TIGER SUSPENSION  NEW CUSTOM BUILT ADJUSTABLE UNIT
 

 

The original Sunbeam Tiger front suspension has had issues from it's initial production, notably the awful reverse Ackerman angle as well as the bump steer due to the steering rack's location.  When the Tiger was built, it seemed that an Alpine front crossmember served as the basis and parts were simply modified or added during the car's limited production.  Over the years, people have desired change, but usually a major change involved either modification to the car or it's components and not many people were willing to sacrifice the parts due to the rarity and value of the car and the components involved.  Let's face it - parts have become rare, and control arm fulcrum pins have suffered breakage over the years due to age, bad geometry as well as corrosion.  So a few years ago, we sought out the possibility of utilizing a different front suspension or components, but realized certain specific pieces wouldn't provide the geometry we were searching for or wouldn't fit the car due to it's small, narrow nature and limited wheel well space.  So late in 2005, we set out to fabricate our own scratch-built suspension utilizing components off the shelf that's readily available and offers adjustability.  We wanted adjustable ride height as well as the general caster, camber and toe alignment options.  Larger, more efficient brakes would be a major improvement in a Tiger as well.  Therefore the monumental task that involved the replacement of the complete existing Sunbeam suspension ensued.  The main objective of the project was to improve the poor Sunbeam steering geometry and provide updated braking technology within a unit that's easily adjustable.  We established one important rule concerning the project before we started - The entire front suspension could be installed in the car without irreversible modification to any Tiger components and be a complete replacement without modification to the Tiger chassis - no cutting, drilling or welding.  The entire Sunbeam front suspension (crossmember, steering rack, control arms, spindles/hubs and intermediate shaft) could be removed, stored on the shelf and preserved for the long term.  The Ford 302 short block was positioned using Tiger motor mounts to simulate the engine's location in my Alpine chassis.  A jig was placed under the car locating the spindles and the steering rack was mocked up in place just forward of the 302's oil pan directly under the crank snout.  Upper and lower control arm location points were mapped out and final positioning of components were completed.  Fabrication continued and following completion, the unit was installed in the Tiger in late May of 2006.  Different fixtures were produced to enable control arm fabrication of various lengths to allow different track widths due to different possible wheel offsets that are currently available.  The differences between the original Tiger crossmember and the new unit are clearly visible in the photos shown on the left, notably the steering rack re-location as well as the position of the upper and lower control arms.  The Flaming River steering rack packaged with the crossmember in the red Tiger was moved 5-3/8" rearward of the original's location, just under the crank in front of the oil pan.  The potential binding due to severe angles is gone and the new suspension has the control arms positioned parallel to the centerline of the car.  After installation, a few minor adjustments were made and the steering shaft was fabricated using Sweet mfg. U-joints.  We decided on initial alignment settings and took the car for it's first test run on June 1st, 2006.  The turning capabilities were simply amazing.  The suspension doesn't have the horrid Ackerman steering issues that have always plagued the Tiger and the turning radius was reduced significantly.  Being fitted with QA1 adjustable coilover shocks, we made a few alignment and ride-height changes and put some more miles on the car over the next few days with good results.  The car handled nicely, was very predictable and we continued with more road tests.  The car ran an autocross in Canada in July 2006 to really push the unit and see how well it performed, and we were pleased. 

After driving the car through the summer months of 2006, we realized the crossmember structure could easily be refined and lightened, so a few changes were made.  The upper control arms were also completely reworked and they utilize components from SPC Performance Products that offer simple, rapid adjustments that a Tiger owner could have only wished for in the past and upper control arms allow infinite alignment adjustability.  The new crossmember itself weighs 28 lbs, 9-10 lbs less than the first unit.  The crossmember structure is built using parts cut from templates and cnc machines using CAD drawings.  The 1" front sway bar is attached to the crossmember directly, unlike the original Tiger factory setup that is clamped to the lower control arms.  The whole package is a snug fit in the Tiger, but if you've ever dealt with one of these cars, everything is.  In May 2007, we installed this new setup and attended the Tigers United gathering in Grants Pass, Oregon in June 2007.  The Tiger ran Top Time Of Day at the autocross and the suspension performed well.  The ability to make "parking lot" adjustments allowed us to change the ride height to accommodate a new set of 245-45-16 Hoosiers, adjust the shock valving as well as change the caster, camber and toe for the autocross. 

A couple of major advantages of this new crossmember is the additional space gained when the original horseshoe-shaped unit is eliminated and that allows more room for large aluminum radiators and electric fan setups that will aid in cooling.  It also removes the steering rack from it's close proximity to the motor's crank pulley where there have been problems.  Also, the unit pictured weighs approx. 148 lbs, which drops over 50 lbs from the front of the car.  When you combine the weight savings of aluminum heads, aluminum radiator and new crossmember design, you've eliminated well over 100 lbs.