Ridetech Arms, Dropped Spindles, and 15" Wheels
 

I know that factory lower control arms interfere with 15" wheels when running a drop spindle. Does anyone know if running Ridetech tubular lower control arms will give enough clearance for 15s with a 2.5" drop spindle?

Re: Ridetech Arms, Dropped Spindles, and 15" Wheels
 

Unfortunately it's not that simple of a question. Wheel offset also plays a part in whether your combination will work. You can have interference between the wheel and the tie rod.
I replaced my factory lower control arms with reproduction ones and I had to grind them so the brake rotors didn't rub. So mixing aftermarket parts causes more problems. What brand spindles? Some of the cheaper ones are not always the drop they are advertised to be. Found that out on a Firebird some years ago. One side was 2 inches and the other side was 1 5/8" needless to say it took us a bunch of messing around to figure out why the car didn't sit level.
Manufacturing inconsistencies will mean that what worked on my truck may not work on your truck.
What does RideTech say?
Can you post the wheel sizes and who's spindles you have?

Re: Ridetech Arms, Dropped Spindles, and 15" Wheels
 

Also, I wouldn't say it's a dire situation either. A little time with a grinder will fix the issue. I'm running 2.5" spindles from McGaughy's with 15" rallies and that's all I had to do for my factory arms. Unless you're putting together a concourse truck, likely no one will notice.

Re: Ridetech Arms, Dropped Spindles, and 15" Wheels
 

275/60R15 with 0 offset on 15x8.5 is what I always thought, but measurements look more like 15x10 (still on truck at the moment)

Looking to buy Ridetech coilover kits with upper and lower tubular arms and CPP spindles.

Re: Ridetech Arms, Dropped Spindles, and 15" Wheels
 

I had ECE 2 1/2 spindles with 15x8 rallies up front. The only problem I had was caliper clearance. Then I found some 15x8 with 4 1/2 backspace, they also mentioned they were for disc brakes. They worked perfect. Trying to remember where I bought them, it was on line
Any way I went with QA1 coil overs. Long story short I went with 20s for better clearance

Re: Ridetech Arms, Dropped Spindles, and 15" Wheels
 

I will probably go 20s in the future but I thinking about trying to take a multi-step approach so I'm not changing everything all at once. I may be lost, but the clapper clearance changes with drop spindles? The truck already has factory discs and the wheels in question on factory spindles.

Re: Ridetech Arms, Dropped Spindles, and 15" Wheels
 

i'm running drop spindles factory arms and have had zero interference.

Wheel vintiques 62 series. 8" front 10" rear.

Re: Ridetech Arms, Dropped Spindles, and 15" Wheels
 

Caliper clearance changes w/the caliper used. Light Duty spindles vs HD spindles use different calipers & rotors. This is a common watch-out when purchasing aftermarket spindles. If the spindle is based off of the 73-87 year models, clarification of which spindle is required. CPP would likely state what specific app the spindle is for so you know what brakes they'll use.

Beyond that, backspacing of the front wheels is probably the No.1 issue for contact related problems. Your stated 15x8.5" w/) offset is roughly 4.75"BS which is crowding the a-arm @ only 15" OD & I would bet comes close or contacts the outer tie-rod end.

Larger OD wheels can pull that width/offset off because things will fit within the barrel better. Tubular arms can yield more clearance near the BJ pocket depending on how it's made (shaped). Better quality arms are usually clearanced by the manufacturer.

Re: Ridetech Arms, Dropped Spindles, and 15" Wheels
 

If you need to do things in stages, try starting w/8" or 7" front wheels that will require less back-space to fit under the wheel arch.