I definitely prefer an IRS instead of independently driven sprockets on trailing arms. She leans quite a bit at speed and that is bound to mess with chain alignment. I understand this entire setup was using parts on hand and experimental, but hopefully a learning experience as well. I'm not trying to be overly critical, its an impressive machine, works well, and made for a lot of cool content. I hope you continue to create 4x4 vehicles. So many other established youtubers have stopped innovating and are just mailing their episodes in these days, I continue to be a fan of yours because you never stop making awesome stuff, and hadn't sold out to sponsors. I'm not going to stop watching if something fails, I'd only stop watching if you stop trying.
Impressed that all of the chain drives are working so well. Your sprocket bent because you threw the chain and it got bound up between the sprocket and swingarm. I'd add top and bottom guides, like a dirtbike and send it.
That was a Rock damaged sprocket.The trailing arms do have torsional twist. Fix those and Fenders,and you'll have an 'Ultimate-Minster'. (Mini-monster).Awesome videos,and build Chris.You built a great machine and your ideas proved to be Awesome !
Rear brake bias can actaully be desirable for cornering! Stops the front wheels from locking up first and understearing. Great video! This is probably the best project yet.
Seeing this second vid makes that mini trophy truck even more impressive! Especially when you consider you essentially have front wheel drive (lose the rear chains), rear wheel drive, and "one wheel peel" and no matter what, that thing just takes it and keeps going!
That’s a great build! You did a fine job. Watching the forward facing rear view frame by frame, you can see some flexing in the swing arm. Boxing as much of the arm as you can with a decent gauge of sheet metal may help take a lot of the torsion load. I have over 50 years in the tool and die / machine fabrication business and education. I really enjoy watching you and the others inspire the next generation of machine / fabricators. Keep up the great work! I wish you success!
Flex is not the issue, it is the lean angle causing the inside sprocket to contact the ground in corners - you can even see a spark right before it happens at 22:50.
Looks to me like the trailing arm is torsionally twisting in the corners, which misaligns the chain sprockets (front vertical, rear tipped on an angle), and the chain jumps off.
This is exactly what I see as well. Flex is not the issue, it is the lean angle causing the inside sprocket to contact the ground in corners - at .25 video speed you can even see a spark right before it happens at 22:50.
dawg this looks like its runs and rides better than a Polaris that can from a dealer and has no problems can't wait to see it fully painted and completed respect dawg respect
Just FYI when off roading try to keep your thumbs on the outside of the steering wheel. If the tire gets kicked hard one direction or the other spins the steering wheel hard it can brake or dislocat your thumbs very easily. But other than that awesome build looks like a good time keep the projects & videos coming.
So cool machine! did notice the huge side dip when taking corners so you should really put a set of swaybars on it,make them so they are easy to take of when you are rock crawling.
Beef up the trailing arm and put some chain alignments close to the back sprocket (so if it ever bends, it'll bend correctly with the sprocket and the chain won't pop off) and this will be the most ultimate mini trophy truck offroader build :D
One thing to consider is that the chains being on the same axle wont allow the rear suspension arms to articulate independently unless one wheel slips from the other. You need something to act as a slip differential. In other words your chains are acting like a torsion bar.
I don't think it prevents the independent articulation but it certainly buts extra strain on the chain drive when it tries to prevent it. I'd imagine the torsion bar effect like you said combined with twisting of the swing arms is what caused the chains to pop off. I think the solution is chain guides as close as possible to the top and bottom of the sprockets that are attached to the hub so if there is twisting the guides will stay aligned with the sprocket. Beefing up the swing arms with plating might be helpful as well. But who cares the thing is a beast anyway haha
The way to do a diy repair like this is camp fire for heat then use a hammer or something to bent it back remember the next time this will happen. Still a great project. Bryce
Such an awesome build man! Cant wait for the next video!! TRY ADDING A JACKSHAFT OF THE SAME RATIO AS THE FINAL DRIVE AS CLOSE TO THE PIVOT AS POSSIBLE AND TURN 1 CHAIN INTO 2, THAT SHOULD FIX THE ISSUE. OR GET A COUPLE DRIVE SHAFTS OUT OF A HONDA OR SUZUKI CRUISER MOTORCYCLE AND CONNECT TO CHAIN DRIVE AT THE PIVOT!
This is exactly what I see as well. Flex is not the issue, it is the lean angle causing the inside sprocket to contact the ground in corners - at .25 video speed you can even see a spark right before it happens at 22:50.
Yes, the lean angle is causing the inside sprocket to contact the ground in corners - at .25 video speed you can see a spark right before it happens at 22:50.
Using the truck as a press is a great idea. Think press setup you could have used sockets or wrenches in the right places to straighten the sprocket. You were so close to finding your solution. Great job.
