I changed mine to progressive springs on the front, a few months ago. The street driving is much more smooth and on the track (autocross) it seems to still do very well. I want to say it’s the same or better on the track as with the regular stock springs, but hard to tell. I know it didn’t hurt, that’s for sure.How many people are running progressive springs up front? Have you tried a linear spring on the front suspension?
I have but only in the front and on a crappy chip sealed road.has anyone else had wheel hop under hard braking?
This can cause the A-arm to want to deflect, one direction or the other when a load is applied at the spindle end due to it being under constant tension from being spread apart.Did your control arms bolt in nice & flush? I noticed that on mockup, my upper arm has about a 1/2”-3/4” gap from the pivot point at the heim joint that will take some torque to squeeze into place.
I have the same situation. By the time I get it all bolted flush to the frame the inner heim is cocked to the point where it contacts the washer. I added a single washer between the heim and the frame so that it doesn't have to stretch the control arm as far when tightening it down. It no longer rubs the washer but still looks less than ideal.Did your control arms bolt in nice & flush? I noticed that on mockup, my upper arm has about a 1/2”-3/4” gap from the pivot point at the heim joint that will take some torque to squeeze into place.
Do you have a pic of your shim setup?This can cause the A-arm to want to deflect, one direction or the other when a load is applied at the spindle end due to it being under constant tension from being spread apart.
I had shimmed the trailing end, chassis mount side of the A-arm to remove any pre-loaded tension to it.
Might be something else to look at.
Good point! Maybe my A arms are already sprung, and that makes them easier to twist. A few washers, then I can take it for a test drive and see if it fixes the issue.This can cause the A-arm to want to deflect, one direction or the other when a load is applied at the spindle end due to it being under constant tension from being spread apart.
I had shimmed the trailing end, chassis mount side of the A-arm to remove any pre-loaded tension to it.
Might be something else to look at.
Ross, I hate to ask, but is the front part of your frame tweaked from the off-road a while back? It might be difficult to make straightness and diagonal measurements on a fully assembled chassis, but it might be worth the piece of mind to to do these checks if possible, IMO. Having a tweaked frame that doesn't provide for a squared up and symmetric mounting points for the suspension could be a contributor to an oscillation. Weird things can happen from asymmetry within dynamic structures and you potentially have a prime example.Unfortunately my car is "special", so I agree, it is not a design issue. Anybody willing to put a camera on their front suspension, and do a hard brake? I would like to see a baseline of a Goblin's front suspension, and if your uprights appear to twist.
I see the uprights twisting before the tire starts hopping... I think. I mean it is suppose to twist when the suspension moves up and down, but I think I see it twisting from the brakes being applied. What do you guys see?
Today I shimmed the front A arms to remove tension in them, and checked the arms for any bends. The passenger side is not quite flat on the upper A arm, and I'm not sure if it is bent, or within normal tolerances, with a small twist before welding. The drivers side was flat, so I decided to video it instead.
Then I mounted 2 GoPros and went for a dusk test drive to capture video.
View attachment 22590
In watching your video it looks like it's the upper A-arm doing the moving. Like its winding up a spring and then releasing.Unfortunately my car is "special", so I agree, it is not a design issue. Anybody willing to put a camera on their front suspension, and do a hard brake? I would like to see a baseline of a Goblin's front suspension, and if your uprights appear to twist.
I see the uprights twisting before the tire starts hopping... I think. I mean it is suppose to twist when the suspension moves up and down, but I think I see it twisting from the brakes being applied. What do you guys see?
Today I shimmed the front A arms to remove tension in them, and checked the arms for any bends. The passenger side is not quite flat on the upper A arm, and I'm not sure if it is bent, or within normal tolerances, with a small twist before welding. The drivers side was flat, so I decided to video it instead.
Then I mounted 2 GoPros and went for a dusk test drive to capture video.
View attachment 22590