Disclaimer: This is from a Jeep forum. It may not all (or any of it) be true. BUT, I think it's interesting and worth a read on the subject of Solid Axle vs. IFS.
Originally Posted by CIJeep
Theoretically IFS should be better. With the right design the tire tread will be flat on the ground at all articulations. In reality the solid axle is more reliable, less parts, more rugged, not so spindly, and can carry quite a load.
I don't remember all the particulars, but the end result for me was decided years ago, solid axles are best. Just my 2 cents.
But then watch a fully independant long armed spindly totally tubular dune buggy with one humongous V8 virtually flying through everything and you will have second thoughts.
Originally Posted by wayland1985
IFS is actually superior in many ways. For one, the differential is up and out of the way. No Pumpkins to worry about! Also, handling characteristics on road are much better, as well as off road. Articulation-wise, I think with the right set up, you can get better articulation with an IFS than a solid axle. Look at BAJA racers. Those things have feet of articulation (mainly due to triangulation and long arms).
The biggest problem with IFS is cost. They need more parts, so they cost more. Also, more parts means more potential for breaking.
Modifying independent suspensions gets a lot more expensive too, so your lift kit will cost you MUCH more. Also, they're harder to work on. One of the biggest questions with the design of the current Mustang was Indepentent suspention or solid rear axle. Cost reasons, and the request of weekend mechanics encouraged the team to build a solid rear axle platform.
Originally Posted by Jrgunn5150
IFS is better when properly designed, look at the HMMV or the Baja trucks. Most are designed for cost and a nice ride though. Not to mention a straight axle is simple, easy to fix, hard to break, and cheap.
Like they said, IS (idependent suspension) is better all around then a solid axle. they have better on road ablities at low and high speeds. A properly tuned IS will exceed a solid axle in flex and ablities. The problem is cost. One of the main reasons a solid axle is so popular is because they are easy to lift, easy to repair, and easy to maintain. Also, one reason a lot of people don't like factory IS's is because its usally hard to disconnect the sway bar. and as almost all of us can testify to, there is a big difference in flex of a disconected and a non disconnected setup. the same goes with an IS system, a disconnected one will flex a whole lot more then a connected one.
This is one reason you see so many H1's, H3's, chevy's, etc with one wheel in the air. because they don't have the ablity to disconnect. I know there are kits out there, a buddy of mine has front disconects on his chevy S10, so it can be done, just most people don't. Baja racers usally don't even bother with a sway bar because they won't be on the road, so there is no need.
Car companies put IS's on the front and solid on the rear of trucks and mid-size SUV's so that they can still have good handling dispite their wieght, and also have that pulling power. a solid axle can be built for pulling for a far cheaper price then a IS can. Thats not to say the solid axle is better, its just cheaper. Proof that an IS can be built for towing is the H1 which has IS all around and can pull over 9000lbs.
Solid axles are strong and can take a beating naturally, but just like an IS setup, depending on the way its designed will determin how tuff it is. a Dana30 will not take the same punishment as a Dana60 will, like wise, a IFS system off a geo tracker will not take the same punisment as the IFS off a chevy 2500. The problem is, like everything else, cost. it cost more to beef up an IS system then it takes to beef up a solid axle.
The only thing a solid axle is better at then an IS, is the cost, that's it...
Link:
Which is better and why? IFS vs. Solid Axle
