Make it handle

[bo-w]

i recently ordered drop springs from no limit , all n all it was a great conversation over the phone all my questions were answered. I will definitely be ordering more through rob's bunch, shock re-locaters and drop shocks are next once i get my ride hight all situated.

[bo-w]

one other question and i looked a bit through this thread, as far as rear trailing arms positioning i know flipping the mount is a good option but as a rule of thumb on the truck arms is level the best position for the arm , im not against just flipping the mount but have the oppertunity at this time to fabricate a bit and position the mount how ever may ne tthe best results within reason. thanks

[DM Garage]

Yes, in my opinion level at ride height is the best position to have the trailing arms in if you can get them there!

[INSIDIOUS '86]

Anyone think the have an idea for making the front centerlink on our trucks stiffer? My WHOLE front end is rebuilt and I notice that you can stand on the centerlink and flex it. I can't imagine this is great for a handling or road feel standpoint. I know a rack an pinion would make this go away but I'm not that rich yet.

Also rob any advise for shock tuning for those of us running adjustable shocks? Just how bound and rebound effect ride/performance?
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[GEARBOXGARAGE]

Originally Posted by INSIDIOUS '86

Anyone think the have an idea for making the front centerlink on our trucks stiffer? My WHOLE front end is rebuilt and I notice that you can stand on the centerlink and flex it. I can't imagine this is great for a handling or road feel standpoint. I know a rack an pinion would make this go away but I'm not that rich yet.

Also rob any advise for shock tuning for those of us running adjustable shocks? Just how bound and rebound effect ride/performance?
Posted via Mobile Device

Hotchkis' front lower A-arm kit comes with a new center link made from bar stock, but are pricy. Here's a link to there page.

http://www.hotchkis.net/6372_c10_tub...trol_arms.html

The rack and pinion kits that are available now for these trucks would definately be an improvement in steering (stability, less bump steer, etc.) and worth the added expense.

[INSIDIOUS '86]

Originally Posted by GEARBOXGARAGE

Hotchkis' front lower A-arm kit comes with a new center link made from bar stock, but are pricy. Here's a link to there page.

http://www.hotchkis.net/6372_c10_tub...trol_arms.html

The rack and pinion kits that are available now for these trucks would definately be an improvement in steering (stability, less bump steer, etc.) and worth the added expense.

Only Prob is I have a square 73-87. Not that I have an issue with hotchkis but I don't like the 60% mark up on their prices because they just can. Kinda like dynomat.
Posted via Mobile Device

[GEARBOXGARAGE]

Yeah, there is a bit of a difference in pricing on their products compared to similar items from other manufacturers. We've installed CPP's A-arms and plan on using them on future builds, as well, and the cost difference is enough to be able to purchase a rack unit and still come out ahead. Not nockin' Hotchkis, great products, we've used them, but it's hard to convince a customer to buy something that has 90% of the same feature/quality for twice the price.

[robnolimit]

It may not be the center links fault, it could be the idler arm. Check out some of the Oval Track race supply shops, like Howe racing or Circle Track Supply. They have custom center links avail for many apps. Check there pricing for a shock

[CSGAS]

Rob, in addition to the wheel backspacing preferences, do you know if anyone's done an analysis of the stock truck geometry? If not I can get some of the pickup points in the next week sometime. If we can get actual critical measurements of different manufacturer's products, we could get a real idea of what actually makes improvements and what is just expensive dressing, and so on. I don't think I have the equipment to get exact specs (no lasers, no wheel mounting face stands, etc) but the numbers I do get, at least for ride height, will be good and someone may have the software (Mitchell? Anything else?) to enter for simulations.

Also, on the centerlink alternatives, if you can get the Hotchkiss measurements posted there just may be a stock car used parts reseller who has a billet piece, some over an inch thick, that was made with a range that can be adjusted to the same measurements using "slugs"...when I post the stock measurements it should be easy to figure out what measurements we're going to need, but you can start off with the distances between a PLUMB LINE hanging from each of the attachment points (tie rod ends, idler, etc) and then the difference in height between the attachment points. We'll get deeper into it, later I'm sure.

