r.barn

Read the following explaination from MM's website. I think I'll believe them and use
the right parts in the right places.

Going cheap on some parts just ends up costing more money in the long run.



From MM:

The rear control arms connect the rear axle housing to the chassis. All of the forces that accelerate the car, as well as the braking loads, pass through the rear control arms. In stock form, the deflection of the rubber bushings prevents the rear axle from maintaining its correct position under the chassis, leading to instability from rear steer. During acceleration, the rear tires push the axle forward, which in turn moves the car forward by pushing on the rear lower control arms. Replacing the rear lower control arms with MM control arms will improve traction and handling primarily because of the elimination of the overly compliant stock rubber bushings. With MM rear lower control arms, the properly designed bushing mounted in a stout tubular arm keeps the axle correctly positioned under the chassis. Traction and handling are both improved because the axle does not move around in an unpredictable manner.

Most aftermarket rear control arms use hard 2-piece urethane bushings, Delrin bushings, or steel bushings. Those types of bushings do not allow the angularity needed for the Mustang’s suspension to articulate freely. The resulting suspension bind causes the rear tires to break loose very easily. Suspension bind not only causes poor handling and poor traction, but it also causes damage to the torque-boxes. As the attachment points on the chassis for the rear control arms, the torque-boxes can suffer greatly from the abuse of poorly designed control arm bushings. After all, the torque boxes are only made of folded sheet metal.

Stop wheel hop
Ford’s solution for reducing wheel hop was the addition of the quad shocks (the two horizontal shocks mounted behind the rear axle). They reduce wheel hop by dampening axle wind-up. Axle windup is caused by two independent deflections: the control arms, and the rubber bushings. Deflection of the control arms is eliminated because the MM arms are over three times stiffer than the stock control arm. Deflection of the soft stock rubber bushings is eliminated by our unique bushing designs. These designs are the result of extensive motion analysis of what actually occurs when the rear suspension moves over bumps, and during body roll. Installing MM’s rear lower control arms eliminates the primary cause of wheel hop, which is the deflection of the stock lower control arms and their bushings. While there are other factors besides the compliance of the control arm bushings that cause wheel hop, the MM arms usually reduce axle wind-up enough to allow removal of the factory quad shocks.

Good Research is the Basis of Good Engineering
The concept of wheel rate is similar to that of spring rate. But, to put it into simple terms, the wheel rate is measured at the wheel, not at the spring. Poorly designed suspension components can prevent the control arms from articulating properly during bump and body roll, and therefore cause suspension bind. This suspension bind will cause the wheel rate to increase unpredictably, adversely affecting handling.

To analyze the geometry involved, Maximum Motorsports used a full-scale mock up of the rear suspension. When we tested other aftermarket control arms, we found that most use bushing designs that actually cause an increase in suspension bind, compared to a stock control arm! Control arms that had hard urethane bushings at each end increased the wheel rate by 400%! For example, as little as a 10% increase in rear wheel rate will have a noticeable effect on the handling balance of a car, because the rear cornering grip will be noticeably reduced.

So, why does the wheel rate increase? In the Mustang’s rear suspension design, whether it is still the stock 4-link suspension design, or has been modified to a Torque-arm or three-link design, the control arms do not simply pivot. The arms also move sideways, with an angular motion (relative to the pivot axis). If that angular motion is restricted because of a poor bushing design, the suspension will bind. While some aftermarket control arms may seem to improve performance because of reduced bushing compliance, it is only improved to a level slightly higher than the stock control arms. Once the car is pushed past that level, the increased wheel rate from the suspension bind will cause unpredictable handling– not to mention damage to the torque boxes.

To avoid that nasty situation, the two different bushing configurations of both the MM Heavy-Duty and Extreme-Duty Rear Lower Control Arms allow the necessary freedom of suspension articulation, while continuing to positively locate the axle in the fore-and-aft direction.

mjr46

[quote]ORIGINAL: r.barn



your free to choose what you want to use..I'm not trying to change your mind ...just dispell some of the sensless marketing tactics , ploys and read theroies many buy into and believe......I base my responses proudly upon defying theroy to prove it CAN be done sucessfully.....my 3 stangs are proof.....I don't just post based on what I read on the internet...anyone can google stuff......I have used between the three current mustangs I have and past ones almost every trick/performance part anc multiple combos to gain real world experience.....you can read how to become a mechanic in a book but once you have to actually put into play that knowledge book smart vs street smart becomes a whole new game...once had a principal who was ase master tech = bought all the books studied them took tests and passed...but he was clueless on how to even fix a car.....anyway, there will be no more COSTING me in the long run as you so think....FYI..they have been on the car for nearly 2 years as it is.....So, I'm not trying to change what you plan to do..cause that won't happen but I don't agree with all the theroy cause that's just what it is....like the 347 Rod rational, 90/10's handle like crap on the street, tubular k-members and coil overs don't perform well for DD....AND THE LIST GOES ON.....all I'm saying is try it and you'll understand....cause I have tons of cases to prove all scenerios wrong

mjr46

OH and FYI...the granatelli control arms do not use the typical hard compound on the lower control arm bushing you are so refering to..they are more of a soft plyable rubber with greasable joints = so squeaks, noises or binding

projectresto83

I have always heard the granatelli's suck. From squeaks to wheel hop. Any suspension can work with the right combination of parts. It just depends on what you want from your can and how much you can tolerate with theharshness of some components. I always wanted to set mine up for road race action but IDk if I would ever attend any events with it. I'll end up doing more drag racing but when I get it up to speed I will be driving it pretty much daily so I figure road race setup would be better for a daily driver. People here in Texas can't drive worth a damn I gotta be able to swerve hard when I have too.

jnsnams

i have them on mine and love them....alot better than stock is how i look at it