Maximum Motorsports Rear Grip Package "The Basics" (MMRG-20) - 1999-2004 Ford Mustang Cobra
Reduce IRS wheel hop and improve rear suspension handling with the Maximum Motorsports Rear Grip Package "The Basics" for the 1999-2004 Ford Mustang Cobra. This package replaces the factory rubber upper and lower control arm bushings with precision-machined Delrin bushings to eliminate bushing deflection, improve dynamic alignment, and provide more consistent suspension performance.
By accurately locating the rear control arms, the Delrin bushings help prevent unpredictable camber changes and significantly reduce wheel hop. Maximum Motorsports designed this package to deliver these improvements while leaving noise, vibration, harshness (NVH), and ride comfort virtually unchanged.
Improved IRS Handling and Wheel Hop Reduction
Wheel hop is a common problem with IRS-equipped Mustangs. The soft factory rubber control arm bushings compress under load and then rebound, contributing to repeated cycles of traction loss and recovery. This undamped movement allows the rear tires to oscillate between gripping and slipping, producing wheel hop.
The Maximum Motorsports Delrin bushings eliminate the deflection associated with the factory rubber bushings. This keeps the upper and lower control arms precisely positioned, helping maintain rear wheel alignment during suspension movement, acceleration, and braking.
Factory rubber bushings provide effective noise and vibration isolation but cannot position the control arms as accurately as the Delrin bushings. Eliminating this movement improves suspension control and reduces unpredictable alignment changes.
Precision-Fit Delrin Bushing Design
Maximum Motorsports includes stainless steel shims that allow each bushing and control arm combination to be custom-fitted to the IRS subframe. This compensates for substantial factory production tolerances in the fore-and-aft positioning of the control arm mounting tabs.
The distance between the forward and rearmost lower control arm mounting tabs can vary by more than 1/4 inch. While the factory rubber bushings accommodate these variations through deflection, precision-machined Delrin bushings require a more accurate fit.
The included stainless steel shims install beneath the bushing shoulders to prevent the control arms from shifting forward or rearward while allowing easier installation into the subframe. Chamfered Delrin bushing shoulders further simplify installation and reduce the sliding-friction contact area against the mounting tabs.
Upper and Lower Control Arm Bushing Construction
The lower control arms experience significant thrust loads along the bushing pivot axis during acceleration and braking. To distribute these forces, Maximum Motorsports uses double-shouldered front and rear lower control arm bushing sets.
Each lower control arm bushing set has shoulders on both sides, allowing both bushing locations on each control arm to transfer thrust loads into the IRS subframe mounting tabs.
The upper control arms experience substantially lower thrust loads, allowing the use of more economical single-sided Delrin bushings without requiring the double-shouldered lower control arm design.
Lower control arm bushings feature thick-walled aluminum crush sleeves with a hard-anodized finish to reduce wear. Upper control arm bushings use zinc-plated steel crush sleeves.
Features
- Designed for 1999-2004 Ford Mustang Cobra models equipped with independent rear suspension
- Replaces factory rubber upper and lower control arm bushings with Delrin bushings
- Eliminates control arm bushing deflection for improved suspension precision
- Greatly reduces IRS wheel hop by eliminating bushing movement
- Precisely locates upper and lower control arms to maintain proper dynamic alignment
- Reduces unpredictable rear camber changes caused by factory bushing deflection
- Improves handling while keeping NVH and ride comfort virtually unchanged
- Easier to install than urethane control arm bushings
- Stainless steel adjustment shims compensate for factory IRS subframe mounting tolerances
- Chamfered Delrin bushing shoulders simplify installation and reduce sliding-friction contact area
- Double-shouldered lower control arm bushings distribute acceleration and braking thrust loads into the subframe
- Single-sided upper control arm bushings accommodate their lower thrust loads
- Thick-walled, hard-anodized aluminum lower control arm crush sleeves resist wear
- Zinc-plated steel upper control arm crush sleeves
- Includes specialized bushing removal and subframe tab straightening tools
- Includes PTFE-based lubricating grease and protective gloves
Package Includes
- Maximum Motorsports MMIRSB-1 Bushing Kit
- Maximum Motorsports MMIRSB-2 Bushing Kit
- Delrin upper and lower control arm bushings
- Stainless steel fitting shims
- Hard-anodized aluminum lower control arm crush sleeves
- Zinc-plated steel upper control arm crush sleeves
- Maximum Motorsports subframe mounting tab straightening tools
- Maximum Motorsports factory bushing removal tools
- PTFE-based lubricating grease
- Protective gloves
Installation Details
Custom Bushing Fitment: The included stainless steel shims allow the bushings to be fitted to the specific control arms and IRS subframe, accounting for factory mounting tab variations. Proper fitting prevents unwanted fore-and-aft control arm movement.
Subframe Tab Straightening: The original installation of the control arms can distort the IRS subframe mounting tabs. Maximum Motorsports includes specially designed tab straightening tools to flatten these mounting surfaces before reinstalling the control arms. This is a critical step to ensure the Delrin bushings allow the control arms to pivot freely without binding.
Factory Bushing Removal: Specialized removal tools are included to simplify removal of the original rubber bushings. Maximum Motorsports designed these tools to reduce a potentially hours-long removal process to just a few minutes.
Lubrication: The package includes high-performance PTFE-based grease suitable for demanding applications. Protective gloves are also provided to keep the sticky lubricant off your hands during installation.
Fitment
- 1999 Ford Mustang Cobra with IRS
- 2000 Ford Mustang Cobra R with IRS
- 2001 Ford Mustang Cobra with IRS
- 2003 Ford Mustang Cobra with IRS
- 2004 Ford Mustang Cobra with IRS
Important Fitment Note: Designed for 1999-2004 Mustang Cobra independent rear suspension applications. The package replaces the upper and lower control arm bushings and includes the MMIRSB-1 and MMIRSB-2 kits. Verify IRS configuration before ordering.
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