There actually was a note in the thread I based my spring swap on about using adjustable UCAs for camber control and the likelyhood of beating them against the shock towers. With that said, increasing preload gives the shock more space to travel. More travel means an increased ability to beat your shock tower with your UCA. Turning your damping stiffer and/or reducing your preload somewhat is the only way to combat that issue, short of raising the ride height. By reducing your preload and therefore shock travel, you'll have to find the line between banging the UCA or bottoming out the shock.
Interestingly enough the rear springs are shorter, by two inches I think. Or maybe just one... I can't remember now. I do remember they are shorter thou. I had at one point dug up a page on tein's site that gave a full component list of whatever kit you wanted... Can't seem to find that now. ?
Besides the difference in height, the front springs have a 65mm inside diameter, and the rears are 70mm. So moving the rear springs up front means I also moved the rear rubber isolators, plastic shims and rear springs perches to the front. 65mm is interchangable with a 2.5in spring, so the front hardware that was displaced moved to the rear and met HyperCo 2.5in ID, 275# 12" springs. Ended up with these because I'm frugal as hell, found these NIB for way less than brand new and I determined I could make 12" springs fit. The original goal was 2.5in ID, 250-275#, 10" from Tein, Eibach or HyperCo.
Here is the rear assembled but not preloaded:
All credit for the Flex Z surgery should be given to BROlando from (that other site). I took all his hard work and ideas (there is a ton) and just modified it to my liking. Shorter springs can definitely be used if you utilize his idea of polyurethane spacers.
Here is (most of) the link to his thread: https://a____z___.com/forums/1g-tsx-tires-wheels-suspension-130/my-tein-flex-z-experience-can-i-make-them-ride-nice-966137/ fill in the blanks. The second half of post #18 contains the info I used to do this, but post 1-19 contain a ton of info about the Flex Z.
Also, this was my favorite part of the whole thread:
View attachment 46972
Before this, I had grown to accept the way the car rode, but now I realize just how much I was accommodating the springs being too stiff. The best example I can think of is before changing the springs, I couldn't push the car hard through any turn I didn't know perfectly, or any turn I knew had any kind of bump in it. One unsettling bump while near the limit and the car would have skipped or maybe even slid. It wasn't as predictable as it should have been. Now, the ride is still firm, but it is also compliant. I am much more confident the suspension will keep my tires on the road at all times. I can still firm up 3-4 clicks in both front and back and be confident the car is sticking to the pavement. They're set where they are mostly for comfort, as I have a much smaller and more nimble secondary car I get my best driving joy from now. I couldn't even tell you what my damper settings are at the moment. I just do it by feel rather than counting clicks...
Yes, the thrust bearings pictured are the standard type. The bearing itself between two washers (I guess they're technically "races"). Since the F/R springs are two different IDs, two different sets are needed. I'll post that info shortly. They are worth every penny. No more fighting to set a significant preload, no more bashing your knuckles inside the wheel well when you slip off the perch while pushing with all you got. It's a mandatory add on for any coilovers I own moving forward.
Update: Thrust bearing info:
65mm ID, 90mm OD for original front springs:
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70mm ID, 95mm OD for original rear springs:
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Figures that one of those costs twice as much as the other right now.... But all you really need is the part numbers, NTB6590 and NTB7095, then if you're picky about where the steel comes from, make sure they come from a reputable manufacturer. There are lots of really cheap Chinese options. Sometimes that's ok, but for me, not when a bearing is involved.
I would recommend using a very thick, tacky grease with these since they will be exposed to elements.
Also, the JEGS sealed kind I mentioned:
Buy JEGS 81804 at JEGS: JEGS Coil-Over Shock Roller Thrust Bearings. Guaranteed lowest price!
www.jegs.com
I think they only have them in 2.5" ID, but I really like the idea. Enough to have emailed them to inquire where they are made.... You guessed it.