Just wondering if anyone has used the 1/2" taller Ball Joints offered by UMI Performance for GM A Body cars and can provide some feedback on the level of improvement they hopefully got. UMI indicates the 1/2" increase optimises the negative camber curve dramatically improving the geometry and ultimately the handling. It does lower the front of the car a 1/2" but that's a small price to pay for a vast improvement in steering. Appreciate feedback from anyone who has used these. Thanks.
​​​​​​https://www.umiperformance.com/home/...um-ball-joint/
https://www.umiperformance.com/home/...oint-1-2-tall/

 

I can't comment on improvement, but what about the UMI upper A arms with the 0.9" taller ball joint? That's what I am planning to do. I don't want to lower the ride height.

BTW, my son bought some rear suspension parts for his '68 Chevelle, found one of the parts to be incorrect. He said UMI customer service was excellent - they confirmed he got the wrong part, physically checked stock of the correct part and shipped it out same day.

 

Thanks for the feedback. I'm keeping the original A arms on my car for the original look but I'm happy to make small enhancements to improve the steering even just a little. Glad to hear that UMI gave a good customer service experience as not many businesses do these days.

 

I have ProForged (Chinese junk) tall ball joints in my 67. It has been the single biggest handling improvement I have done yet. I highly recommend it.

 

Thanks for the feedback, it's good to hear that there is a noticeable improvement, just sad that they're made in China

 

I know; it's pathetic. A bunch of companies make them. I was just too lazy/cheap to look, so self inflicted. Maybe check out some circle track supplier, like Howe?
If you're redoing the front, stay away from the CPP kit. The aluminum adjusters are garbage and the center link isn't quite right. Spohn Performance seems to carry some decent stuff. I like their steel adjuster sleeves.

 

If you only run the taller ball joint on the upper, you won't lower the car. I'm not sure the stock arms can take tall ball joints on both upper and lower without binding - definitely check into that before committing.

I'm running UMI arms with the .9 upper and .5 lower. I did a bunch of other things at the same time (rear arms, sway bars front and rear, shocks all around...), so I can't isolate just the increase in effective spindle height, but overall the difference in handling with this combo is absolutely massive compared to stock.

 

^^^^X2 I did this same modification on my ‘72 vert, completely changed ride handling.

 

You can get extended length studs from Howe - those are the parts that SC&C sold. Super nice stuff, just you have to do a bit of research to get the right parts and assemble correctly. I think their calendar has gotten better in the past few years and it's easier to map to stock applications. Their main business is sprint cars and similar.

Raising the upper ball joint improves the camber curve and that will improve many aspects of handling. It can be difficult to get a good alignment with stock arms and you can hit the edge of some rims.

Raising the lower ball joint further improves the camber curve (*) and it also changes the relation between the steering arms and the lower a-arm for the better, resulting in less bump steer. But the lower ball joint can get close to the edge of the wheel or, like in my case with the cheap Hotchkiss knock-offs, can force the lower a-arm into the disc brake. The tall lower stud is usually 1/2" extended, so it only drops the ride height 1/2". If you really wanted you could add a 1/4" spring spacer to lift it back up.

Adding a lot of caster - say 5 degrees - instead of the stock minimal caster will improve handling, but takes away the soft and floaty feel. It can also be hard to accomplish this with stock arms, especially if also doing the tall upper joints.

(*) Basically we want more distance between the upper and lower balljoint. That's why new car front spindles will have these giant swoopy lengths that actually wrap around the wheel and put the upper joint *above* the tire!

Mark's shop (SC&C) has closed, but his book is still a good reference - "How to make your muscle car handle"

 

So on the Howe website, it looks like they offer their 22303, which is a Moog K5108 replacement, and you can choose the stud with varied height. This looks like it could be the USA version of the proforged product. Are these appropriate for the street? Is my assessment correct?

 

I've been running mine on the street for >7 years. They are a rebuildable design, not like a normal balljoint. The cap is adjustable and removable so you have to adjust the lash on it.

 

I've installed the Howe balljoints on my car; +.9" taller upper and +.5" taller lower. The Howe part numbers are as follows: Upper housing - #22303, +.9" stud - #22389A; lower housing - #22495, +.5" stud #22483. Howe sells the studs separately so you can play with different combinations to see what works best without having to remove the ball joints from the arms. I couldn't find a vendor for these parts so I bought directly from the Howe website. I'm currently running stock lower arms and SPC uppers which allow for much more aggressive caster settings without huge shim packs. I can tell you from my mockups that a 14" rim might not allow this much added height on the upper ball joint. I did a mock up with 15" SSII rims and it just barely cleared the wheel lip but I had a 1/2" spacer between the upper control arm and the ball joint. You can checkout pics in my build thread see post #42 & #71.

https://classicoldsmobile.com/forums...e-57404/page2/

My caster is set to +5.5 degrees with -.5 degrees of camber. It looks like a f'n Mercedes-AMG with the wheels turned hard. I'd like a bit more caster but I'm getting close to rubbing the back side of the inner fender liners and I'm already rubbing the sway bar in full lock turns. I could get more caster with tubular lower arms (I'm running the stock lower arms) the more reputable manufacturers design their lower arms with 1-2 degrees of additional caster which would push the wheel forward in the opening giving me more clearance at the rear. I've read other project threads online and it's usually not possible to run the +.9 taller uppers with stock upper arms as the upper arms need to be shorter as the upper ball joint gets taller. If you decide to make these modifications, it goes without saying that you should cycle the suspension through the full range of motion and check for binding or interference. A binding ball joint could break and that would be a very bad day!

I plotted the camber curve of my set-up while moving the suspension through it's full range from full bump to full droop. I did this before installing the springs and made a good guess at the ride height starting position. I wish I had taken these same measurement with the stock arms & ball joints for comparison, but the stock parts were long gone by the time I was mocking up the SPC/Howe parts. The pro-touring guys seem to agree that 1 degree of camber gain per inch of travel in bump is the max needed for a street car. Here is my data, with a 1/2" ball joint spacer and without; I opted to go without the 1/2" spacer.



Rodney

 

wow those ball joints are not cheap

 

Looks like you pay basically twice what Proforged would cost but you're getting USA made and you can swap out the heights. There is some value for each of those features....