Front upper control arms
08-29-13, 04:04 PM
#26
Have you modeled the roll center correction from moving the upper ball joint with the FD's geometry?
I just sketched out moving the upper versus lower ball joint for R.C.C. and it looked like you get about half the correction using the upper ball joint instead of the lower?
Maybe my sketches proportions were too far off the FDs actual dimensions?
I just sketched out moving the upper versus lower ball joint for R.C.C. and it looked like you get about half the correction using the upper ball joint instead of the lower?
Maybe my sketches proportions were too far off the FDs actual dimensions?
09-01-13, 10:59 PM
#27
Have you modeled the roll center correction from moving the upper ball joint with the FD's geometry?
I just sketched out moving the upper versus lower ball joint for R.C.C. and it looked like you get about half the correction using the upper ball joint instead of the lower?
Maybe my sketches proportions were too far off the FDs actual dimensions?
I just sketched out moving the upper versus lower ball joint for R.C.C. and it looked like you get about half the correction using the upper ball joint instead of the lower?
Maybe my sketches proportions were too far off the FDs actual dimensions?
I have sketched out the Roll center corrections when I was building these for our race car (tomsn16).... I plan to put them into 3D CAD to get a better and more accurate definition of what is going on. This way I will be able to include spacers with the kit with a close indication of where the RC would be in relation of which spacer was used.
Please remember the purpose of the control arms are to have an adjustment for RCC unlike any on the market. So half is better than nothing. Also the rear mounting point is moved forward to gain space for bigger tires when you turn. This is an advantage of current upper A-arms on the market.
I am using a custom LCA out RCC stud which makes a great match to my uppers. I have replaced the stock Ball Joint with a spherical bearing which allows to fit a RCC stud to be fitted.
Also a quick note on the status:
I have had issues with getting the custom upper ball joint made locally for a decent price. Also I am working on a mass production fixture so I can cut the angles accurately to get better welds.
I am planning on getting back to this full bore after my return from the SCCA Nationals this week. Other project we are working on will be continuing like the 2-in one brace next build and the in process TNT. tomsn16 is keeping me very busy these days.
10-17-13, 11:00 AM
#31
Good question. This leads me into one of my dilemmas of making a custom ball joint. The actual part that will rotate would be an off the shelf spherical bearing "mono ball". The one I use on my race car is a high mis-alignment one which will be the exact same one in the kit. The part that will be the ball joint stud is the issue of replacement. Therefore I am going to propose the to group to use this type of bolt. I also use this same bolt on my race car currently and have been for three years.
AN bolts (my first choice)
https://www.pegasusautoracing.com/pr...p?Product=AN10
Mono ***** ( same as I use)
NHBB - ABYT Spherical Bearings
Hiems
NHBB - ARHT Rod Ends
I use all NHBB bearings but I might have a street option and a race option too.
The progress of the arms is as follows:
10/18: I will visit a fabricator to price out multiple pieces for the A arms. It takes me 2 hours to cut them at home. I will never finish at that rate.
11/15: Plan to have first set built.
CT
10-29-13, 12:28 PM
#34
Trying to follow the thread, pardon my reading comprehension:
What is being built here now? LCA's or UCA's?
For camber, you could rework either to get more, but it seems like the lower would be better from practical perspective—I'm imaging trying to actually get your hand(s) up into the upper to actually adjust/tighten while on the rack.
And, for roll center correction, correct me if I'm wrong, if you don't get the lower arm back to parallel (at least) with the ground, what you do (if anything) with the upper is that much harder.
Also, seems like the only way to match the correction at the rear, could be a new hub carrier or a new subframe pickup. Anyone working on a solution for the rear?
What is being built here now? LCA's or UCA's?
For camber, you could rework either to get more, but it seems like the lower would be better from practical perspective—I'm imaging trying to actually get your hand(s) up into the upper to actually adjust/tighten while on the rack.
And, for roll center correction, correct me if I'm wrong, if you don't get the lower arm back to parallel (at least) with the ground, what you do (if anything) with the upper is that much harder.
Also, seems like the only way to match the correction at the rear, could be a new hub carrier or a new subframe pickup. Anyone working on a solution for the rear?
11-19-13, 07:29 PM
#41
Trying to follow the thread, pardon my reading comprehension:
What is being built here now? LCA's or UCA's?
For camber, you could rework either to get more, but it seems like the lower would be better from practical perspective—I'm imaging trying to actually get your hand(s) up into the upper to actually adjust/tighten while on the rack.
And, for roll center correction, correct me if I'm wrong, if you don't get the lower arm back to parallel (at least) with the ground, what you do (if anything) with the upper is that much harder.
Also, seems like the only way to match the correction at the rear, could be a new hub carrier or a new subframe pickup. Anyone working on a solution for the rear?
What is being built here now? LCA's or UCA's?
For camber, you could rework either to get more, but it seems like the lower would be better from practical perspective—I'm imaging trying to actually get your hand(s) up into the upper to actually adjust/tighten while on the rack.
And, for roll center correction, correct me if I'm wrong, if you don't get the lower arm back to parallel (at least) with the ground, what you do (if anything) with the upper is that much harder.
Also, seems like the only way to match the correction at the rear, could be a new hub carrier or a new subframe pickup. Anyone working on a solution for the rear?
All very excellent points. i will try to answer them as best as I can.
1. With a shorter UCA the camber is still adjusted from the lower control arm bolts. You will just start from 1.5 degrees to 3 degrees. Also you can dial in the caster just a tad with the UCA adjustments. this gives you a little more freedom. Once they are set the arms will not need to be adjusted just adjust the lower just like stock.
2. The UCA I am offering has the ability to make RC adjustments unlike any on the market. You are correct this adjustment needs to be made at the hub height although if used with a LCA modification like I have both together will get you the same result as the so called drop spindle. My LCA's are level and with the adjustments on the UCA's I have adjusted them to were I want them. Also when you have the lowers level you can move the RC up or down by the UCA adjustments. You can not do that with the spindles.
3. The rear is a different animal. I do not have a solution other than Spindles. Please remember I am designing these for a purpose and I am following a rule set that does not allow suspension pick up points to be moved or modified. Also I am investigating drop spindles but the cost is very high. All of my parts on my race car are basically one offs and the cost is always a factor in making parts of that nature.
I hope this helps. very good questions.
01-19-14, 10:09 PM
#49
I appreciate everyone being patient, these are taking longer than expected.
Here is a picture of the A-arm. I did not press the front bearing in all the way, just sat it there for the pics.
