C10 suspension options.

This weekend got offered a set of stock truck arms and crossmember/mounting stuffs for my 78. I know Nascrap uses this on the cup cars and I know it's an aftermarket option. But should I look into something different?

Truck is going to be a street driven, auto-x machine that will eventually wear some serious meats. The current leaf's are plenty stiff, but they're still leaf's with all the things that make them less desirable in an auto-x/track vehicle.

I was originally considering the composite leaf, c-notch etc. Also considered a 3-link and coilovers. Need to make a decision because this winter is the time

Id rock truck arms. At some point, good enough is good enough.

Truck Arm suspension is pretty good stuff. There are plenty of upgraded parts for it through Ridetech and CPP. And Hotrods 2 Hell has made a business out of truck arm suspension kits for all sorts of different vehicles.

Yeah, I've made my decision to deal with the SM465 for another year. So that leaves me the money for completing the suspension, diff and seats. Seats may come sooner if I can sell this damned Forte crap. I've got a great intake, header, cat and exhaust that no one appears to want that could buy me two seats right now.

These are coming off of a 67 IIRC. I wonder how much work it would take to make them fit mine?

Also what I'm fighting: Boom

Bob, if you convert to the truck arms I can help you out with springs/shocks/RSB/Track bar (probably). Front end stuff I should know about soon enough as well.

So I have found a set of upper and lower tubular control arms for $800 for the front. Viking Shocks for $300 and some 3" springs for $130. If I go with the truck arms, rear viking shocks ($330) and I could use my 700lb eibachs. Would this be a wise move?

Truck arm conversion would involve new mounts on the diff, a panhard bar, making sure the driveshaft is the right length to mount the centerbearing in the truckarm mount, upper coil spring mounts, and probably several other things I've forgotten.

I wonder whether converting to a four link plus panhard with coilovers wouldn't be simpler.

Even though the rear leaf's aren't ideal, I'm definitely considering leaving them for right now. A flip kit/c-notch will get me the ride height I'm looking for and not really be out if I go a different route later as I'd still need the c-notch to get as low as I eventually want. The rear leaf's are the heavy duty critters so spring rate is decent still and a good set of shocks will help control it. Lots of fast leaf spring car and trucks out there.

I'm looking at just under $2k for control arms, shocks, flip kit, coils and spindles to get it ~4.5/6" dropped with adjustable and rebuildable shocks. Add in another $150 for bushings and mounts and I should be good. Once I add some serious meats if I am still unhappy with the rear end I can upgrade as I won't really be re-doing much.

shouldn't be that hard to make it fit.. the frames are the same width from 1960 to 87.. i would not use the stock panahrd bar, tho, since it only goes to the center section of the differential.

axle mounts are easy... panhard bar mounts are easy... front crossmember should be an almost bolt in deal.. no need for a 2 piece driveshaft.. might be a worthwhile upgrade to call LMC truck and get their adjustable front mounting crossmember for lowered trucks instead of using the stock one since it not only allows you several mounting options but also has holes in it already for the exhaust system to pass thru instead of running it under. might want to also look at coilover shocks instead of the stock springs to make installation and adjusting easier.

3 link and coil overs for the rear.

There are OEM heavy duty suspension that does not use rubber bushings. Quick steering might be difficult. Dropped spindles and probably long upper balljoints. Fat OEM sway bars.

bentwrench wrote: Quick steering might be difficult.

Does that Grand Cherokee fast ratio steering box that all the GM muscle car guys like not work here?

BrokenYugo wrote:

bentwrench wrote: Quick steering might be difficult.

Does that Grand Cherokee fast ratio steering box that all the GM muscle car guys like not work here?

I see no reason it wouldn't work. Might need a different rag joint or other minor stuff, but it should be usable.

bentwrench wrote: 3 link and coil overs for the rear.

Why a 3 link and not a 4 link? If it'll fit, a triangulated 4 link would be better than a 3 link + panhard IMO.

I'll second a triangulated 4-link and coilovers on the rear.

Much rather have truck arms than a 4 link.

