crazy shake/bouncing
 

so i have 2 set of wheel for my x5, in winter i have the fat tire 18 inch wheel, the car is doing great no issue, but in summer i put my stagger 20' 4.8is wheel with the slim tire ... and the car shake/bounce from right to left every time i hit a bump/road imperfection etc, its really hard to keep the car in control ... but no problem when the road is flat ... the problem is it the shock absorber ?

Wider tires tend to "follow" the road more aggressively than a narrower tire (within reason) and having offset rears vs fronts can high light that issue.


Few things I'd check as a starting point.
- Make sure your summer tires aren't directional - and if they are, make sure they're mounted in the correct rotational direction.
- Make sure your tire pressures are good and roughly equal across the front and rear - they can be different front to rear but should be the same across the pair, if that made sense.


It's possible it's a shock, larger wheels and tires will put more weight on the suspension and can high light issues like that, but I'd check the most obvious things first.

Put the other set of wheels back on and see if problem goes away. If it does then it is a problem with the summer wheels and tires or the install. If it doesn't and the problem wasn't there before it is likely that something happened during your work- check your work.