100% Correct. HOWEVER.. a lot of those negative effects can be marginalized by shock, spring and roll rates. Without re-engineering the whole suspension (like you do) Camber and bump curves are way better on our cars the lower you get the suspension, and the static settings can be more aggressive. If you want shopping cart handling, by all means, do the drop spindles and keep the suspension at or near factory settings. If you want dynamic suspension that kills the competition, you need to get your suspension lower on these cars.
School me on drop spindles...
- Thread starter cam.man67
- Start date
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100% Correct. HOWEVER.. a lot of those negative effects can be marginalized by shock, spring and roll rates. Without re-engineering the whole suspension (like you do) Camber and bump curves are way better on our cars the lower you get the suspension, and the static settings can be more aggressive. If you want shopping cart handling, by all means, do the drop spindles and keep the suspension at or near factory settings. If you want dynamic suspension that kills the competition, you need to get your suspension lower on these cars.
Exactly. And thank you.
Drop spindles lower the CG the same amount as lowering the car 2" with the torsion bar adjusters. Which is VERY possible, as I've done it on my Challenger and my Duster.
Drop spindles do not change the roll center vs the stock ride height, because they keep the same control arm angles as stock, just put the car 2" lower on the spindle. Which is why the comparisons in the suspension modeling I posted show a higher roll center for the drop spindle car, because both of the cars in the comparison are at the same ride height. The car lowered with the adjusters has a lower roll center because of the improved control arm angles.
The best suspension geometry curves on the stock suspension occur when the lower control arms are roughly parallel to the ground. This is also a pretty good point to stop lowering, as it puts even above-the-steering headers like Doug's and TTI's about 3.5" off the ground. Track only cars can probably go a bit lower, but lower than that on the street starts to cause problems with speed bumps and angle changes like driveways.
Most of the suspension geometry is not changed vs STOCK with the drop spindles. But why compare the drop spindles to stock ride height specs? The best comparison is between a car lowered 2" without drop spindles, and a car lowered 2" with drop spindles. The car lowered without drop spindles will have better geometry, which is what all of those charts and graphs that I posted earlier show.
But if folks want to spend $450-$500 on spindles that are 100% unnecessary to lower your car 2", I guess that's their business. I'd rather use $500 of my budget on something that I actually need.
So to mix things up a bit, Lower the A body with the T.B adjusters and add B body spindles.
The B body spindle is taller then the A body spindle and will raise the upper control arm.
The B body spindle is taller then the A body spindle and will raise the upper control arm.
isn't the problem with lowering the car without the drop spindle is that the LCA rides on the bumpstops....upsetting / negating the suspension?
I enjoy your inputs....it is good to BS with you guys.
I enjoy your inputs....it is good to BS with you guys.
how much drop....with any decent usable suspension can you get with those lil' fellers. (I use them on my set-up)
when I was messing around with ride heights on a stock set-up....to get any decent drop in ride height the suspension basically had to be compressed. The LCA was just about on the frame bump stop with the stop removed, add the UCA severe angle and don't forget the extreme neg caster and shortened shock absorber. The only plus was the suspension had a lot of drop.....if that is a good thing
that is why the drop spindle still makes a lot of sense to me for the low ride height / lowered stance.
Sorry, you're right there. The instant center location won't change relative to the car with the drop spindles. But, since the whole car is lower, the instant center will be exactly 2" lower as long as you leave the torsion bar adjuster settings alone. The caveat to that is, 2" is a lot of drop, even from factory height. If you don't use all of that 2" of drop, you'll raise the roll center when you compensate higher with your adjusters. So, if you drop the car 2" your roll center will be 2" lower. But, if you only go 1.5" lower, your roll center will not be 1.5" lower, it will be higher than that.
But, the instant center will be more than 2" lower on a car lowered using the torsion bar adjusters because of the change in location of the ball joints relative to the frame. That's actually why Peter (GMachineDartGT) went to drop spindles for a little bit. He was lowered to the point that the control arms were actually angled up slightly, so he was getting a negative roll center. I know he stopped using the drop spindles, I think it was due to rim clearance.
That's why the best geometry occurs with the LCA's about parallel to the ground.
As far as the suspension travel at that point, with the "button" style bump stops I have about 1.5" from the frame to the bumps on my Duster right now. The LCA's are pretty close to parallel to the ground, and I have a little under 4" to my header flanges. With 1.12" bars I don't suspect I will ever hit the bumpstops. I actually plan on dropping the car slightly to put the header flanges at about 3.5" of the ground. If you take a look at the picture I linked earlier showing autoxcuda's car, you see he has about 1.5" from the frame to the LCA (no bumpstop) in that picture. That was with 1" bars, and he said he never hit the frame. With the buttons installed at that height you'd have a little over 1.25" of clearance from the bump to the frame.
I have my Challenger just as low now, lowered with the torsion bar adjusters, as I did when I had it lowered with 2" drop spindles. Again, that's with 1.12" torsion bars. I haven't had any issues with hitting the bumpstops, and I actually drive the Challenger semi-frequently on gravel/dirt roads that have serious pothole and "washboard" issues.
The trick to losing the suspension travel is going with bigger torsion bars. You just don't need that much travel anymore. And since I think that the right spring rate for these cars is in the 250-300 lb/in (1.04" to 1.12") range for most street/autox/roadrace applications, you can lower the car that much without worrying about the loss of travel to the frame, since your actual travel will still be less than that.
