I have been pondering recently on how to design the lower front wishbones around the rather cumbersome mounting arrangement of the stock Miata ball joints.
File comment: Ugh!
Miata MX5 Lower Ball Joint.jpg [ 34.97 KiB | Viewed 1132 times ]
Ideally, I would like to replace the Miata ball joints with readily available press-in type ball joints. Unfortunately, I haven't been able to come across a loaded type ball joint with the same stud taper and diameter that wasn't originally used in a 1960's muscle car and is the size of my fist! Also, I don't want to re-ream the Miata uprights if I don't have to. So instead I have started looking at if I can replicate the design of the Caterham lower wishbones which use a spherical bearing specifically designed for racing suspensions and proven in day-to-day use in Sevens for decades.
File comment: Simple and elegant...
Caterham Braced Lower Wishbone_1994 Onward.jpg [ 64.23 KiB | Viewed 1132 times ]
A few minutes of Googling and I found the manufacturer and part number of the spherical bearing. It is a New Hampshire Ball Bearing (NHBB) model ABWT10. At about $40 each they are comparable in cost to a reputable brand Miata lower ball joint. So far, so good.
ABWT10.jpg [ 53.69 KiB | Viewed 1132 times ]
A bit of layout time in CAD, a bit of rendering time and voilà!
LCA_Low Res.jpg [ 483.62 KiB | Viewed 1132 times ]
LCA_Render_001.JPG [ 73.64 KiB | Viewed 1132 times ]
I haven't been able to find commercially available bearing housings and taper studs yet. It looks like the bearing housings will have to be custom machined. For the taper studs, the ones used on early model Mustang bump steer kits look promising. Mazda used the same 1-1/2" per foot taper as Ford. When I get a chance I am going to see if a Mustang outer tie rod end fits in the Miata upright.
Steeroids Tapered Outer Tie Rod Bolt_67-69 Mustang Spindle.jpg [ 15.2 KiB | Viewed 1132 times ]
Keeping my fingers crossed....