Buldawg76
Well-Known Member
- Joined
- Jan 11, 2022
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- Location
- Alabama,USA
- First Name
- Mike
- Vehicle(s)
- 2020 Ecoboost Premium, 76 Harley shovel, 77 KZ1000
No, it uses the orientation of the rolling direction of all four tires to determine the thrust angle based off the fixtures that are attached to the wheels. It does not care about the centerline of the vehicle and has no way other than the wheel positions to determine the centerline.Have a somewhat academic question re: alignment--
When a car is put on a modern alignment rack, it bases the thrust angle off not only the rear axle, but a line between the center of front and rear axles (i.e. geometric centerline), correct?
If it was just the rear I'd imagine you wouldn't need an alignment after installing the irs centering sleeves, as an alignment machine only knows the position of the wheels, not the body.
The wheels will have a natural tendency to want to roll away from the center of the vehicle when moving and it calculates this force as a thrust angle for the positions of the 4 wheels combined to give an indication of how straight the vehicle will want to travel when moving or put another way how much force there will be trying to push the vehicle in one direction or the other when moving.
When you loosen the rear subframe and install the centering bushing or do anything else to the subframe it will never be bolted back up into the exact same position as it was before it was loosened so the rear alignment will be off from before the work was performed. It's up to you if you are willing to take a chance on it being close so as to not wear the tires out in a few hundred miles or not or have a car that want to track one direction or the other constantly that you will always be fighting to keep straight in the road.
When I did mine the 4-wheel alignment only cost 58 bucks and my thrust angle in 0.02 degrees so well worth the cost IMO.
BD
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