Dropped front end question

[PRattenbury]

So, I put together my front suspension using DJM tubular drop arms (3"), and 2" drop springs. At the end, I have no room to install the sway bar bushings to the LCAs, and have about an inch between the bump stops and the crossmember. I have a feeling I'm not the only person that's run into these issues. I'm wondering if just that little bit of clearance from the bump stops is normal, and what can be done about the sway bar. Any thoughts???

[PRattenbury]

Early evening bump

[lolife99]

Got any pics?

[tubbedII]

Bump stops can probably just be removed, but the bigger concern is the scub line with that type of control arm while using a drop spring. I've always read it's something not to do, but never have seen pics of it.

[PRattenbury]

So being close to the bump stops like that is not a good thing. What if I put stock springs in instead of drop springs, and used drop spindles instead? Wouldnt I get my suspension travel back? Would that cause other awful problems?

[lolife99]

Your not suppose to use drop pocket a-arms with drop spindles.
You would have to swap back to a stock lower a-arm.

[PRattenbury]

So there is no way to have suspension travel in the front end if you lower it? I have drop springs, drop lower control arms, drop spindles. Is there any combination that will give me 5" of drop and still have more than an inch of clearance between the bump stops and the crossmember? Right now I have the 3" drop LCAs and 2" drop springs. Just seems like there is very little room for the suspension to compress in this configuration. Why can't drop spindles be used with drop arms and stock height springs? Seems like I'd be able to have travel in the springs then. What specific problem is caused? Just trying to learn here. I appreciate the info.

[tubbedII]

Drop spindles and drop springs is probably the best option. The bump stop moves up towards the xmbr with either the control arms or the springs, but the reason is mainly scrub line issues and the chance of scraping or even worse hanging up on something.

Either way with 5" of drop in the front, the bump stop becomes an issue. You'll have to either fab up one that's much shorter, don't run one at all or live with it (I don't recommend the last one).

[PRattenbury]

I agree, the amout of room between the bump stop and crossmember becomes less with drop springs and arms. Since I have both, I have very little room between, so my suspension will not be able to allow the chassis to move down much more than an inch. So the combination of drop arms and drop springs seems to be a bad idea. So my proposed solution is to put stock height springs back in, and gain 2 more inches of suspension travel. To get that amount of drop back, I was going to use the drop spindles. But I am reading this is a bad idea. It seems regardless of how I drop the truck 5 inches in the front the scrub line becomes a concern. I can roll or trim the fender lip to mitigate scrubbing. And I can limit the width of the front wheel, and play with backspacing to minimize that problem. But it will exist no matter which combination I use, correct? Are there other factors I'm not considering? I'd like to get 5" of drop in the front, have reasonable travel in the suspension, and naturally not scrub the tires in the fenders. Can I do it?

[lolife99]

The issue with drop pocket a-arms and drop spindles,... is that the bottom of the a-arm pocket is too close to the ground.
If you have a flat,... you will be skating down the road on that plate, making your front brakes (on that side) useless.
Use a drop spindle and a drop spring, and you will be fine.
I've been doing it for 30 years.

[lolife99]

Here's a good illustration of suspension scrubline.
Your drop pocket a-arm will hang below this "scrubline" if you add drop spindles to them.

[PRattenbury]

That is some awesome information, and a very good point. Thank you very much for that. I will definitely keep this in mind, because it certainly is an important bit of safety information. And I'm all about that.

[Robznob11]

in my opinion drop pocket control arms are a bad option all to geather. you cant really run them with spindles or drop springs because of the issue you have and the other issue he discribed. your best bet is springs and spindles. to me spindles is always the best option because it changes none of the travel of the suspension if you want to go lower deff springs is the next best option. our trucks have control arms that sit low and cause interferance with the ground any how why drop the bottom down and make that worse. if you want to go lower than that body drop it. it is easy and cheap I did mine in the garage lost 1 3/4 in in the cab floor just across the frame but the bed was just a matter of flipping the wood and brackets over and zd the frame between the core support and steering box no biggie. drop you cab mounts down on the frame wahlaa! 3" body drop

[PRattenbury]

Could the scrub line not be overcome by using a lower profile tire? Like instead of running a 237/75R15, go to a 245/35R20?

[tubbedII]

Originally Posted by PRattenbury

Could the scrub line not be overcome by using a lower profile tire? Like instead of running a 237/75R15, go to a 245/35R20?

Yes it could. However, when a part of the suspension hangs too low, there's still a possibility of it catching something at speed. There's a few horror threads/pics of totaled cars/trucks due to control arms being too low and catching something. The design of the drop arm itself just increases this risk given its already the lowest part of these trucks. One of the other reasons spindles/springs is a more popular combo for dropping.

[lolife99]

The size of the tire still doesn't matter if you have a flat.
You might overcome the scrubline issue with a bigger diameter wheel.
My opinion,... drop pocket a-arms like DJM drop a-arms,... should not be used.
They are old technology.
There are much better options now.

[kieth]

Not trying to argue just to understand, why don't you add airbags to the front with the drop spindles and pocket A arms ? You could cruise down the road with the bags aired up so the front end is fairly normal, then let it down when sitting still ? would that work ?



how low would it go with bags and spindles ?

[PRattenbury]

Good question! Could it be done??? I have spindles already.

[tubbedII]

Keith is right, but the only reason I said yes is because the example sizes went from a 15" wheel to a 20" wheel.

To the other kieth, I don't think you could even install an airbag onto the drop'd lca without some type of lower cup which would lose some if not all drop and defeat the purpose. Even if you could, I can't see the scrub line changing much from either full lift/full dump.

With just bags and spindles it would be as low as my avatar, I just have bags and spindles. Tire height plays a big part in how low it actually gets...