I hope you realize that there are people who go to school for years and years to do what you're doing and still can't do it as well. You're going to go Places. Keep it up, really enjoy your videos.
At least you do have tested redundancy on your setup. Specially for the tyoe of aggresive driving, having certainty that you won't be easily stuck in the middle of of nowhere is great!
Looking at where the weight of the entire vehicle hits when those bump stops hit that is what would twist those trailing arms on a high impact corner plus add to that the power of that engine. What an amazing machine. The next season is the re engineering of the rear end. Maybe add another shift half way down the arm and move the sproket next to the wheel where the twist won't affect it. And the brakes can go where the sprocket is now. Probably not easy but a great winter /spring project content.
Could make the section the swing arm with smaller diameter (and a 1:1 ratio) sprockets. That way, the chain's tighter, it won't bash and you move the power bits closer to the body, which means those chains are shorter, thus less prone to floppage. Caveat, you need the swing pivot to be both swing pivot and axle for the sprockets. Not impossible, been done with a lot of things (including some industrial things like ditch cutting machines) but it's extra bearings to change.
The sprockets are actually on the swingarm pivot on this and the CBR project, in fact I doubt the chains would have a snowball's chance in hell of lasting even a day if they weren't. If you check out part 4 of the build, at 15 seconds in you can see the layout clearly.
Can't wait to see how you fix the flex issue of the trailing arms. I can't help but to think the cheap chains contributed to the issue though with the way they stretched
Steel sprockets might help. I stopped using aluminum sprockets in my dirt bikes because they always wore faster and I did have one bend. Are there any readily available shaft drives/transmissions that can be used in this application? I have a Kawasaki Concours with a 1400cc motor which is shaft drive. With a chip and a pipe they make 150hp. Might be something to try on the next project. I guess that’s the question that I’m sure you’ve thought about. I’ve always found chains pretty much continue to stretch on motorcycles. Maybe less so than when new but the stretching continues. In a dirt atmosphere even worse.
Chris, I’d try building new trailing arms, where they are an enclosed chaincase. As a box shape, it’ll stand up to torsion better, and you could conceivably run oil in the chaincase to lube the chain.
First off, well done, it is a beast and worked really well, all in all. I don't think it's an issues with swing arm flex. The chain came off when the wheel was unloaded (on the inside of the turn) and not when it was loaded. I'm guessing it is a chain tension / guiding issue. Like someone said in the video... dirt bikes all have chain guides. The chain pulls from the top and feeds onto the bottom of the rear sprocket, so it would be a good idea to hold it in alignment at the bottom of the rear sprocket.
Chains did better then I expected they would but I still think shaft > chain drive 💯%.. just a lot stronger, more reliable and no matter what you do they aren’t going to pop off sprockets and such.. idk just my opinion
When I saw your test video on the mud trails I had a concern about mud and other debris getting in the chains....do you worry about accelerated chain ware when mud and dirt gets in there
Hello, I am a motorcycle mechanic, I have 20 years of experience in the area and I can tell you that the suspension was bent due to the jumps and the engine could be failing due to problems in the purifier box. They are very strict, you have to install the original purifier because if Not that type of motor fails, the motor sounds like it is not working well. That's my advice, good luck with your project. 👍
Chain drive for the 4wd system seems good but mabye you could try to make the rear axle a solid axle with a jimny rear end and make a 4link suspension to spice it up some perhaps?
I'm thinking you need to go with a single chain to a center section, and independent driive axles to the wheels. The side force on that rig is starting to get up there. Something holding that carrier bearing from torquing inward is in order at this point if you want reliability. Love the build, lets get the doors on. They finish the smooth lines on the sides. Live it, be well and have fun.
Your machine is obviously amazing, but I still think you need a differential in your chain drive. No idea how it would be done, but I'm sure it could. I'll keep thinking about it.
Can’t believe you guys didn’t try flipping the jack upside down 😂, I know it’s jank but it might of worked. Great build though loved watching your build it
Good job dude. You got to run the heck out of him to find out how far they go. Now you know what needs to be hardened PS. I'm surprised those cheap chains lasted that long
I started watching your channel with this project and I have to say I love your content and found you skilled and looking easy and calm doing complicated stuff. One thing I did not like about this project from the start is chain drive.
What gear you running it 1,2,3? I’ve been thinking you definitely need to gear it lower, so you can actually crawl in first. And a rear sway bar. And lastly if you’re going to use china chain you should make a block protector for the engine case.
You can combat all the body roll with proper front end geometry with a higher roll center. Not much you can do in the rear with that setup besides a stiff sway bar that is going to limit one wheel travel. I would guess the rear control arm flex is in the chain tensiner as much or more than anything. Plating the arms between the tubing, even with fairly thin sheetmetal would decrease any flex a good bit.
