jason. I’m pretty new to RC and what drew me to it was this stuff. Can’t tell you how stoked I was to find your channel as I’ve been working on bikes you’ve designed for my whole career as a shop mechanic and fell into suspension work in the last decade. The “Trevor tune” is incredibly useful with NICA athletes that watch too much KZbin 😂 The first thing I did when I got a crawler was suspension tear down and I was relieved to see the simplicity. 20wt has been my go-to from the start, and I’ve found trail trucks to be more confusing because of the lack of adjustments. Definitely a fine line for those. Thanks for sharing your wealth of knowledge!

[@BoomslangSuss]

Thanks so much! On crawlers you pretty much live in the low speed damping realm. On faster, moving cars almost everything is controlled by the piston, head shape and design. I’m gonna do a video on that because it’s pretty interesting. What you can do with one valve and no moving parts. Contrast that to the number of valves that are in Fox bike shock.😳

[@SOBRRC]

@@BoomslangSuss Awesome, excited to see that! Also so glad at the end of the day when working on RC to not having to worry about what shims go where 🤪

[@BoomslangSuss]

Don’t get into buggy racing then - SOOOO many piston head options.

[@HoloEN_GawrGura]

I think the big confusion with setting up a crawler is the waaaay slower speeds. In a highly dynamic setting like a buggy on a high grip race track with fast direction changes or in an onroad setting, you absolutely can use dampers to keep body roll in check, if you don't want to use a sway bar. This can have benefits, as a sway bar is working all the time and you might not want that, whereas a damper is only really working when you need it. At slow speeds like we have in a crawler, you don't have a lot of fast load transfer, especially not side to side.

[@2blackfox1]

great video, very helpful. I’ll be changing oil in my crawlers in the coming days. Thank you!

[@BoomslangSuss]

Thanks for watching!

[@hairybloke]

I've been saying this to people for ages. if you're using a heavy weight oil your shocks, your shocks won't work, I used to rid DH mountain bikes and I always had my rebound set quicker than my bound to keep the wheels in ground contact. I was at sst a few weeks ago and I see people running their shocks to stiff. I say to them your shock arn't working, they say it is and push their rigs down with their hand to show me. Yes it will work but you're inputting a higher force than your rig is capable of producing. If your shock are to stiff then you might as well us an RSJ. One of my rigs weighs in at 7+KG and I'm using 20w .30 spring on the front .45 on the back. My rule of thumb is if I can lift a wheel, the other 3 should remain on the ground until the lifted wheel fully compresses then the opposite corner should start to compress. and the return is quick and doesn't hang in the air.

[@BoomslangSuss]

I’m right there with you.

[@stefan-norge]

Again, great content 👍🏻

[@BoomslangSuss]

Thank you

[@SandroNischwitz]

Great Video...as Always...Top..

[@BoomslangSuss]

Thank you! I’m trying hard.

[@alanbachman6453]

Finding just the right balance is tricky. Also have side hilling to contend with. Slightly heavier oil can keep a shock from dumping over to quickly and causing a roll over. But too heavy can cause a roll as well.

[@BoomslangSuss]

I almost included some commentary on side hilling. Maybe in an upcoming video.

[@themountain59]

Paul Thede is the suspension god! I own probably every publication he released🤩. For rc crawling its most times better you end up slightly underdamped than overdamped because it makes light vehicles "jumpy".

[@BoomslangSuss]

I take it that you mean jumpy is a good thing? I’m surprised how many people run 60 or heavier weight oil. I would agree that under this better than over on a crawler.

[@extec101]

Im int the belive for the time no matter if its crawler or track car always run as soft suspenssion as you get away with that makes the wheel follow the road and not bounce or the car doing crazy stuff from to soft suspenssion.

[@BoomslangSuss]

💯

[@curtkelsey2136]

Totally off topic but seeing your mountain bike photos I have been flying the helicopter to setup the Red Bull rampage for the last few years small world. I enjoy your videos very informative.

[@BoomslangSuss]

Nice! My buddy is a medic. Do you fly the camera heli during the comp too? I might be down there this year. Good RC crawling. WRRCA nationals is the same weekend in Cedar City.

[@curtkelsey2136]

@@BoomslangSuss no I just do the lift work.

[@BoomslangSuss]

I was there two days after. We tried to hike the course but they were still working. Sounded like you coming in the next day for lift out??

