Make it handle

[robnolimit]

Originally Posted by NBryant

Hey Rob I am setting up the rear axle a Ford 9 inch and a parallel 4 link with air bags. Its going in my 1983 Chevy long bed 2wd. I have back halfed the frame just behind the cab. My question is where do I set the pinion angle?

OK, here's the basics. *** Disclaimer *** This is for normal stance street vehicles. Not drag cars, 4x4's, jeeps, tow rigs,...... OK.

To start with, you need to be able to set the vehicle (or at least the rear suspension), at Ride Height. So, here is what I would do.

1) put the truck or chassis up on some jack stands, as I get older, I realize the value of not bending over and/or laying on the floor. Get it nice and level all the way around.

2) With the rear suspension mocked up, make up a spring block (coil spring or bag) or a set-up bar (coil over) that holds the suspension at Ride Height. This would be appx half of the shock travel for a coil-over, for a coil spring or bag, give yourself 3" to 4" to the frame for up travel. (you results may vary, depending on chassis mods, this is for you to decide) But, try to get it close. Kugal Komponents has cool adjustable set-up bars for builders. Check them out.

3) Measure the angle of the crankshaft. Yes, you have to put the motor and trans in. Or, at least a shell of each. The oil pan rail is on the crank CL. Also, you can use the balancer face, as the are 90 degrees to one another.

4) As a starting point, set the pinion at the same angle as the crack. Not 'pointed at it', but the same angle (see pict) Using the face of the pinion yoke is easiest.

5) Now, make adjustments to match the type of suspension you have.
Leaf Springs - push the front of the pinion down 2* to 3*.
Coils or Bags on Trailing Arms - Push the front of the pinion down 1 1/2* to 2*.
4-Bar with poly bushings - push the front of the pinion down 1* to 1 1/2*
4-Bar with Delron or Heims - push the front of the pinion down 1/2* to 1*

OK, that's how I do it. I'm sure others have different ways, but this method had worked great for No Limit for 30+ years. Can't argue with success.

[robnolimit]

Originally Posted by Possmguts

Hey Rob.. I just came back to refresh my memory on what Ive read in this wonderful thread. I thank you for taking time to give your expertise here.

Im double thinking the setup I have going on right now. I did 2.5" drop spindles with 3" springs in front and 5" springs in back... Still dont have all the weight back on the truck yet, but I fear, like Ive been told, that this may be no good. I used your adjustable panhard bar kit along with the shock relocation kit and rear above frame sway bar. What I was looking for was maybe 2" higher in back than the front, but I didnt want to do a C-knotch... what would you recommend? Am I too low in front and should I do what you just said here and go with blocks and 3" springs in back? Still dont have the bed on and the front clip is just tacked on with a few bolts right now, so now would be the time to go back if I need to... the wheels and tires are what I'll be running in this pic... no engine (350) or trans are in it yet... Thanks in advance...

I think your close. And, remember, spring changes are easy. You may end up with a 2" spring up front, but why worry now? Get the truck on the road, and see how it sits. BTW, the hood looks great! If it's not 'just right' when your done, a set of springs is cheap and swaps in in a few hours. I don't think you need to C the rear. (I may add an "Anti-C" post soon) blocks and springs may ride a bit better, but again, I'd leave that till later. Keep pushin and start driving.

[69gmcc10]

Rob,

I am currently moving my lower control arms forward 3/4" on my 69 GMC by re-indexing the the holes on the cross shaft and was wondering how that is going to effect my factory sway bar? Should I be moving my upper sway bar mounts forward 3/4" for clearance or efficiency, or should I not worry about it?

Also, thank you for not abandoning this page and continuing to answer questions!

[jlsanborn]

Originally Posted by 69gmcc10

Rob,

I am currently moving my lower control arms forward 3/4" on my 69 GMC by re-indexing the the holes on the cross shaft and was wondering how that is going to effect my factory sway bar? Should I be moving my upper sway bar mounts forward 3/4" for clearance or efficiency, or should I not worry about it?

