On earlier Mustangs, it's...
On earlier Mustangs, it's called a K-member, but on S197's, the two-piece subframe that holds the engine and locates the suspension is called a cradle. The Griggs cradle provides needed strength, relocates the steering and suspension pickup points, and eliminates many pounds of frontend weight, among other things. The separate rear crossmember section-the flat plate-and the fact the engine mounts are welded to the main tube section means engine swap requirements are easily accommodated. Griggs also reports the S197 chassis is precise. You still want to check measurements, but so far the company has found its suspension bolts in and requires no adjustments for precise component alignment (cradle cross-dimensions, and so forth).
Stock, the '05-and-later Mustangs use a strut front and three-link rear suspension. It's a good arrangement, but Ford builds it with too much understeer. The steering could be quicker and more communicative, and the rear axle hops under hard acceleration. Furthermore, the S197's front lower ball joint, spindle, and K-member are inexplicably lightly built and aren't ready for higher loads imposed by better/larger tires, according to Griggs.
Griggs' goals for the S197 suspension were the usual suspects-less under-steer, better steering feel, faster steering, more precision, and so on-along with the specific need to eliminate wheelhop and strengthen the front ball joint, spindle, and K-member.
Because not everyone can afford anSLA frontend, Griggs would normally offer a strut frontend as its entry-level and the SLA as an up-market option. But the company prefers Koni dampers, and Koni has yet to import struts for the S197, so the Griggs strut-based suspension is yet to come. In the meantime, the all-out SLA option is the only choice. If you have the financial stones, it's the best option there is.
In back, Bruce believes a three-link suspension isn't bad, but a torque arm is better. The Griggs Racing Products' offerings at the rear begins with improvements to the three-link and move on to a torque arm system.
Griggs' front suspension begins with a new K-member-actually it's a pair of crossmembers that Griggs collectively calls the front cradle. It substitutes SN-95 spindles for the flexible S197 variety, uses new triangulated lower control arms,and adds upper arms and the mounting brackets, replacing the strut. This SLA system naturally takes a coil-over spring/shock unit. The sway bar is also replaced for rate and geometry reasons, and the steering rack is replaced with the earlier SN-95 unit because the S197 unit is too short, as are the stock S197 lower control arms.
A tubular cradle gives a huge...
A tubular cradle gives a huge improvement in working room, such as around the steering shaft and headers. Griggs says the S197 steering rack is too short in length, so SN-95 racks are used in the kits. The company also offers high-precision racks for track warriors.
In other words, the entire front suspension is new. Its advantages make an impressive list. The system is 30 pounds lighter than stock, headers have maximum room, engine swaps are much easier because the mounts can be adjusted when ordering the kit, the ride height can be brought down to a mere 2 1/2 inches (measured at the main crossmember), the geometry is right, the system is rigid, and huge 285-18 tires on 10-inch wheels can be accommodated under the stock sheetmetal. Installation of this front suspension calls for drilling four 7/16-inch holes and no welding. The rest is bolt-in.
An important option is Griggs' newly developed spindle. This strong billet-aluminum piece provides a 2-inch drop in ride height for a lower center of gravity, but without the geometry-destroying characteristics of lower springs or other tricks. The catch is the cost. The billet spindle, while the right way to lower a performance car, retails for $2,999.95, including brake hats. If you want the ultimate in low ride height and suspension geometry, the spindle is a must. General street performance cars will do well with the SN-95 spindle in the standard kit and save three grand in the bargain. Racers will have a tough time winning without it.
Griggs offers its front suspension in three levels: Ultimate Street Performance, Autocross/ Open Track, and World Challenge/American Iron. The first two are similar, differing mainly in quiet rubber versus noisier rod-end attachments. They're also close in price at the mid-$6,000 range, including everything in front suspension: coilover shocks, arms, bars, front cradle, and so on. These kits use the SN-95 spindle, with the billet Griggs spindle optional. The pure race World Challenge/ American Iron front suspension comes only with the billet spindles and rod-end bearings, explaining its $9,320 price.