thoughts on dropped spindles

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mattm

mattm

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ok tryin to get my suspension squared away finally figured out my torsion bar choice n they are on their way i went with pst 1.03 bars james assured me they are of new design n are indexed. so i cancelled my order with summit on the .920 bars i want stiffer bars in hopes a less nose dive on hard braking n aggressive driving. brings me to my next question should i adjust the torsion bars to my desired height or by some dropped spindles n crank em way up? one thing i am afraid of is with spindles if suspension does compress excessivly in a turn the tire will hit the fender were as with the wore out small bars now it will hit the bump stop before the fender. id imagine just putting the new 1.03 bars in would keep it off the bump stops far more
 
I'm afraid that thing is gonna ride awful stiff.

I personally like ( for the coffee getter) the smaller torsion bar (spring) with a sway bar to help control the roll.

I would ONLY use the drop spindle if you wanted to lower the front more than an inch or two, just to keep the LCA off the stops.

just my .02.....good luck with your build
Denny
 
My son has the MFR 2 inch drop spindles on his '68 Dart, with 1 inch torsion bars from Just Suspension and a Hellwig front sway bar. The thought with the drop spindles is we could get the car low and still have some suspension travel for compliance on bumpy roads. His Dart is lower than most, with 4.5 inches under the K-member. Rubbing in the wheel wells can be minimized by picking the right backspacing on the front wheels. His fronts are 205/50-16 tires on 16x7's with 4 inches of b/s, and they do rub when he has the wheels turned sharp and the suspension moves, like turning into a driveway. Eventually we plan to move to 17 inch wheels and will pick a b/s closer to 5 inches on a 17x7. FYI, this setup has been on the car for over a year, first with a 318, and now with a 383. Stiff...? A little, perhaps, but chassis control with the big block was the plan from the start. And as far as riding on the bump stops goes, ever watch a slammed Honda run down the road..? All that bouncing around is transmitting large stresses through the chassis, and our old Mopars weren't built that tight to begin with..... You need to let the suspension do what is was meant to do.
 
oh im sure it will firm it up my logic was its spending most a its time on the bump stops now its probably less then 1/2" at rest between the bump stop n the rail n its bouncy ya gag it it comes way up you lay on the brakes car feels like its ready to do a endo. I want it to handle i know i will have to compermise a little ride. the car is very heavy got the big fed bumpers n a iron headed 360 still feel like i added more weight then removed with bigger t bars front n rear sway bars sub frame connectors etc. im just wonderin if its any real added benifit havin 2" between the bump stop
 
The 1.03 is a great bar for a good handling car. Drive it for a bit and see how you like it. The drop spindles are a great way to maintain suspension geometry and lower your COG. That said, you'll have ore worry of ground clearance before you run out of room with low profile bumpstops and factory spindles.
 
reddartowner i went 17x7 with 4" on front with 205 50 17s i plan on goin to a 205 45 17 soon as we have something wrecked come in with some good ones on it lol im a little cheap in that aspect probably one a the few to spend money on new 17 n 18" wheels but skimps n gets tires off a wrecked cars out the yard at work. wish id a did more research id i went more back spacing they work pretty good but 4.25 or 4.50 woulda been ideal
 
shocks are cheap replacements i intend to get some qa1s right after first of the year
 
really not worried about the adjustability kinda want budget friendly n functional u wouldn happen to know the pt#s on the kyb s off hand would ya?
 
mattm said:
really not worried about the adjustability kinda want budget friendly n functional u wouldn happen to know the pt#s on the kyb s off hand would ya?
Click to expand...

KYB fronts:

http://www.summitracing.com/parts/kyb-kg4509/overview/year/1968/make/dodge/model/dart

KYB rears:

http://www.summitracing.com/parts/kyb-kg5511/overview/year/1968/make/dodge/model/dart

These guys have a better price than summit if you're buying a full set:

http://www.justsuspension.com/catal...trut-suspension-kit-for-dodge-dart-1963-1976/
 
KYBs are too stiff for some people (but I didn't find the 1.14" torsion bars or KYBs too stiff in my son's Barracuda). I will be putting those on my Barracuda convertible, but with .890" bars and factory big block sway bar.
 
I'd skip the KYB's. I have them on my Challenger with 1.12" torsion bars, and although I've put over 40k miles on the car in this configuration I wouldn't pay money to buy a set of KYB's brand new. They're ok, but-

I also have 1.12" torsion bars on my Duster. I installed them with a set of Bilstein shocks. Even though the wheel rate on the Duster is higher (300 lb/in vs 270), the Duster rides MUCH better than the Challenger. Not harsh at all, even with 1.12" torsion bars. The trick to a nice ride quality is matching your torsion bars to a set of shocks that can keep up with them. The Bilstein's from RCD or Fox shocks from Hotchkis would be at the top of my list for anything over 1".

