Mixing aftermarket upper & lower control arms

[ed1le]

I recently picked up a set of used Global West uppers. I was considering possibly running SPC lowers control arms b/c they also lower the car 1". Car currently has Eibach springs and thought this combo would allow me to achieve the desired ride height w/out throwing things off by using dropped spindles. Is there any reason I wouldn't be able to use the Global uppers with the SPC lowers?

[claytonisbob]

I've been very happy with the quality of the SPC lowers and delrin bushings they came with. I also used the shims with SPC springs to get the ride height where I wanted it. It worked really well.

[JRouche]

I dont see any reason why you cant mix and match. The key is the matching part. Not that you are, but say a guy was thinking of using really long lower arms with a stock type upper then yes, problems. But if you are using arms that are made for your car the make of the arm should not matter. Im sure GW might have something to add. Like if you use their lower arm it is better for this or that. Or they might even say they have a lowwer arm that will do what the SPC arm does.

But really, the SPC products are pretty nice, so is the GW stuff. I dont see any issues with mixing manufactures. I have SPC uppers and TCI lowers. I didnt have to modify the SPC arms at all. I did beef up the TCI arms though to deal with the other suspension mods. JR

[monteboy84]

Just be careful, I believe GW adds caster in their lowers, whereas Savitske adds it in the SPC uppers he specs, so using them together could put you overboard on caster. Just check to make sure you're not shooting yourself in the foot.

-matt

[ed1le]

Just be careful, I believe GW adds caster in their lowers, whereas Savitske adds it in the SPC uppers he specs, so using them together could put you overboard on caster. Just check to make sure you're not shooting yourself in the foot.

-matt

That's the opposite of what I'm looking to do though...I have GW uppers and looking at SPC lowers.

[6spdcamaro]

The spc lowers add caster also. It just gives you more tire clearance.

[JRouche]

And some added camber gain in the turns, which I see as a plus. Too much camber dialed in with the uppers give you straight line camber also, tire wear and other issues. Camber gain induced with large caster numbers only comes into play on the turns. And thats where we want more camber. One of those suspension adjustments that happen to give more than take. Im a BIG fan of large caster numbers. To a point yes. But heavy caster numbers are usually harder to get with most simple aftermarket upgrades.

But... Too much caster? Im not sure where that is. Ive read some papers where guys were using 6+ numbers. I have 5* of caster and a manual rack and pinion steering system. The steering at speed is not overly heavy. Actually very nice. The wide front tires track great, even over some really heavily grooved freeway surfaces. Where some of my other cars, on the same stretch of road want to wander about gripping the lines in the road.

Large caster numbers seem to be ok. I have yet to see any writings where there was too large of a caster. And I looked and looked so I could set up my front end. Because I can bump the caster up to just short of 7*. That seemed really large compared to what the OEM specs said to set it for.

I mostly saw some thoughts on how it could make the steering heavy. But I haven't experienced any of that even with manual steering. Ok, maybe on slow right angle turns. Say taking a right or left turn from one road to another at 15mph or whatever the normal speed would be. It is a lil heavy then.

But say on a 35mph sweeping turn (where 35 is fast for the turn) its not heavy, just positive. Where I steer she goes. Same with a 50mph sweeping turn. It will feel a lil heavy on a switchback. Say going from 50 to 20. But I expect the car to feel a lil heavy and not too light going through the turns. And Im not talking about the way the car actually feels. The car can still be light and over steering in a way. But the steering wheel will have some weight to it. Which is fine for me. I drive better with a heavier feeling steering wheel and a loose car. The heaviness of the steering gives me more feel for the road and control when I have my car set up loose.

Hard to explain. But for me Id rather have a heavy steering feel with a loose (fast) suspension than a light steering input and a loose car. Thats just double trouble. A twitchy loose (light) steering along with a loose suspension. For me thats my car in the weeds or a curb if there is one. Before that (loose and loose) Id choose for a loose steering and tight (under steering) car. And many do. It makes for some fast speeds and keeps you off the curbs or ditches.

IMO. Crank up the caster!! Give it the max till you run out of fender to contain the wheel or you run into other problems which Id love to hear about. JR

[monteboy84]

IMO. Crank up the caster!! Give it the max till you run out of fender to contain the wheel or you run into other problems which Id love to hear about. JR

Right, I agree. It's just my original thought was if the lowers add 4 degrees, and the uppers add 4 degrees, he may end up with 9 degrees of caster, which I do think may be too much. It's possible to have too much camber to where the contact patch isn't working perfectly, so I'm guessing that's the issue with too much caster, it'd add too much dynamic camber in turns. But, I'm just speculating too so it'd be good to hear from the experts.

-matt

[61ragtop]

I know that for the GW arms (for my impala anyway, not sure for your car) they told me they add 5.5* caster to the uppers as well as adjust the BJ location to help out the camber on turns, they said how ever that the lowers are stock geometry.

I would suggest calling what ever manufacturers you want to use and just ask what improvements they have made to each piece you want to use from them. Then if it all ads up to what you need you are good to go, if not well i guess keep looking.

[monteboy84]

61ragtop is right, they both add caster in the uppers, sorry for the misinformation, I must have misread about adding caster with lowers somewhere check here:
http://www.globalwest.net/64-77buick-control-arms.html

-matt

[JRouche]

Right, I agree. It's just my original thought was if the lowers add 4 degrees, and the uppers add 4 degrees, he may end up with 9 degrees of caster, which I do think may be too much. It's possible to have too much camber to where the contact patch isn't working perfectly, so I'm guessing that's the issue with too much caster, it'd add too much dynamic camber in turns. But, I'm just speculating too so it'd be good to hear from the experts.

-matt

Good thinking!! But the camber gain from even 9* of caster wont be too much. Ive measured my suspension for many suspension adjustments and found out the camber gain with a massive 9* of caster doesnt give me much more than 1* of camber change for the entire compression cycle (I measured the diff from 5* of caster to 9* of caster and the camber gain wasnt that much, ,thats why I settled for 5*).

Thats not a big tilt over of the tire. And 1* of camber gain in a turn is usually very helpful for most cars, specially our really old cars that dont have a great camber profile anyway.

But good point.. JR

[monteboy84]

Good thinking!! But the camber gain from even 9* of caster wont be too much. Ive measured my suspension for many suspension adjustments and found out the camber gain with a massive 9* of caster doesnt give me much more than 1* of camber change for the entire compression cycle (I measured the diff from 5* of caster to 9* of caster and the camber gain wasnt that much, ,thats why I settled for 5*).

Hmm, good point there, I've never run the numbers, but that's really not bad. I suppose if a guy has a beefy enough power steering system it wouldn't be a problem.

-matt

[DarkoNova]

6 or 7º isn't much. Most newer cars run upwards of 10º. IIRC, my old BMW had 11º of caster. Granted, we're talking old control arm suspension vs macpherson-strut suspension, I still prefer to run as much caster as I can get.

[Rick Dorion]

My GW uppers added about 7* caster. I backed it down to 5.5* but ran out of space for shims on the rear bolt. With 5.5 I get a slight rub on the inner fender when turning.