Can I Use Tennis Balls For Suspension In The Wooden Car? Or Bungee Cord? 

Squash balls have been successfully used in home built microlight undercarriages, the extra bonus of squash balls is they come in three levels of hardness so you can tune it to your vehicle, they are also smaller than tennis balls. Keep up the videos, I’m really enjoying them.

One possibility is "Kong" rubber dog toys. They are actually modeled after air springs (the inventor was a car mechanic whose dog liked to play with them) and they come in a wide variety of sizes and also several levels of hardness.

nice, i think i am fan of the tennis ball solution more for its durability. Once appropriate angle and contaiment are sorted than it sounds like they should work better than the cord solution. This Tim is just excellent, had he been born 2 centuries ago he could have done his true calling and make some headway on these new fanagled railway ideas.

I love the tennis ball pivot arm idea. The bungee cords seem to work very well also. Nice to have multiple options!

You can salvage a lot of free extension springs from a worn out/broken kids trampoline. Compression springs are easily found in old cilinder heads. Cool project!👍

if you want to mimick car shocks you could add in a squash ball or two to even out the springiness. Remember to mill a monroe decal into the plywood for added performance

*@Way Out West - Workshop Stuff* 7:40 Bungee cord is probably a bad idea, because they contain rubber. I have learned from *JoergSprave* (The Slingshot Channel) (and he REALLY knows rubber), that rubber looses it's elasticity when stored in a stretched out way. Rubber works best when it gets stretched out for as short amount of time as possible, then is stored in a "relaxed" state.

How about wooden leaf springs. May need to steam some pieces of wood to get a bend in the leafs. May work better than bungee cords. As others have said, rubber likes to be relaxed most of the time.

Tim, if Wimbledon doesn't go ahead we'll know why. 😂 I think the bungy idea looks better than the tennis balls, if you go into production they'll be easier to change if you need to. I think keeping things simple is the best way to go, as would be easier to repair if you had too. 👍🤗

I believe the tennis ball idea is preferable. Three balls inside a sealed pvc tube with piston arms through the pvc caps. Worth a trial anyway.

This is just brilliant 👍. You're approach to "Research and development" in a complex field with practicable on hand materials is something that should be encouraged to all budding engineers. A true, easy to follow inspirational creator. Well done 👍. Cheers Pete' New Zealand.

OMG ! this is genius, where were you when i was a kid, you would have revolutionized kids into engineering, as i child we used to build go-karts just for fun, no internet, nobile ment you had to use your imagination and the scrap yard never minded a few of the kids going over and picking a few old wheels and pipes, now it's called the soapbox challenge lmao. fantastic job.

This took me back to the war years when many kids built trollies with salvage from damaged properties. What you are doing Tim is ingenious and also great fun. Well, for me anyway. And you seemed to be enjoying yourself. Will you make a warning device or just shout 'Olly! Olly! Olly! as we did? Great stuff.😀

@2:03 - There are people who own electronic drum kits in apartments make platform risers out of tennis balls to prevent their downstairs neighbors from complaining about the bass pedal. Pretty crafty.

I think the bungee system is more or less how the wheels on world war 1 aircraft were sprung. It worked for them. It is so nice to find an engineering project with technical jargon that I can follow!

this lil thing is gonna be delightful when its complete and rolling around. Watching the mock up frame go just with gravity makes the image much clearer in my head. Excited, even though I'll never ride it myself.

Great job but another idea is coiled rope like a roman balista or mangonel catapult could be a better alternative that's also cheap. Love the ingenuity. Cheers J

I was questioning everything, now I'm convinced. This awesome

Reminds me of Sir Herbert Austin and his draughtsman drawing up the Austin7 on his billiard table. We all know where that project went! Keep up the good work. Best wishes.

We used to make these when we were kids. Old planks of wood and pram wheels. The were called ‘Weans Bogies’ in Scotland. I loved flying down hills at breakneck speeds. 😊

I would go with springs if they are free combined with rubber balls. The springs holding the majority of the weight. Ive had no luck with bungees lasting any length of time. I imagine you'll have them in the rear to protect your backside 😂 and was testing concept for now. Great job by the way

Bungee cords rot and/or stretch way too easily. Especially if they are left outdoors. I suppose they would work as long as you had them oriented in such a way as they could be replaced very easily. Honestly I like the tennis balls better. Well, the fancy ones that don't go bad as quickly as regular ones, anyway. You could probably soften the tennis balls further by not containing them sideways with a baked beans can. Allow them to stretch more. Roll a piece of sheet steel into a tube with 2 or 3 layers. Add hose clamps to keep it cylindrical, and place the clamps at the centers of the balls inside the tube. Then, adjust the hose clamps to let the balls squish more or less. And make a pivot for the tube on the bottom, and a pivot for the ball squisher (lol) so you don't need to worry about angles.