Spun Bearing
Lost in Space
I don't see how all of the charts on the previous page can have any
significance whatsoever other than possibly to show the poster's own
car's specs.
If drop spindle's are installed there should be NO change in UCA angle,
NO change in the LCA angle and NO change in tie-rod angle or length.
The wheels and tires will mount 2" higher on the car (spindle), thus
lowering the car with NO other changes to suspension angles or
settings. This is the one and only purpose of the drop spindles.
How you could ever get any bump-steer without changing these settings
at all needs to be explained; in fact, I'd say it's impossible.
For any given amount of suspension compression the bump steer factor
(if any) should be identical as it was before the spindles were changed.
significance whatsoever other than possibly to show the poster's own
car's specs.
If drop spindle's are installed there should be NO change in UCA angle,
NO change in the LCA angle and NO change in tie-rod angle or length.
The wheels and tires will mount 2" higher on the car (spindle), thus
lowering the car with NO other changes to suspension angles or
settings. This is the one and only purpose of the drop spindles.
How you could ever get any bump-steer without changing these settings
at all needs to be explained; in fact, I'd say it's impossible.
For any given amount of suspension compression the bump steer factor
(if any) should be identical as it was before the spindles were changed.
You're missing a VERY important piece of the puzzle.
There is no change in the geometry using drop spindles vs a car at the factory ride height, you just sit 2" lower.
But there IS a change in the geometry for a car lowered with the torsion bar adjusters. A very significant change in fact, and an IMPROVEMENT over the stock geometry. Lowering the car with the torsion bar adjusters improves the control arm angles and ball joint locations relative to the frame. That lowers the instant center MORE than just 2".
The graphs I posted earlier do not compare a car at factory ride height vs a car lowered with 2" drop spindles. That is pointless, as the geometry would be the same.
The graphs compare a car lowered with 2" drop spindles vs a car lowered the same amount with the torsion bars. That's why the geometry is different. The cars are sitting at the same ride height, but because one uses drop spindles it retains the factory control arm angles. The car lowered with the torsion bars does not. And, the geometry of the suspension is IMPROVED by changing the control arms angles, especially when the LCA's sit close to parallel to the ground.
Plain and simple, the suspension geometry from the factory, at factory ride height, is not ideal for handling. It was set up for use with very low spring rates, horrible tires, and poor shocks. With modern tires, 2x to 3x the spring rate, and improved shocks, the geometry is better when the car is lowered with the torsion bar adjusters.
I agree 72 blublu.....lowering the car and keeping the stock spindles does improve the control arm angles, therefore the roll center.....BUT then we are back to the old issue. The stock suspension is basically in compression with the LCA near or on the frame stop.
Let me perhaps put it this way...for us coffee getters those drops still look good.....lowers the car and still gives full range of suspension. We will just have to keep our speeds down when we turn into the coffee shop or car show.
Let me perhaps put it this way...for us coffee getters those drops still look good.....lowers the car and still gives full range of suspension. We will just have to keep our speeds down when we turn into the coffee shop or car show.
Hyper-Performance
Late Apexer
From my experience, the only negative effect using drop spindles may/will have is:
- Caster adjustments may not be able to be reset to factory specs - HOWEVER - if you are looking for increased negative camber (road race - auto-x) you are gaining adjustment!
- The jury is still out on the effect on scrub radius, there is a small change in the Akerman. (Remeber - the tire contact point in relation to the control arm pivots has changed)
- The change in axle centerline in relation to the control arm mounting points MAY increase forces on the pivots and control arms due to the change in the moment arms. For most applications there is nothing to worry about, for severe duty (road racing and hitting corner curbs or off road rock climbing) you need to be careful.
- Reducing the front roll center is a good thing for handling, however, by lowering the nose the weight is distributed further forward - no a good thing for an already nose heavy platform.
- Caster adjustments may not be able to be reset to factory specs - HOWEVER - if you are looking for increased negative camber (road race - auto-x) you are gaining adjustment!
- The jury is still out on the effect on scrub radius, there is a small change in the Akerman. (Remeber - the tire contact point in relation to the control arm pivots has changed)
- The change in axle centerline in relation to the control arm mounting points MAY increase forces on the pivots and control arms due to the change in the moment arms. For most applications there is nothing to worry about, for severe duty (road racing and hitting corner curbs or off road rock climbing) you need to be careful.
- Reducing the front roll center is a good thing for handling, however, by lowering the nose the weight is distributed further forward - no a good thing for an already nose heavy platform.
After reading all of this ,, All I know is that they worked and was happy with it.My buddy and his 89 year old father drove it from Las Vegas to Pittsburgh and said it ran and drove flawless and they had a blast crusin' the country in a 50 year old car. So is the new owner.:cheers:
375inStroke
Well-Known Member
Aren't the drop spindles based on the later R and M-Body spindles, which are taller than the earlier B-Body, and A-Body spindles? The upper ball joint location is higher, so it does change your geometry.
"Designed by Magnum Force and based on the big bearing, big ball joint 1973 and up spindles"
http://www.bigblockdart.com/techpages/spindles.shtml
"Designed by Magnum Force and based on the big bearing, big ball joint 1973 and up spindles"
http://www.bigblockdart.com/techpages/spindles.shtml
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