wheel weight observation

[Elastokinematic]

This is a pic of 8 grams of lead bird shot and 8 grams of tungsten BBs. The reason for this picture is I had a thought...an observation...a theory about the friction caused by all those small pellets of lead rubbing together inside the tires. When I weighted my tires a while ago with lead I noticed a dramatic increase on how well the crawler performed, but I also noticed that my battery life was decreased. Im sure the fact that the motor was pushing more weight uphill is a factor, but I suspected more was at play.

I started researching on RCC for what other peeps here are using for wheel weight and all that. Lead shot and BBs (steel/zinc) seems the most popular for dynamic weight. Lead weights and solder inside wheel are the most popular static weight options. Now I have had a run in with a lead weight when I first got my micro. I had a weight fall off and I thought the dog ate it and I really didnt wanna have to call my girlfriend and tell her that the dog she just spent 5000 in vet bills on is going to die a slow painful death within the week. So I started thinking of other nontoxic options.

Tungsten came to mind and I started looking for suppliers of BBs and stuff. Tungsten is 40% more dense than lead and about 3 times more dense than steel. Less material is less friction due to less surface area rubbing together.

Spin test... I had 2 wheels and tires mounted. 1 with 8 grams of lead shot and 1 with 8 grams of tungsten BBs. My thoughts on that was that the tungsten would spin alot better due to friction and I was right. I didnt get 2 turns with the lead and I got maybe 6 with tungsten. and when I spun it really fast the lead would just centrofuge to the wheel and tungsten keppt rolling around in there.

Cost/benefit factor... I dont know. none really... 1oz of tungsten BBs was 5 bucks plus shipping. lead is friggin dirt cheap. The real benfits are increased battery life and the fact I dont have rogue toxins in apartment that stupid doggies can eat if lost. People with small children could also relate to that. Not that Im calling your children stupid...but that they tend to eat anything on the floor. ...you get me.

 

[BerticusPryme]

this is actually interesting. I know I use a combination of steel bb's, lead solder wrap, and BWD wheel weights. I have debated about using lead shot but as you said kids eat anything off the floor. So this is a nice option. I am curious on standard steel bb weight compared to the lead and the tungsten. You have any laying around you could do some comparison with?

 

[Elastokinematic]

I have looked into the weight of a single steel/zinc BB. They weigh 5 grains. 15 grains = 1 gram. so thats 3 BBs to a gram. The .190mm or 3/16inch tungsten BBs I got are .9 to 1 gram each. You can pull up a density chart here..

http://www.engineeringtoolbox.com/metal-alloys-densities-d_50.html

As you can see, tungsten is the best heavy metal option without spending CRAP LOADS of cash on gold or platinum or getting onto an NSA terrorist suspect list with the uranium.

i purchased tungsten from Maximum Velocity. A pinewood derby car site.

http://www.maximum-velocity.com/pinewood_derby_weight.htm

and they were refered to me by the manufacturer of the tungsten spheres found at this site.

http://www.tungsten-spheres.com/inventory.html

anything larger than 5mm will be too big for a micro tire. keep in mind that a regular BB is .177 inch. 5mm is almost .2inch or in the area of 3/16.

 

[spoo76]

Good Info! I was just wondering about lead shot VS BBs.
I felt BBs were a bit light and was thinking about trying lead shot. maybe I will give this a try

 

[BerticusPryme]

no doubt this has been extremely helpful. now I know how much weight that i have in the tires with just bb's and can reduce it down quite a bit.

 

[bouncingbabyboy]

Like the lead stick on weights, but tungsten. Not sure how easily you can cut them to fit in the wheel groove, but some guys are milling custom parts, so I bet you can figure it out.

http://www.golfclubs.com/tungsten-c...gn=products&utm_source=google&utm_medium=base

 

[Elastokinematic]

from what I understand tungsten is hard as hell to cut. tungsten carbide is the stuff they use to cut the stuff thats hard as hell to cut. Im thinking that most of us wont have to stuff at home to get around that issue. Im sure a rotory grinder and alot of time will do the trick but small parts and cutting with rotory grinder sounds like a trip to the ER. prolly be easier to use the tungsten putty and mould that stuff in there and maybe run a bead of hot glue over the top of it. the putty is neat stuff. it doesnt harden but it looks to me like the ball of it that I have sitting on my table at home is beginning to deform itself downwards. I was thinking of moulding it to the bottom of my steering knuckles but the stuff doesnt stick to the axles and I have to find a way to mount it up. hmm..im getting ideas...

mouldable weight...tungsten putty.

http://www.maximum-velocity.com/tungstenputty.htm

 

[bouncingbabyboy]

I know tungston tools and jewelry is tough but there are a lot of products for pinewood derby that say you can cut them with an exacto knife. Probably not as heavy as pure tungsten. I like the idea of sealing the putty with hot glue. I used four layers of masking tape to make sure the weights stay in the center of my wheels. I am sure a dremel tool with a cutting disc would get the job done with minimal waste. Don't go cutting off fingers and saying I told you to try it. If you go slow and take appropriate safety measures it could be done.

 

[BerticusPryme]

it's a little ghetto but what about using the tungsten putty and do a wrap around the wheel on th einside of the rim? use a small amount and then wrap with solder and that could be massive weight addition.

 

[Elastokinematic]

i was trying that last night. I imagine you could do that. I broke out the digital scale last night and weighing out some stuff. I took 14 grams of putty and it moulded perfectly into the groove in the stock wheel. The wheel, tire, putty, large and small BWD weight disc was 35.6grams. I had an interesting idea to just use the tire foam to hold putty in place. Cut it down to a bit less than half and put some shot in the tires for some static weight. For some reason Im shooting for 50g in front and 35-40g in rear. These measurements are with stock wheels and roklox tires. Ill do some measurements tonight with Miclaw and Vertex wheels tonight.

