Static balance with CCM brake rotors attached

I touched on this question here, in the 458 section:

http://www.ferrarichat.com/forum/458-italia-488/528395-458-not-stable-high-speeds.html

But I wanted to ask it in the Technical Q&A area also...

My question is this:

Has anyone ever used a motorcycle type static wheel balancer to balance their tires (in this case, I'm asking about the 458 Italia) - and if so, what were the results?

Additionally, has anyone ever gone to the extent of attaching the CCM Brake rotors to the wheel/tire assembly, in order to balance the entire assembly as a unit? Again, if so, what was the outcome.

I've purchased some cones and a wheel spacer which I intend to use and/or modify so that I can do my own static balance on my 458 front wheels. I've had very good luck balancing my motorcycle tires, so I don't see any reason why I can't produce the same results myself on the Ferrari wheels.

If anyone else has done this using a manual static balancer (not the spin type tire shops have, but the kind where you find the heavy/light spot of the wheel/tire yourself and then counter balance until the wheel/tire stays statically positioned), I would love to hear from you regarding your experiences.

Thanks!

Ray

 

The rear tire of my motorcycle is fairly wide and I have never had any problem static balancing it by placing the weight directly in the middle line of the wheel.

On the car tire, I plan to put the weights in the center line of the wheel and if that doesn't work, then I'm going to split up the total weight and put 50% on the inside and 50% on the outside.

I'm going to also research how automotive tire balancers work as well.

It will be interesting to see how it all works out in the end

Ray

 

My current tires were balanced by a machine (at the Ferrari dealership) and I have to say I'm not all that impressed. Far too much vibration.

I believe I can do a better job balancing the tires myself, using a static balancing method. With the motorcycle tires, I balance them to approximately 1/4 to 1/2 of a gram. That's approximately the weight of a 1" length of scotch tape. I don't think the machines they use at tire shops do as perfect a job. I think they balancing they do is usually plenty good for most cars and probably even for track stuff, but I just feel like doing it the old fashion way, by hand, might yield superior results.

If I'm wrong, then that's okay and I will make changes down the road. For now, I am going to explore this method of balancing car tires and see what sort of results it produces. I just don't believe there is enough difference in how a motorcycle tire needs to be balanced vs. a car wheel.

Like I say, perhaps I'm incorrect in my thinking, but I like to do my own tests and see what sorts of results I can achieve, as opposed to just going with the masses and accepting that a machine always produces better results than doing it by hand.

So, we'll see soon. I have most of the parts here to setup my jig. I'll post picture if I make some progress as well as whatever results I end up with - good or bad.

Ray

 

I've seen those bubble balancers; that's not what I'm using here. I'm talking about the static balancer where you suspend the wheel on an axle, then allow it to rotate to the heavy location and offset that area with weights.

When I have a minute, I'm going to do a little more research into the difference between static and dynamic wheel balancing. However, I still feel like if it works for a motorcycle wheel, it should work pretty well for a car wheel as well.

Ray

 

Here is some helpful information on the subject:

Hunter GSP9700 Wheel vibration Control System solves wheel vibration and tire pull problems that balancers and aligners can't fix

One thing I'm going to do, also, is static balance the brake rotor independently of the wheel - and then pair the two together so that the light spot in one helps to offset the heavy spot in the other.

I think that will also help to move some of the mass more to the center line of the whole assembly, which might help me out as far as not doing any sort of dynamic wheel balance. With that said, I wonder if mixing a bubble balancer with the rotating static balancer might come at the problem from two different directions.

Like I say, I am still doing research on the whole idea. If I do the static balance, I'll report back as to how it all goes. Right now, there is some vibration in the steering wheel, so whoever mounted these tires didn't do much of a job balancing them.

Ray

 

That's sort of how I feel too. I've had very good luck balancing motorcycle tires here using this static balancing approach. When I first purchased my bike, I had awful vibration that took a long time to track down. I finally tracked it down to the tires/wheels.

I've seen plenty of so-called professionals balance tires and I have never been impressed with neither the time spent, nor the final results. Now, there may be some exotic racing shop out there or wheel/tire place, where people pay attention to detail and actually have read the entire manual for their fancy computerized wheel balancer, but knowing people in general, I kinda of doubt it.

Even on my truck, I cringe when I see how they balance the tires. Last time I had a spare mounted, the guy put the wrong tire on the rim. I had to take it back and point out they put someone else's tire on by accident. After that, they came out and told me they were unable to get the wheel/tire to balance. I politely pointed out that they had failed to remove the enormous mount of lead balancing weights that they had put on last time I was there and that perhaps if they did that, then the wheels might balance properly.

"oh dang, we didn't even notice that"

Once they removed the old weights, magically the wheel balanced out okay.

