Tarmac 2 ride height issues
 

The below scenario happened upon initial install in 2018:

"Im having a strange issue with a Tarmac2 Clubsport install on my 2014 FR-S.

Im going for a conservative 1" drop from stock. My stock heights measured dead on published spec of 26.25" front, and 26.5" rear. Fronts installed fine and adjusted to 25.25" with zero issues.

In trying to set rear ride height Ive run into an issue where the right rear is way out of adjustment compared to the left side. Left side is set at 25.5" ride height with nothing out of the ordinary/expected. Threads showing below the spring seat is approx. 2.5" with a very small about of compression left in the tender spring. No measurable main spring preload (~7" free length).

On the right side however is totally different. Ride height is still too low (25.25") but the spring perch is turned up much higher, with approx. 4+" of shock threads showing below spring perch. Tender spring is completely compressed, with about 1" of preload on the main spring at full droop.

Ive disconnected rear swaybar on both sides, Ive dropped and reattached lower control arm. Ive driven and rechecked, Ive even tried another garage floor to double check measurements. Stock suspension had no issues...nothing bent.

Rear Tarmac2's are using stock tophats. Using new bumpstops (not being compressed yet so not a factor). There are no apparent leaks."

At the time, I pinged both Myles and Andrew at RCE and we went back and forth and after a sh!t-ton of farting around I believed I finally got ride height set without totally coil binding the RR spring.


Fast forward to last October at a DE at our local track I just happened to be garaged with my buddy with a BRZ (on Ohlins, but that irrelevant). The downtime gave me time to compare/contrast our setups and I noticed my car looked significantly lower than his. We broke out the ride height gauge and my car was almost an inch lower. More importantly, my ride height was ~ 5/8" - 3/4" lower than where I had set them.


Which brings me to this week. I finally got around to investigating/resetting the ride height and Im back to the original scenario. Front ride heights were easy to get close. Moved to the back and the Right Rear will not go high enough before coil binding the spring. I am running the tender springs at all four corners. Sway bar endlinks are disconnected.



Does anyone have any ideas I might not have tried? I haven't pulled the tender springs, but fully compressed they are about 13/16" thick and I dont know if that would buy me anything...but then again, I'm at a complete loss at this point.


Im not new to this, but Ive never had this type of issue crop up on any other car/chassis I've setup. And for it to happen the way it has (consistently) has me even more confused and hoping for insight.


Any input welcome.

I had KW springs not live up to their spring rate, collapse, and coil bind. Switched to Eibachs and problem solved. Hyperco and Swift would also work. Check the paint to see if the springs have collapsed and are binding, double check the markings in case an incorrect Spring got packed.

The other thought is confirming if there are any spacers that are supposed to be installed between damper and top that, having a spacer installed differently left to right would be my second guess, but I’m not super familiar with KW installs on this car.

Sorry if this is redundant shit, hard to diagnose with just text.

I remember this, super weird. I need to see pictures if you have any, especially off the car. Can you mail me at
andrew@racecompengineering.com?

I don't think it's a spring quality issue. Would like to see the markings on the springs and the top perch assembly.

- Andrew

I wonder if I'm having a similar issue. A few months ago I left for a 1500 Mile trip, midway through the trip it started raining and I couldn't go over 50mph due to the car wanting to send me into a ditch. I stopped and looked at the car, I had alot of toe out and way more negative camber than I should. Before leaving for this trip I set my toe to zero, and camber was somewhere around -2. Once it stopped raining my car drove like normal, I made my way back home (10 hour drive). Once home I got under the car to check things out and my rear tires were nearly completely bald, with only 2000 miles of use. Rear toe was 7/8" out, and I looked like a silly stance kid with my camber. I checked over everything and all seemed to be perfect, I redid my alignment, and have had to keep playing with it every few weeks since.

I guess I need to really inspect the rear coilovers, adjust the height and measure, then measure again in a couple weeks.

I should also mention that I've also always had a bit of a ride height issue. Fronts are nearly lowered all the way, and the rears are raised so high its compressing the main spring slightly. But prior to that trip I actually lowered the car a bit in the rear until the helper spring was no longer compressed.

Toe won’t go that far out just due to ride height changes, it’s physically impossible. One or two of your adjustable links slipped. Make sure to torque them to spec, factory toe link adjuster is 76 ft-lbs.

All of my arms were tight, and were exactly where I left them. I actually wrote down measurements for comparison from side to side before the trip. And then measured after the trip, I came up with the same results. Ride height was the only thing I didn't have wrote down before the trip. There were no essentric bolts that could have slipped either.

This. Your toe link probably slipped. Aftermarket toe arms with an eccentric lockout are helpful.

- Andrew

At that time I had verus arms on the car, with their lockout kit. No signs of slippage, and the bolts were torqued to oem spec. I switched to spc arms and a lockout kit after the trip, just incase it was the toe arm, but I still have the issue coming back slowly after a couple hundred miles. I haven't been able to mess with it these past few weeks to dig into it more.

Something is broken and it doesn't sound like the spring/shock. Send me some pictures of the rear suspension assembly.

- Andrew

Might be a couple weeks. Since this problem started I've replaced everything except the coilovers. Switched from spl trailing arms, verus toe arms, and verus lca to some non adjustable Megan trailing arms, spc toe arms with eccentric lockout, and spc lca's. Also installed whiteline diff and subframe inserts mainly to verify that my subframe isn't shifting around causing toe issues (I figured very unlikely). I removed every single suspension part from the rear other than the upper arms. I checked those for worn bushings and they are fine. All suspension parts looked fine. The car still rides great and handles great, just gradually Gains camber and toe as the miles increase. I haven't messed with it in the past month or so, just been daily driving back and forth to work. I need to stop driving it and look at it soon though since I can feel the alignment starting to get out of shape again.

K let me know. The rear coilover doesn't have any affect on alignment outside of setting ride height. If it's that drastic of a change in alignment, signs point to a bushing or arm losing spec.

- Andrew

I'm not sure I should interrupt at this point, seeing how the thread went off the rails with the original topic, but I believe I've corrected my issue.


I ended up pulling all 4 coilovers and reassembling. The one change I made was reassembling the rears without the helper springs. Originally, the fronts were assembled with the lighter helpers up front (3-60-80), and the rears were assembled with the heavier (I couldn't verify rate as the markings rubbed off) helper springs. I recall not being able to find documentation on location at the time of original install, but based it on multiple photos of product, and a youtube video JustinCo put out of the unboxing of his Tarmac 2's.


After reinstalling all 4 corners, my ride height could be dialed in without the strange "weight jacking" issue I had before. In fact, the rear spring perches are now at the same height on both sides...down to the 16th of an inch (fronts vary .25"). That translates to the same ride height measured at the wheel arch....wish I did it sooner.


The helpers I had on the rear (the heavier ones) have a compressed length of 13/16" and I think that height combined with the rate were just too long/heavy on my car with a moderate drop of 1.25" from stock. The coil bind was weight jacking the opposite corner (the same phenomenon that happens during corner weighting actually) and not allowing the ride height to be set. I did end up ordering some shorter and lighter helpers just in case the droop causes spring rattle/banging, but the 170mm springs are almost tight at full droop....just a touch of rattle.


Anyway, thanks for the offer of help to those that did.