Let's beat shock mounting to death some more!

[GRINCH]

I am still playing around with different ideas on where to mount my shocks on my 72.

Ideally you want the shocks as close to the tire as possible. Center line of the tire would be the best. But we know that is not going to happen. Also the more straight up and down the shock is the better it's dampening effect will be. Some say that you should also angle the shock 2 degrees for every 1 inch of lift. The angle should also be parallel with the shackle. Although this is debatable.

Now we know the ground rules lets mess them up by actually trying to mount them on our blazers.

First and most ideal option. For shock function that is.

There is some room depending on the offset of your rim to mount them between the tire and the leaf spring. Problem is the frame is 6" away at the top of the shock. You would need to make some type of bracket to extend the mount from the side of the frame outward. This would need to be well braced to the frame.

Second option

Mount them on top of the spring pad. Dan at Roughstuff makes mounting hardware for this. This option has 2 problems. The first obvious problem is shock length. With a 4" lift. (either shackle flip, block or spring) there is only about 16" total for shock length. It will be very hard to find any shock that will allow you to have 3-4" of up travel (Most blocks or shackle flips will be less) and 5-6" off droop. Remember you do not want to angle the shock. Second problem again is the distance to the frame rail. A lot less this time but still will require a mount to be built.

Third option.

Mount them on the inboard side of the springs. This option puts the shocks back to the stock location. What's wrong with this, GM did it right! Well the shocks are actually closer to the center of the axle than they are to the tire. The forward angle of the shock is to far forward.

Discuss

 

[bigblock72]

The general rule of thumb for the most effective dampening is to mount the shocks perpendicular to the axle housing and perpendicular to the leaf spring (imaginary line drawn between spring eyes) or control/radius arm at FULL compression. It's also best to have the shock mounted as close to the wheel as possible for better roll/sway resistance.

In the real world on a trail/street type of rig building effective and strong mounts is probably more important than having the shocks in the most "ideal" mounting location. For most of us there is a limited amount of space to actually put a shock that has the needed length to do what we need. So as long as the shocks are pretty close to vertical (within 10 degrees or so) they'll work just fine.

That just leaves the mounts. The general rule of thumb I use on shock mounts is to make them strong enough to mount a leaf spring to and they'll be just about strong enough. Most of us don't realize that a fairly stiff shock will transfer and hold thousands of pounds of pressure through it's mounts and can easily bend and break even the stoutest looking brackets clean off of a frame or housing. Even if the mounts don't break the flex is preventing the shocks from doing an effective job of dampening the spring. Mix that with the funky and long brackets that get used (ford shock brackets are a prime example) to mount the requisite long shocks we all use and it's easy to see what kind of problems we create for ourselves.

If you have to mount the shocks fairly high above the frame then you'll have build some hoops that attach to the frame in several locations. It is also a good idea to either connect the shock hoops together (hoop over motor) or place at least two attaching points on the shock hoops right by the engine crossmember (or other strong crossmember) to minimize frame rail twist. The farther the mounting point is from the frame the more leverage there is to twist the frame rail and the stronger your triangulation has to be. Again don't underestimate the amount of stress on a shock mount because you will have a pile of broken stuff if you do.

Bottom line is spend more time figuring out how to get those shocks mounted effectively even it means slightly compromising shock mounting angle.

 

[sponsoredbydad]

I need this thread to survive. I know just about enough to f-up my truck real good at this point. First off MAYBE my eyes were bigger than my stomach and I jumped the gun on purchasing shocks for my Blazer(69) way early in the build and now I want to make then work rather than sell them and lose 1/2 of my hard earned money. I have a 4" shackle flip lift with zero rates in the back and springs in the front. Did I get too long of a shock (14") for that little of a lift? Seems to me I did but I'm gonna fab till they fit. Has anyone used the original mounts on the rear axle and punched threw the floor straight up behind the rear bench with a hoop. If so who has a picture.

 

[Greg72]

SBD, install those shocks to allow for whatever uptravel your rear leaves give you and let the rest of that travel go to the droop side.

You'll end up cutting the floor or wheetubs, but if you're willing to build a tubular mount anyway it won't make a difference if the upper mount is a few inches higher than it should have been with a 12" travel shock.

The closer you can mount the shocks to the back of the brakes, the more likely it is that you can come through the wheeltubs and possibly tie the shock mount to the rollcage in that area. That would be a lot less intrusive than having to build a shock mounting structure in the center of the rear bed area.

 

[Smokinthehippies]

So now from what I've read. It sounds like you wan the shocks to be as far out towards tire as possible. Then how do the inboarding kits for the rear work or improve things? Wouldn't that make it worse?
Sorry to hijack. Just tryingto get my head around this suspsension design.
Thx

 

[Greg72]

Inboarding shocks is a lousy solution.... but as you've noticed, it doesn't stop people from doing it.

