Make it handle

[robnolimit]

The headlights are from a dealer called "Richard's Stuff" he's at all th goodguys shows, or online. The led' ring is split in half, and can be wired as run, turn, or both. I used a diode/resistor to wire the ring - dim for run, - bright for turn. he also has them with amber leds. They fit into reg 6011 buckets.

[robnolimit]

HAHAHA, it's pronounced F....or....Die!!!!

[robnolimit]

Lets get back to the main topic, HANDLING. One of the best upgrades you can do is swaybars. Swaybars, or Anti-roll bars, work by adding traction (downforce) to the outside tire. To do this, the swaybar has to take downforce away from the inside tire. So if you think about it, you can go 'too big' on the bars. If you went so stiff that the inside tire lifts off the ground, then that tire isn't helping at all. The balance between the front and rear bars is called "roll couple", and here's where a truck layout changes normal thought. In a normal performance car, with say 52% front weight and a low CG, the roll couple needs to be up around 80% (calc for this is really complex, so think of this as a comparison number), but in a truck, with 58% front weight and a higher CG, you aqctually need to move the roll couple BACK, maybe to 65%. This means that in comparison to a Camaro that would run a 1 1/4" front and a 7/8" rear, the truck would tend to 'need' a more evenly matched bar set. Say 1 1/4" front and 1 1/8" rear. Most retailers/manufacturers are missing this and selling bar sets in 'car' sizing, so be carefull.
From the set-up you have now, you can use the following rules for tuning.

A larger FRONT bar will "tighten" the chassis, making the truck tend to push, or not want to turn into a corner, also the rear of the truck will seam a bit stickier. A smaller front bar will do the opposite.

A larger REAR bar will "loosen" the chassis, the truck will turn into a corner easier, but the rear may want to slide around.

Last weekend in Pleasonton, I was explaining this to a few people and most believed that a smaller rear bar would help the truck turn, do to the added cross weight from the inside rear to the outside front - as the truck leans over. So, I pulled one of the rear swaybar links on our 55, effectively it had no rear bar. The truck pushed like crazy, and on the second lap, I spun out trying to throttle steer it through a corner. Bad outcome, but it was a good demonstration of swaybar tuning.

How you mount and connect swaybars is equally important, we'll get to that later. Think out this and ask away. Oh yeah, We won our class in P-town, even with the demo run!!!

[Mechanic77]

Excellent information I'm getting started on my own project and I wanted to back up a little bit to what you had discussed earlier. You said that increasing caster on these trucks will help with the handling, what is a good target caster angle? Also, do you have any ball-park figures on what roll center height to shoot for? I bought FSGP4 so I can analyze what moving some of the suspension points will do, but the program doesn't give you any idea what is good or bad. And back on the current subject, would a 1 1/4" front bar be a good place to start?...and what size bar would be good to start with on the rear of a trailing arm set-up? Sorry for all the questions, but I want to learn all I can before the fab work begins

[cajundragger]

the people at speedwayengineering are very helpful with choosing and installing sway bars. Plus their product is top notch.

[robnolimit]

Caster is a tricky thing. More + caster will give you added steering feel, or driver input, but, it will make it harder to turn. With modern power steering, the additional effort needed to steer is not reall noticed. The overall goal is to keep the tire contact patch as large as possible. Remember that as you turn, all sorts of forces are acting on the tires, pushing and pulling them around. As the sidewalls and tread flex, the patch gets smaller, and you loose traction. Setting up in anticipation of that flex is what were trying to do. I would be willing to give up some of the contact patch/traction when going straight, and max traction isn't needed, to gain some in a corner entry where it is needed. Stock trucks came with 1* or 1 1/2* + caster. The new Hotchkis kit will push that up to 9*+. For a "street driven" truck, I think 5* or 6* is the right range. Roll center hieght is a toughr goal to hit. Lets think about what is "reasonable" to acheive. It would be awsome to set the RC at the same height as the spindle pin centerline, but thats not going to happen. As a general rule, "higher is better", for RC. Try to keep it above 1/2 of the spindle height. So, if the tire diameter is 27", spindle height will be around 13", try to keep your RC above 6 1/2". This means drop spindles in favor of springs. Try to keep the swaybars close in size. 1 1/4" front with 1 1/8" rear is good for more streetable trucks, 1 1/2" front with 1 1/4" rear for more aggressive handling. - Remember that increasing caster will raise the pivit point ot the outer Tie Rod End, and could create additional bumpsteer, which will ned to be adressed in your design calcs.

[cajundragger]

sway bar length is important to.

If you run 1.25 front bar and a 1.125 or 1" rear and the rear is considerably shorter, than you have way too much bar in the rear assuming they are both say hollow .25" wall with similar spring rates.

I had this problem on a '56 truck Im building for grip. I had to drop to a .75" solid bar in the rear to be correct match to a 1.25 hollow in the front.

