One of the best products to get a show quality undercarriage is Chemical Guys Bare Bones Premium Dark Shine Spray. Before using, you should definitely foam/wash the undercarriage and definitely use a brush to get the dirt out.
Here are some benefits:
- PROTECT AND ENHANCE SHINE: Restore the original shine to any vehicle’s undercarriage, tires and trim. Versatile spray dressing works on any car, truck, off-road vehicle and RV to protect and enhance the underside of the vehicle. Great for hard-to-reach areas like wheel wells, subframes, springs and fender liners
- PROTECT AGAINST FADING: Premium dark shine spray features enhanced UV solar protection that enhances and protects undercarriage and trim surfaces from the harmful effects of the sun
- VERSATILE SPRAY DRESSING: Premium sprayable dressing works great on undercarriages as well as plastic, rubber, vinyl, tires and bumper covers on any car, truck or off-road vehicle