Wheel balance

[FredandJeannesRacer]

When it's time for me to get new tires, which is going to be soon, how should they be balanced? I get my car tires done on a high speed balancer, and I never drive it faster than 65mph. I don't like the idea of using a bubble balancer or similar (spin balance on a stand) for something that's going a lot faster. I tried a search, but could'nt find what I'm looking for. Help. :huh:

 

[Scab]

Dynamic balancing is always best. (IMHO) I have never seen a "buble" balancer for a bike tire, but I know what you mean. There are several here that use a non-dynamic balancer system. (not sure what you call that) But, I think most that use that system do so because they a: get charged too much $ at a dealer b: have had experiences with poor technicians c: they just like doing their own stuff.

I have never heard of anyone hear that had anything negative to say about dynamic balancing.

 

[Constant Mesh]

I don't believe the wheels/tires are dynamically balanced at the factory. With the wheel weights mounted on the center rib of the wheel a dynamic balance isn't possible.

https://www.gsp9700.com/pub/features/intro.cfm

 

[Scab]

What is most preferred on bikes? High-speed spin?

 

[Rickster]

It is my understanding that car wheel/tires are 'dynamically balanced' to allow proper weights on the inside and outside rim to also balance concentricity.

Motorcycle wheel/tires are so narrow, I don't think there's enough width to require this type of balancing.

Typically the FJR is weighted on the center rib -- so there is no place to balance on the left/right of the wheel.

I use a Marc Parnes balancer here

 

[exskibum]

I balance my own using a Marc Parnes balancer. I'm pretty anal about matching light and heavy spots on the tire and wheel to minimize the amount of weight required, and in balancing the wheel with just the right amount of weight (I even cut the stick-on weights to fractions). Not that it isn't done, but I've never seen a motorcycle wheel dynamically balanced anywhere, and have no doubt that my efforts are far more anal (and accurate) than any dealer would do. Never had a problem, and I have seen 150+ mph more than a couple times.

Seems to me that I'm already at overkill on what is necessary, and that dynamic spin balancing would be even more so (although I wonder if they'd be near as anal in trimming weights to fractions as I am).

 

[vectervp1]

You'd be better off just sticking weights wherever you wanted than using a bubble balancer.

Go with either a static wheel balancer (ala Marc Parnes) or a dynamic wheel balancer.

 

[charismaticmegafauna]

<snip>It is my understanding that car wheel/tires are 'dynamically balanced' to allow proper weights on the inside and outside rim to also balance concentricity. Motorcycle wheel/tires are so narrow, I don't think there's enough width to require this type of balancing.

Motorcycle rear wheels are not so narrow, anymore. And, BMW (and maybe some other Euros?) have used rim edge wheel weights with a spring steel weight holder that fits between the tire bead and rim. That sort of weight would be consistent with dynamic balancing.

Having said that, I've often watched major brand tire techs in the paddock area at road races fitting-up new tires for racers -- and they static balance them (just like I do).

Altho I admit, it's been a few years -- don't know 'bout Vale's wheels/tires at Laguna Seca, for instance......

 

[Scab]

Okay, this is good info. But, which is the better way? Originally, by 'dynamic' I meant 'in motion.' Clearly, though, when referencing tire balance, that is not entirely correct. (as explained by Constant Mesh) Also, I realize that alot if peeps use a static balance like the Marc Parnes or equivalent, even at the track, etc. But, which is best? A balancer that moves (spins) the wheel or static (gravity makes it work)? I would still think that the one that moves under its own power would be better. All things being equal, both types functioning correctly, etc. I still think that most techs just get it within acceptable specs, which may not be acceptable to every individual. But which machine is capable of delivery the best, most consistant result?

 

[Shane]

I've only seen static (Marc Parnes style or equivalent) balancers in use at BIR for racers of every level.

Since turn 1 at Brainerd is possible at about 180 mph, and since front straight speeds are well in excess of that at the AMA level, I guess that's good enough for me.

In this non-shop application, low-tech might be the most valid reason to use this method, and the results are repeatable and accurate.

Watching the tire guys work is a lesson well worth the price of admission, and will inspire you if you don't already do your own.

Rock on,

Shane

 

[Scab]

I don't even know if the racers could even bring a dynamic(moves the tire under its own power) balancer if they wanted to.

And, are their tires made to the exact same specifications as our street tires? I don't think so.

 

[ionbeam]

A spinning balance a.k.a. dynamic balance, using a machine that can measure radial and lateral run-out (side to side imbalance), with a trained and experienced operator should always produce the best balance. If there is no is no lateral run-out it would be best to place the balancing weight in the center of the rim. If there is lateral run-out, the weight would be split side to side and most likely the weights would not be placed directly opposite each other. A spinning balance will also let the operator detect an out of round condition. For motorcycle wheel/tire setups the dynamic balancer may be of more use as a diagnostic tool than as a workhorse balancer.

A static balancer like the Marc Parnes should yield a balance in one plane (radial) every bit as good as the spinning balance. This is a KISS tool that is fast and easy to use with great results.

As long as the tires you are receiving are first quality, a dynamic balance is superfluous. If your dealer has a dynamic balancer and doesn’t charge a premium for its use then go for it. In terms of radial balance you should be able to do as good at home with a static balancer as what you would get off of a dynamic balancer at a dealer.

Just as important, or perhaps even more important than the balance is to be sure your rim is true and the bead is fully and evenly set around both sides of the wheel.

 

[GreyGoose]

Great topic considering i just had a problem with my new BT021's. I thought i had a bad tire, but turned out to be a balancing issue. couldnt tell a damn thing till i got to 90. up to 90, everything was smooth as silk. At 90 or above, felt like i was rolling down the train tracks in between the rails.

