An Independent rear suspension is an advantage in many ways, but when it comes to acceleration, independent rear suspensions can cause wheel hop and traction loss. This month we’ll correct that issue by installing upgraded parts from Hop Not.
Performance, styling, and the Hemi engine are all features common to both late and early Mopars, but there are some things about Chrysler's new performance offerings that have nearly nothing in common with the classic Mopars we love. Sure, the new Mopar vehicles have many similarities to the Mopar cars built during the sixties and seventies, but looks and nameplates can be misleading. In many ways, these late-model Mopars are far more advanced than our older muscle cars, with amenities such as satellite radio and navigation that weren't even available when the first Road Runners or Challengers rolled off the assembly line. And with computers controlling the engine's fuel injection and ignition system, as well as the transmission and even the vehicle's traction, there's no doubt that these advancements make the latest Mopars amazing performers, while also being a pleasure to drive. One area of the new Mopar LX platform cars that helps in many ways is the independent rear suspension. Unfortunately, while there are many advantages of independent rear suspension there's also one disadvantage. During hard straight-line acceleration, these cars can have a tendency to spin the tires, resulting in wheel hop.
01. The rear cradle holding...
01. The rear cradle holding the independent suspension to the car is held in place by large, soft rubber bushings. While these bushings likely improve ride quality and dampen harmonics, they allow the entire rear cradle to move, which is counterproductive in terms of straight line or cornering performance.
As the name implies, independent rear suspension means that unlike our older Mopars which incorporate solid rear axle housings, each wheel of a modern Mopar can move up and down independently of each other. To facilitate this independent movement, the center section of the differential is essentially a part of the rear frame and doesn't move. Individual axle shafts that incorporate universal joints on each end allow each rear wheel to travel up and down without transferring the motion to the other wheel. In many ways, independent rear suspension benefits the performance of a car by allowing each rear tire to remain planted firmly on the road surface during cornering and braking, and while accelerating over rough surfaces or around curves. Independent rear suspension also provides improved ride quality, but when accelerating straight ahead, like when drag racing, independent suspension is more prone to inducing wheel hop when traction is marginal.
Wheel hop can happen in any car where traction is an issue, but cars with independent rear suspensions like the new Dodge Challenger, Charger, and Chrysler 300 have a rear suspension cradle that is attached to the rest of the car using four large rubber bushings, making matters even worse. These large OEM bushings allow the rear cradle, and thus the entire rear suspension, to move around during both normal and aggressive driving conditions, and especially during acceleration. Fortunately there's a company called Hop Not that has engineered a solution to wheel hop issues found in late-model Mopars. Hop Not offers two kits for the rear suspension of late-model Mopars. The first of which is called the Stage I kit, and it eliminates the movement of the rear cradle associated with the OEM rubber mounts.
02. Hop Not fabricates CNC...
02. Hop Not fabricates CNC steel spacers that eliminate the movement allowed by the factory rubber bushings. This is a simple idea, but very effective and doesn’t require dropping the rear cradle or re-aligning the rear suspension. The Stage I kit includes spacers for all four cradle attaching points.
03. The Stage II kit from...
03. The Stage II kit from Hop Not includes rear spacers, brackets, and an additional set of shock absorbers to help eliminate wheel hop. These kits are available separately or can be purchased together for maximum traction control and a reduced price.
04. The spacers are installed...
04. The spacers are installed one at a time, and by using the factory bolt and provided spacer tool the front triangular steel plates can be pried off the rubber bushing. The OEM rubber bushing is then trimmed so the Hop Not spacer fits properly.
The Stage I Hop Not kit truly is a bolt-on upgrade, involving the installation of CNC produced spacer plates in conjunction with the OE bushings, virtually eliminating the movement of the rear cradle. Since the plates on each side are installed individually, there's no need to drop the cradle from the car or worry about rear end alignment when installing the Hop Not parts. In addition to helping eliminate wheel hop, the Stage I kit also helps the car's handling and braking by eliminating cradle movement. A quick visit to hopnot.net, Hop Not's website, will allow you to view videos showing the large amount of movement the OEM rubber cradle bushings allow, as well as the dramatic increase in movement once the Stage I kit is installed.
The Stage II Hop Not rear suspension kit can only be installed after the Stage I kit is already in place, and involves mounting horizontal bracket stabilizers and proprietary upper and lower mounting brackets. Stage II is also a bolt-on upgrade, and doesn't require the cradle to be dropped or any specialty tools. The Hop Not rear suspension kits are available for all LX platform rear wheel drive Mopars, and compatible with both automatic and six-speed equipped cars. Kits for six-speed equipped cars are slightly more expensive due to the adjustable sway bar end link that is included. In addition to kits for cars with factory ride height, Hop Not also offers kits for cars that have been lowered, and even offset brackets to accommodate larger than stock rear tires. After researching Hop Not's products, watching the videos, and reading the testimonials on the Hop Not website, we decided to test these products for ourselves and ordered the complete Stage I and II kit for Associate Editor Scott Ross' automatic transmission equipped 2007 Dodge Charger police package car (basically a Charger R/T).