Nick (Bo) Comstock wrote: Much rather have truck arms than a 4 link.

Any reason why?

rslifkin wrote:

bentwrench wrote: 3 link and coil overs for the rear.

Why a 3 link and not a 4 link? If it'll fit, a triangulated 4 link would be better than a 3 link + panhard IMO.

3 link articulates better and is easier to adjust the instant center

An adjustable watts link instead of a panhard because you are going to turn both ways and the ability to change the rear roll center is bad ass.

Watts link is a good solution instead of a tri-4.

However, a 4 link articulates fine if it's built right. And built right means flex joints and not bushings. Rubber bushings are too squishy and let things move in ways they shouldn't. Poly bushings aren't flexible enough in the directions they need to be, so the thing binds. Flex joints are stiff along the length of the arms but move freely in other directions to let the suspension work.

The limits of a 4 link before binding becomes a real concern with decent geometry won't happen until there's far more travel involved than a race truck is going to need.

Now if we want to talk about binding, there's always radius arms... Nothing like trying to twist the axle when the suspension flexes!

I don't know how to square "a 4 link articulates fine if it's built right" against "Poly bushings aren't flexible enough in the directions they need to be, so the thing binds".

Seems like the only way to reduce bind on a triangulated four-link is to make the arms long and keep rubber or something like that in the ends. Don't know what these flex joints are that you're talking about.

Three link or torque arm (which is really just another three link) seems cool to me, a guy that don't really do anything with suspension, so grain of salt with everything above.

In reply to pres589:

Use heim or rose joints instead of rubber or polyurethane and the flexibilty will be better with the downside being the maintenance will be higher as heim joints wear out quickly on the street.

pres589 wrote: I don't know how to square "a 4 link articulates fine if it's built right" against "Poly bushings aren't flexible enough in the directions they need to be, so the thing binds". Seems like the only way to reduce bind on a triangulated four-link is to make the arms long and keep rubber or something like that in the ends. Don't know what these flex joints are that you're talking about. Three link or torque arm (which is really just another three link) seems cool to me, a guy that don't really do anything with suspension, so grain of salt with everything above.

The flex joints are a type of enclosed spherical bearing. Here's an example:

http://www.4wheelparts.com/Fabrication-Tools/Currie-2-5-Inch-Johnny-Joint-CE-9110.aspx?t_c=86&t_s=528&t_pt=101460&t_pn=CURCE-9110

Triangulated four-links work best if all the linkages can move freely on multiple axes vs. most suspension systems where it's rare for any part to have to move on more than one axis. Rubber does this but it allows a lot of unwanted squish and wears out quickly, and poly doesn't want to flex much at all. So basically, you want a spherical bearing in this kind of suspension and anything else is going to be a compromise.

I wouldn't swap a triangulated fourlink into anything. Having run truck arms, three links and four links in a number of stockcars, if I were starting from scratch I'd go with a three link. It gives you the most adjustiblity and is lighter than a truck arm set up. The downsides are that it will need more fabrication and can eat bed space if you planed on keeping the bed useable. You can get caught up constantly searching for a perfect setup and in the process bypass very good ones and eventually make things worse. Truck arms will almost always work very well with a minimum of tinkering and remain consistent over the course of an event which granted isn't much of a concern in an autocross but it's one less thing to chase. They will also obviously fit below the bed. A triangulated fourlink lives in a state of bind in order to eliminate the centering link. It's a big compromise that you can live with if you have to but there's no reason to purposely install it. Instead of a true three link a Camaro style torque arm might be a good choice as well to keep fabrication simple but I don't have much experience with them and couldn't tell you how it would differ from either truck arms or a traditional three link.

BTW, here's a pretty good compromise, an hourglass-shaped rubber bushing clamped inside a torus. Still has some squish but it offers equal resistance to vertical and horizontal movement, which is better than any cylindrical bushing. Used on many Land Rovers including the Defender:

Wall-e wrote: I wouldn't swap a triangulated fourlink into anything.

Triangulated 4-links are the best suspension system for offroading with solid axles.