Not sure what type of balance was used at the stealers, but they did get it right the second time around.

GreyGoose

 

[Scab]

Just out of curiosity, GreyGoose, where are the weights? Center or sides?

 

[Shane]

I don't even know if the racers could even bring a dynamic(moves the tire under its own power) balancer if they wanted to.And, are their tires made to the exact same specifications as our street tires? I don't think so.

I don't know what the limit of facilities are, but the guys changing the tires are doing so under Michelin, Pirelli, Dunlop and other banners, with fully functioning Coates changers, so whether or not they could use a dynamic balancer if they wanted to is a good question. I might ask next time I'm up there.

But now that I think about it, why would accommodation not be made for this type of balancer to be available if a quantifiable benefit could be realized? They seem to spare no expense for any and all pursuit of perfection, sometimes with questionable merit.

Just to clarify, I haven't seen racers doing their own at the track, though I've been known to change a few for a friend between race weekends, so I'm sure many of them do their own as well.

As to the specs of race vs. street tires with regard to balance...the last set I changed and balanced was for Radman; they were the new BT 021's and took less than two squares front and rear. Most of the well-known name brands are remarkably well made, and if you take the time to align light and heavy spots on the tire and rim, use very little weight.

Usual use of weights at the track are in the 2-3 square range per tire. They don't take the time to align light spots and heavy spots, but the lead weight tape residue usually shows up on one quadrant of the rim, indicating relative consistency of manufacture quality.

Good stuff,

Shane

 

[e2b]

When it's time for me to get new tires, which is going to be soon, how should they be balanced? I get my car tires done on a high speed balancer, and I never drive it faster than 65mph. I don't like the idea of using a bubble balancer or similar (spin balance on a stand) for something that's going a lot faster. I tried a search, but could'nt find what I'm looking for. Help. :huh:

My dealer in Redlands uses a dynamic balancer, he charges $19 -$25 to change out, balance and Recycle fee. When radial car tires came out static balancing became a time consuming difficult proposition. Modern spin balancers tell the operator where and how much in a matter of few minutes. They can if they so desire tell you your tire is not right. The only better system I ever saw was a balancer grinder that made the tire just about perfect weight wise and round. I would only static balance as the next to last option (no Balance would be the last). I don't race but considering the life expectancy of the tire some deviation can be overlooked and a really good mechanic can do a really good job.

 

[Harald]

I suspect that a dynamic balance could be accomplished quicker, but I can't quite justify the expense for my personal use

Using my homemade static balancer I've had no problems doing my own tires. Even at 165+ they roll smoothly.

 

[radman]

After Shane and I mounted the BT's, not only were they vibe free, I gained 11mph on top. Apparently there is a direct correlation between tire and crank balance. Hey, I'm just the reporter!

 

[EasyRider]

I worked in a garage years ago and balance many tires on the shop wheel balancer.

Static Balancing:

It is my understanding that static balancing takes readings of imbalance at only one side to the tire and recommences were to place weights to counter the heavy spots on the tire. The balancer can be set to take its static balance reading from the either outer edge or the center. A measuring arm on the balancer is used to tell the balancer where you wont the reading taken on the wheel so you can place weights in that area. With this method he machine will only requires weights on just one side or the center based on where you set it to take a reading. This way you only have to have weight on one side. People use this method to hide the weights on the inside of the wheel so no unsightly weights will be seen on the out side of the care wheel.

Dynamic Balancing:

With Dynamic Balancing the balancer takes reading from the both sides of the tire and recommends weights to counter balance heavy spots on each side of the tire.

This method is better than static balancing because the tire may have different heavy spots on each side of the tire and can recommend counter balancing weights for each side’s heavy spots separately. This method takes care of any shimmy in the wheel due to opposing heavy spots on the tire that are not directly across from each other on the tire.

Being new to motorcycling, I bet motorcycle shops don’t use dynamic balancing because motorcycle tire are so much narrower and because the tire is crowned. That being the case, motorcycle tires don’t have much of an issue with different heavy areas on each side the tire like a wide flat car tire can have. Also the factory and shops like to have the cleaner look of having weight only placed it the center of the wheel. Very wide rear ties may benefit from Dynamic balancing but you most likely will not feel and shimmy issue coming form the rear tire on a motorcycle unless it is defective and in need of replacement.

Also, I have no idea if the car wheel tire balancer manufactures make adapters to mount motorcycle tire on their balancers. From what I can see searching for motorcycle tire balancers on the internet, I looks like the balancer manufactures make balancers of the same type scaled down a bit for motorcycle shops to balance motorcycle tires on.

Self spin balancers?

From what I can see of the low cost self spin balancers used for motorcycles have you spin the tire and what for it to stop. If it repeatedly stops in the same area of the tire and wheel combo, you are to try putting weights on the opposite area of the wheel until it no longer favors stopping on any area of the wheel? That would also be static balancing, motorized or not.

If that’s true, I can’t see how that could be very accurate. Such a method could not be much better than the old bubble balancers that I am just old enough to remember used on car tires. They were almost all gone when I was a teenager in the late 70s.

One more note:

Most wheel balancer operators don’t know how to correctly mount a tire on the balancer. They need many mounting cups and cones and other mounts for the many different types of wheels. If the tire is not mounted correctly you will get a bad balancing job done. If its not mounted corectly you might as welll have no wights on the wheel at all. And most operators also don’t understand how to use the deferent types of methods for balancing the balancer has been designed for. It is very hard to find a shop that has a properly trained operator balancing your tires. So dont asume the ballaning job was done correctly when you get it back.