Make it handle

[c10seconds]

Im using RideTechs rear trailing arm kit on my 67 and i've noticed the pan hard bar is a bit shorter than other adjustable bars being used. Its got that bracket that mounts to differential housing keeping it pretty close to the factory position. If i went with a different longer adjustable bar would it make a diffence?
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[Tony@AirRideTech]

C-10 ...... No, you should not need to make anychanges. Combination of that billet brackets and panhard bar length ought to be optimized for that truck. Easiest way to tell... is the rear axle centered under the truck at ride height? If it is .... leave it alone

Rob.... contingency ? Am I smelling some Blue mountains?

[ksbrktracer]

I'm sure it's been said before .... but I will say again ..It is because of people like you Rob and Tony also that I keep coming back to this websight . Thank you for putting in the time and explaining this so WE can understand it . This subject is something that has always intrigued me ... And will be useful knowledge when building my truck and will relate to my camaro build also.

[M5-]

Here's where I'm at. I want a truck I can drive to a show a 1000 miles away and I want it to be able to do half decent in a slalom when I get there. I have a car with ride height adjustable coilovers on all 4 corners that corners like its on rails but truth is on the street its not that nice cause it rides kinda hard. My truck is a shortbox 65 Chev stepper.

Questions I have:

1. For a streetable setup that won't float your teeth what is a realistic goal for G's, .8 or .9 or???

2. Is the rear trailing arm setup of the stock 65 worth trying to work with?

3. Same question for the front end. Should I spend the $$ on a full IFS

4. What would be a realistic budget for making the trailing arm set up work and/or what would be a better option for maybe a little more $$$? Just say as a number I had $4000.00 to spend on the suspension could it be done?


Thx M5

[robnolimit]

Thanks guys, glad to help. M5 - I'm thinkin about your question.

One more vocabulary word for today : Radial Deflection. ?? OK , Radial - used here to describe a type of motion. In a radius, around a fixed point. Deflection - when something is "deflected" it has changed it's desired path of motion. We want the rear axle to move straight up and down (no side movement) So, we want minimal "radial deflection" -the rear axle being deflected sideways due to the radial arc motion of the panhard rod. lost yet? OK, take a yardstick and lay it on the ground. Mark each end, carefully lift one end up 6" off the ground, and put a mark on the ground directly under the raised end. The two end marks will have gotten a little closer together. (about 1/16"). Now, repeat this with a 12" ruler. The arc that the ruler travels on is much smaller, and the two end marks will have moved much closer to one another. (about 2") When discussing "radial Deflection" you must know how much travel there is, to compare. The rule is, the longer the bar (radius) the less deflection (side movement)

Rear Roll Center. - the height of this can be calculated by getting the average hieght of the chassis mount and the axle mount, as the truck is setting at ride hieght. Watch the Nascar teams, when you see the guy drop an extension down into the back of the car, and turn it around once or twice, they are changing the roll center. The chassis side mount on these cars is on a slide, and can easily be screwed up or down to tune the car.
Todays homework, - What is your Rear Roll Center?
Tony, did you mean Blue Moons?

[project 67 sub]

hey man where you at in san berdoo?

[blindman]

all i know is this i got my wide ride set up and fat bars dialed in new tires on the way and in 2 weeks im going to roll out paint booth and give it hell i wanna see how she handles

[robnolimit]

We are at 455 so. D street. corner of D and Mill.
Blindman, how about putting up some picts? let me know when its up and running and i walk you through some set up and tunning. It would be good for the forum too. If you can, get some wieghts on it once its running. Find a truck scale, get a total wieght, then roll the truck back so that only the fronts are no, and get a front #. What Tires are you getting?

