kt411gcn

Hey guys. I'm absolutely stumped and hoping you guys could help me out.

I have been trying to set the ride height for the front. I have been measuring the height of the car by measuring from the fender lip to the center of the wheel. The ride height is not changing no matter if I thread the shock body up half an inch or down half an inch. I thought I was going crazy so I tested the other front shock, lowering half an inch and measuring, and raising half an inch and measuring. The ride height is not budging. Not even a millimeter.

There are three collars..2 that lock up against eachother and compress the spring for adjusting preload, and the other one locks the lower shock body. The way I have been trying to change the ride height is I will loosen the collar that locks the lower body, and make sure the 2 collars compressing the spring are tight. I will utilize those two collars to either thread in or out the shock body. I was able to adjust the rear height with no problems utilizing the above method.


I made sure to preload the suspension via ramps before tightening the upper control arm and lower shock bolt when installing. I made sure to measure the shocks to verify they were at the length Ohlins recommended before installing. Also worth noting is that every time I readjust the shock, I make sure to reset the preload by 2mm per the Ohlins instructions. One last detail that I wanna include is that the preload increases when I lengthen the shock body, and the preload decreases when I shorten the shock body.

Really hoping you guys could solve this mystery for me. It's probably something really simple and stupid that I may have missed.

King Tut

I see your problem. You are definitely adjusting the ride height properly, but you should NOT be messing with the preload at all when adjusting the ride height. When you adjust the preload like that you are counteracting the change in ride height adjustment.

kt411gcn

I should also add that ride height for the front passenger is 12.5" fender to center of the wheel, which is roughly half a finger gap. Driver's side front is 1mm lower than that. Ride height isn't budging. I'm 100% sure the lower shock body is threading in and out because I have been using the bottom collar as reference.

King Tut

I just wanted to quote this, so you understand what I am telling you. Lengthening and shortening the shock body DOES NOT CHANGE PRELOAD. Preload is the distance from the upper spring mount to the lower spring mount. When you have zero preload, that distance should be the exact length of the spring. Ohlins recommends you use 2mm of preload so the spring is compressed 2mm. It doesn't care what you are doing to the shock body or how you are adjusting your ride height. The bottom threaded part of the shock body changes your ride height. You only need to loosen the bottom collar that locks to the lower shock mount to adjust ride height.

kt411gcn

That is my original understanding of how a coilover design like the Ohlins should work; adjusting ride height should not affect preload.

However, when I am rotating the body and extending the shock (doing so by utilizing the two collars that lock against eachother, for some reason it increases preload. I know this because after I am done extending it a half inch, I find that to get to 0 preload, I have to decrease preload by about half an inch (preload is always set at 2mm from 0 preload before I adjust the actual height). When I shorten the shock body, preload decreases. I know this because the spring has about a half inch of slack when I am done rotating the body into the lower mount. All this is why I am constantly finding I have to reset the preload after Im done adjusting the height. Also, I am 100% sure the threaded shock body is moving in and out of the shock body when I am adjusting the height, because I am using the bottom collar that locks against the lower mount as a reference to measure.

Thinking about it some more, I feel that I am adjusting height the right way, but for whatever reason, I don't think the overall length of the shock is changing. I feel that somehow, by rotating the shock body in and out of the lower mount, instead of lengthening and shortening the overall shock length, I think somehow it might be moving the shock body into the shaft more or less instead. I am stumped as to why this is.

King Tut

You are definitely not adjusting the ride height properly if you are ending up with a half inch of slack on the spring. You must be rotating the two locked perches instead of rotating the shock body in the lower shock mount. Here is a video I found:

https://www.youtube.com/watch?v=B4GI2QbZ8fI

See how all three of the locking collars spin with the shock body while it moves out of the lower shock mount? That it what should be happening. Because you have 2mm of preload on the spring, it is not going to freely spin like that with your hands like he does in the video, so you have to make sure that the two locking collars for the preload are locked tight to each other and the shock body so they can't move. Then you use your wrench on one of the locked collars to move the entire shock body and two collars together to adjust the ride height. I hope I explained it better this time.

kt411gcn

I know what you're saying. Trust me, it doesn't make sense to me either.

Here is what I do. Let's say i want to "extend" the shock/raise the car. Keep in mind 2mm of preload is set for the current height. I make sure the bottom collar is just loose enough so that it doesn't contact the lower mount. I make sure the two topmost collars are tight against eachother, and that they never come loose as long as Im still adjusting the height. I use the second collar, and looking from the top, rotate counter-clockwise, which should raise the vehicle, but in my situation, doesn't do anything at all. I know that I'm threading it out, because when I start, there is a hair gap between the bottom collar and the lower mount. When I'm done, there is a half inch gap between the bottom collar and the lower mount. I then proceed to tighten the bottom collar against the lower mount, which sets it.

I'm positive the bottom collar (which is loose) and top two collars (which are tight) are all spinning the same direction with the threaded shock body whenever I'm attempting to adjust the height. In any other circumstance, the preload shouldn't have been affected, and the ride height should have changed. That is not the case for me. The preload changes for me every time I change the height, or try to. I know it's not supposed to.

I do remember measuring the shock from the tophat to the middle of the bottom bolt, and then adjusting for the height, remeasured the shock, and saw that it was still the same length. I just assumed with the wheel off and the the same corner jacked up, that the free length was determined by the swaybar/endlinks/control arm etc, not necessarily the shock . Not sure what to think now.

I know this is really confusing. It confused the heck out of me, too. I appreciate you being patient with me.

kt411gcn

I'm using the exact same method as the guy in your video, except im using a spanner wrench on either of the top two collars depending on if I want to raise or lower. This is exactly what I'm doing, except my ride height isn't budging: https://www.youtube.com/watch?v=wcq7Xm-PssI

King Tut

Yeah I am super confused, and I just installed Ohlins and adjusted the ride height on my S2000 multiple times two weekends ago with no issues. The spring preload never changed, and I did my measurements for the ride height adjustment as the distance between the two most bottom collars. I ended up going with the Ohlins recommended 103 mm in the front and went -15mm on the rear for a measurement of 12 mm. I definitely noticed the ride height changing each time I messed with it. I would put the car back on the ground, take a drive, and then measure from the pinch welds near each wheel. I guess the only thing you could do is make a video of you adjusting the coilovers and taking measurements similar to this video:

https://www.youtube.com/watch?v=S34KmnCGRIA

King Tut

See in the video how the spring was staying preloaded the entire time and not moving while the entire shock body and perches were moving. Does yours do that? Notice how he made a huge ride height change and his preload never changed. I don't doubt you are doing that part correctly, but I want to know why your preload is changing.