As far as drop spindles, you probably don't need them. Your torsion bar adjusters should have more than enough range to lower the car to your desired height. And unless that height is absolutely on the floor, you should still have enough travel to avoid bottoming. A 1.03" torsion bar has close to DOUBLE the spring rate of even the original 340 torsion bars (.87" diameter). That roughly means that you'll use half the amount of travel you used before. Even if you "add" that travel back in by using a drop spindle, its unlikely that you'll actually ever use it, unless you're planning on running the Baja 500.

I ran drop spindles on my Challenger for awhile as well, before realizing I could run standard spindles at the same ride height without bottoming. I've never hit the bumpstops on my Challenger, although I do use the polyurethane button style bumpstops. My header flanges only sit about 3.5" off the ground. You can't get much lower on a street car without leaving your exhaust behind you after a speed bump...
 
Just for perspective, here's what the upper ball joint looks like with light pressure on the bump stop. 8-[
 

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Idaho said:
Just for perspective, here's what the upper ball joint looks like with light pressure on the bump stop. 8-[
Click to expand...

Yeah but how far off the ground is the frame or exhaust in that picture? I doubt that you'd clear any speed bumps like that either.

I like low, but its for handling. Best geometry for handling occurs with the UCA's and LCA's parallel to the ground. You're a bit past that in your picture. :D

My Challenger is pretty close to having the UCA's and LCA's parallel to the ground, it sits with the frame/exhaust that low because of the relatively short tires, 275/40/17's, that I run (25.6").

But you still need room for travel, which is why I run the short bump stops. Not because the car would be sitting on them otherwise. With larger torsion bars, you don't need a ton of room, and you won't spend any time on the bump stops. I know I won't with my 1.12" bars- I only need about a third of the originally allotted suspension travel.

The problem with the drop spindles is that they limit your backspace options even with 18" rims, so your stuck with no more than ~5.6" backspace, which limits the front tire width pretty significantly. No more than 255's for sure. They also introduce a small amount of bump steer, and raise the roll center of the car. None of those are huge effects, but if handling is truly the goal then you're better off setting it up so that the UCA's and LCA's are fairly close to being parallel with the ground. That's still a fairly low stance, you'll still tuck the top of a normal height tire (25.5-26") behind the fender lip and it will keep you from wearing out ball joints like they're going out of style.

If you truly want to lay the car on the ground, then you'd best look at some kind of air-ride.
 
So with drop spindles, the car sits 2" lower before you contact the bump stop. Or, if you think of it another way, the k-member, pan and headers are 2" closer to smashing into the road before you contact the bump stop.

There are lower profile bump stop pads out there, or you can cut the rib off the center of a factory pad. Either way you trade a little of the progressive nature of the factory pad for more clearance.
 
I had drop spindles and big bars on my duster before I went RMS. my two cents,they are ok,you will get some bump steer and a little wander. my be able to play with alignment on that. I don't think I ever bottomed my car out on the street.
I had qa1 single adjustables also. they worked,but as you get greedy and adjust them up they get to stiff and the suspension doesn't do it's job. not sure on the kyb's,but spend money on shocks. I agree with a couple of the other guys though,let the swaybars do their job. I had big Firm Feels on mine and they were awesome pieces.
 
C130 Chief said:
So with drop spindles, the car sits 2" lower before you contact the bump stop. Or, if you think of it another way, the k-member, pan and headers are 2" closer to smashing into the road before you contact the bump stop.

There are lower profile bump stop pads out there, or you can cut the rib off the center of a factory pad. Either way you trade a little of the progressive nature of the factory pad for more clearance.
Click to expand...

Yup. The drop spindle moves the wheel axis up 2", so it lowers the car 2" without changing the torsion bar adjustment. But it does add some bump steer, and it does raise the roll center. Not a huge problem, you're still probably ahead of the handling game vs stock because of the lower center of gravity, but at least in my experience I can get as low as I want to be without using the drop spindles.

Here's the thing with the factory bump stops. They were in fact designed to act in a progressive nature, adding rate as the car neared the end of its suspension travel.

BUT, with 100-120 lb/in rates you NEED that progressive bump stop feature, because otherwise you'd constantly be slamming the suspension into the frame. With a 1" bar, your spring rate is ~200 lb/in depending on the manufacturer, so you don't need that additional rate. And the shock technology out there today makes it possible to have that high of a rate and still have a comfortable ride, which is something the old shocks couldn't do. Hence the smaller torsion bars and giant rubber bump stops.

With 1" or larger bars, you don't have nearly the amount of travel to worry about, and you can use the smaller bump stop as long as you've set the ride height up so that you're not going to be constantly hitting it. If you do that correctly, you shouldn't hit the bump stomps at all during "normal" driving, and you'll have a nice, constant, predictable spring rate to count on.

The stock bump stops certainly give you a larger margin for error when setting up the suspension. But the factory was setting up tens of thousands of cars, you're only setting up one. And they couldn't get a set of Bilsteins to make a 1.12" bar ride well, so they undersprung the suspension and added progressive bump stops. Even with 1" bars you should be able to lower the car significantly without worrying about ever hitting the bump stops.
 
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