Locost people, experts in parts bin suspension engineering. http://www.locostusa.com/forums/ and http://www.locostbuilders.co.uk/
I've always thought as HAMB as a place for people pretending its 1964 at all costs.
Locost people, experts in parts bin suspension engineering. http://www.locostusa.com/forums/ and http://www.locostbuilders.co.uk/
I've always thought as HAMB as a place for people pretending its 1964 at all costs.
If I was trying to make a front suspension from scratch, I would try to find something that handles well and copy its geometry. I'm sure people have figured out the miata front end geometry by now...
+1 for copying, easiest way to do it.
But what are your goals? Unless you're trying to give it WRC-like handling this is massive overkill.
If you're going offroad there are already aftermarket suspension arms out there that can increase wheel travel, and suspension geometry isn't worth much offroad. The limit of corner speed will be the conditions or the stability of the truck, not the limits of grip.
If you want to go fast on smooth pavement, it would be easier to use the go-kart theory of suspension design - "any suspension will work, if you don't let it." Dial in good static camber and run hard-as-hell springs, add roll center spacers to get the curves generally in the right direction if that helps.
GameboyRMH wrote: If you want to go fast on smooth pavement, it would be easier to use the go-kart theory of suspension design - "any suspension will work, if you don't let it." Dial in good static camber and run hard-as-hell springs, add roll center spacers to get the curves generally in the right direction if that helps.
+1
How deep do you want to go? Because doing this the right way is very involved. If you do, this is how I would go about doing it.
First step: Find what you have.
Get the cars on some ramps (a four post lift is perfect for this). Than measure the position (height and side to side) of the following point: lower control arm inner bushings, lower ball-joints and strut top mount. Take those dimensions and the static alignment values (for camber and caster mostly) and plug them in a front suspension software to figure out your roll center height and camber gain. Don't forget to measure your springs to find out their rate.
Second step: Find more about the rest of the car.
Get some corner-weight scale and find your weight distribution. Than, find the height of your center of gravity. "Race and Rally Car Source Book" by Allan Staniforth has a nice method in annex 6.
Third step: Figure out what you want.
With all this information, you can see the short-comings of your suspension geometry. I would guess: not enough caster, not enough camber gain and too much distance between your CofG and your roll-center height. Those are the usual off-road suspension problems. You can also figure out what kind of spring rate you want.
If this all looks too complicated (and it is complicated), than just do what the others have suggested and make it as stiff as possible. Unless you have data, any other change will be an educated guess at best.
^^^He speaks the truth...every word of it, right down to recommending that you consult the holy texts of staniforth. Seriously, they're the best thing that I've found for someone like myself; i.e. without an engineering degree.
iadr wrote:
Does a solution like this even change the roll center? Looks to me like the relationship between the wheel center/LBJ pivot/LCA pivot will all remain the same, while merely changing the angle of the control arm. The ball joint is still in the same place WRT the upright, so the virtual LCA is the same as it was originally.
Right?
sobe_death wrote:iadr wrote:Does a solution like this even change the roll center? Looks to me like the relationship between the wheel center/LBJ pivot/LCA pivot will all remain the same, while merely changing the angle of the control arm. The ball joint is still in the same place WRT the upright, so the virtual LCA is the same as it was originally. Right?
Correct.
iadr wrote: the front now has a tendency for the outside front wheel to feel like it's "digging in" when cornering hard, for lack of a better way to wor
Totally understand, my Samurai does the same thing.
This is caused by a combination of not enough camber gain and too much body roll. Basically your front outside tire is leaning out too much.
You can solve this with roll center spacers (to get more camber gain - so the top of the wheel tucks in more under compression) and a good bit of static negative camber (so the wheel is leaned in more throughout its travel). Also harder springs will help. If it's too harsh for the potholes you can try harder sway bars instead. These will help reduce body roll.
Custom suspension is major, major work, in fabrication and especially in design, so you should try to avoid that.
Struts make for perfectly workable suspension UNTIL you try both putting power through it AND making it steer, one or the other and its fine, Lotus used rear struts on some of their cars. See the 911, winningest car ever, struts up front.
You'll need to log in to post.