[blindman]

Originally Posted by robnolimit

We are at 455 so. D street. corner of D and Mill.
Blindman, how about putting up some picts? let me know when its up and running and i walk you through some set up and tunning. It would be good for the forum too. If you can, get some wieghts on it once its running. Find a truck scale, get a total wieght, then roll the truck back so that only the fronts are no, and get a front #. What Tires are you getting?

im getting 15x8 smoothies with 245/60r15 for daily driving but for show im getting coker bf silvertowns and chrome reverse wheels should look killer .... has anybody ever moved the coilover top mounts up 3 inches to really drop rear i welded mine were the paper said just wondering to get a lower center of gravity and also transfer weight to rear lmk thanks rob

[M5-]

Blindman

Who makes that 4 bar kit or did you piece it together yourself?

Thx M5

[SCOTI]

Originally Posted by M5-

Blindman

Who makes that 4 bar kit or did you piece it together yourself?

Thx M5

Answered in post #107 above....

all i know is this i got my wide ride set up and fat bars dialed in new tires on the way and in 2 weeks im going to roll out paint booth and give it hell i wanna see how she handles

WideRide w/fat bars is what No Limit calls their 4-bar kit.

[robnolimit]

Looks great, Yes, you could move the mount up. But. it would end up going through the wood floor, right now it has about 3/8" clearance. If its not low enough when your done, we can swap you for a 4" stroke shock, and a 10" spring. That set up has a ride hieght of 12 1/4", compared to the 14 1/2" RH of the 5" stroke shock. It will drop the rear another 2', but I would wait until you have it all together to decide.

[robnolimit]

Wide-Ride is our front suspension IFS for those trucks, The rear kit is a Fatbar 4 bar.

[blindman]

Originally Posted by robnolimit

Wide-Ride is our front suspension IFS for those trucks, The rear kit is a Fatbar 4 bar.

not trying to turn this to a sales pitch but you all have great suspension parts cant wait to drive it i went from a straight axle setup to this it will be like going from a radio flyer to a cadillac

[robnolimit]

Thanks, the cool thing is I know how its going to ride. You'll love it.

[68Stepbed]

Great stuff!! I'm gonna have to go through and re-re-read some of this stuff to get a full understanding, but great info. My 68 handles really good as of now, but I want to start upgrading in the future to make it really hang some corners.

I really don't want to go with an airbag setup if I can keep from it. I really like THIS kit from Hotchkis, but apparently, so do they. What else is available for the 63-72 truck chassis? Links would be great.

What are some of you guys using? Can I see some pics?

I have a really good test track...er...road. I'm about a 30 min. drive from US129 aka "The Dragon". I'm definetly gonna try the checking heat on tires trick and see what I find.

[robnolimit]

The H kit is nice, but $$ +. I am currently looking at a bunch of A-Arms. The key is, You can only fix so much. If you're not changing the inner pivits of the suspension, and the geometry of the spindle is the same, there isn't a lot you can do. What they need is more caster. Combined with a spring, spindle and swaybar, they can be made to handle very well. The A-arms can be made to correct the ball joint angles, assist in camber gain, and get the caster in line. And this is what you need. I have about six sets of arms in my shop that I am testing to find out what they REALLY DO, and DONT. So, be a little patient and I'll let you know what I find out.

[SCOTI]

The 'H' kit touts +9° caster ability but utilizes a 1000lb+ spring-rate coil which sure seems excessive (extremely cost prohibitive for many as well....). I know Ride techs arms are advertised to allow 'a couple more degrees' but there's no definitive. I should of asked Tony when I was BS-ing w/him @ Ft.Worth.

[Portmod7]

I was going to ask if anybody had tried the H kit. I stumbled onto it a couple months ago and it sounded pretty sweet. Pricy, yes. But you know what they say, how fast do you want to go? Although, its very hard to know if you're getting the speed you pay for unless you can buy the whole gammot of options and do some testing.

I have been thinking long and hard on what to do in the rear of my truck, as far as lateral location of the rear goes. Yes, a panhard bar is simple, and NASCAR uses it, but NASCAR also only turns in one direction most of the time. I can't seem to convince myself that a panhard bar will NOT cause the vehicle to act differently in a RH turn compared to a LH turn. Depending on which end is mounted to the frame, which end is mounted to the housing, and which direction you intend to turn, it seems like there would be a separate preferred mounting orientation for each turn direction.