 

[Midlife Crisis]

I just added 50 steel bbs (16ish grams?) to each front tire and 30 (10 grams?) to each rear tire. Too effin heavy IMO, but traction and CG is soo much better now. I may take out 10-15 per wheel, but not ready to break down the beadlocks again....... Makes me glad I have 2 LiPos to run. "thumbsup"

 

[bouncingbabyboy]

The trick with the putty is getting it to stay put. Sealing it in the rim means blocking the vent hole. Once you glue tires on it will be hard to tell unless it is clumping in the tire. Then it will be a pain to fix. There are some round slugs for pinewood derby that you could tape or glue in place that would not block the vent hole. They would leave more air space, but would be pure tungsten so would be a little heavier than putty. there is also this stuff you can cut with an exacto which would stay put better than putty. There is also tungsten wire which you could use the way many people have been using lead solder, which many of are flux core so you are loosing weight and adding acid which may cause your wheels and tires to break down faster from the inside.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAEPV&P=FR
http://derbydoc.com/products/tungsten-cube-weights-2-oz
http://derbydoc.com/products/tungsten-cylinder-weights-2-oz
http://www.eaglealloys.com/c-16-tungstentungsten-alloys.aspx

 

[Elastokinematic]

I just added 50 steel bbs (16ish grams?) to each front tire and 30 (10 grams?) to each rear tire. Too effin heavy IMO, but traction and CG is soo much better now. I may take out 10-15 per wheel, but not ready to break down the beadlocks again....... Makes me glad I have 2 LiPos to run. "thumbsup"

I used some cornstarch to lube tires when installing onto the wheel. It made the miclaws drop into the vertex groove a hell of alot easier and it made it so that the lock ring could pivot a bit to line up the screw holes. I just used 2 toothpicks to use as a prybar.

Also... I did take the vent hole into consideration. I thought about stabbing a toothpick into the vent hole and moulding around it. Then removing the toothpick.

I like the look of those cylinder weights and the cubes. Ill have to measure the gap in the stock wheels. The cubes look promising. I might pick some of those up and hot glue them inside vertex.

 

[Elastokinematic]

im thinking im a bit heavy. I have crawler together and was motoring up and down my tester obsticals and i think im experiencing new issues. Im too heavy. I weighed crawler with both wheels on scale 173.6 grams. 6.1oz. Thats for front only. 122.3g with battery. I crammed 14g of the putty in the spokes of the wheels. looks like there is enough room for 4-5 more grams.

tires are getting caught between rocks and getting all twisted up. Im thinking about inflating tires. Any comments?

 

[Midlife Crisis]

Id suspect you are too heavy if the thing binds up at ledges and stuff. Too much traction and soft tires and these things will just wedge up anywhere. Take a little more weight out/off the wheels and tires and you might be able to break traction again. I ended up with 25 bbs per front and none in the rear now. Oh, and foams help tremendously to keep the tires from fully wrapping around an obstacle and causing the issue you are experiencing.

 

[Elastokinematic]

this little thing sure is hooking me up with the tinkering addiction at home. the fun continues... ty.

 

[Remo]

not to start a fire here, but like Lead,tungsten is a "heavy metal" , and IS in fact Toxic. I guess we all pick our poisons in life, I think I'll be using steel BB's. good luck with whatever you decide to use.

 

[Elastokinematic]

Health effects of tungsten

Tungsten has been shown to act by antagonizing the action of the essential trace element, Molybdenum. Long industrial experience has indicated no pneumoconiosis to develop among workers exposed solely to W or its insoluble compounds (at air concentrations of the order of 5 mg/m3).
Acute health effects: Irritating to the skin and eyes on contact. Inhalation will cause irritation to the lungs and mucus membrane. Irritation to the eyes will cause watering and redness. Reddening, scaling, and itching are characteristics of skin inflammation. Follow safe industrial hygiene practices and always wear protective equipment when handling this compound.
Chronic health effects: This product has no known chronic effects. Repeated or prolong exposure to this compound is not known to aggravate medical conditions.
All tungsten compounds should be regarded as highly toxic. The metal dust presents a fire and explosion hazard.

Read more: Tungsten (W) - Chemical properties, Health and Environmental effects


its toxic...true. is it more toxic than lead? prolly not. but Im not going to research all the scientific data. Im just throwing out other options for folks with small dogs and kids who would rather not have them chewing on a chunk of lead. Lead is a crap load cheaper than tungsten any day and I certainly dont wanna promote consuming either one, but I am 100% positive that tungsten wont start the zombie plague before lead. ...and if you dont like it... I curse you with a crappy slipper clutch and a burnt ESC!!
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[Evilinside]

Who is taking apart their wheels and eating the wheel weights to were toxins are becoming an issue!?

:lmao:


Though Tungsten male wedding bands have been the highest selling bands for the past few years... and beer kills just about every digestive organ in your body along with killing brain cells... and fluoride in toothpaste is highly toxic... and we soak bleach into our clothes... and we sit right next to gallons of highly explosive and toxic liquids anytime we travel...

OMG, I just realized something... I really want a beer! Just let me put my wedding band back on, brush my teeth first, take the clothes out of the laundry, and I better go fill up my car before I start drinking too.

"thumbsup"

 

[Evilinside]

Oh, and I forgot, I better get to taking the tungsten weights out of my wheels that are encased with rubber tires, that run on lithium polymer batteries, made almost entirely of plastic... lord knows I don't want anything to do with toxins!