HarleyTechTalk

Anyone ever balance  the wheel before mounting the rim strip, tube and tire? Was wondering if it was worth it. Was just messing around with a stock one in the man cave for the heck of it. Actually was surprised how far outta whack it was.

My buddy has a Snap-on top of the line spin balancer (both static and dynamic) and He has checked my rims (tubeless) before mounting tires and they are pretty close.  My BMW were 100% balanced without rubber.

I tried it once.  One of my rims was somewhat off.  I guess the theory is that is where you mount the dot on the tire instead of next to the valve stem.  Anyway, that is what I did.  Still, in the end required about the same amount of weight as always (~1-1.5 oz) with a front D402.  Couldn't see any real advantage.  Quit doing it after that one time.  No discernible vibration/hop/bad behavior either way.  This is all static balancing with a crude setup (2 jack stands and a tire changer center post as an axle).  Rear tire with a 402 normally stops at random with no weight, front always seems to use 1-1.5 oz in the same spot every time.  Just my backyard experience.

I'd be more concerned with truing the rim without tires, rim strips, etc. (especially spoked rims) than I would balancing it. Guess checking the balance would be another way to true one but way overkill. All rims should be checked on a truing stand occasionally. It will point out spoke problems and problems due to hard hitting on potholes, etc. It's a good idea on cast or aluminum rims too.

There's no point balancing just the rim. The complete wheel with tyre and tube etc is what needs balancing as a system.
Static balance will do for most bikes - use solder wrapped around the spokes. Cheap and easy. And I suppose too ugly for America...
With tubeless, it has to go to the tyre shop anyway so let them dynamically balance it.

>>With tubeless, it has to go to the tyre shop anyway so let them dynamically balance it.<<

Just curious as to why you say that? I mount and dismount tubeless tires all the time using nothing but a bead breaker and tire irons. A good air source to get them beaded properly and they are good to go ... after balancing.

Quote from: ederdelyi on November 20, 2009, 05:57:31 AM
>>With tubeless, it has to go to the tyre shop anyway so let them dynamically balance it.<<

Just curious as to why you say that? I mount and dismount tubeless tires all the time using nothing but a bead breaker and tire irons. A good air source to get them beaded properly and they are good to go ... after balancing.

Do I hear a static versus dynamic argument coming up?    Max

Quote from: ederdelyi on November 20, 2009, 05:57:31 AM
>>With tubeless, it has to go to the tyre shop anyway so let them dynamically balance it.<<

Just curious as to why you say that? I mount and dismount tubeless tires all the time using nothing but a bead breaker and tire irons. A good air source to get them beaded properly and they are good to go ... after balancing.

As do I. In fact, I'd rather mount and balance tubeless tires than mess with tubes. Can't say I've ever checked the balance on just the wheel. I guess if the wheel was off the right direction, it might be a benefit to rotate the heavy side of the tire some.

>>Do I hear a static versus dynamic argument coming up? <<

Not from me. That said, I have done static and taken them to be dynamic balanced ... If they didn't pull the weights off that I put on the difference they came up with (if any) was minimal ...  

EDIT: If you know the heavy spot of the rim and the tire it can help to minimize the amount of weight needed to balance the assembly.

I know a guy that does all the bikes in a big tire shop. He's been there over 20 years. A few years ago they bought a really nice spin balancer for him just for all the bike tires he does (he's a LOT cheaper than H-D). Anyway...he used the thing for maybe 6 months to a year and didn't like it. Had customer complaints about the balance wasn't as good as when he did it on his old static setup. So that's what they went back to. I'm sure he was running it correctly...all computer controlled and all that...don't know why it didn't work so well for them.

Well, I do true my wheels. I was just curious and had nothing better to do at the moment (no hockey on!) and was wondering if it was part of the reason some folks are having to have 3 or more oz's added to balance out. I static balance mine, spin the rubber if it's more than I want to add. Good piont about knowing where the heavy point of the wheel is. Could help in tire mounting. Ya know what they say, idle minds.....

Btw, I have never had to add more than 1 or 1.5 oz to mine. Luck I guess.

I use a Harbor Freight tire changer and a MOJO lever to change tires. I made this setup to balance them. I made the support arms from 2" X 2" square 6061-T6 aluminum and shimmed them to be square and parallel when I mounted them on my workbench. I ordered some ball bearings from RBC bearings (2 pairs) to support the shafts I use for axles. All the shafts are 416 stainless steel and I have several different sizes for H-D's and metrics. If I come up with a wheel that I don't have a shaft for, I made up some tapered spools from 416 SS (you can see them sitting on the back side of the support arms). These spools have a 1/2-13 threaded I.D. so I can use a stick of all-thread and the tapered spool will seat in any wheel axle diameter greater than 9/16". I slotted the top of the support arms with a ball-nose end mill to give a bit of clearance to the shafts as they sit in the cradle of the bearings. I like the shafts being able to spin on the bearings instead of relying on the wheel bearings to turn. This setup works really well for me and is dead-nuts repeatable. You can spin a wheel and it will return to the exact same position every time all day long. Makes them easy to balance.

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An argument about static vs dynamic balancing? No need. Dynamic is better so there's nothing to argue about.

There is a limit to how many tools I want to keep in my garage. A bead-breaker and an air compressor for working with tubeless tyres aren't likely to happen. I do enjoy the cursing and swearing and skinned knuckles that go with changing tubed tyres. I expect to be able to put that pleasure off for another year though!