Point is, I have very little interest in "letting the pros handle it", unless I can establish that either the person and/or the equipment they have is superior to something I can do here at my garage myself - with a little ingenuity.

Right now, my money falls with the "if it works on my motorcycle, it will work on my car". The motorcycle is exponentially more sensitive to minor imbalances in the wheels/suspension than the Ferrari. On the bike, even a 10 degree difference in outside temperature changes the handling. 2 PSI on the tires makes it a different bike all together. So my gut tells me that if I am able to get the static balance within a gram or less, the rest might very well take care of itself.

If not, I can always go to track down someone at the local track with a wheel machine and see what they have to say for themselves

I'm about to measure some of the fixtures and stuff here, so I'll see if I can post some pictures soon.

Ray

 

You're entitled to your opinion and it may very well prove to be true in the long run. We shall see

Ray

 

Speaking of wasting money, here are some shots of the adapter I'm setting up as a test. Ultimately I may weld a different axle into the hub, but for now this should allow me to at least accomplish some further testing to see if I'm on the right track or not.

I'm also wondering if I could setup a dial test indicator to check for wobble somehow (such as on the side of the rim, but not touching it or something). Anyway, so far things seem to be on track as far as doing a test of how the static balance works.

I may need to expand the distance between the pillars there and/or turn them around for additional clearance.

Anyway, you get the idea.

Ray
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I'm not sure if they balance those brake rotors or not at the factory. However, I do intend to mount one up by itself to see if it's statically balanced or not. I'll follow up with what I find just for the sake of interest on this thread.

I'm also going to switch that little mounting bolt that holds the rotors to the hub to titanium. Not sure about the pin thing yet.

Once I finish a few other things around here and the kids head back down south, then I will pull a wheel off the car and take a closer look at things.

Ray

 

That about sums up leaving it to the "professionals" all right.

I was just reading through a manual regarding wheel balancing and they stated that 90% of the problems encountered during wheel balancing are due to operate error.

Here is the link to the PDF download:

www.nussbaum-group.de/deutsch/datenschutz/download_file.html?sse_idupl=4800

Ray
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The bad wheel I mentioned above was from my truck. That was just an example of how closely you have to watch people at these shops.

With regard to the Ferrari, I will have to see once I pull the front wheels back off the car. As I recall, not too much. I'll update this thread with my results and findings - good, bad or otherwise. If the static balance routine doesn't work for the car, that's fine with me. However, I still want to try it and see if it works enough to smooth out the vibration I'm getting.

If it doesn't, then I will try something else or throw in the towel and take the wheels to a tire place and see what they can do using a balancing machine. However, in reading over how the tire balancing machines determine where to place weights, it appears it's largely a function of movement of an extended lever off the center axis, which is transmitting and magnifying the wobble produced by uneven weight. If that's the case, I might be able to measure that using something like a dial test indictor myself.

A lot depends on how much balancing is actually needed here. As mentioned before, I balance my motorcycle tires to between 1/4 and 1/2 a gram (static balancing). That's well beyond the balance done at most tire shops. I'm guessing they are balancing only to about 1/2 an ounce, which is about 14 grams. For me, at least with my experience with balancing motorcycle wheels, 14 grams is a gigantic amount of weight. Even 1 or 2 grams is huge.

I remember a few years ago I was given a small tour of a military base where they work on Marine Attack helicopters. I can't remember if they let me sit in a Cobra or something else, but I asked the guys how accurately they balance the helicopter rotors. 5 grams.

I'd let that guy balance my tires anyway.

The main reason I'm investigating this isn't because I have some distrust of the tire balancing machines at tire shops. I think they probably do a nice job balancing the tires. The issue I have is with the people running the machines. I don't have a lot of faith that they actually know what they are doing or that they are paying attention to details enough to actually produce a high quality balance which will be smooth at higher speeds.

Anyway, we'll see how it goes soon enough

Ray

 

I'm about 5 minutes away from Laguna Seca.

I just rebuilt and tuned the front Ohlins forks on my Yamaha R1 . So yeah, I believe you

Ray

 

I've been sitting here trying to think about how I could address issues of balance relating not just to static balance, but also dynamic balance (i.e. wobble due to unbalance areas in different areas of the tire).

I wonder if part of the jig was on mild springs and then you used a drill (or something) to spin the tire up to 1500 RPM's. That would be about 120 MPH. If the tire was unbalanced, it would cause the tire and fixing axle to wobble a little bit on the springs. This would allow the tire to move very slightly, which would allow the use of a marking pen to mark the wheel in the location where the excessive weight caused to to move back and forth.

Just thinking out loud here, but I wonder if something tricky along these lines could be made that would allow you to zero in on where the tire was heavy or light when rotating...

Ray

 

I hope you mean .040"

Ray