DusterRT
09-13-2006, 09:32 PM
I'm having alignment issues with my DD/Auto-X car (*cough* Neon *cough*). Basically, I have run out of toe adjustment in the rear; not an uncommon problem with this model of car. I want to replace the fixed/bushed control arms with rod ends so I can adjust my camber as well as correct the toe situation. However, I usually see this application fitted with phone pole-like links. Not only does this seem a little overkill (and consequently costing and weighing more than it has to), but after I thought about it, it seems like there might be more to it.
These links are attached to the body and knuckle in single shear by M12 8.8 hardware. According to the information I found, I came up with a shear strength of around 7200 PSI {(84.3mm^2 * 375 N/mm^2 shear strength) = ~32000 newtons => 7200 lbs).
I've seen this application fitted with 3/4" SRE's and 1" solid hex turnbuckles. Extremely strong, yes; but it seems to me that having the weak link be the hardware is a bad idea; as in the bolts will shear before the links give. Wouldn't it be better to have suspension links bend before the hardware fails?
They make 12mm rod ends; but they just 'seem' entirely too small. But I might just be used to seeing things made overkill. 2500# static load is the rating I have found on that particular size (3380# dynamic strength is also given; I will assume that is absolute strength, and the smaller figure is sort of a maximum normal load figure?). There are two links per side though, so there would be 2 rod ends at each connecting point (knuckle and frame). Given that it is a lightweight car (2650 w/ driver) on relatively small street tires (195-60-14), it seems like it is going to take an accident (or a huge "oops!" with a curb or something) to put anywhere near that kind of lateral force on the links.
Anyway, thanks for any input!!
These links are attached to the body and knuckle in single shear by M12 8.8 hardware. According to the information I found, I came up with a shear strength of around 7200 PSI {(84.3mm^2 * 375 N/mm^2 shear strength) = ~32000 newtons => 7200 lbs).
I've seen this application fitted with 3/4" SRE's and 1" solid hex turnbuckles. Extremely strong, yes; but it seems to me that having the weak link be the hardware is a bad idea; as in the bolts will shear before the links give. Wouldn't it be better to have suspension links bend before the hardware fails?
They make 12mm rod ends; but they just 'seem' entirely too small. But I might just be used to seeing things made overkill. 2500# static load is the rating I have found on that particular size (3380# dynamic strength is also given; I will assume that is absolute strength, and the smaller figure is sort of a maximum normal load figure?). There are two links per side though, so there would be 2 rod ends at each connecting point (knuckle and frame). Given that it is a lightweight car (2650 w/ driver) on relatively small street tires (195-60-14), it seems like it is going to take an accident (or a huge "oops!" with a curb or something) to put anywhere near that kind of lateral force on the links.
Anyway, thanks for any input!!