Make it handle

[suville]

Rob and all participating I'm enjoying this thread but as there some Burb guys here would or could you possibly note what differences we might encounter or is there not enough weight difference between pickup and Burb to consider? I would think the two would have different requirements. Appreciate you sharing your time ,experience and knowledge! Hope ya'll had a wonderful Thanksgiving!

[pharmd]

Originally Posted by 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. $450 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!!!

Thanks Rob, you da man.

Just gotta few follow ups now...

Say I didn't mind paying a little extra for "matching" parts vs cutting springs etc. Would I improve my situation at all buy doing a 4/6 or 4/5 kit from a manufacturer (if that were the drop I was after) vs the cut and mod approach you mentioned?

If I were willing to buy a new set of trailing arms 1) would I gain anything, 2) which set do you recommend?

List your top 3 springs in order of preference from your list above...so I can contrast performance vs $$ and make a decision.

How important is a C notch in this type of setup (not really knowing how suspension travel in the rear is affected here, especially under the small chance I might actually still haul something).

Crossmembers? I may need one anyway to allow a custom exhaust system, if that is the case what is your preference of the options out there to hopefully add to structural rigidity, improve exhaust clearance and improve asthetics.

Thanks again man, your a big part of what makes this forum so awesome!

[SBTork]

Thanks for the reply Rob, here is the link on the chromemoly rear bar. http://www.summitracing.com/parts/HEL-7437/

http://www.hellwigproducts.com/produ...suv-sway-bars/


I am not sure of it's accuracy but there it is.

[robnolimit]

Pharmd - As to kits vs. pts, You can get new springs if you want, but buy quality. some are not as good as stock. New trailing arms aren't going to change the handling, you can weld the seams on yours if you want to. At a 4" drop a "C" is optional, but necessary if you go any lower. I like the Early Classics "C", bolt and weld it in. As for the raised crossmember, nif you go for it, again i like the early classics unit for a mild build.

[robnolimit]

Remember in "Days of Thunder" when Harry said "it's all about tires, tires win races" well, he was right. To understand about suspension tuning, you have to understand TIRES. All tires are different, and each will deliver a certain amount of traction. The amount of traction varies with the amount of LOAD on the tires. Yes, traction increases with load, BUT, the tires efficiency falls with increased loads. Tire manufacturures will post a "Tire performance chart", but they are to come by, as most in the business have never heard of such a thing. The chart will show a graph, with a curve showing traction in relation to verticle load (weight). Here is some info from a chart for a 245/40/18 KDW Goodrich.
LOAD TRACTION EFFICIENCY
250lbs 490lbs 1.96
500lbs 700lbs 1.4
750lbs 890lbs 1.18
1000lbs 1000lbs 1.0
1250lbs 1125lbs .9
1500lbs 1260lbs .84
1750lbs 1365lbs .78

This willgive you an idea of how the tire LOOSES traction as it GAINS load. The efficiency is in "G" forces (this is the simplified approach) and is simply Traction divided by Load. If you had the perfect set up, to get the max contact patch, you can chart out the max traction available. So, heres an example. The average C-10 weighs in about 4000 lbs. and scaling it would look like this:
LOAD LF 1195 RF 1160 58%

LR 860 RR 830 42%

Total wieght = 4045

Notice the 58% nose weight? thats pretty common, and it's not good for handling. '47-'59 guys just subtract 100lbs from each corner. If we apply the Traction Curve, we can chart the avail traction. It looks like this:

TRACTION LF 1075 RF 1055 52%

LR 963 RR 938 48%

Total traction = 4031

You can see that the front has 58% of the weight, but only 52% of the available traction. And, at this point, were rolling dead straight, with no accel, brake, or turn. This is the best it will ever be for this set up. At first, you might think that dividing total Traction by total Weight would give you the max G avail ( 4031/4045 = .99G) Looks great! - ahh, no. You know the whole 'weakest link of the chain' thing? Apply the efficiency to each tire:

Max G LF .899 G RF .909 G

LR 1.12 G RR 1.13 G

The LF will loose traction first, at .899 G, and then it's over, thats the best the truck can do. So, can our example truck pull .89 G? - no. We haven't added any cornering forces yet. OK, give this some thought. What does your truck do when you turn hard into a corner? If it's normal, it will PUSH (understeer) going into, and throught the turn, and then transition and get LOOSE (oversteer) as you throttle out of the turn. I'll add to this later. Just think on this a bit.

[tubbedII]

Originally Posted by robnolimit

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. $450 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!!!

This single post should be sticky'd!
On repositioning the trailing arm mounts. Can you flip them upside down and swap sides to move the mount up? If that's even possible, is that moving the mount too high?