[G8DAN]

So yesterday when I was testing the truck out on some canyon roads and I noticed the truck was heavily under steering towards the other lane. I do know that since the majority of the weight is on the front head the truck will tend to push alot but this time seemed excessive.

But since I am running stock length shocks up front with the 3 inch drop springs, will that affect the handling on the truck? The way I'm thinking is that the front suspension is not transfering the weight correctly causing the truck to understeer even more than usual. Am I on the right track with this mindset?

[C0UCH]

I've narrowed down my search for suspension. After talking to Porterbuilt on the phone for quite a while I'm going with a coilover touring dropmember front end and mild c-notch in the rear. I'd go lower but I don't want to raise the bed.

From what I've read the Hotchkis TVS (as I previously mentioned) kicks ass, but I don't want to mix and match parts between Hotchkis and Porterbuilt and I'd rather support PB anyways. Pulling the engine possibly today and starting the teardown as soon as my brothers S2K is out of the shop. Blasting the rails and will mockup everything once PB components arrive.

I'd like to order the wheels/tires asap though but without all the parts, I'd rather not risk it. Any luck with the backspacing chart mentioned above?

[robnolimit]

No luck yet on more wheel info. Does Nate have specs for his suspension?

[Can't kech me]

i don't really know if this fits in the suspension forum, but it does go along with handling.

for us auto tranny guys, would running a ratchet shifter with reverse lockout be hugely beneficial for us on an autocross course, but still be able to put it in drive and cruise? seems like something project JT needs. just curious, because being able to upshift/downshift one at a time knowing that it will be one gear, and keep it out of park, reverse, and neutral would be just as beneficial. anyone running one have any imput?

[robnolimit]

Originally Posted by G8DAN

So yesterday when I was testing the truck out on some canyon roads and I noticed the truck was heavily under steering towards the other lane. I do know that since the majority of the weight is on the front head the truck will tend to push alot but this time seemed excessive.

But since I am running stock length shocks up front with the 3 inch drop springs, will that affect the handling on the truck? The way I'm thinking is that the front suspension is not transfering the weight correctly causing the truck to understeer even more than usual. Am I on the right track with this mindset?

First of all, ALL trucks will push if your going fast enough. It's simply a wieght balance vs. force equation. Our goal is to tame it as much as possible. As far as the shocks, remember that a stock shock allowed full travel all the way to the bump stop. Now, the shock may not be in the center of its travel at R.H., but shock valving is linear, or constant, so it should react about the same. The shorter spring probably has a stiffer spring rate than stock, making the push worse.
Work with what you got first. Add some neg. camber, do it the easy way. Just pull one shim out of the front, and two out of the back of the upper A arm mounts. This way you can put them back easy. Then, add a little toe out. A little. This is easy too. Loosen the lock bolts on the adjuster sleaves and rotate the sleave 1/2 turn to make the tie rod longer. - look carefully at the threads to get the rotation right. Do this to both sides, again, easy to go back. Take 4 psi out of each front tire (make the two even as well) and 5 psi out of each rear. Then go drive the same road.
One more tip. "late braking" on street tires is a bad idea. - Especially in a nose heavy truck. When you approach a corner, brake early while still in a relatively straight line. As you begin to turn in to the corner, add throttle a little bit at a time. You wil learn that adding throttle will help to get rid of the push, this is becauce the acceleration is taking weight off of the front tires and allowing them to turn. It's not natural to do this, but it works. Happy New Years.

[AJohn6]

Rob,

I have a question for you. I am in the middle of rethinking my brake setup since the underdash pedal assembly I have isn't going to work for me. I had planned on using a 7" booster and a corvette style dual master cylinder and a pro-valve. My plan now is to use the Wilwood reversed brake pedal kit without a brake booster and with dual master cylinders, one for the front and one for the rear.

My question is how do I figure out what bore size would be best for me?