[@curtkelsey2136]

@@BoomslangSuss Yes sir we came in and pulled everything back off.

[@HHxRC]

Rebuilding some shocks as I watch this. Did I have any clue what weight oil I was going to use for my VS4-10 Zoku build, nope. Did I just grab 70/50 and say, "just send it?" Sure did.

[@BoomslangSuss]

Nothing wrong with that!

[@HHxRC]

@@BoomslangSuss I finished the rear shocks with 50w while watching, so I'm going to keep moving along but I'll end up going way lighter on the next shock build and just swap them in on the zoku just to compare. I used to run really light when I first started out in the hobby and everyone said go heavier.. so not knowing much about it, I did.

[@BoomslangSuss]

Now you know how heavier performs. Try the other end of the spectrum and try super light and see if you like it better.

[@daddyj7901]

15:20 yup, ive noticed thicker shock oil isnt the best for side hilling, once that weight is thrown to the side it will just hold it in that position

[@BoomslangSuss]

Stuck in the WRONG position. So true.

[@CraigOverend]

Maybe those people running 80wt have enormous or lots of holes in their pistons; did you mention piston holes? I kinda tuned out after you said no one has implemented active roll in RC and was daydreaming about whether the active suspension design I just came up with while watching was viable. :)

[@BoomslangSuss]

Nice. I hope to see this active roll set up. For sure the 80 wt-ers could have big holes. No one knows. 😂

[@BoomslangSuss]

I have not met many Overends before. Are you related to mountain bike legend Ned?

[@snörre23]

That means like i read somewhere that shocks in a crawler are just another pair of links, correct ? Then why do we even buy expensive shocks and "tune" them or care if they leak a bit ?

[@BoomslangSuss]

I’m not familiar with that idea. If you have 4 links on each axle then the shocks are isolated and should act like shocks.

[@pocketfuloducks1062]

Honestly I’m a bit surprised at the theme of this video. But then, that’s probably why I’m here

[@BoomslangSuss]

Surprised how?

[@taterscustomfabs7946]

Jason this may be far out there but, but how much do you feel ambient temperature affects the oil weight used? I'm in Arizona and I feel 25 works well.

[@BoomslangSuss]

Not far out there at all! Perfectly relevant. Silicone oil is specifically selected for its stability under temperature changes. If the ambient air changes by 20 deg you’d probably start to notice a difference on a crawler. I don’t think I’d put the energy into changing the oil though. Maybe have a winter and a summer oil choice. Great topic for a future video.

[@themountain59]

The change in tire compound probably is more significant 😉

[@BoomslangSuss]

And tire inserts are more significant than the tire compound😜

[@ToppersRC]

Im running a TRX4m with the alum Traxxas shocks. I have 10wt oil & the softest (0.072) springs. I cut 3 coils off the front & 2 coils off on the rear then got it to sit smooth like I never cut it. As well as stretched it out to the full travel length of the shock. Shock are angled in to give me the articulation I want. I still feel like I could use softer springs.

[@BoomslangSuss]

Nice!I love it. Cutting coils off the spring actually makes it STIFFER because the torsion spring is now shorter. kzbin.info/www/bejne/hX3VZad9Z7OVjq8

[@ToppersRC]

@@BoomslangSuss I did watch that video a few times before choosing to cut them. This stuff is tricky, I did just watch some of it again & see where I got confused but still kinda am. I dont really understand how more coils on a spring makes it softer than if you cut one coil off. It would be the same diameter wire & shorter in overall length. Thank you for responding, I really appreciate your channel!

[@BoomslangSuss]

Imagine a torsion spring. Is it easier to twist a rod that is 1 foot long or 20 feet long? The longer it is, the easier it is to twist. Same thing on a coil spring - longer is easier to twist, shorter is harder to twist. Less coils means less total wire length.

[@ToppersRC]

@@BoomslangSuss That does make sense if you think about it as a straight bar. Sounds like I need to order some new springs & not cut them. Thank you.

[@BoomslangSuss]

For sure shorter is stiffer. Try other brand springs too - you might find softer ones. I just bought and returned 10+ shocks on Amazon until I found the right ones. 💀

[@kjflyte5088]

I'd like to see the rc10 - 0 I use bds shocks they are better rc shocks than all the ones you mentioned. Lol.

[@BoomslangSuss]

I wish I still had it! I only have a couple dozen blurry photos. I put on red Kyosho shocks. I’m sure the hobby shop convinced me they were better.