How to check "roundness" of wheels?

[Fred K-OR]

I think I have posted on this problem before but still have not solved my problem. Sorry about a repost.

But my problem is that with my 29 coupe when it goes down the road at low speed ( 15 to 25 MPH) it seems to "bounce" up and down. It doesn't "waddle" back and forth like a duck but rather seems to go up and down.

I have about 8 or 9 21" wheels around here and am trying to find which ones are "round". That is one that would not cause a rig to "bounce" up and down. I tried various methods, putting them on a hub and rotating then and trying to measure how much they go up and down when having them close to the floor, and other measurement methods. But so far have not found a good way to measure the roundness of a wheel either with or without a tire on it. Does anyone have any good ideas on how to check a wheel either with or without a tire on it or is there some kind of tool to check this?

I could have the possibility that one of my tires has a high spot on it. But they are almost brand new Firestone tires and find this hard to believe, but-----. Or is there another reason for this problem?

Thanks for any ideas you all may have.

[Mitch//pa]

maybe you have a tight shock
you should be able to spin the wheels // tires on the car. lift the back on stands and put it in gear
a tire making the car bounce should be easily detectable

[BRENT in 10-uh-C]

Install u mounted wheels on a front hub. With the axle on a jack, lower the wheel until it is within a quarter inch of the floor. Rotate the wheel and watch the gap to see if it varies.

[Ron W]

A friend had a bouncing car with new tires. His problem was that the tire was not seated properly on the rim. After seating the tire properly, no more bounce! Ron W

[Fred K-OR]

Originally Posted by Ron W

A friend had a bouncing car with new tires. His problem was that the tire was not seated properly on the rim. After seating the tire properly, no more bounce! Ron W

Ron you may have a good point. I will have to check. That is I will check when the weather warms a bit around here.

Question about how to seat it properly. Before filling with air, do you "bonce" it on the floor a few times? Or how do you make sure it is seated correctly?

[Fred K-OR]

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Originally Posted by BRENT in 10-uh-C

Install u mounted wheels on a front hub. With the axle on a jack, lower the wheel until it is within a quarter inch of the floor. Rotate the wheel and watch the gap to see if it varies.

Ron thanks for the idea. I have tried this with the tire on the wheel and mounted to the hub. And on three of the four wheels it seems like there was little or no gap. But on the fourth wheel, it did have a gap of 3/16 to 1/4 of an inch. And I tried to get a "reading" on the wheel rim and not the bottom of the tire to try to see if it was the wheel or the tire but did not have the tools or a method to measure just the wheel. So maybe I need to take the tire off, do the same with just the wheel on the hub and check for gap. Anyway maybe I have answered my own question as to how to check just the wheel. And maybe by taking the tire off the wheel of the rim and putting it back on again and make sure it is seated like Ron mentioned above may solve the situation.

Thanks guys for the ideas and maybe I have answered my own question. But I am going to wait till the temps around here get up a bit.

[harleytoprock]

You wouldn't have to take the tire off of the rim to re-seat. Just break the bead on both sides, brush in some tire lube between tire bead and rim, over inflate by 10 or so pounds, and then return to normal pressure.

[Fred K-OR]

Originally Posted by harleytoprock

You wouldn't have to take the tire off of the rim to re-seat. Just break the bead on both sides, brush in some tire lube between tire bead and rim, over inflate by 10 or so pounds, and then return to normal pressure.

Now that is something I could do in this cold weather. Will give it a try.

[Tom Wesenberg]

I was thinking the same thing Ron said. My friend had that problem and I had to let all the air out, then push the tire sides in and spray some WD-40 on the tire bead. It slipped right into place then, as soon as I put air back in.

[Fred K-OR]

Thanks guys. Will try to give the tire refilling idea a chance. I should be able to do like Brent mentioned above to check it before I do it and then afterwards. But I am a warm blooded guy and need to wait till the weather warms up a bit. Don't think I want to start the pellet stove in the shop with two Model A's and a pickup stored along with all kinds of gas. Will report back to see how it worked.

