Make it handle

[Scottshotrods]

Originally Posted by robnolimit

Yeah it was a lot of fun. We'll be at the Tx Goodguys in a few weeks, come by and see us.

Rob
Truck looked good going around the cones,we will be in texas as well
see you there.
Justin

[N2TRUX]

Originally Posted by Scottshotrods

Rob
Truck looked good going around the cones,we will be in texas as well
see you there.
Justin

Justin- You guys bringing anything to run, or just coming as a vendor?

[robnolimit]

OK class, todays topic, rear locators. I chose my words carefully. Diagonal locators, Panhard rods, Watts link, wishbone,...... there are many. More than one way to skin a cat. for street performers, I like a panhard rod. I know, many favor other types. I have two reasons. 1. K.I.S.S. - keep it simple stupid! - fewer moving parts, easy to set up correctly. 2. Panhard rods allow you to set the rear roll center, and adjust it easily, without a complicated formula. While we may think (dream) about a high roll center with a low center of gravity, we are playing with trucks, not corvettes. High roll centers on the back of a truck will help keep it flat, it will also keep it spinning around. The high roll center plan works if you have a low C.G. and close to 50/50 weight balance. We dont get those with a p/u. So, you need to create some "side bite" to keep it on line.The lower you roll center the more side-bite you create, thats a plus, also, the lower the R.C., the more the truck leans over (bad). Thats why you need to be able to test/tune. Here's some tips. Made your panhard rods as long as possible, this has less angle change and pulls/pushes the rear less side to side. (Radial Deflection) Try to keep the P.R. close to level at ride height. If you are building mounts, put two or three mount holes on each set of brackets - housing and chassis. Try to start with a centered mount (height) about even with the axle center (height). You can tame some of the induced roll with a sway bar, but this also reduces side bite. It's all a balance. some amount of body roll is OK, as long is you can tune out its bad and keep its good effects. In a truck, at some point you will have to rely on the outside tire to keep you on line, and the tire will be the limiting factor. The trick is to tune up to the ability of the tire, with just enough side bite to keep it stuck.

[robnolimit]

Sometimes a little drift is the fast way around, - a lot of drift is not

[robnolimit]

should i get RideTech contingency? Nice sticker placement

[N2TRUX]

Originally Posted by robnolimit

Yeah it was a lot of fun. We'll be at the Tx Goodguys in a few weeks, come by and see us.

Originally Posted by robnolimit

should i get RideTech contingency? Nice sticker placement

I think you should hit Tony up. I'm sure that would be good for a burrito at Ft Worth.

I'll be in Ft Worth as well, with the 77 in the Ride Tech display.

[robnolimit]

Did I go too fast on that one?

[JNJchev77]

Can you briefly explain what you mean by rear roll center? feel dumb for asking but I just want to make sure I understand what you are saying here

[SCOTI]

Originally Posted by JNJchev77

Can you briefly explain what you mean by rear roll center? feel dumb for asking but I just want to make sure I understand what you are saying here

Don't 'feel' dumb for not knowing; it's a good question.

[robnolimit]

Not a problem. Sometimes I go by this stuff so fast I get lost myself. Lets start with "roll center" or R.C., or RC for us lazy ones. The RC is the point that the truck wants to pivit around. OK, may have lost ya. When you put your truck into a corner, there are all sorts of things happening. The laws of physics are acting out all at one time. And all of these forces add together to force the truck to lean over. The RC is the pivit point, and we can change it, a bit. If you think of a picture of a truck, from straight in front of it, you would see it the front view. If you could mentally 'cut the picture out' and then hold it with a tack, you can imagine rotating the truck around the tack - ya? if you put the tack between the front wheels, even with the ground, this would be a LOW RC. And, no matter where you push on the truck, it tips over easily to the other side. Now imagine the tack throught the mirror, at the top of the winshield, and if you push on most of the lower part of the truck, it leans the other way. A HIGH RC. Now RC is only important when you compare it to something, like CG (center of gravity) think about this as the center of mass, or the balance point. Front to back is easy to understant. its the balance point front to rear. But height wise, theCG is the point at which there is equal weight above and below. For a standard, most vehicle CG hieght is about the center of the camshaft. This is where the 'Push" comes from. Now think about it, the closer you 'push' sideways on the RC, the less our picture wants to tip, or lean. Sounds great - but, it doesn't force any tires onto the pavement. In the front, where there is a motor and other weight, gravity is helping to keep the tires stuck. In the back, no weight, so no sticky-sticky. So, in the back, if we get the RC lower than the CG, it will force the truck to lean, and put pressure on the outside tire "bite"
I'm going to stop here. This is tough to describe without pictures. Let me know if this makes sense to you. RC and CG are pretty important if you want a good handle on this stuff. (pun)

[SCOTI]

Excellent description for explaining the difference RC & CG can play on a truck vs. a car. I hope to see your rig go round & round @ GG's Ft.Worth.

[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.