Vibration at 20mph

[Almoalla6997]

I own a 15 gmc sierra regular cab.

Yesterday, I got this vibration at 20mph that dissapears after around 30mph. The steering wheel is not shaking but I can feel the vibration with it and if someone sits next to me he can also feel the vibration in the seat.

When im driving at 25mph and start to brake slightly the vibration will increase. Note that if i brake at higher speeds there is no vibration.

 

The car is equiped with a CAI and exhaust as well as an eibach lowering kit that was installed months back. However the CAI has been installed before 2 weeks.

 

The rims and tires are 100% okay with no issues.

[JerryCanada]

I'm no professional but if you still have the stock tires it could just be one of the belt broke in one in the back.

[Almoalla6997]

I'm no professional but if you still have the stock tires it could just be one of the belt broke in one in the back.

 

Thank you jerry but i changed the set of tires and wheels today and the vibration didnt go.

[deputy]

If you lowered it more than 2 inches you may need 2 degree shims on the axles. You may also need to relocate your shocks with

McGaughys 34044.

Go to their website and do a chat. They'll probably give you some suggestions.

[brawls]

I lowered my RCSB with 2" drop shackles and then had a similar vibration. Mine would appear when traveling between 25 - 35 mph. After installing 2 degree shims the vibration was gone and the truck drove smoothly again. Apparently on my truck the drop shackles moved the pinion angle just enough to introduce the vibration. A good alignment shop should be able to help you.