[Mitch//pa]

try and use tire soap as mentioned its not detremential to the rubber tube.

[harleytoprock]

Originally Posted by Mitch//pa

try and use tire soap as mentioned its not detremential to the rubber tubes.

I agree, solvents are not good for rubber.

[rocket1]

many years ago when I first got my A I installed new tires,what a ride, truck went up and down as it rolled along,I deflated the tires and centered them several times before I got a smooth ride.

[J Franklin]

When I mount new tires I add about 2-4# and bounce them while turning them 4-5 revolutions and then fill with air and always have a seated bead. Maybe I have just been lucky.

[Girl with wrench]

Guys, if this bounce is not corrected after reseating the tire, could balancing perhaps solve the problem? Yes, I know it is not usually done on rear. Just asking if it might help.

Girl with questions

[Girl with wrench]

Mitch // pa,

What is "tire soap"? Special product? Or plain old dish soap and water?

Girl with dishpan hands

[Mitch//pa]

Originally Posted by Girl with wrench

Mitch // pa,

What is "tire soap"? Special product? Or plain old dish soap and water?

Girl with dishpan hands

do a google search "tire soap"

[scrapiron]

As for checking for correct mounting, Check to see if the witness line on the tire is equally spaced from the rim.

[J Franklin]

The "tire soap" I use is called RuGlyde.

[Girl with wrench]

Originally Posted by Mitch//pa

do a google search "tire soap"

Read up on tire soap. Appreciate your help and patience with my newbie questions.

[JackA]

As to the original question, how about a dial indicator from HF?

[Mitch//pa]

Originally Posted by Girl with wrench

Read up on tire soap. Appreciate your help and patience with my newbie questions.

"Girl with reading glasses"

[Fred K-OR]

Originally Posted by JackA

As to the original question, how about a dial indicator from HF?

I was thinking the same thing. Does anyone know of a HF dial indicator that could be used on some kind of rack, post, jack, or ??????

[crock]

You could use wire pulling lube that the electricans use.will not contaminate the rubber.

[C26Pinelake]

Originally Posted by BRENT in 10-uh-C

Install u mounted wheels on a front hub. With the axle on a jack, lower the wheel until it is within a quarter inch of the floor. Rotate the wheel and watch the gap to see if it varies.

Brent as usual has the answer !
Wayne

[harleytoprock]

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Using a dial indicator to check trueness of a wheel might be a bit over kill for a car that goes 45-60 mph.

[JackA]

The HF dial indicator comes with a magnetic base and adjustable arm. It's not overkill, it is cheap and easy. No need to read in thousandths, just minimal variation.

[Fred K-OR]

Thanks JackA. Will have to try one of these. Just need something to play around with anyway.

[Fred K-OR]

Originally Posted by harleytoprock

Using a dial indicator to check trueness of a wheel might be a bit over kill for a car that goes 45-60 mph.

But the bump I have that I am trying to fix happens at 15 to 25 MPH. Things are great at 40 to 50 MPH.

[whirnot]

Originally Posted by Fred K-OR

I was thinking the same thing. Does anyone know of a HF dial indicator that could be used on some kind of rack, post, jack, or ??????

Any small pointer can be rigged up, such as a piece of stiff wire in a clamp laying on the floor. It you can't easily see it by eye, it will probably not be a problem. This can check it radially as well as laterally.

[harleytoprock]

One of the problems I see using a dial indicator is that the friction from the rubber tire will try to move the whole indicator throwing off any accuracy. The indicator would need a friction free wheel on the shaft that contacts the tire. whirnot's pointer idea is good. You'd be amazed what the eye can see. I can easily see .005" runout when using my lathe. I true spoke motorcycle wheels that go 100mph using a wire pointer with no problems. I doubt if even 1/16" (.0625') runout on the tire would be felt at 15 mph. I think things would get pretty bumpy at 1/8" (.125") to 1/4"(.250"). Nobody would even need their glasses to see that much runout.