ArosaMike

Well, I knew that the balance on them wasn't 'quite' right since I picked up the car. There was a noticeable wobble at around 40 and 70mph but I really didn't expect them to be as bad as they were. Whoever had 'balanced' them before needs locking away! Needless to say though, one of the wheels needed 75g! Anyone else had similar issues? You'd have thought that VAG could get their act together to make sure their wheels had approximately the same amount of material around the rim! Car feels totally different now, and I don't need to worry about my bearings so much anymore.

__________________

Railroad

Tyres as they wear cause wheels to be out of balance, and not so much the wheels themselves. Wheels are balanced in two ways.

1. An off the car machine splits the wheel down the middle and checks for dynamic lateral (side to side) difference. Weights if necessary are applied to both the front and back of the wheel. This should always be done first.

2. An on the car machine or finishbalancer checks for static works by spinning the wheel on the car, and a pickup under the suspension flashes a stroboscopic lamp every time a heavy spot passes it. The spinning wheel appears to be stationary under the lamp, and any weights are applied to the front of the wheel only. The wheel is balanced when the lamp doesn't flash when the wheel is spun. This method will balance the wheel, hub, driveshaft and brake disc together.

Many garages now no longer finish balance, as off-car balancing is usually good enough.

ArosaMike

Cheers for the run down of balancing techniques, although I have to say it was my knowledge of those that led me to comment

Worst wheel I've actually seen is a brand new 13in for our racecar that was off center by about 5mm! Admittedly they were only 2kg each, but it was pretty amazing considering they had only just come out of the box. The Mag centre also has a habit of flexing by about 30mm during hard cornering!

It seemed that the original 'balancing' on my car was static ie did not take into account imbalance in the horizontal direction or run out over the width of the rim. The one that required 75g was without any other balancing on it. In other words the manufacturing tolerances on the wheel are terrible! There is no way a tyre could loose that much weight unless I had been flat spotting them.

__________________

sam the man

I have just switched front to rear wheels to fit new verdestein sport 91 v's 205/55/16v tyres.The same tyres on th original fronts once balanced with minimum weights were rock solid at all speeds. The new tyres on what are now the front wheels needed balancing twice. I have since had one re balanced at another tyre place,this had 60g's added to bring it into balance.Even now the car does not feel as stable as it was on the original fronts I will swop them back soon i think
Sam the man

sam the man

I too have had similar problems with wheel balance on straight wheels.I swopped my fronts to the rear fitted new verdestein 91v tyres (same as the rear) they had to be balanced twice.Ihave since taken them to another tyre fitter who re balanced one of the two.They are still not as stable as the original front wheels I will be swopping them back fairly soon
Sam thr man.