If the P-bar is mounted to the frame on the D-side, housing on the P-side, and you make a LH turn, the body will pivot and roll to the right. In my head, it seems like the body would pivot at the frame mount of the P-bar which is a LONG way from the RR spring, generating the majority of the roll-stiffness to the right at the RR spring. The body and CH would also "climb" around the housing mount. With the same P-bar orientation, a RH turn would cause the body to roll about the frame mount to the left, causing the CG to "climb" up and around the frame mount. It seems like the roll stiffness to the left would come from from the CG trying to "climb" because the pivot is located so close to the spring. But I suppose as it tries to climb, it will load the LR as the CG moves more to the left and above the LR spring. I'm not sure I'm anywhere in the ballpark with any of that?

So I guess my question is: Is the dynamic loading on the LR spring in a RH turn the same as the dynamic loading on the RR spring in a LH turn with a P-Bar? Also I have concern with the "radial deflection" mentioned above. Even with a long bar, it's still a factor.

A watts-link would cure radial deflection. I invision one mounted horizontal, either above or below the housing. Although, either position presents mounting/clearance challenges. My question about a watts-link is: where is the RC? It seems like the lateral location would be at the center pivot, on the housing. But what about the horizontal location? Would it be at the center pivot on the housing, or at the height of the mounting points of the links at the frame, or a combination of the two?

The watts-link, as I have suggested it, is a bummer because I'd either be mounting it above or below the housing, and moving it to one or the other will make a HUGE difference in handling. It would be really hard to tune. You could mount it vertically behind the housing, but it seems like it would deliver inconsistant handling from RH to LH turns because of the necessary difference in height of the link mounting points at the frame.

So anyway, sorry for writing a "novel". Suspension geometry intrigues me. I am a race car driver. I work on my own cars, I am my own crew/car chief and mechanic. I get to make suspension adjustments every week trying to go faster. It doesn't always work the way you think it should. I am also a mechanical engineer by profession, so that helps me understand a little more where common sense fails me. I was just looking for some friendly discussion on the topic.

Thanks for posting all the great information!

[robnolimit]

Hey, it was good to meet you guys in Tx.

[smbrouss70]

If any of you guys are seriously thinking about the Hotchkis system, you can get it through Summit for about $1000 less... http://www.summitracing.com/parts/HSS-80390/

[Portmod7]

Originally Posted by smbrouss70

If any of you guys are seriously thinking about the Hotchkis system, you can get it through Summit for about $1000 less... http://www.summitracing.com/parts/HSS-80390/

WOW! Great link, thank you!

[Portmod7]

Ok, a quick visit to the No Limit site has converted me. Really impressive Rob! I think I know where I'll be getting the suspension for my truck when the time comes.

[robnolimit]

One thing I will always push is education, and those are great questions. Search online and buy Herb Adams suspension design and tuning book. It is the best I have read, and it is understandable. NEXT, buy a copy of "suspension geometry pro" software. its only like 80 bucks. the rear suspension program isadaptable to mock up the questions that you are asking, and will show you the RC graphs for each. well worth the money.
Remember that "every action has an equal and oposite reaction" - physics class, so, the left/right force is a average of the two mount points of a P-rod - RC, and an average of the three points in a watts. As to radial deflection, yes, there is some. how much? get a 30" string and draw an arc with a 30" radius, and then measure out any 5 or 6 inches of the arc, the radial deflection is easily seen. Try it.

[robnolimit]

YOUR INPUT NEEDED As I am testing A-Arms, vs. performance set-ups, one thing is becoming clear. If you dail in enough caster to make it turn, you create another problem. When tipping the spindle back to get the caster in range (7 to 9 deg), the steering arm lifts up, in relation to the other steering components. I.E. the center link. One solution is to drill out the hole for the Tie Rod End in the spindle, and use a Rod-End style TRE that can be bolted up from the bottom side of the steering arm. this type of TRE gives you the ability to adjust the hight of the TRE pivit point, and tune out any bumpsteer. So, Are you guys willing to drill out the spindle, or not??What do you think about this??