Gotta love this channel, reading the comments is almost as fun as watching the video, so many people have cool ideas.

These are the people that make the world go round.

Got 11 minutes in as I was looking for the suspension from a crop duster for you and you got there yourself. The AgCats and like had bungee cord shocks.

Well one thing is for sure it is giving plenty of enjoyment along the way bro. Safe travels. Ken

Wonderful R&D. Note how in your test rig, you had a rigid rear suspension and things went fairly well: backs up my earlier point about keeping your rear suspension arms on the stiff side. An air ride suspension is a neat idea: you probably could bodge one of with innertubes and some lathe turned parts, but I don't suppose you've got a lathe handy (the tools you do have access to are amazing, things I don't have and don't think about, but I've got a lathe) and while it would be more refined and tunable with air pressure, your design with bungee cords is just a little more low teach and obvious to the user should anything start to fail (making repair and service easier). Keep going I say and thank you for making and sharing these videos.

Pretty cool! You'll get it working the way you need. You always do!

The most wonderful voice I’ve heard!

That oversized dog @ 8:19 is quite lovely, you should make sure it's paid in apples for it's role in this video ;)

Really like your video’s and especially your humor. Please carry on! 👍😁

If only I had 1% of your ingenuity

We sometimes used tennis balls to support vibration isolation tables. Wheel barrow sized inner tubes worked too. Neither was perfect but for the price to performance ratio it was pretty good. Air tables are quite expensive.

I must say that is a very unique way of solving that problem. Perhaps the blocks putting tension on the balls could have an adjustable rail so you can tweak how low the wheels should be, but also you could add on slots for an adjustable amount of bungee cords as a combination along with the balls to adjust the dampening. Your videos are great, inspiring, and I hope you continue to do this, but no matter what this community will support you if you need to take a break from video making.

The answer is yes, here in outback Australia as a young lad. Depending on if it was wet or dry or if the roads had been graded, we used to shove tennis balls inside the springs to improve the drive. Made the bumps better for spotlighting.

For recording the springs around 11:00, mounting the camera directly to the bar show would give a clearer view, especially if recording at say 60fps & then slowing the footage while editing.

Your car is really interesting and I am amazed at all the clever ideas you have. Great job, Tim!

I'm in awe! That looks so steady! And so, so fun! Fantastic job!

Interesting stuff. Bungee cord worked on early airplane landing gear for years.

I frequently watch videos by "the bus grease monkey" (Scott Crosby). He frequently replaces air bags used for suspension, but they seem to require compressed air to work and are only used on vehicles so equipped.

It seems that the bungee cords are working better!

Looks good. Plus your having fun. Cant beat that. You might even end up in casualty but lets hope not.

It would be interesting to see a comparison camera view for 1/ mounted firmly on the body with suspension and 2/ mounted firmly on part of the car without suspension. This could give a comparison of the with/out suspension and show how the ride is improved with suspension.

Excellent work Tim!! Best to keep it simple :) much less to go wrong and easier to fix!! :)

I have considered using solidly mounted plywood arms that are also the springs. Old fiberglass skis might work too.

Belville spring washers?. (maybe try the "plastic hats" , that are frequently used for sports training) They are Usually metal disks with hole in middle, that have been bent to form a cone shape. Under a compression load, the cone tends to flatten. Add more washers in same orientation to stiffen spring. Flip orientation of some washers to weaken spring and increase travel. Or otherwise adjust spring characteristics.

Looking good Tim.

The Colditz Cock, (the glider built by Allied POWs being held in the castle) used tennis balls in compression for the landing skid.

While there are many potentially useful ideas offered by readers, all seem to be low hysteresis, meaning you may need some form of shock absorber. My garage door used to slam shut when it finished closing because it uses a low-overhead closer that pushes the uppermost segment straight into the header at the end of the closing stroke. I found a pair of snowmobile friction shocks and installed them to cushion the closing. And they are wrench-adjustable.