[robnolimit]

Yes, you can flip & swap the mounts. Remember that when you lower the truck say, 4", you lower the front trailing arm mount 4". To get back to the original geometry, you need to raise the mount 4", or as close to that as reasonable. I dig the blazer, short & wide is the way to go!

[robnolimit]

SBTork, I took a look at the links, and although I'm still not 100% convinced of the "chromoly" claim, I will say that there are many grades of nickled steel alloys. So, Helwig is a good bar, notice that their front and rear are the same size? Hmmm, they may be onto something, or at least catching up with those 'in the know'.

[SBTork]

Originally Posted by robnolimit

SBTork, I took a look at the links, and although I'm still not 100% convinced of the "chromoly" claim, I will say that there are many grades of nickled steel alloys. So, Helwig is a good bar, notice that their front and rear are the same size? Hmmm, they may be onto something, or at least catching up with those 'in the know'.

Thanks a ton for the reply Rob. I also am not too sure on their chromoly claim either, but they have the best price and it seems to be a decent product. The knowledge I have gained on sway bars from you in this thread is just awesome, thanks a lot.

[tubbedII]

Originally Posted by robnolimit

Yes, you can flip & swap the mounts. Remember that when you lower the truck say, 4", you lower the front trailing arm mount 4". To get back to the original geometry, you need to raise the mount 4", or as close to that as reasonable. I dig the blazer, short & wide is the way to go!

Cool! Sounds like and easy/cheap way to make things just that much better. Looks like I gotta add some 12 more rivets to the list of popping off...yay...

I'm not trying to autocross, but I'd love to be able to take the on-ramps at a decent speed and feel semi-safe while doing so.

[D13]

wow.

All these years I've been driving trucks with NO sways.

So here's what I'm going to do. Victim is 82 1/2 ton LWB strippo model with 250 and 700R4, 3.08 10 bolt. Target is a reasonable daily driver.

NO drop. I live on a bad dirt road and will drive this in the winter with 6" of snow on the road. I might do a shackle kit to level it (have to see how it sits when assembled).
First, I wil put a Posi in the rear ($600) (not counting this in the prices below as it really is a seperate item).
Second, rebuild front and steering using Moog components ($600), and brakes using the thicker rotors ($150).
Third, convert rear to Impala discs ($300) (already have most of the parts....)
Fourth, upgraded shocks ($250)
Fifth, alignment ($150)
So $1150 later I have a decent base suspension and upgraded brakes.

At that point, Jyard raid for front sway stands and bar, rebush them ($75)
Sixth, Hellwig rear bar ($300).

So for around $1500 I should have a 'decent' handling, good braking truck.

If you just look at the front it's about $1000. How much is a Porterbilt with coilovers, with all of its engineered upgrades? But I don't want any drop.

[Mechanic77]

I have a question about ackerman....I know some of the upper and lower control arms available move the front wheels forward to center them in the front wheel wells. Doesn't that affect ackerman? And does it make it better or worse? Would it be better to move the steering box and idler arm mount forward a like amount in order to maintain factory ackerman? And on a related note, with changing the caster to 9*+, would it work better to raise the steering linkage in order to correct the bumpsteer, or would it be better to do as you suggested, switch to a heim joint for the outside tie rod and mount it on the bottom of the spindle arm?
Sorry for all the questions, but I'm in the middle of the designing my front suspension and I want it right

[robnolimit]

Ackerman, is the relationship of the steering copmonents relating to the wheelbase. Imagine looking down from overhead of your chassis. Draw a line from the center of the outer tie rod end pivit, through the center of the lower balljoint pivit, and continue on this path (line) to the rear axle. If it is "perfect", in the textbook definition of ackerman, this line should pass through the center of the rear axle (side to side). Now, "perfect" ackerman may make the vehicle twitchy at high speed, but very responsive at lower speeds (say, under 60). Here's a simple way to check yours. Park your truck on flat ground. Then slide under it with a small plumb bob and a sharpie. Hang the plumb bob from the underside of each lower ball joint, and the two outer tie rod ends. Use the grease fittings as the center. Mark the four locations on the ground. Also, mark the center of the rear axle on the ground. Roll the truck out, and then use a chalk line or string to project the two lines back to the axle line. Unless you are willing to modify your spindles, there isn't much adjusting this. It is what it is. Moving the spindle forward a 1/2" or so doesn't have much of an effect.

[robnolimit]

YES, you can modify the spindle/steering arms. Can this be dangerous? YES. But so can improperly installing an air bag. So, I'll give you some hints. Racers have been doing this for a LONG TIME. If you just want to move the steering arm, you can heat and bend the arm. Heat it slowly, it will take about 7 or 8 minutes to get it hot enough to bend. Keep the torch back at least 5" away. Make sure you don't over do it. I usuallt have an old rotor installed, and then use a clamp to pull the arm towards the rotor, leaving room for the TRE to clear. If you are swapping to a rack, you may want to shorten the arm , this means cut and weld. You must have this done by someone who has experience here, as it can be VERY dangerous.

