Static balance with CCM brake rotors attached

I'm not disputing that using parallel bars and a ruler is a good method. If you measure the distance between the bars on each side of the car, and calibrate them to some known point on the frame, then that's very accurate. In fact, that's what I was originally going to do also. The method I'm using (and have described here) duplicates that method exactly; the only difference is I'm fixing the measuring point to the car itself (and calibrating off the center caps) vs. having everything sitting on the ground.

The only thing I was saying before was that you can't simply measure from the ground up to the wheel using a square placed on the ground, unless you know for certain the surface you are using is perfectly flat, level, true, etc. When you use something which is calibrated parallel to the car itself, then you are removing that potential for inaccuracy.

Ray

 

Well said...

And actually, I usually do go ahead and just omit the impact of the rotation of the earth from most of my calculations

Ray

 

The more people that tell me it won't work, the more I know I'm probably on the right track

Ray

 

You'll be happy to know that I just finished rebalancing one of the wheels. Without the brake rotor attached, it took only 25 grams (vs. 70 grams) to give it a perfect static balance. We are talking dead perfect balanced.

I'm working on the other wheel now.

I'm also building a slightly better axle for balancing the wheels, but that's another project...

Ray

 

Just finished doing the static balance on the other rim. 45 grams and as perfect a static balance as I get on my motorcycle wheels. So I'll be very interested to see if there is any detectable vibration when I test drive the car next time.

Here's a photo... I'm using some clamps from the garage to help seat the new wheel weights I just purchased off eBay.

With both rims, I tried to concentrate the weight in as small an area as possible - and as far inboard on the wheel as possible. With the balancing, I slowly shifted the weight up and down the inner lip, until the static balance was basically perfect to within +/- about 2.5 or 3 grams I figure.

So if there is any vibration from the front now, I'm going to be pretty surprised, but you never know.

Ray
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There is a famous quote by Theodore Roosevelt, from his "Citizenship In A Republic" speech of the early 1900's, which is worth remembering. It often sums things up for me, in life, business - and especially in the face of a lot of raised eyebrows when it comes to wanting to do things for myself that the average person would otherwise hire someone else to do. I wish I had a nickel for every time someone said "leave that to the pros" or "let the old timers who know what they are doing do that", because I would easily have a dollar or two by now

In Roosevelt's speech, he basically said you learn by doing and don't forget that even in failure, you can often learn a great deal; if nothing else, credit is due the individual making the attempt, in spite of criticism received along the way. It's a long speech, but here's the famous part everyone quotes:


"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, and comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows the great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who know neither victory nor defeat."


Off to test drive the 458 and see if my static balance has made any difference. If it hasn't, then so be it; either way, I have learned quite a bit this week fiddling around with the wheels - and I would rather make an attempt at balancing my own tires than to simply be beholden to some guy pushing buttons on a dynamic balancer, who most likely has never balanced a single rim by hand in his entire life.

Ray

 

Well, just returned from a very wet test drive into town and back...

I'm pleased to report that the vibration is gone and she rode as smooth as glass. The only feeling via the wheel now is road feel. I got up to 100 MPH, but didn't wanna go much faster since it was raining out. Very smooth though.

So I'm going to mark this one down as a success. It seems the trick is to put the weight on the inboard lip of the rims, since this is where (I believe) most issues of vibration and wobble probably stem from (since weight furthest away from the axis where the wheel mounts to the hub has the most leverage - although in terms of rotational weight, that might not be exactly the correct term to use).

The car seemed to drive pretty nice, so I'm not even sure adjusting the toe is needed. I'm going to reserve judgement until the pavement is dry. I still kinda feel like just turning the tie rods in 1mm on each side to see what happens - even without measuring anything.

I think - based on the balance being so far off from the dealership - next on the agenda is going to be to do a static balance on the rear wheels, just for good measure. As mentioned, I have some parts coming from McMaster, which I am going to weld up and use to increase the rigidity of the axle on my static balancer. I'll post photos of that, for anyone that might be interested. I am also (I think) going to have to fabricate up something which will allow me to extend the width of the static balancer supports slightly, since the rear rim is wider and I don't think it will clear as things stand now.

Anyway, I've been up all night working, so I'm going to knock off and worry about the rest of the stuff later.

At least the car is smooth finally and there is no longer a vibration coming into the steering wheel. So that's one less thing on the todo list

Ray

 

Have you tried different toe adjustment settings? Such as going from toe out to 0 to toe in - and if so, what is your feeling regarding how the car steers and feels under acceleration and at speed given any different settings you may have tested out yourself?

Ray

 

Back at it...

I'm doing the balance on the rear tires. I purchased some thick wall tubing, in order to help prevent any flexing in the threaded shaft. It also helps the surface roll more smoothly on the bearings of the stand (previously, the threads of the acme lead screw were catching a tiny bit and stopping the rotation of the wheel somewhat).

Anyway, the car feels a lot smoother since balancing the front tires. I'm hoping balancing the rear a bit more precisely will improve things even further as far as smoothness goes.

Ray
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