[robnolimit]

Very true. When using splined bars, like the ones from Speedway Engineering, There is a lot more tuning available. Length is important, as a shorter bar is stiffer that a longer bar. Speedway Engineering has rate charts on their web site that are very helpfull. When using this type of swaybars on trucks, I try to keep the rear bar rate at appx 80% of the fron bar rate. This is also dependant on driving style. Arm length of the bar is also a factor, and can be used as a tuning tool.

[Mechanic77]

Originally Posted by robnolimit

Caster is a tricky thing. More + caster will give you added steering feel, or driver input, but, it will make it harder to turn. With modern power steering, the additional effort needed to steer is not reall noticed. The overall goal is to keep the tire contact patch as large as possible. Remember that as you turn, all sorts of forces are acting on the tires, pushing and pulling them around. As the sidewalls and tread flex, the patch gets smaller, and you loose traction. Setting up in anticipation of that flex is what were trying to do. I would be willing to give up some of the contact patch/traction when going straight, and max traction isn't needed, to gain some in a corner entry where it is needed. Stock trucks came with 1* or 1 1/2* + caster. The new Hotchkis kit will push that up to 9*+. For a "street driven" truck, I think 5* or 6* is the right range. Roll center hieght is a toughr goal to hit. Lets think about what is "reasonable" to acheive. It would be awsome to set the RC at the same height as the spindle pin centerline, but thats not going to happen. As a general rule, "higher is better", for RC. Try to keep it above 1/2 of the spindle height. So, if the tire diameter is 27", spindle height will be around 13", try to keep your RC above 6 1/2". This means drop spindles in favor of springs. Try to keep the swaybars close in size. 1 1/4" front with 1 1/8" rear is good for more streetable trucks, 1 1/2" front with 1 1/4" rear for more aggressive handling. - Remember that increasing caster will raise the pivit point ot the outer Tie Rod End, and could create additional bumpsteer, which will ned to be adressed in your design calcs.

Power steering is in the plans anyway, so I wasn't too concerned about steering effort. So is running caster in the 9*+ range going to cause any ill effects on a street truck? And how much will tire width/wheel offset going to effect the contact patch? I will have to experiment and see if I can raise the roll center. I also have experimented with moving some of the steering linkage in order to reduce the bumpsteer and bring everything back to where it needs to be

[robnolimit]

CAJUNDRAGGER, do you have picts of your setup to show how you did it? Also what type of front/rear suspension are you using?

[robnolimit]

MEC77, check into a p/s box from Lee Machine, in So. Cal., if your using a rack, try the Flaming River billit rack, it has 6" of stroke. Consider positioning the TRE under the steering arm, this can help with more clearance. You can fit a 275 tire if the offset is right, - check out srub radius on your program, it will get better with a wider track and a wheel with more backspace, like a vette. 9* caster will wear the tires a bit, but other than that, no real problems.

[robnolimit]

Also, if you are building everything, look at late 80's - early 90's Impalla spindles. Factory 12' brakes, low mounted TRE, and much lighter.

[cajundragger]

Im doing a '56 chevy truck. Hedits MM2 front end with their tuber arms/ dropped spindles. It will receive coil overs front/rear so ignore the coil hats. Im also moving the upper arm location for more camber gain. Front bar is from Speedway engineering. Rear suspension is 12 bolt/parallel 4 bar with a pan-hard/swaybar is from welder-series which doesn't offer custom rates but the stock rate will get me going and I can change it later if I need to. Basic pics...unfinished. I'll get back on it and finish it in a little while.





ride height on 27" tires...





front may come up just a hair.

[robnolimit]

Looks pretty good, I dig the Cameo sides. Howe racing has upper A-arm mounts with 5" centers, they are shim style align. you may want to add a lower set of mounts for the panhard rod, say even with the bottom of the housing tube. This will give you more bite on the corner exit. looks great, keep us posted.

[cajundragger]

the pan hard is pure level right now. Im trying to keep it very neutral right now, but Im not opposed to changing stuff. I really just want to get it going and modify as I see fit. Going to be a bear to get the I-6 to run boosted so Im keeping the suspension as simple as possible to where I know it'll still work well. Time will tell, I'll keep everyone updated when we get it going.

[wickid demon]

So when building a one of ifs setup the impala spindels would be good to go with, or is there something better to use.

[cajundragger]

vette spindles are nice too btw.

[robnolimit]

There are a lot of spindles to think about if your starting from scratch. Weight, height, steering arm, and basic geometry are all factors. The truck spindles are pretty heavy, and the steering arm isn't so hot. To me, "unsprung" weight is a big deal. Also the type of brake set up is something th think about. Vette and dropped Tri-5 are pretty nice, but both rely on an inverted lower ball joint, which can make dialing in the RC a bit more difficult. Fatman's 'tall' A-body spindle is nice, good brake options a,d a bolt-on steering arm, but I'm not sure if they have it in a 'dropped' format. The nice thing about a bolt-on steering arm is that you can fab an arm that sets the acreman perfect for your truck.

