Make it handle

[dirtball]

Hmmmm....good info. Your pictures really do help to understand these concepts. It does sound as though I should keep my dropped spindles for now.

[JNJchev77]

The pics are a big help... This thread is one of the best I've seen!

[Hotchkis]

Originally Posted by dirtball

Looks like this could be a good time to ask something that I have been scratching my head over. On the Hotchkis site, they show that their spring rates for 67-72 trucks are 1100/380 lbs/in! Those rates sound extremely high to me, I can't afford to drive down the road and knock the fillings out of my teeth. What do you think of these rates Rob? I gather you like the soft spring/ big bar approach. Hotchkis is using a 1 1/4" front bar with those springs in the TVS kit. The other question is about them using a 4" drop spring and no dropped spindle. I don't see that as being an ideal set up. Thanks for all your input Rob!

Hey Brett,
Those spring rates would be extremely high if we used them on an early Camaro.

A 69 Camaro would take about a 650 to 700 lbs spring depending on the engine size and application. The difference would be that the Camaro and the 67-72 Chevy trucks have different control arm length, spring position, and weight, which change the amount of leverage needed to compress the spring. These differences necessitate different spring rates.
By watching the PCH Rods truck on the track, it definitely doesn’t have too much spring rate. Rob really has the truck dialed in with our TVS suspension system for the ’67 through ’72 Chevy Trucks. On the autocross, Rob's truck beat many well-setup cars at the 2010 OUSCI event (shown). He even beat Steven Rupp's '68 Camaro from Camaro Performers Magazine (event Champion from 2008)!



If you were up for a road trip from Colorado, you could come to our big open house. Hotchkis is having a C-10 Show and Open House event on February 12. You could see our facility and see how we continue making high-quality products that perform. You could see us in progress of rebuilding the Hotchkis C-10 project truck in person.

http://www.hotchkis.net/press_release.html?ID=54

[dirtball]

Didn't know that you Hotchkis boys were here. Thanks for the clarification on the spring rates. It does make sense to me about the distance of the spring from the pivot point. I can relate to your comparison to a 69 Camaro. I have a 69 and use 650lb Afco springs and adjustable spacers on the front of it. Before I knew there was such a difference in the A-arm ratio, those 1100lb springs looked to be a misprint on your website.

Since you are here, could you enlighten us a little bit on the use of a 4" drop spring. Is that 4" spring well suited with stock control arms or designed for your tubular arms and TVS as a whole? It is hard to argue with the performance of Rob's truck. I was aware of the fact that he put the smack down on Bad Penny....very impressive!

[robnolimit]

As the discussion continues, there have been a few questions about Roll Center vs. Center of Gravity. If you were to built a truck from scratch, and your goal was to get these in check, your truck would look alot like a Lotus. So, bad to the business of Trucks. I've had a few chats with Nate Porter lately, and I can tell you that he is on the right track with his new performanced based Dropmember. This concept is simple. The raise crossmember drops the truck, and thus the C.G. without negatively effecting R.C. Although drop spindles are better than drop springs (for that 2 1/2" of drop) they still drop the R.C. some. Appx 1/2 the drop of the spindle, so about 1 1/4". If the Dropmember, or raising the stock crossmember, or Z'ing the frame, drops you 3" without any loss in R.C. hieght, then with drop spindles you would have a 5 1/2" drop for the truck, and C.G., with only a 1 1/4" drop in R.C. This combo would get you a net 4 1/4" gain from R.C. to C.G. This is all with a stock spring. Food for thought. If you are in the area, I suggest a trip to the Hotchkis open house on feb 12. The TVS aproach is a simple bolt-on uprade, and it is worth a good look to see how they sorted out the steering geometry.

[52 choptop]

Originally Posted by Mike Bradbury

The single wall construction of the Bilstein shocks gives it the advantage of having a much larger piston, with much more efficient valving with much less fade. I have broken a set of Bilsteins bottoming out my truck when I hit a huge dip and they replaced them no questions asked. If you find a custom dealer then they can order you a set that is valved for your application. I also would not have any other shock on my truck.

Mike and Rob, thanks much for your input (I recieved the post today!) When I built the truck I had "fast & in a straight line" in mind. I put the Bilsteins on the front last weekend (like I said, I recieved your posts today) and now the rearend is like a rollercoaster with nasty body roll. The rear is tubbed with 15x18.5x31.5's. My buddy set up the leafs with the shocks at about a 40 degree angle to the center of the truck. He said this was for handling, but in hindsight, it seems that the shocks have no dampening value at this angle. Would you suggest leaving them in place and adding a second set in the vertical? Or relocating them to the vertical? Or selling my house, filling the bed with cash, parking it in Rob's driveway and picking it up when the cash runs out? I really appreciate your knowledge and help. Thanks, Eric

[robnolimit]