I have a '71 stepper, porterbuilt mild dropmember with bags, and a fatbar 4-link with Shockwaves. For the brakes I have the following Wilwood kit-

13" Forged Narrow Superlite 6R Big Brake Front Brake Kit
13" Forged Narrow Superlite 4R Big Brake Rear Parking Brake Kit

[robnolimit]

Well, this is the set up I use in the HellBoy C10. A nice thing here is the 'balance bar'. This takes place of the prop valve, and is easier to tune. I started with the recomended 13/16" bore rear, and 3/4" bore front. - also a 3/4" bore clutch. And, I run 4-piston superlights on all four, 1.75" bore front, and 1.625 bore rear. My wieght balance is 52% ft. - pretty good for a p/u. Our J.T. shop truck is 57% ft. So, it was OK this way, but I couldn't get the rears to lock up. Even with the balance bar max'd out. So, I switched to a 3/4" bore rear master. That worked good for me. The balance bar is close to center, which gives me some tuning room. Now, I am playing with pads to get the last little bit out. - haha, don't ever try 'A' pads on high $$ rotors. - they will have a 1000 mile lifespan. - just so ya know. Really agressive!!! lol.
So, try the same set up to start,(13/16" and 3/4") it may match your 6/4 piston set up well. But, don't be shocked if you want/need to change one or both later. For a softer pedal you might try a 3/4" and 5/8", but this will have more pedal travel. Oh ya, the one piece aluminum cylincers are the ticket inside. The plastic resivours seep just a tiny bit.

[derrickmanx1]

So From what I can tell it would be better to have the front part of my truck arms as low as possible to make the trailling arms as close to level at ride hieght? I have a cpp x-member and they recomended installing it with the pad-eyes in the upper pos. Should I flip that over modify if needed and try that? By the way have not installed the mounting pads for the rear-end so I can still adjust the pinion angle.

[jayman68]

Originally Posted by derrickmanx1

So From what I can tell it would be better to have the front part of my truck arms as low as possible to make the trailling arms as close to level at ride hieght? I have a cpp x-member and they recomended installing it with the pad-eyes in the upper pos. Should I flip that over modify if needed and try that? By the way have not installed the mounting pads for the rear-end so I can still adjust the pinion angle.

What part of the trailing arm are you thinking to be level at ride height? I would think you would want the part where the axle mounts level, not the forward part. Just that would be alot of drop in the front mounts.

[derrickmanx1]

Originally Posted by bo-w

one other question and i looked a bit through this thread, as far as rear trailing arms positioning i know flipping the mount is a good option but as a rule of thumb on the truck arms is level the best position for the arm , im not against just flipping the mount but have the oppertunity at this time to fabricate a bit and position the mount how ever may ne tthe best results within reason. thanks

This is what I was looking at and wanting to clairify. It seems to make some sense because of the whole thought of the use of leverage. I'm hoping someone can help this make a little better sense. Thanks in advance for all of the good advice.

[robnolimit]

The hieght of the front trailing arm mount will directly effect the "anti-squat", or "rate of rise" of the rear suspension. Raising the mount will raise the anti-squat value.
Here's what may happen.
For an A.S. value of 50%, the front would lift slightly, the rear would drop, or "squat", and a majority of the axle's rotating force would be used to push the truck forward. But, this will reduce the total tracion available.
At 100% A.S., the truck would appaer to lift evenly, ft/rr, during a launch, splitting the axle forces between a forward push and tire loading.
At 150% A.S., the rear of the truck would rise, with the majority of forces being used to plant the rear tire. But, this takes away from theforward push.

Ideally, you want the lowest A.S. value you can have, that still keeps the rear tires planted. For most of our trucks, that would be just above 100%, and that woul 'ideally' put the front trailing arm mount even, or just above the floor.

