balancing a small tire/rim

[Alagnak]

Odd question and thanks for ANY leads provided. I have a small wheel that needs to be balanced. It's on a rim and rubber inflatable tire. Do tire shops/ motorcycle shops have any adapters for doing smaller than normal wheels? Has anyone heard of such a thing? Or does anyone know of any other calibration place that could maybe do it?

Thanks!

[Macgyver55]

How small, like a trailer tire size?

[Jeremy airjer W]

Typically "small" wheels are not balanced. So I'm curious also as to what it is and why it needs to be balanced?

[Scott K]

Also most trailer tires will get flat spots after sitting for a period of time, and usually after 20 miles of driving the flat spots tend to level out, so to speak, and all is good. Modern tire in Eden Prairie used to balance abnormal sized tires, not sure if they still do or not.

[Alagnak]

Well, since everyone is so nosey ;-)J/K- I appreciate you even reading it!

It's for a HS robotics team I help coach/supervise. It's a tire about 9" tall. They have it mounted on an electric motor and it shoots frizbees around a track at a target of different heights. Of course that small of tires are not made for high speed and we're having a hard time finding one that is, or that is already balanced. Any other 'outside' the box ideas are welcome, but I'm afraid it's too late for them to turn away from this design based on the robot needing to be shipped for competition in about 10 days.

[Alagnak]

Also most trailer tires will get flat spots after sitting for a period of time, and usually after 20 miles of driving the flat spots tend to level out, so to speak, and all is good. Modern tire in Eden Prairie used to balance abnormal sized tires, not sure if they still do or not.

Thanks Scott! I'll call them in the morning, they are even close by.

[delcecchi]

I had a dealie I bought for balancing lawn mower blades. It was basically a cone shaped piece of plastic.

Second thing would be to statically balance by spinning and to see if one side consistently goes to bottom.

[CAMAN]

Check out a machine shop that does Dynamic Balancing.

[JOHNBIGDOG]

Two blocks and a rod through the wheel. Spin the wheel the wheel should stop with the heavy spot on the bottom. Go to your favorite tire place and ask for some sticky wheights. Place the weight on the opposite side of the heavy spot till it spins for a long time. One could get a motorcycle wheel ballancer from freight harbor....

[MJ1657]

Bubble balancer would be perfect for what you need.

I don't know where to tell you to find someone that has one though.

[Alagnak]

Thanks again guys. I have a lawn mower blade balancer- that didn't get me very far. I'll have to try to just hand spin balance tomorrow. Instead of changing using sticky weights that i already have (I'm afraid of one flying off) I think i'll just shave off rubber traction nubs with a razor blade to try to balance better. You wouldn't think it would cause THAT much vibration but it does- and she gets spinning pretty darn fast too.

I'll try to find a machine shop with the dynamic deal. What exactly is the bubble balancer?

[delcecchi]

A bubble balancer is basically a fancy version of the blade balancer with one of those bubble levels that folks use on their campers.

[Tom7227]

The problem with cutting off little nubs of rubber is that you can't put them back on if you booger it up. Are you sure it's the wheel and not the shaft that it is mounted to? Could it be some part of the device that locks the wheel onto the shaft? My guess is that you are running it at a very high RPM and so even the smallest thing could make it goofy.

Isn't there some sort of robotic forum(s) someplace where you might be able to get better advice. These guys are into 20 inch diameter wheels, not some robotics stuff,

[CAMAN]

Isn't there some sort of robotic forum(s) someplace where you might be able to get better advice. These guys are into 20 inch diameter wheels, not some robotics stuff,

LOL! Everybody who has a robotics and/or machining background raise you hand...

*raises BOTH hands*

Which is the reason I suggested finding a machine shop that does dynamic balancing. A process that can get a part so perfectly balanced they can spin it up to hundreds of thousands of RPMs without even a hint of vibration. Would I run a tire that fast? NEVER! The rubber tire deforms at high speeds and will throw it out of balance faster than you could hit e-stop causing a highly dangerous situation and ruining your machine. But from what I assume he doesn't need speeds that fast, probably closer to 10k or less, which dynamic balancing will still work perfect for.

[Dave S]

I know we machine parts that need dynamic balancing but I have no idea where we send them to.

[Alagnak]

Isn't there some sort of robotic forum(s) someplace where you might be able to get better advice. These guys are into 20 inch diameter wheels, not some robotics stuff,

Aren't "these guys" anyone on here who may have some advice/knowledge/experience with something related to automotive? Last time I checked autos have wheels, and they need to be balanced. I'll tell you what- I'll do all my posting in the robot forum. Deal? ;-)

And we better open a new forum up for wheel diameters 14-19 and then another for 21 and over since this is a 20'' only forum. Give me a break man. You can't make this stuff up.

lol

[harvey lee]

Two blocks and a rod through the wheel. Spin the wheel the wheel should stop with the heavy spot on the bottom. Go to your favorite tire place and ask for some sticky wheights. Place the weight on the opposite side of the heavy spot till it spins for a long time. One could get a motorcycle wheel ballancer from freight harbor....

My son raced go karts for years and we balanced all our tires with a mrethod similar to above with a balancer that was purchased.

It worked very well with the tires running up to 100mph.

[delcecchi]

OK, so just how fast is this wheel spinning and how big is it?

If it is like a 6 inch diameter thing at 5000 rpm, automotive equipment isn't going to be much help.

[LightningBG]

Yeah, an RPM would help out some.

Not to get overly involved....but... If the wheel is spinning at a ridiculous rate, lets say 5000 rpm, will the rubber be able to grip the Frisbee good enough to shoot it out, vs just rubbing it (basically grinding it down/ burning rubber)?

I'm just thinking about it in comparison to a pitching machine (baseball) which normally run at about 1500-2300 rpm.

If my calcs are correct... a 9 inch diameter wheel, spinning at 5000 rpm (just for a point of reference) is about 133.87 mph.