52 Choptop, dig the truck. Lets get on the same page first. I built many a pro-streeter, and owned a few. My 58 chev p/u was a favorite. You see these guys with the flat hats, rollin the late model lifted trucks, 37" tires, you've seen 'em - right? You ever look in and see that they have two shocks? Now, realistically, they don't need them, but the gods that they prey to, the dirt warriors, do. So, the street-runners copy. The off road guys are pretty savy on shocks. And they get the "unsprung weight thing. Your tire is HEAVY, I'm sure you picked them up once or twice, thats a lot of unsprung weight. (first problem) And, your tire has about a 7 1/2" sidewall, that flexes a LOT. It's supposed to, thats the whole drag racing 'wrinkle wall ' concept. But not great for handling (second problem) And, at 40 deg. your shocks have lost 38% of their effectiveness. I'm not sure if this is leaf, coil or bag, but, you need a really soft spring rate. If it's bags, I'd use the skinny 1100 lb slider bags. You can stand the shock up, or get a different shock. The goal is to get a shock with a soft compression, and a firm rebound. This way you can let the axle move up, on a bump, and control it on the way back down. Afco, and Pro shocks, have split-valve shocks that work well, and aren't too much $$. If you get me some measurements, I'll help you find some. Lastly, ever think about new tires? (don't kill the mesenger) M.T. 29x18x18 radial is about the same size, and would be a night and day difference. Weld doesn't make an 18" drag star, so that means new wheels - sorry. Just a thought. Get me some shock info and lets see what we can come up with.

[52 choptop]

Thanks Rob, I like options. I'll measure what the shocks will be after the relocation. The option of buying new tires may include the wife shooting me. I'll let you know what I come up with.

[N2TRUX]

Originally Posted by robnolimit

.... Weld doesn't make an 18" drag star, so that means new wheels

A set of these in 18's or 20's would look sweet and allow you to reduce some of that sidewall flex....just sayin...

[Greywolf200]

Greetings Rob and other folks,

I had a '71 K5 w/ 37" tires for 35 years and decided I didn't have any futher use for it and sold it to the sheriff. Here I am a couple of years later and couldn't stand it, so I bought a '70 C10 SWB. See my signature for my first mods. I'm buying the AGR 12:1 box off the thread here to cure my steering problems and will also put in a tilt wheel. The springs are too soft, so next will be A arms(with a 1" shift on the lower), disc brakes, spindles, springs and power assist from a '76 C20. Will probably use C20 springs in the back also. Not considering lowering until I decide on wheel/tire size. It came with 15" rallys with new 28" BFG's and I'm considering 18" alloys with 31" Goodyears. The PO also had recently replaced lower ball joints, tie rod ends, and some cheap Monroe shocks and the handling really sucks. It sits fairly low and level and with the old 350 tranny in the back, the tail's draging, so I don't have a clue what has been done. I can't remember my K5 handling that bad when I got it, although I did make some mods to it.

So much for the introduction, I've been reading about sway bars (1 1/4 front and 1 1/8 rear) and that the CPP rear bar isn't optimum for performance because of the mounting location. Solution, find a suitable bar and mount it to the axle and frame. In terms of a bar, does the arm length affect the performance of the bar. I'm thinking a smaller bar with 8" long arms might be just as effective as a larger bar with 16" arms because of the greater leverage.

Finally, thanks to Rob for sharing his knowledge so freely and know that I'm also watching the build up of your C10 shop truck.

[52 choptop]

Trux, thanks for the pics, which I have forwarded to a buddy that owns a tire store. It doesnt make sense to play with the suspension when you have learned that your tires will not meet your needs. I think the wheels and tires on the 52 might look good on my 69 Firebird.

[robnolimit]

Greywolf. It realy shouldn't be that bad. Our JT 72 has no sway bars yet, and now, with the right springs, and an adjustable panhard rod, it's OK. Check the Idler arm, could be giving you fits. The stock design is not so good, but it's all there is for now. If you have no swaybars, and its neer stock hieght, thats a problem. As luck would have it, we are currently working with Helwig to build us a custom sway bar based on our specs. Also, last week we finished prototyping rear 'long-travel' rear shock mounts for trailing arm trucks. I'll share picts next week.

[Mechanic77]

Hey Rob, quick question, how long do you suggest I make my sway bar arms on the front? I've already bought a Speedway Engineering 1.25" dia, 38.5" long bar and a set of their straight steel arms. Obviously the shorter I make the arms, the stiffer it will act. I'm just looking for a good starting point.
Thanks, Andy

[michaelnolimit]

Mech77, you may need to bend the arms outboard to get to a good connection point on the A-arm. 10" is a goo starting point. I mount the bar close to the stoch location, and start from there. Make sure that your arms clear at full L/R turn.