So, I think you should mount the CPP X-member as designed, with the mounts up.
BTW, the 'bend' in the factory arm was designed in for purposes of "packaging". As far as the axle is concerned, the arm could be straight. The axle saddle's rotation would change to keep the pinion angle the same. But, if the arms were straight, mounting a coil spring would be difficult. The bend in the stock arm was all about mounting the coil spring as efficiently ($$) as possible. The one thing that iI wonder about is the shock mounts, in this regard. It may have been cheaper to form the lower shock mounts right on to the end of the trailing arm, moving the shocks outboard, and improving the ride and stability. But, they need a stamped lower plate for the U-bolt nuts anyway. Hmm. Then there is the idea that the shock is more protected from rocks and road junk if its inboard. - we may never know.

[AJohn6]

Originally Posted by robnolimit

Well, this is the set up I use in the HellBoy C10. A nice thing here is the 'balance bar'. This takes place of the prop valve, and is easier to tune. I started with the recomended 13/16" bore rear, and 3/4" bore front. - also a 3/4" bore clutch. And, I run 4-piston superlights on all four, 1.75" bore front, and 1.625 bore rear. My wieght balance is 52% ft. - pretty good for a p/u. Our J.T. shop truck is 57% ft. So, it was OK this way, but I couldn't get the rears to lock up. Even with the balance bar max'd out. So, I switched to a 3/4" bore rear master. That worked good for me. The balance bar is close to center, which gives me some tuning room. Now, I am playing with pads to get the last little bit out. - haha, don't ever try 'A' pads on high $$ rotors. - they will have a 1000 mile lifespan. - just so ya know. Really agressive!!! lol.
So, try the same set up to start,(13/16" and 3/4") it may match your 6/4 piston set up well. But, don't be shocked if you want/need to change one or both later. For a softer pedal you might try a 3/4" and 5/8", but this will have more pedal travel. Oh ya, the one piece aluminum cylincers are the ticket inside. The plastic resivours seep just a tiny bit.

Rob,

Thanks again for your advice. A couple questions so I can really understand this. Did you end up going to the 3/4" bore for the rear of JT or Hellboy? Also are you talking about the Wilwood solid aluminum M/C (has resevoir built on it)? My plan was to run a remote aluminum dual F/R resevoir on the firewall and I am not sure how to do that with the solid M/C.

Thanks again,
Adam

[robnolimit]

Originally Posted by AJohn6

Rob,

Thanks again for your advice. A couple questions so I can really understand this. Did you end up going to the 3/4" bore for the rear of JT or Hellboy? Also are you talking about the Wilwood solid aluminum M/C (has resevoir built on it)? My plan was to run a remote aluminum dual F/R resevoir on the firewall and I am not sure how to do that with the solid M/C.

Thanks again,
Adam

Oops, I was just giving the JT's weight balance. It has a 85 C10 booster/master. The Wilwood stuff is on the HellBoy. If you are using the low mount set up, then the plastic remote cans are good. Just keep your eye on them.

[AJohn6]

Originally Posted by robnolimit

Oops, I was just giving the JT's weight balance. It has a 85 C10 booster/master. The Wilwood stuff is on the HellBoy. If you are using the low mount set up, then the plastic remote cans are good. Just keep your eye on them.

I ended up getting the compact remote M/C 3/4" bore for the front and rear (p/n 26010372) and the brake pedal assembly (p/n 34012509).

Thanks for your help,
Adam

[69gmcc10]

Rob,

I was noticed that you added a splitter and a spoiler to Hellboy and it got me wondering about mechanical vs. aero grip on these trucks. We spend most of our time working on mechanical grip, but what and where are the gains of a sleek 67 hood, tonneau cover, splitter and spoiler? Can you elaborate on the principles, you must have done those things for a good reason?

Thanks for your willingness to share your wealth of knowledge.

[hotrod1]

Originally Posted by AJohn6

I ended up getting the compact remote M/C 3/4" bore for the front and rear (p/n 26010372) and the brake pedal assembly (p/n 34012509).

Thanks for your help,
Adam

Hey Adam

Let us know how the 3/4 front and 3/4 rear works for you.