Also, thank you for not abandoning this page and continuing to answer questions!

I did the same LCA modification and didn't have any clearance issues with the sway bar. It just pokes through the bushing an extra 3/4". I suppose you could saw a bit off the ends if you wanted to. It did introduce a little more interference with the wheel (15") and I had to do a bit of grinding on the LCAs near the ball joints.

[Greywolf200]

Does anyone know if welding ends on a sway bar will cause any strength problems?

[tinydb84]

Originally Posted by Greywolf200

Does anyone know if welding ends on a sway bar will cause any strength problems?

In general you dont want to weld on springs or anything heat treated.

[tinydb84]

Rob can you talk about the addition of tube connecting the body to the frame in order to stiffen the chassis up?

I got these pics off the protouring forum:




This guy was making a cage in which he can remove the body (obviously) but would it be beneficial for us who arent running a cage to add tube in a similar fashion using 6x6 1/8'' plates to distribute the weight on the body?

I dont know if I want to do a cage but I like the idea this guy had.

[Bowtie001]

What exists to adjust bumpsteer following a relocated ball joint height?

[68c10airstream]

Good question. If your upper control arm length was correct before changing ball joint height you would have to shorten/lengthen the upper control arm length to compensate for the change.

I have NOT purchased any aftermarket front end system yet because very few address bumpsteer correctly when designing a new system. All you have to look at is if the upper control arm can be lengthened/shortened within the "A" arm itself, (this is based on the fact that the lower control arm is a fixed length). Slotted upper arm mounts, eccentric cams, shims, affect bumpsteer.

As i think about this a little more the spindle contains the 3 pivot points, upper and lower ball joints and the outer tie rod end so if the relocated ball joint height is part of the spindle and is on the same plane as stock you should see no change If you had an adjustable upper "A" arm. If not, you would have to move the upper arm in/out to correct for the ball joint change to maintain your desired alignment angles and would impact the bumpsteer amount.

[Bowtie001]

Why not move the steering idler and box around and leave the control arms alone?

[Domer]

Here are my bumpsteer adjusters i built. They are stainless steel, machined taper to match c10 spindles, with a 5/8-18 thread to use a 5/8 heim.

[Bowtie001]

Originally Posted by Domer

Here are my bumpsteer adjusters i built. They are stainless steel, machined taper to match c10 spindles, with a 5/8-18 thread to use a 5/8 heim.

How do you use those? Not trying to be ignorant, but I can't figure out what you're doing there.

[tinydb84]

Originally Posted by Bowtie001

How do you use those? Not trying to be ignorant, but I can't figure out what you're doing there.

I am assuming he bolts the tapered side into the spindle and uses a heim joint instead of a tie rod end on the other side. It would allow the height of the tie rod to be adjustable.

[Bowtie001]

Originally Posted by tinydb84

I am assuming he bolts the tapered side into the spindle and uses a heim joint instead of a tie rod end on the other side. It would allow the height of the tie rod to be adjustable.

Ahh, I see. So are we comfortable using a heim joint rather than a ball joint on steering gear for the street? I thought that was rather difficult and expensive to do properly.

[SCOTI]

Originally Posted by Bowtie001

Ahh, I see. So are we comfortable using a heim joint rather than a ball joint on steering gear for the street? I thought that was rather difficult and expensive to do properly.

Many aftermarket R&P set-ups are connected using Heim joints. Not as good or durable (from a maintenance perspective) as a better sealed Tie-Rod end but definitely usable.

[skorpioskorpio]

Originally Posted by Domer

Here are my bumpsteer adjusters i built. They are stainless steel, machined taper to match c10 spindles, with a 5/8-18 thread to use a 5/8 heim.