It would be interesting to see a side by side stress test of the two different ideas. I feel like the tennis balls would be a better option for longevity. Especially if you could contain it as you described.

Wonder what the insurance will be on this one 😂 . Love the tenisball suspension! Always looking forward to your videos. Cudos from Norway.

Brilliant! Keep it up Tim.

Two men of any age and a kart makes for a fun day ;)

Great stuff Tim! As an alternative to bungee cords I use old bike tyre inner tubes for various jobs. My son used to compete in a cycling team that was sponsored, so punctured tubes were always being replaced rather than repaired. You might get free scrap tubes from a bike repair shop. Inner tubes should be stronger than bungee cords, and you can easily inspect for wear. Whatever expansion spring system you choose, it occurs to me that you could have some adjustment system built in (turnbuckles?). If this was via rope and pulleys, then each front axle could share the same tension spring, keeping them equally balanced. All the best, Chris.

In the 1960s there was a sprint motorcycle that used bungy cords for front suspension. I think (memory!) it was called “Ag’s Barra”. The bungies were used in tension via rocking links at the base of the front forks. I would have thought that a small fat inner tube (scooter?) squashed between two plywood boards would be viable too. Have you looked at Citroen 2CV suspension? And surely those bicycle suspension units could be modified (softer plus longer travel) by using the principles of leverage.. Les in UK

The chickens in the coup were clearly very interested in the suspension, so it must be good. You can rely on chickens to give a reliable critique in progress.

You can run the bungee cords from the bottom of the arms near the wheels, across and under the center rod, and attached to a frame on top.

ICE trike uses short cylinders of elastomer for their suspension. It comes in soft, medium or hard. They work very well on my recumbent ICE trike. You might look into using elastomer as it’s a very simple solution.

Don’t for get Alex Moulton and his rubber suspensions for the Mini and many Bicycles. All great stuff to think about. Thanks for exploring,

I would have recommended going to the scrap yard and salvage some scooters for their suspensions. Costs next to nothing and better than most self built stuff, but this is very good work you did.

If I remember right in a old combine they use leaf spring made of hickory wood in some part of the mechanical function

I'm really liking those tennis ball air springs myself. A little more refinement, and I think those would be cool!

I bought a score of pound shop tennis balls. Most of the bounce was gone, so I suspect that the reason they were cheap was that they were long past their sell by date. As you say, they worked fine as dog toys!

Reminds me of the rubber cone suspension of the classic Minis, my own is hydrolastic but they switched to rubber springs after a while due to production cost.

on a more serious note, this is most excellent! A proof of concept that rolls comfortably down the laneway! I'd just like to suggest that you put at least one wrap of "bungee cord" ('s what they're called here) above the axle, to prevent massive uncontrolled droop. Cheers!

If those tennis balls are filled with an aerated rubber foam and not pressurised, then you can probably drill and run a rod straight through them with stops at either end like a shock absorber.

You could use old bicycle tires. Here in Russia a guy named Данник build a solar powered carriage from junk with both front and rear suspension build using old tires used as bangee cords

Race cars use push-rod or pull-rod suspensions. Basically a pivoting lever to transfer the motion laterally into the middle of the chassis. Maybe that could help?

One thing to think about might be failure modes. I'd be concerned with the bungee cord snapping under tension and turning into a very dangerous whip right as you lose control

Try rubber surgical tube. The type used in sling shots. Very stretchy and very strong.

Nice work so far, keep going…

Very clever idea; having the ball holders & squashers moving would eliminate quite a few problems.

IMO (yes I do have a humble opinion), may I suggest the less complicated a system is, the more likely it is to function well for a longer period of time. The bungee cords do work but looks to me like a lot of extra stuff do achieve the task of suspension. I'd be if you sat down and give it a bit more head scratching, you might find an easier solution... still, you have an interesting solution at the moment 🙂

what a great idea! (to use tennis balls).

Get four old bicycle pumps and connect the outlets in an X (when seen from above) with a pressure rated pipe/tube for suspension. :)

Love the concept. A wooden car. Get out of my head!! OK, not an engineer, but let me try to make a contribution here. Seems over complicated. Guess what has excellent spring characteristics? Wood. Leaf springs. They were all the rage once upon a time. Plus, in engineering terms, if you can have one part play two roles: Winning! Horizontal leaf spring could replace the upper 'wishbones', and provide spring. Experiment with different spring count easily. U clamps. It's all cheap. Best of luck.