[basemodel67]

Do backspacing and axle width matter at all when setting up a suspension? Any advantage/disadvantage to running narrowed axle with deep offset rims? Thanks Rob for your insight!

[robnolimit]

Backspacing vs. axle width. Thats a good one to think about on a fresh build. Darg racers will use a shorter axle, and an offset wheel (less backspace) because the shorter axle is stronger. Some drag racers are starting to go back to a more centered wheel due the wheel strength and load issues of ultra high horsepower. A 'centered' wheel is the stongest. A wheel with a lot of backspace tends to be easier on the axle bearing. (think of a front wheel on a dually, or big rig). In the front, a wheel with less backspace will widen the track, and help resist body roll, but a wheel with a deep backspace will have less 'scrub radius', and steer easier. See, everything is a trade-off. It depends what is most important to you. I usually build a fresh project to take a centered rear wheel, and a front wheel with more backspace. You can widen the front track by making longer A-arms to help with body roll. On my new roadster project, I am using an 17 x 8 wheel with 6" backspace on all four corners. I am doing this to get "O" scrub with my fabricated spindles, and I want to be able to swap front/rear to help with tire life. HP is low, about 260 from a Duratech 4 cyl., and the car will only wiegh 1900 lbs. So, the extra axle width is not a factor for strength. It is a factor for unsprung weight, which we want as low as possible. Speedway Engineering is building us a 'MiniStock' quickchange with 1* neg camber on each side, aluminum hubs, and .120" wall chromoly tubes. It uses an 8" ring & pinion, and the whole thing weighs just 78 lbs. so I'm not too worried about the extra pound or two of the 4" longer axle, 60"overall, to get the wheels to match. The last part was just to give you some insight on other builds. Hope this helps.

[robnolimit]

Todays hot tip. TRACK WIDTH. There are three ways to describe this. #1. Center of tire - to - center of tire. #2. Hub face - to - hub face. (wheel mounting surface) #3. Outside of tire - to - outside of tire. Unless your building a custom IFS or A-arms, #2 is off the table. Increasing the track width will reduce body roll, and improve the handling. So, wheel offset, and overall wheel/tire width can play a big part. If your not too low, any chevy from '55 to '87 can fit a 285 tire up front, givin the correct offset, and wheel. If you notice in many magazine articles covering suspension upgrades, they always throw on a new set of wheels/tires. These are always stickier and wider than before. Hmmm? You think this helps the other parts look good? Keep this in mind if your planning some upgrades in the near future.

[68 SWB]

So rob, I'm curious what your setup would be on a 68 with a mid to aggressive street ride with the option to auto X and maybe a few track days in mind? Ideal drop would be 4/6 to 5/7 for looks and 20" rims, or would 18's be preferred. A break down of components would be nice. I think you covered shocks earlier in this thread, KYB or better and multi adjust preferred?

FRONT-

A-Arms:
Spindles:
Springs:
Anything I'm missing:

Rear-

Crossmember:
Arms:
Panhard:
Anything else I'm missing:

[robnolimit]

68 SWB - Lets start with the easy answer. There are several good quality kits on the market. Hotchkis, Ridetech, Porterbuilt, Early Classics, and others. You can spend $4000 to $6000 and get it done. And probably, the next guy will run faster than you. Does that mean these parts are no good? No, they are good parts, but thats not enough. It's the other things that will make the difference. I like 18's better than 20's, but thats me, and unsprung wieght makes a difference on the track, and the ride is better. Tires win races. Kumho, Bridgestone, BFG, Falken, but stay with 300 treadware or less. Most Autocross clubs, and Goodguys have a 180 treadware rule. Wieght is a big issue, put that pig on a diet, and focus on the front end. Every pound helps. Motor placement, If you can move the motor down and back, DO IT!! OK, so on to your question. Spindles and springs, I like McGauphy's or Western chassis, spindles. Doetch tech lowering springs are pretty good, so are Hotchkis. If your Really cool, you'll learn how to tune springs, and start searching some Oval track suppliers, who have many more choices avail. I have used Porter, Ridetech and E.C. arms, and like them. I have not used the new Hotchkis arms yet. If I didn't mention others - well, you guess. In the back, 2" block and 4" spring. I like the E.C. raised crossmember, but others are good. Swaybars. GO BIG, but keep the back within 1/4" of the front. Move the tank back. I sell them, buy one so I can eat. Move the battery back. I sell battery boxes too . Take the time to shim the pinion angle. It's free HP. Here's what you forgot. BRAKES. Save up and do it right, and put an adjustable proportioning valve in the rear line. Steering, AGR or LEE box. If you get out to the 7-9 deg caster range, you will need to work on bumpsteer. Hotchkis's center link will help, or modify the stocker. Replace the rag joint and coupler with good quality U-Joints. Again, I sell the Flaming River joints. Steering feedback is needed. Spend $ on shocks. Now it's on you. Let us know your plan, and the results.

