Soft springs/big bars set up question...

[DavidBoren]

When dealing with factory A-arms, is the geometry correct for using the more modern approach of high travel/low roll?

Or do you need longer A-arms for that concept to work?

Although a question of general theory, I am asking in regards to my S10. If I use stock A-arms, which originally had stiff springs and a little sway bar, and I install soft springs and a big anti-roll bar, would the additional travel allowed by the softer springs mess with the geometry of this suspension?

[SSLance]

The factory S10 upper and lower control arms are very similar to the G-Body arms which had poor geometry for performance concerns from the factory. The arms add positive camber (tilting the top of the tire out) under compression instead of negative camber.

Most aftermarket upper and lower arms correct this as well as reposition the upper and lower ball joint to aid in being able to dial in more caster as well.

Will soft springs and a big bar work with the factory arms, probably yes...will it improve the handling of the S10, probably not just by themselves.

[DavidBoren]

Thanks for the reply. Building a whole new rear suspension to be balanced with a poorly designed front seems like it would be an effort in futility.

Looks like I need to address the front suspension's downfalls before I worry about the rear.

I need to research aftermarket spindle kingpin angles and aftermarket A-arm caster angles, see if I can find some that match up correctly.

Anyone with first hand knowledge of aftermarket S10 front suspension components that go together with an emphasis on handling? Brands I can trust? Kits designed for function, not just going low for looks...?

[SSLance]

There are a lot of options, both bolt on and custom configured...for that platform. I'm still running the factory spindle but have reworked just about everything else up front on mine and it handles great. The world is your oyster, just depends on how much time and effort you want to put into making the truck handle. You don't necessarily have to spend a lot of money on parts, just make smart choices with your final goal in mind. I did mine in stages but knowing what I know now, if I had to do it again I'd do it right from the start.

[samckitt]

Lance, where is your build thread?

[SSLance]

Uh, which one... :D

Here's the one on this site

http://www.lateral-g.net/forums/showthread.php4?t=43529

This thread probably details the work that Ron Sutton and I did on the car a bit better though.

http://www.pro-touring.com/threads/98063-Need-a-little-help-figuring-something-out/page3

[samckitt]

LOL. I want to see what you did to front suspension. I currently have the blazer spindles with Vette brakes & adjustable upper A arms I got from SC&C. But using stock lowers A arms. I have some high rate S10 springs, 1LE sway bar & billstein shocks. Thinking of changing lowers & using some tall Howe ball joints.

For rears I have BMR arms, poly/poly, adjustable uppers that I have had for years. Want to go with the Roto joints, looks like I cant just change the joints out, gotta get new arms.

[DavidBoren]

I am definitely trying to do it right the first time with this. And my end goal would be handling corners at speed, with a well-balanced neutral handling suspension.

Most of what I find being sold online, or discussed in forums is drag-your-frame, put-your-dime-on-dubs, bag-it/sag-it bull$#!+ and that is not what I am after. I would like either a kit, or proven combination of parts, geared towards optimizing steering geometry using the factory mounting points.

I can afford a set of $300 lower control arms here, and $300 upper conrrol arms there, maybe some spindles... but I want the parts to influence better cornering at speed... not to just see how low I can go. If that makes sense.

Right now, I am really considering the global west upper and lower control arms, because they are the only manufacturer that mentions making an effort to improve the geometry of the suspension.

Anyone have experience with global west control arms on their S10? Particularly for road racing or autocross?

[bret]

To clarify...

The design of the control arm has NO INFLUENCE on the core front suspension geometry.

The suspension geometry can only be influenced by the control arm attachment point or the ball joint attachment point. Some hotrodders relocate the control arm pivot point...aka the "Guldstrand Modification" where the cross shaft of the upper arm is moved down by some amount.

Other manufacturers move the position of the ball joint via a taller upper and/or lower ball joint, or a taller spindle. We use both methods depending on application. On the G body / S10 we use a taller upper ball joint to improve the camber curve of the suspension. As mentioned above, we want the top of the tire to lean INTO the turn, not away from it. If the attachment points or the effective height of the spindle does not change, neither does the suspension geometry.

Tubular control arms do not change the front end geometry, but they do compliment it.

MUST you use a tubular control arm[s] to compliment the change in ball joint or pivot point location? No, but the best ones offer several other advantages:

1. optimized ball joint position to re-center the ball joint in its travel at a lowered vehicle height to avoid binding
2. upper ball joint moved back to increase caster alignment
3. lower ball joint moved forward to re-center wheel in the wheelwell
4. better bushings. We prefer delrin.
5. redesigned upper cross shaft to allow easier front end alignment
6. lowered coilover mount to allow a longer stroke unit for better ride quality
7. Strength...many oem arms are fatigued and or rusted. Strength typically becomes a problem during braking...that 3800 lbs you are trying to stop from 130mph is trying to twist those arms right out of the car.

Keep firmly in mind that not all tubular control arms resolve all of these issues [some resolve none]. When you find yourself attracted to a set of arms that are priced at less than half of a respected brand, you may want to ask some of these questions of that manufacturer.

[bret]

Thanks for the reply. Building a whole new rear suspension to be balanced with a poorly designed front seems like it would be an effort in futility.

