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Originally Posted by Path_Finder Thanks for the clarifications – it will also be good to explain wheel alignment and how it is different from balancing. |
Basic layman's difference between wheel alignment and wheel balancing - the former affects the wheel (hubs, if I may), the latter affects the alloy / steel rim, on which your tyre is mounted.
While performing a wheel alignment, the
toe and
camber (funky names for
angles) are adjusted so that the car's wheels are as parallel to each other as possilble, and make an angle as close to 90deg with the road as possible. Suspension settings are taken into account.
If you see a truck or taxi on Indian roads, you'll notice a lot of them appear to have the body pointing in a slightly off-angle, compared to the wheel, and yet they're managing to move straight somehow - such a vehicle is desperately yearning for a wheel alignment.
Nikhilb2008 and others have laid out great information.
irags - we await your picturesque writeup.
To add some a few more cents worth from my side:
Even though your new alloy wheel is nice and round it's not a perfect product. There is some imperfection in the alloying process, which leads to the weight imbalance.
Same goes for your tyre. Due to the different materials used in the manufacture of a single tyre, the weight imbalance is expected.
Wheel balancing is performed to balance out these imperfections so that the tyre and wheel combo can rotate without vibrating.
You see a car on the road with it's wheel bouncing unnaturally or vibrating like a dying spinning-top, you know the fellow needs to spend some money on getting his wheel balanced.
Using old / new weights isn't the issue here because it's only in very rare cases that a wheel without a tire mounted on it is balanced.
The tyre is aligned with the wheel in such a way that the heaviest points of each face away from each other. Weights are then added to points to negate the imbalance.
Nowadays a new technique called
Road Force Balance is becoming popular. A balancing machine having this
road force technology basically has a surface along which the tyre & wheel combo is run, to simulate a real world road surface. The effects of minor variations in the surface are checked by bouncing the combo, and weights are added to balance this effect.
I spoke to a tyre expert today, and he said that the Road Force system helps in balancing certain after-market rims, which are difficult to balance as they have a less stricter quality norms compared to an OEM / well known manufacturer like BBS.