The effective angle is bad for damping and the shaft speed becomes too slow to really do much for you. I guess some people want to be able to brag about having long travel shocks even if they aren't doing anything useful.

You are right, the most effective shock is the one that is closest to the wheel/tire and the most vertical to the wheel travel.

 

[Smokinthehippies]

Inboarding shocks is a lousy solution.... but as you've noticed, it doesn't stop people from doing it.

The effective angle is bad for damping and the shaft speed becomes too slow to really do much for you. I guess some people want to be able to brag about having long travel shocks even if they aren't doing anything useful.

You are right, the most effective shock is the one that is closest to the wheel/tire and the most vertical to the wheel travel.

Wow. I'm glad I asked that thanks for the info. I'm suprised soo many people do that without learning bout it first.

Jack off.

 

[Greg72]

who are you callin' jack off?

 

[Smokinthehippies]

who are you callin' jack off?

I spose that should have said hi, jack off. Nope that's not right either. What would be the ideal, practical way to do it then? Just build some hoop mounts that are tied into the cage??

 

[Greg72]

Ideally, you need to know how much travel you REALLY have out back. Flex it on a RTI ramp and get some measurements to know for sure. Uptravel is a function of the leafspring you use and how far it will go before it's completely flat and the shackle is maxed out. It may only be 4", and maybe not even that much...

After that you need to select a shock that gives you the enough travel to match what the truck is capable of. Set the shock so that the shaft is extended the same as your uptravel amount, then measure between the eyelets. THAT'S the number you need to fit....somehow. You can usually fudge a few inches up or down on the axletube by playing around with the mount position, but whatever height is left needs to attach to the upper mount. You may get lucky and fit it on a frame-mounted bracket, or you may need to cut a through-hole and build a strong mount that ties to the rollcage. It really depends on the specific application and existing suspension you've got.



-Jackoff

 

[sponsoredbydad]

Could a floor jack under the rear tire suffice as a RTI ramp, and then am I looking for the point where the front tire on the same side just leaves the ground as a maxed out point . Per Say.

 

[Greg72]

If you have a jack that goes that high.....

Remember the action of jacking one side is going to compress the other side too, so even if you're only expecting 4" of uptravel you'll need a lot more than the typical jack to max out the suspension. I've seen guys use a cherry picker to do it, but I'd worry about it slipping and crunching into the rear qtr panel.

Just find a loading ramp if you can. They always have those great tapered concrete walls you can back onto.


-Jack

 

[GRINCH]

I Uptravel is a function of the leafspring you use and how far it will go before it's completely flat and the shackle is maxed out. It may only be 4", and maybe not even that much...

The easiest way to figure your up travel is to use a string or a straight edge from the eye bolts on each end of the spring, then measure the distance in the center from the line to the top of the leaf. This usually gets you pretty close.

 

[Smokinthehippies]

If you have a jack that goes that high.....

Remember the action of jacking one side is going to compress the other side too, so even if you're only expecting 4" of uptravel you'll need a lot more than the typical jack to max out the suspension. I've seen guys use a cherry picker to do it, but I'd worry about it slipping and crunching into the rear qtr panel.

Just find a loading ramp if you can. They always have those great tapered concrete walls you can back onto.


-Jack

What about using a forklift? I have Access to one of those at work.

 

[mnstrburbon]

yes a fork lift will work.

I used an engine hoist and a big ratchet strap to help compress the spring to measure up travel all i had at the time and not ideal.

I did a bed cage in my sub i set it up to almost bottom shock out at fool compression or up travel and let the rest droop i think it was 6" up and 9" down at ride height. i Have bottomed the shocks out so bumps are in order and i want to lower the bottom shock mount to gain more up travel. I think i could use a little more shock, i got 14' travel fox's 18 would be a better set up. I also mounted the shock on top of the spring pack about as close to the wheel as you can get.
I am going to get 18" travel F.O.A for the front and maybe change shock shaft's in the rear for 18" travel as the body's are the same for a 14" and 18".

 

[Recon!]

The easiest way to figure your up travel is to use a string or a straight edge from the eye bolts on each end of the spring, then measure the distance in the center from the line to the top of the leaf. This usually gets you pretty close.

You confused me in a bad way

 

[GRINCH]

It is the distace your spring will compress before going to a negative arch. See pic below.

View attachment spring.bmp

 

[Recon!]

with the picture I could totally understand it, I don't know why it wasn't clear before

 

[GRINCH]

They say pictures are worth a thousand words!!

You will also gain a little more up travel as your shackle rotates back. Not much tough.

 

[hvy chevy]

Good info...any pics?