SKU #: BDS-729FDSC-Main BDS 6.5" Coilover Conversion Suspension Lift Kit 11-19 6.6L GM Duramax

Purchase BDS 6.5" Coilover Conversion Suspension Lift Kit 11-19 6.6L GM Duramax
    • 2011-2019 6.6L GM Duramax 4x4


Bring your Chevrolet or GMC to new heights (literally) with this monster 6.5" system from the suspension gurus at BDS. By converting to Fox 2.5" coilovers in the front, you'll eliminate the troubleso ... read more

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Bring your Chevrolet or GMC to new heights (literally) with this monster 6.5" system from the suspension gurus at BDS. By converting to Fox 2.5" coilovers in the front, you'll eliminate the troublesome torsion bars to create an indestructible suspension that has a ride far superior to that of stock.

The BDS 6.5" coilover system is a game changer for HD performance. Building upon the tried and true BDS high clearance IFS system, this system allows HD owners the ability to eliminate the traditional torsion bar suspension in favor of FOX 2.5 factory series remote DSC coilovers.

At the heart of the system is a pair of FOX 2.5 Factory Series Coilover with remote DSC reservoir. These coilovers offer vastly superior dampening for impressive capability to soak up the harshest terrains offroad while offering comfort on your daily commute. These FOX coilovers feature a smooth bore and honed seamless alloy body, 7/8" hardened stainless steel shaft, FOX coil springs, black anodized machined 6061-T6 billet aluminum mounts and FOX's DSC (dual speed compression) adjustment technology. The DSC adjustment allows for easy adjustment of the vehicle's suspension compression dampening to dial in the ideal ride performance to soak up the bumps, both large and small. The DSC has 12 adjustment points for the high speed compression as well as 10 adjustment points for the low speed compression allowing you to make large or small changes to further improve your performance. Adjustments can be made by simply twisting the "blue" high speed and "gold" low speed compression knobs located on the end of the remote reservoir of the FOX 2.5 coilovers. No tools or shop adjustments needed, allowing you to tune the suspension out on the trail. The coilovers come fully assembled, preset for 6.5" of lift for optimal wheel travel, but can be adjusted between 5.5-7.5" of lift with the use of (#129600) spanner wrench. To mount the coilovers BDS supplies a bolt-on bracket that installs on the frame in the shock mount location. A weld-in support gusset is used to reinforce the upper mount, however still allows the kit to be completely reversible if the owner ever chooses to revert back to the torsion bar style suspension and upgrade the suspension on another truck.

In addition to replacing the factory torsion bars, the upper and lower control arms are upgraded to improved strength, travel, and accommodate the new coilovers. The uppers are FOX's new performance upper control arms designed specifically for this system to integrate with the 2.5 coilovers. The arms are fabricated from large 1.5" OD x .120-wall chromoly tubing, fully TIG welded for the highest quality, strength and durability. The arms utilize premium Moog brand ball joints and factory style rubber bushings for smooth, quiet operation and superior durability when compared to arms with uni-balls, poly bushings or heims. The ball joint cups are repositioned for optimal performance allowing a 30% improvement in wheel travel. The FOX upper control arms are finished in a durable black powdercoat and include a FOX branded billet aluminum ball joint dust cap. The control arms come fully assembled for easy install right out of the box. To compliment the uppers, the new lower control arms are built from high strength steel, fully boxed with internally gusseted. These lower arms integrate new reinforced lower coilover mounts and similar to the uppers use durometer specific rubber bushings at the frame mount and high quality Moog ball joints at the knuckle mount for quiet, low maintenance operation.

Along with the coilover conversion, this 6.5" system includes a pair of one-piece laser cut high clearance crossmembers, CNC machined ductile iron steering knuckles to correct tie rod angles, heavy duty front skid plate and differential skid plate to increase protection, multipoint differential relocation brackets to secure differential and correct CV axle angles, longer sway bar links and braided stainless steel extended brake lines. In the rear, BDS offer both a 3" and 5" rear block and u-bolt kit to lift and level the stance. The 5" rear block kit includes a u-bolt flip kit with new spring plate and the preferred round u-bolts for increased strength and ground clearance. To compliment the performance in the front this system includes precision tuned FOX 2.0 IFP gas shocks in the rear. This system allows for up to 37" tires to be installed.

FOX Coil-Over Dual Speed Compression (DSC) Adjuster Technology - The Dual Speed Compression (DSC) adjuster provides added control and comfort tuning for on-road use while also offering more aggressive damping for use off-road. The adjuster allows for precise suspension tuning with the simple twist of two clearly defined knobs: No tools and no mess, just a way to easily fine-tune your suspension to best suit your needs in any conditions. The DSC increases both low and high-speed compression levels up to 25%, allowing you to maximize small bump compliance and traction while still having the extra damping required for big hits.

- LSC Adjustment Range - The Low Speed Compression (LSC) adjuster knob offers 10 clicks of adjustment and primarily affects compression damping during slow suspension movements such as G-outs or smooth jump landings. It also affects wheel traction and the harshness or plushness of the vehicle's ride.

- HSC Adjustment Range - The High Speed Compression (HSC) adjuster knob offers 12 clicks of adjustment and mainly affects compression damping during medium to fast suspension movements such as steep jump faces, harsh flat landings, and aggressive wash board roads.

Please select from the various options to customize your BDS suspension system. If you have any questions, do not hesitate to contact us.


  • 3" Blocks No Overload = 13.5" long U-Bolts for vehicles that are NOT equipped with factory top mounted overload spring.
  • 3" Blocks With Overload = 15.5" long U-Bolts for vehicles that ARE equipped with factory top mounted overload springs.
  • 5" Blocks No Overload = same as above but with 16" long U-Bolts. 
  • 5" Blocks With Overload = see above. 


  • ManufacturerBDS Suspension
  • MPN727FDSC | 728FDSC | 729FDSC | 730FDSC
TIRE & WHEEL Combinations:
  • 37" x 12.50" w/17 x 8 and 4-1/2" to 4-5/8" back spacing
  • 37" x 12.50" w/18 x 9 and 4-1/2" to 4-5/8" back spacing
  • 37" x 12.50" w/20 x 9 and 5" to 6" back spacing
Installation Information:
  • Estimated Installation: 8-10 hours
  • Difficulty Level (easy 1 - 5 complicated): 4
Important Kit Notes:
  • Torsion Bar Tool required to unload the torsion bars.
  • Requires frame bracket and differential modification
  • Minor welding required for coil-over mount installation
  • Stock 17" 18" wheels cannot be reinstalled
  • Stock 20" x 8.5" wheels with 6" backspacing or less will fit with a max tire size of 35 x 12.50
  • Models with two piece rear driveshaft may require carrier bearing drop kit (#121612)
  • Coil-over designed for Diesel trucks. Use on gas models requires reducing coil spring preload to set at 6.5" of lift
  • Will NOT fit dually applications.


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BDS 6.5

BDS 6.5" Coilover Conversion Suspension Lift Kit 11-19 6.6L GM Duramax

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