[robnolimit]

So, I just looked it up, and the fatman tall spindle is a 2" drop. They sell for 299 pr. I should know this since I'm a Fatman dealer - oops. at least I learned something today

[wickid demon]

I was thinking vette but found there is better alternative to there spindels. I’ve also thought about ATS spindles machined aluminum with vette bearings and caster built in, but they want your unborn child for them. Fatmans might be a good alternative. There is just so many ways to go with building the suspension and components. Everybody has there opinions on what are the best that it confuses me, I just need to stick with one and go with it.

[Mechanic77]

I've considered running fabricated spindles like what Coleman and other Nascar suppliers sell but I'm not sure what other problems they might bring up. The nice them about them is they have that bolt on steering arm so, like you said, you can set the ackerman and bumpsteer exactly where you want it. They also open up a hole range of brake options, but you're going to have to do your homework to get it right. Has anybody actually built a setup off of them? Pics would be awesome, even if it is for a Ford

[robnolimit]

LOL, I caught that. I'm trying to get faster at posting picts. I am currently building an IFS with fabbed spindles, it's a bit different. '27 roadster, using a pinto spindle spud, and a 4 lug billit hub, 12" wave cut rotor. A-arms are aluminum fabbed from .090 flat. It's all about weight. Going to run an all aluminum 4 cyl Duratec 2.3. A friend of mine is building the sister rod, '29 chevy, same suspension, with a 2.5 Ecotec chevy. Both to be on the 2011 powertour. Oops, getting Off track. If you want to build your own IFS, Try the Impalla. or the Fatman. - you'll be happy.

[SBTork]

I am shopping around for a rear sway bar for my Sub and I see two options for material. One is steel and the other is 4140 chromemoly. Is there a drawback to one compared to the other, given that they are the same size?

[72k5zl1]

just found this thread, good stuff. N2TRUX turned me on to it. thanks. i will keep checking in. glen

[robnolimit]

1. Do you have any info on the bar manufacturers? I would like to read about this chromoly swaybar.

2. PHARMD In response to a question and an article about budget handling. I was forwarded an article about suspension upgrades and the performance gains. The article compared a stock C-10 to the same truck upgraded with a host of suspension and brake parts, and compared the results. The parts installed were Dropped spindles and brakes, springs, shocks, P/B, front swaybar, and rear adj. panhard rod. Ohhhhh, and a set of 17" 55 series rubber to replace the old 15" 78 series rolling stock. WHOA!! we're not comparing apples to apples any more. Just keep that in mind. The big question is, how can you make it handle and drive on a budget? Easy.

Lets start with a stock truck, and a plan of dropping it about 3" ft, 4" rr. This mild aproach keeps it drivable, and on a budget. $519 gets you dropped spindles and disk brakes, you get two for one here, it's the smart way to go.It's up to you to decide if you need to rebuild the A-arms, if you do, check out "PST suspension", you can get a complete rebuild kit for about $280. Stock A-arms are fine. If your truck sits level now, the spring are fine. (we can all argue about spring fatigue later, but I'm right), Cut 1/2 coil off of the fronts and put them back in. In the rear, it's a matching of parts. Start by cutting the rivits off of the trailing arm mounts, and re-position them to move the mount holes up as far as you can on the crossmember. Bolt or weld them back in. This raises the anti-squat %, and helps out of the corner. Next use a 2" dropped spring, $99, and a 2" lowering block, $129. This combo rides better that a 4" spring, and since you saved money on the front springs, spend it here. Also the 4" drop will re-set the pinion angle change that happened when you raised the front mounts. If, you want, put urathane bushings in the trailing arms. $48. You MUST change to an adjustable panhard rod to center the axle, so get a LONG one, $129. Now, if your only going to buy one new swaybar, buy the REAR bar. $189, and use the stock front bar for now. In the articlce tha truck didn't get a rear bar, and you can see the understeer in the picts. Here's one everybody misses, buy a set of urathane cab mounts, $89. This leaves three things to do. Power brakes, it's easy to put a 73-87 booster/master on a earlier C-10, get a wrecking yard unit and go for it. Steering box. This is important, so run the stocker and save your money. Go with AGR or Lee. they aren't cheep, $430-$600, but they'r worth it. And last and VERY important SHOCKS. Run your old ones and save up if you have to. Here's a list of shocks in order - Monroe sensitrac - KYB - Doetsch tec Nitro - QA-1 single adjustable - Bilstien inertia valve - Romic single adj - any quality double adjustable shock, these will range from $40 bucks a shock (160) to $200+ per shock (800). So, if you add a hundred bucks for P/B, choose the AGR box, and DT shocks, that totals $2183. You can do this in steps, and if you watch E-Bay and Craigslist, even some specials here, you can do this for about $1750. So get to it, and let us know the results!!!