Cut a disk / use washers the same diameter as the top of the can tin. Attach disc to pieces of wood, the wood then irun vertically. You could use a round pieces if wood and not have the disks, attach the same way, put a bolt though middle of wood and bolt at the end. Bolt feds through to spring plate, runs through piece of wood and is bolted fully other end

Вы мастер на все руки!

When you get to the shock absorbers, look into how Austin 7 friction shock absorbers worked, very simple and they work too as a bonus.

I've found the elastic properties of the rubber in bungee cords doesn't last very long if it's constantly under tension. The tennis balls are probably a better idea.

In my opinion you definitely be fine leaving a solid rear axle like on the four-wheeler, it would flex with the frame and it's highly unlikely that you would reach rough enough terrain to get the wheels off the ground. Also neat idea with the tennis balls😊

On the one hand the bungee cords might stretch over time, on the other hand they're cheap. You might want to try trampoline springs like another feller in the comments suggested. (unless there aren't a lot of trampolines where you live) They're not terrible to get second hand and might be just the thing. Either you could set it up so they're being stretched, or set them up like your bungee cord system where they're being pushed sideways.

I have learned a lot about tennis balls thanks

The closer to the wheel you position a compression device, the more vertical the movement will be. As is the nature of an arc, if you were to lengthen the pivoting control arms and somehow hinge them from the opposite side of the cart, the end of the bar would move "inward" even less through its range of motion, making it even easier to contain something like tennis balls in a tin. Also, have you considered a "live axle" setup? You could have a rigid front axle cross member, with control arms reaching toward the rear of the cart in a |= shape. I'm not sure how you'd apply steering, but a single pivot point could be achieved through converging the rear arms like |> . I think that presents new difficulties such as extreme levels of negative castor, however.

You appear to have recreated a “swing axle” suspension. Might not matter with your intended use, but you might want to look up the “wheel tuck” issue which is why they’re not used on cars anymore, at least in the US. You might find a “torsion bar” and trailing arms easier to work with- you can make them out of a number of different materials including wood.

What a novel idea of using tennis balls for springs and the bungee cords also. You will soon have it all figured out.

Hello from Detroit Michigan USA 👋

What a load of balls! Tennis balls to be exact. 🤣🤣🤣 Great video BTW! 😎

Cool I can't wait to see the final product I have an idea 💡 for the final product suspension use go kart suspension of course it would be expensive at frist but you could sale the production versions at different build stages from chassis and body to complete car.

If you haven't already, you should try radius arms and tennis balls as the rear suspension. :)

Tennis balls are a bit similar to the rubber cones used on the classic Mini. Not sure on your bungy idea as from experience they don't survive well when left outside. Fascinating project.

Have I seen you using those coiled tines off a hay rake on something recently ? I bet you could incorporate one each side to do your springing ? You could mount the coil on that central bar, with the tines going out to the wishbone and could use them "trailing arm style" for the rear axle too ?

I'm sure that bungee suspension featured on WWI aircraft. By the way, when British POWs at Colditz built a glider in order to escape, they incorporated tennis ball suspension into the design of the simple skid which served as undercarriage. When a replica of the glider was tested, half a century later, the tennis ball suspension worked perfectly.

If you made the yokes on the central pipe bigger you could have the upper and lower suspension arms parallel instead of diverging. This might make the geometry for the steering hubs a bit better. 🔧👍

Look into the "Spanish windlass" mechanism. It's a torsion spring made out of elastic or semi-elastic ropes. Basically how catapults made with classical construction methods are built. Fully adjustable with the amount overlapping ropes and number of twists you put in vs. the lever being acted upon. But if you use it you'd want to make sure you build a sturdy stop for it at the extent of its range, and you need a way to release the tension for servicing as well. (A rope with high elasticity such as a nylon one with a lot of turns could easily store as much energy as an automotive coil spring, so some due caution may be needed.) If implemented cleverly, it would be much better than either of the options presented in the video title. It should offer a much larger range of travel than either while providing spring pressure.

Yesss new video❤❤

Very Nice!

That thing is a _lot_ more aerodynamic than me car (a Swedish brick)!

with the bike suspension you can find different rated springs for your needs ive seen them as low as 150 lbs 68kg and as high as 600 lbs 272kg

Ha,ha. Reminds me of Henry Ford in his first motorized cart with a tiller. The rear axle could be suspended with a spring fashioned like Henry's spring.