Test drove it and they loosened up real bad and they were flapping when you were hitting the gas it was skipping remember because there's too much space not enough tension that's why dirt bikes have a chain tensioner at the sprocket to keep them from skipping and jumping off when they loosen up from racing and jumping and suspension travel that's what that little plastic guide is for to keep the chain on the sprocket from coming off and doing exactly that
The body roll you have is probably slowing you down but I'm sure is a ton of fun! I'd be hesitant to correct that with a sway bar? I think you're on to something about the trailing arms twisting a bit and helping that chain slip off. Maybe resize all of your cogs and sprockets to ultimately get smaller chain rings on the rear axle to help combat that and give them more ground clearance? You'd probably never get to use your High Range 3rd gear outside of an airfield though. Tough packaging with the chain being partially trapped in that trailing arm too. Or just bring a lot of spares? :-D Maybe big bash guards for the rear chain rings?
I suspect that the chain bent the sprocket as it probably stuck to the big sprocket when the chain came off on the other end and then it was forced through the tiny gap between the swing arm and sprocket.... which bent the sprocket. fix ? move the sprockets out 1/2" to 3/4" ....EVEN though you Shouldn't Need it, I think a chain tensioner on each side should solve this.... something to keep the slop out of the chain like a spring roller pressing against the chain.... and I think you are correct in your assumption that the swing arms are twisting in the corners.... time to beef them up alot !!!!!
Very cool bit of kit and amazing that you built it all yourself. Seriously impressive. I can't believe you didn't have a hammer 😂 doesn't a hammer fix most things? That sprocket will need some heat, straightening and some quenching. Could an anti-roll bar be the answer?
Chris, you should never stretch a chain after you recently bought one or more of them. Do you know the reason why. They will never stop stretching. That's the nature of metal. Belts are superior to metal. The problem with them is that they're much wider than chains. This means that you'll need to design the chassis in a different way so that those belts will be able to fit within the tubes of it. How much more distance will you travel with belts? They could last 3 to 5 times the distance than chains. There are people who traveled 20,000 miles with a single belt. How do I know this? I asked Google. Whatever question you ask of it, it will answer those questions more than ninety percent of the time. Of all the questions I asked it, it answered them all. Every time I ask Google a question, I become more intelligent, and the more of a genius I will be.
There is a LOT of body roll, looks like the tire sprocket it twisted relative to the jack shaft in the turns. Personally think the chain is being twisted till it pops off or bends the sprocket and chain like was seen on the right side. A sway bar could likely fix that.
Overall I say you had a giant success, performance was great! Good job! As for the chain, seen that before, inside a machine indoors with no rocks around. it wasn’t a rock, the chain came off the sprocket and wedged between the sprocket and the arm, the power and speed of the engine jerked the chain out so fast and hard you probably didn’t even hardly feel it, but the damage was done. You might be getting some flex that need’s attention but the biggest issue is you don’t have enough idler sprocket for that length of chain at that speed while bouncing around on a trail. The speed and weight of the chain causes the slack side of the chain to sway, add mud, sticks and pebbles…you gonna get slack and side load…add a little flex and it peels the chain off the sprocket. Add idlers closer to the sprocket, buy better chain and the problem should go away.
ive said in your other builds that you need to build sprocket/chain guards or just start building with drive shafts. Which you really need to build with like a honda 4 cylinder k motor or something anyways and get away from these bike motors. im still waiting for the clutch to smoke on woods riding/hill climbs.
You should be using Toyota front axle front and rear so you can have rear steer and the transfer case that way you can use driveshafts instead of change the brakes when you have someThing that heavy chain doesn't stand up!
When you do the body panelling you really should install some mudguards, even something simple would be better than nothing especially if you ever want to actually use your mirrors. Seems from the first couple of minutes they're basically unusable so if you're not going to bother with mudguards then you may as well get rid of the mirrors as well. I'd cover the entire bottom of the truck in sheet metal and I'd say both trailing arms need strengthening up a bit don't change the tyre size they seem perfect and look so good. STRENGTHEN THE ARMS! In fact I'd be tempted to go all out on the sheet metal and basically build it a "body" covering the entire thing other than the windscreen and above the door areas obviously.
In the long run, think of it as an intentional weak point. An aluminum sprocket is easier to change out than to rebuild that bit if the swingarm everytime a rock gets caught if you were to switch to steel sprocket. There is a pro to the situation!
Bro if ur gonna run this independent rear set up it’s doin two conflicting geometry. One front has rigid different upper n lower nd second the rear twist when front forces even geometry. So if there is no way to connect rear two arms with a center linkin creating a solid axel then u need to run moderate sway bar sys in rear and go stiffer spring or add tender stiffer spring in front then slow compression down