Just curious, what kind of stainless? My concern would be to make sure you are over compensating for the significant reduction in strength between stainless and a tempered steel part especially with an undampened part. Even exotic stainless alloys like Inconels are about 75% of the strength of hardened tool steel and more typical stainless alloys fight to equal the strength of 7000 series aluminum alloys.

I am all about stainless fasteners and parts, for all kinds of things, just make sure you take into consideration the requirements of the piece. Not saying you didn't, just don't want to see someone go off a cliff for pretty.

[Domer]

I'm using a 304 stainless, but plan on adding a double shear plate to the top that bolts to the spindle.

[skorpioskorpio]

Just checking, blown small block, manual trans and California curves. If you got that speed bug here, you better trust your machine.

[Domer]

Thanks for looking out.. shouldn't be any sheer issues.. definitely working on over building the chassis..

[robnolimit]

Good topic. Tall or raised ball joints will have little effect on bump steer, and are usually used to adjust the roll center and/or quicken the rate of camber gain. Adding caster, and thus tipping the spindle back, and raising the outer tie rod end pivot center, can have big effects on bump steer. These types of studs are common, and can be found at Speedway, How Racing, Coleman Racing, and other circle track suppliers. Google 'bump steer kit' and you can find a bunch. Good bumpsteer curves come from the initial design, and can be tuned (slight bump out in compression is best) bad bump curves are a design fault, and usually cannot be tuned out with studs/spacers. Keep pushing the design.

[Domer]

Thanks for the good words Rob.

[Dudler]

This is a great thread and thanks Rob for all the info.
I'm already starting with a disadvantage because my truck has a BB in it so the front end is heavy but still would like to make the truck handle its best until I get around to an LS swap.

A couple quick questions I have are based on wheel and tire width. This is what I was thinking:
20" wheels,10"wide front and 12 on the back
295 or 305 (28" tall) front if they fit and 15" wide (29" tall) MT on the back
5/7 drop - 1.5" sectioned CM with 2.5 spindles and 1" drop spring with coilovers (outside frame rails) and blocks in back

Can too much rubber a bad thing? Wider in the back or matching width as the front?
Better to center the offset on the front rim and narrow control arm or have regular length control arms with more offset?
In the back is it worth the money to center the offset and narrow the rear end?
Do you see any issues with what I have planned?

Thanks in advance and sorry if something like this has been covered!

[mcmlxix]

Hey Rob, have you seen the Wilwood ProSpindle kit? It has a modular design with a removable steering arm, sealed bearing for slip on rotors and a 2.5" built in drop.

http://www.wilwood.com/PDF/Flyers/fl427.pdf ..................... http://www.wilwood.com/PDF/DataSheets/ds1194.pdf

[solidaxel]

Complete spindle and hub and only 750 more to my build!

[rcodea]

Question regarding bump steer and my alignment guy. Specifics on my truck are below. Having the truck aligned to -0.5* camber, 1/8" toe, and as much positive caster as possible. Hoping for 7-9* caster total.

Am I going to have a big bump steer issue?!?! If so, what center link do I need to buy to fix/improve it?

Basically the alignment guy said that anything more than 3* caster would cause huge bump steer and he would not align it, despite the directions stating specs from Ridetech. I tried to explain that the arms take this into account, but he still refused. Needless to say I got on the phone with Ridetech the next day, and they again stated that the arms have taken this into account. Looking through this thread, it seems that the lowered truck with high caster would actually help improve bump steer, but I may have read that wrong....with the 5/8" too high ITR mounting point on the center link....or conversely 5/8" too low on the OTR mount. By adding caster, we are actually improving this....right?

'71 c10 LWB
Ridetech Shockwave HQ bagovers & StongArms
1.25" MuscleBar
new ITRs, OTRs, pitman, and idler arms
stock center link
billet adjuster sleeves
Belltech 2.5" drop spindles
AGR steering box
29.5" height at the fenders, on the 265/50/R20

Thanks!

~Ryan