How much to cut cups?

[Frizzle Fry]

If you make them too short the bag will rub on the arm. The spring pockets are too small.

[justpball]

someone said you could trim the pocket out is that true?

[Frizzle Fry]

Originally Posted by justpball

someone said you could trim the pocket out is that true?

Here you go

[ob1monkey]

I'm not running a cup on my 66. 2 1/2 inch spindles, firestone 2600 bags and no cup will lay the crossmember in the front aired out, runs 85 psi for ride height. kinda stiff but better than what the po had he was running 2500's up front with 2 inch cups had to run 105 to air it up and drove like s**t. I have been running this setup for just over three years with no signs of wear on the bags daily driven 90% of the three years. I was considering adding a 1 inch cup to reduce the pressure, but worry that I will then need a sway bar to keep it level in the turns.

[kev2809]

so u run the bottom of the bag with no cup?

[ob1monkey]

yep I use a large washer and bolt it to the control arm right in the spring pocket.

[kev2809]

and the arm doesn't rub on the bag? do u have any pics

[ob1monkey]

I will try to get some this afternoon. It rubs, but I have inspected the bag and it's just like a hand print no scartches or frayed rubber, the inner side of the bag just looks cleaner than the outter side. The arm is smooth where the bag contacts it and it only touches when aired out. Pics will help explain. Hope it isn't raining when I get home so I can get pics

[N2TRUX]

If it rubs, it will fail. It may take a long time, but it will fail.

[ob1monkey]

no arguments there. Maybe we should justify what rubbing consits of, When I say mine rubs it's more like touches there is no acctual rubing going on. When the bag is inflated it touches nothing and is mounted in a staitionary position with the arm when the bag in empty it rests on the cotrol arm and is not being moved because the truck is on the ground the only motion that runs throught the control arm is up and down.think of it as a beer belly when someone with a beer belly sits down it does not rub his legs as he sits just rests on top after he sits once he stands it no longer resides on his lap is suspended above his legs. NOT trying to start contriversy here. I am just running off my experiences and what I see with my setup.. I f you measure the bag and the open space in the arm you will see the are almost perfect the lowe below curves just right to sit in it resting against the arm when deflated. not really rubbing just resting. when a bag is inflated it gets taller and slightly skinier. giving the beathing room to now rub in the process of inflationor deflation. Once again I am not an expert. I did spend plenty of time under my truck installing these bag making sure they were not in harms way. I have clocks over 100,000 miles with them in over the last 3 years including multiple trips out of state. If I removed and washed them nobody that saw them would be able to tell that the were touching the arm.

[ob1monkey]

[AirMale]

good pics. thanks for posting.

[kev2809]

got any pics of the truck layed out with that setup? so the bag is "touching" the tie rod?

[ob1monkey]

I will move it to the drive tomorrow and take some aired out pics. the tie rod is much further away than it seems just an illusion making it look so close. only thing I need to get to purchasing and changing is upper plates for safety. would get them tonight but light is gone.

[smashingchuck]

I know that you already mentioned getting upper plates, but man does that look unsafe. It also appears to be rubbing pretty hard on the top, is that because that small peice of steel is bending?

[ob1monkey]

that setup has worked good but I should have used plates and will be getting some soon. I always felt that it was the weakest link. yeah can see the wear from my home made brackets. going to use these bags on my 60 impala once I can aford a new set for the truck with plates.

[smashingchuck]

The plates are really easy to make. You can use 3/8 steel and trace the shape of the crossmember... bolt them in and you're good to go.

[N2TRUX]

My point was this. There might be many things that work, and have worked for a while, but that doesn't make them correct.

In my mind, there are certain things you can cheese out on, but brakes and suspension is not one that I would consider taking short cuts on.

A good example is heating coil springs. We all know it can be done, and many have done it and never had a spring collapse or fail.

Regardless of how long your set up has worked for you, that is not a good choice, so I will never recommend it, especially to someone that doesn't know better.

[ob1monkey]

I completely agree. I just see alot of bad press on not using cups, and since my situation has worked for me I thought I would share. By no means run them the way I do unless you are will ing to check them alot for wear. I checked them almost daily for the first three weeks then weekly for a few months after, now I know there not in any immediate danger but anything could happen.

As for making the plates, I didn't realy have the time between the 66 and my wifes 73 nova she was daily driving most was spent keeping them going and dependable. now that they are not driving as much the short comings are going to get fixed.

[N2TRUX]

Plates can be bought so cheap, it's almost not worth making them unless you have the materials on hand.

Several forum vendors sell them.

[ob1monkey]

I should just by them, my problem is trying to support 4 projects at once, 66 c10, 60 impala, 63 nova wagon, 73 nova coupe. I try to make the pats or salvage from donors over cost which ever choice is cheaper without compromising safety when possible. Do you think I may benifit from the reduced bag pressure with bottom plates also? I think they would be about the same as ! inch cups.

[N2TRUX]

Focus dude. Too many projects usually end in lots of unfinished business. Don't let things distract you.....ooh, shiney object...uh what were we talking about?

Maybe some of the experts that do tons of installs will chime in here. If you look back in this thread, I asked the question of "Why cut your cups?". Not to be sarcastic, I just don't see the advantage.

The response was to allow you to go lower, which I disagree with in theory. On my old 82 Blazer with stock ART cups which I think are 1.5" and a 28" tall tire I could lay the A-arms on the ground. You can not get any lower with out crossmember mods or replacement. The ground is the ground, period.

Ok, so maybe cutting the cups allows more air pressure at lower heights so you can cruise lower. I still don't see that as a good choice as it will demand higher bag pressure at a "reasonable" ride height.

I must be missing something, cause it sure is popular.

[kev2809]

im not tryin to but in between you guys here, but you said your cups were 1.5" on your blazer. the suicidedoors cups come in like 2"+. so if we cut them down to 1.25" or 1.5", its the same right?. i havent done it yet to my cups because im not focused on suspension just yet, but a lot of guys here say cut down cups = a lower drop. not tryin to step on your toes here lol. just tryin to figure out what will go lower and still be "the right way"...

[AirMale]

My original question was never definitively answered. I bought plates/cups from S.D. many years ago and never got around to installing them. The cups are well over 2" tall and that seems way too high for 73-87 arms. I hoped to get some advice on bag pressure/ride charateristics with cup heights. I understand people who try different things to get the desired drop. I admire those who have engineered some very unique ways to drop these trucks. With all of the bagged 73-87's on here I'm amazed at the lack of info on this topic.

[N2TRUX]

No prob kev2. This is an open forum, feel free to interject. I don't know for sure that the ART cups are 1.5", but I "think" they are. Look below and see what you think.