[robnolimit]

GREAT NEWS OK, well it's news anyway. We bought a new project. A semi clean 72 c-10 sb. Going to get it this weekend. The plan is to do a standard aproach build up, while track testing and posting ALL RESULTS. Good or bad. We are willing to test out any part, so if your a Mfg. rep, let us know. I plan to start with a stock parts makeover, and go from there. We'll keep you posted.

[SactoJim]

Originally Posted by robnolimit

GREAT NEWS OK, well it's news anyway. We bought a new project. A semi clean 72 c-10 sb. Going to get it this weekend. The plan is to do a standard aproach build up, while track testing and posting ALL RESULTS. Good or bad. We are willing to test out any part, so if your a Mfg. rep, let us know. I plan to start with a stock parts makeover, and go from there. We'll keep you posted.

I'll be tuned in......what a wealth of info! Probably one of the (if not the) best threads of all time for this forum!

You sure you wouldn't rather use my truck as a "guinea pig"?....

[Mechanic77]

Hey Rob, do you have a suggestion on an affordable adjustable shock for the front? I'm building all my own shock mounts, so it doesn't have to be a stock replacement. I was curious if there was an aftermarket (maybe oval?) shock that is more affordable. I'd like to spend less than $300 on a pair of front shocks

[robnolimit]

Mech77, you may have to expand your shock budget a bit. We use and sell "Romic" aluminum smooth body and threaded body shocks. Smooth single adjustable 5" stroke shocks are 174.50 each, with 5/8 or 1/2" bushing, or 1/2" bearing. Also check Pro, and Afco. I looked on E-bay and found a bunch to choose from, stay in the 5 to 6" stroke range. Also, look at the rancho 9000, not sure of the lengths. You want a medium to firm compresion, like a #4 to #6 valve, and adjustadle rebound.

[Mechanic77]

Thanks Rob, I was afraid I might have to spend a bit more to get what I want. I'll do some checking around

Thanks again, Andy

[68 SWB]

Originally Posted by robnolimit

68 SWB - Lets start with the easy answer. There are several good quality kits on the market. Hotchkis, Ridetech, Porterbuilt, Early Classics, and others. You can spend $4000 to $6000 and get it done. And probably, the next guy will run faster than you. Does that mean these parts are no good? No, they are good parts, but thats not enough. It's the other things that will make the difference. I like 18's better than 20's, but thats me, and unsprung wieght makes a difference on the track, and the ride is better. Tires win races. Kumho, Bridgestone, BFG, Falken, but stay with 300 treadware or less. Most Autocross clubs, and Goodguys have a 180 treadware rule. Wieght is a big issue, put that pig on a diet, and focus on the front end. Every pound helps. Motor placement, If you can move the motor down and back, DO IT!! OK, so on to your question. Spindles and springs, I like McGauphy's or Western chassis, spindles. Doetch tech lowering springs are pretty good, so are Hotchkis. If your Really cool, you'll learn how to tune springs, and start searching some Oval track suppliers, who have many more choices avail. I have used Porter, Ridetech and E.C. arms, and like them. I have not used the new Hotchkis arms yet. If I didn't mention others - well, you guess. In the back, 2" block and 4" spring. I like the E.C. raised crossmember, but others are good. Swaybars. GO BIG, but keep the back within 1/4" of the front. Move the tank back. I sell them, buy one so I can eat. Move the battery back. I sell battery boxes too . Take the time to shim the pinion angle. It's free HP. Here's what you forgot. BRAKES. Save up and do it right, and put an adjustable proportioning valve in the rear line. Steering, AGR or LEE box. If you get out to the 7-9 deg caster range, you will need to work on bumpsteer. Hotchkis's center link will help, or modify the stocker. Replace the rag joint and coupler with good quality U-Joints. Again, I sell the Flaming River joints. Steering feedback is needed. Spend $ on shocks. Now it's on you. Let us know your plan, and the results.

My project is a ways off in the future, still in the planning stage. I left the brakes, tires, steering, and back spacing out of my original post as I figured they were different considerations to the chassis geometry, components, and dampening setup. After all you can't put slicks and wheels on a dump truck and have it beat a Corvette ZR1 around the Nürburgring. I guess ideally if the truck could run with a prepped Miata or C5-C6 Vette without building a tube chassis for it or spending 10K on suspension that would be great.

Getting weight off the front would important, but with it being a truck I'm sure you would limited on how much could be transferred to the rear within reason. By the way, what is the ideal setup for the pinion angle?