Looks like I need to address the front suspension's downfalls before I worry about the rear.

I need to research aftermarket spindle kingpin angles and aftermarket A-arm caster angles, see if I can find some that match up correctly.

Anyone with first hand knowledge of aftermarket S10 front suspension components that go together with an emphasis on handling? Brands I can trust? Kits designed for function, not just going low for looks...?

In answer to your specific question...

We do a Tru Turn system for the G Body / S 10 suspension. It consists of a taller upper ball joint and a bumpsteer kit that works nicely with the OEM spindle, and tubular control arms to tie everything together. Our tubular control arms resolve all the issues that I mentioned in my post above. http://www.ridetech.com/store/1978-88-gm-g-body.html

[hp2]

Most of what I find being sold online, or discussed in forums is drag-your-frame, put-your-dime-on-dubs, bag-it/sag-it bull$#!+ and that is not what I am after. I would like either a kit, or proven combination of parts, geared towards optimizing steering geometry using the factory mounting points.


You need to start looking for/at lower level oval track providers. While you are turning both right and left and may not think it is applicable, there actually are a lot of stock stub oval track cars utilizing soft spring/big bar set ups. Just use their advice as a symetrical set up instead of a left/right bias.

[BMR Sales]

LOL. I want to see what you did to front suspension. I currently have the blazer spindles with Vette brakes & adjustable upper A arms I got from SC&C. But using stock lowers A arms. I have some high rate S10 springs, 1LE sway bar & billstein shocks. Thinking of changing lowers & using some tall Howe ball joints.

For rears I have BMR arms, poly/poly, adjustable uppers that I have had for years. Want to go with the Roto joints, looks like I cant just change the joints out, gotta get new arms.

Scot, give me a Call, I might have an Option for you

T.C.

[DavidBoren]

Awesome. Thank you for the informative replies, gentlemen. I especially appreciate the specifics of what needs to be changed as far as ball joint position. I still have a lot to learn, because there is A LOT to learn pertaining to front suspension design and steering geometry.

I will certainly check out those A-arms from ridetech, thanks for the link, Bret.

Looking at the tru turn system for the G-body, it looks like what I am looking for. Will it work with the S10 spindles you offer? Or would it be better to use factory spindles and get all my drop from adjusting coilovers?

[Ron Sutton]

When dealing with factory A-arms, is the geometry correct for using the more modern approach of high travel/low roll?

Or do you need longer A-arms for that concept to work?

Although a question of general theory, I am asking in regards to my S10. If I use stock A-arms, which originally had stiff springs and a little sway bar, and I install soft springs and a big anti-roll bar, would the additional travel allowed by the softer springs mess with the geometry of this suspension?

Hi David,

This is the second post of your I'm tagging into today. When someone decides to go with a modern high travel /low roll angle front suspension strategy ... with a factory stock suspension ... there are a few things to work out.

The first is pretty basic. You need to find out how far your suspension will compress (from ride height) until it stops. Something will stop it. Either a shock will bottom out, a control arm will hit the frame, a ball joint will angle until it binds, etc. When you find out how far it will travel in dive ... say 2.5" from ride height .. and then something stops it ... you need to make a decision is that enough travel ... or do I want more ... and am I willing to correct the issue to achieve it.

In many production cars ... especially when we lower them ... the two common culprits that limit travel are:
1. The LCA hitting the snubber or frame.
2. The shock bottoming out.

#1 solution options:
a. Remove or trim the snubber if that is what hits first.
b. Trim the metal off that hangs down from the frame that the LCAs are hitting. The metal I'm referring to has no structural value & is simply left over in the punching & forming process during frame manufacturing.
c. Switch to tubular LCAs.

#2 solution options:
a. Buy or make ... and install a taller upper shock mount that allows you to run a longer shock with more travel.
b. Modify your LCA (with plenty of strength in the design & materials) to extend the bottom mounting point of your shock ... that allows you to run a longer shock with more travel.
c. Switch to a LCA with lower bottom shock mounts designed in ... that allow you to run a longer shock with more travel.

So ... after you have enough travel ... whatever that is ... then we can cover the "geometry part" of your question.

The length of the UCAs & LCAs are not a limiting factor to high travel or optimum performance with high travel. Can we achieve better dynamic geometry with longer control arms? Absolutely. Are they required? Absolutely not.

The key parts of your front suspension geometry that will matter when you go to a modern high travel/low roll angle front suspension strategy ... are, in order:
1. Dynamic roll center location (dynamic meaning when the car/truck is in full dive & roll).
2. Camber gain ... don't want too much.
3. Jacking force of the UCAs ... which comes from excessive UCA angle.
4. Bump steer ... don't want too much.
5. Caster gain ... just need to take the amount into account.
* Frankly ... these 5 things matter to optimum handling performance of everyone's front suspension ... regardless of their strategy.

So, to summarize ... the length of the controls is less of an issue. Achieving the desired travel without suspension bind ... and hitting the target with the 5 suspension geometry items listed ... are the key things to focus on initially. Of course, you'll need to work out what spring rates & bar rates front & rear .. along with optimum shock valving. But my tip is to start with what we've covered here.

If you ask me any questions in your thread ... would you please PM me so I know to visit your thread? Thanks !