O.K. I thought you may have had some other reason you felt it was a must to take tubeless t(y)ires to the shop. I bust my knuckles on a regular basis on most things, tire changing is just one more to add to the collection, 

I should have also added that this was a stock steel spoked rim. From what I have read, this type rim is more apt to be out of balance as opposed to a mag style rim. Yes, Dynamic balancing is better than static balancing, but unless you are using stick on weights and spilt the weight side to side, it is pretty much mute on a steel spoked rim as most shops use the spoke weights which places the counter balancing weight at the center of the wheel anyway, same as a static balance. I will concede that a dynamic balance machine may get the weight amount and location quicker, but a guy good at static balancing a M/c tire in the pit is pretty dang quick, accurate and good. Car tires and bikes running those wide tire setups are a different story because you have a lot more width to work with and that is where dynamic balancing pays off. At least that is my understanding of it. Not trying to start a post war on this topic, but I do find it interesting. The whole rim spiltting thread just got me thinking about the whole setup. At any rate, great dicussion. Guess I will play around with it this winter.

Mathematically, the moment of inertia of the wheel is a tensor.

The physics of Tire Imbalance

hat is, to a first approximation (neglecting deformations due to its elasticity) the wheel and axle assembly are a rigid rotor to which the engine and brakes apply a torque vector aligned with the axle. If that torque vector is not aligned with the principal axis of the moment of inertia, the resultant angular acceleration will be in a different direction from the applied torque.

In practical terms, the wheel will wobble.

I just liked the way the engineer wrote this,  taking a three word description and making a paragraph.

I've always pulled mine off the bike and let the shop balance them based on the research Static works but Dynamic is better because you are balancing not only the tire and rim but how the forces of rotation cause the assembly to perfom.

Seems to me you could indicate on the wheel the imbalance area of most concern, then when you go to mount the tire, put the dot opposite it...

In theory ... dynamic should and often is "better".

In practice ... If one knows what they are doing and takes the time to do the job properly either method should work for all but the most critical applications. I won't lose any sleep over it if I can't get them dynamically balanced as long as I'm not headed for the flats! As I stated before, I've checked my static balance against a good dynamic balance ... same weights and the location difference was miniscule. The balance is going to change with tire wear anyway, the dynamic may well lose it's edge as fast or faster than a good static balance. How many here re-balance tires between tire changes on their bikes or cars?

And yeah, that's the whole point of knowing where the heavy part of the wheel assembly is and where the heavy point of the tire is so you can reduce the amount of weight needed to balance the entire unit.

The wheel with bearings but without the Rotor, tire, tube, and rimstrip was 455 grains heavy according to my scale (I'm an archer and make my own arrows). That calculates out to aproximately 1.03 ounces. Of interest to me in this is that if I centrally located that weight in the center of the tire well in the area of about 1 inch square, it was difficult to acheive a static balance. So I spread the weight out over 4 inches long with about 1/2 the weight centered, and it was perfect.

I know this is just playing around, but hey, it's interesting to me anyway. Know what they say about simple minds....

You can find the heavy spot on the rim, but how do you know where the heavy spot on the tire will be? Is it where they place the little circle?
Mike

Quote from: MaxxV4 on November 20, 2009, 02:57:10 PM
You can find the heavy spot on the rim, but how do you know where the heavy spot on the tire will be? Is it where they place the little circle?
Mike

The heavy spot is always opposite of the dot. Dot goes with the valve stem, which is suppose to be the heavy spot on the wheel. I did a tire change for a friend last week and his wheel is way heavy the opposite of the valve stem. Go figure.

Quote from: Coyote on November 20, 2009, 03:54:10 PM

Quote from: MaxxV4 on November 20, 2009, 02:57:10 PM
You can find the heavy spot on the rim, but how do you know where the heavy spot on the tire will be? Is it where they place the little circle?
Mike

The heavy spot is always opposite of the dot. Dot goes with the valve stem, which is suppose to be the heavy spot on the wheel. I did a tire change for a friend last week and his wheel is way heavy the opposite of the valve stem. Go figure.

That's why I like to check my wheels before mounting a tire....usually the heavy spot is a little off the valve stem.

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Mine was about five inches away from the valve stem hole.

Have you considered using dynamic beads in your tires? I started using them 6 years ago in 18 wheeler. No problems.
Three years ago put them in car and pickup, again no problems. Last year when I changed tires on Ultra, I put them in those tires as well. Once again, no problems. I see no reason to not use them in road bikes. 1 oz in front tire, 2oz in rear. You don't even know they are in there. Tires rebalance themselves every time you pull away from a stop. If anything, the tire is better balanced with beads as opposed to lead weights. With way over a million miles logged on all vehicles using beads, if there was going to be a problem, it would have showed up long ago.

Back when I had my 750 Honda and then a 900 BMW I used the weights on the spokes and when I didn't have the weights I used Solder and wrapped it around the spoke. I never had a problem with tire balance and I used to run 100 mph or more on both bikes and never NEVER had a balance problem. Also I clamped the axel with the wheel on it to a fixture and used the axel bearings only to balance the wheels. Never knew the made a machine to balance motorcycle wheels back then (mid 70's) or to dismount or mount them.
   Bigs

I have used the Dyna Beads and was pleased with the results. I mostly use the static balancer because I have one and weights are cheaper then beads. A plus for the beads is that they won't fall off and no ugly weight on your expensive custom wheel
kemo