[michaelnolimit]

Greywolf, I just got off the phone with Helwig, we have been working on new C-10 rear bars. I should have final prototypes in about 2 weeks, then production bars in another 3 weeks. This is a tubular 5140 bar, with adjustable links and tunable mount points. They mount over the top of the chassis, so the bad news is you have to lift the bed about 3" to get the bar inplace. The link assy allows the bar to be used with stock - to - 8" drops. If we made them in solid, the kits would retail for about 190, in tubular form the cost is going to push retail up to the 225 mark. We think the quality of the bar, finish and performance is well worth it. We are testing on our JT and a few others. I put up some picts as soon as we have a final.

[dirtball]

Originally Posted by michaelnolimit

Greywolf, I just got off the phone with Helwig, we have been working on new C-10 rear bars. I should have final prototypes in about 2 weeks, then production bars in another 3 weeks. This is a tubular 5140 bar, with adjustable links and tunable mount points. They mount over the top of the chassis, so the bad news is you have to lift the bed about 3" to get the bar inplace. The link assy allows the bar to be used with stock - to - 8" drops. If we made them in solid, the kits would retail for about 190, in tubular form the cost is going to push retail up to the 225 mark. We think the quality of the bar, finish and performance is well worth it. We are testing on our JT and a few others. I put up some picts as soon as we have a final.

You have my attention!

[robnolimit]

Some basic info about sway bars. The vehicle suspension all works together, and there are many parts and considerations. No one component is isolated from all others, so each component is effected by the others. Sway bars, or - "anti roll" bars are no exception. The basic job of the sway bar is to reduce vehicle side roll, by increasing the "ROLL STIFFNES". The basic parts involved in the suspensions roll stiffness are the springs, sway bar, lower A-arm ratio, and track width. Changing any of these things will effect the others, and the roll stiffnes. Each can also have a negative effect on other ride considerations. Here are some examples. While increasing roll stiffness, these negatives may/will result. Stiffer springs = harsh ride, less weight transfer. Longer A-arm ratio = harsh ride, less travel. Stiffer sway bar = twitchy ride, may start to 'push' more. Wheels offset to increase track = increased scrub radius, harder to steer. The perfect setup is again a combination of these, with the minimun of negatives. I'm working on a sway comparison chart for you guys to look at. Give this some thought.

[robnolimit]

New...1963-72 Chevy Pickup Rear Shock Kit
NO LIMIT ENGINEERING
New Rear Shock Kit to fit 1963-72 Chevy Pickups!! - I'm feelin pretty good about this. After dropping another 2" in back, we ran into the same trouble as everyone else. The shock issues. After researching the other kits, and solutions, and thinking about it, we came up with a plan. Here are some of the problems we noted. 1. No room for a longer shock, even with reworked or 'dropped' mounts. 2. shock angle gets worse, the lower you go. 3. If we go another 2" (8 total) we're screwed again. 4. the exhaust is a nightmare. 5. the inboard shock design doesn't handle that great. With this in mind, we set out for a fix. This is the whole idea behind the JT, to come up with tested components that WORK, and will HELP get more trucks on the road to be enjoyed.

[robnolimit]

We are also using this forum, and site to set the record straight. I am sure we will be copied. Now there is lasting, dated proof, and those who 'knock-off' will be called out. This kit will come with 2 different length shocks. A 10" stroke shock for the stock to 4" drop guys, and a 8" stroke shock for the 6" to 10" drops. Once the stock shocks and mounts are gone, the new lower mounts are a direct replacement.

[robnolimit]

The new upper mounts locate to the frame with a factory 5/8" hole. We provede a big bolt to hold and align the new mount. You have to drill the two 3/8" holes.

[robnolimit]

Then your all but done. Just bolt on the shocks and mount studs, all included.

[robnolimit]

After some drive time, I am happy to report that the difference is clear. Body roll is reduced, and the ride is very smooth. The outboard location is a benefit in many ways. With a good quality monotube shock, these kits wil run about $185.00 I think thats a good deal for the gains. Just remember, You saw it here FIRST.

[PBFAB.COM]

Originally Posted by robnolimit

After some drive time, I am happy to report that the difference is clear. Body roll is reduced, and the ride is very smooth. The outboard location is a benefit in many ways. With a good quality monotube shock, these kits wil run about $185.00 I think thats a good deal for the gains. Just remember, You saw it here FIRST.

Looks great Rob! Good price for a good product!
Posted via Mobile Device

[robnolimit]

Thanks Nate, I think this will be a nice upgrade for the guys that are working with mostly stock, or lightly (bolt-in C) modified frames.

[basemodel67]

Hey Rob - any chance the new shock mounts could hold up if used with a coilover? That would be awesome if they would!

Speaking of coilovers... could they be mounted midway up the rear control arm and still be effective? I'm thinking of like how trophy truck coilovers are placed closer to the pivot end of the control arm than the axle end. Sorry if that is the most confusing description of what I'm thinking. Thanks for any input!