Ohlin RT guys: front wheel/tire sizes/offsets

[LSB4Me]

I spoke to Ohlins today. They confirmed what I/we suspected—the springs were adjusted (for height) but the rear shocks were not adjusted to match.

Sounds like my shocks are approx. 15mm too long, which is keeping the shocks outside of their operating range. My shop will adjust (shorten) them this week, but Ohlins was extremely confident that we identified my issue and that comfort was in my near future. Here’s hoping . . .

My shop is installing an Evolve airbox at the same time. I’m more excited about the Ohlins adjustment.

PSA Request: Does anyone know the stock rear ride height on 18s and OE suspension? This will help me do some math to shorten the shocks more accurately.

[Grke46m3]

I spoke to Ohlins today. They confirmed what I/we suspected—the springs were adjusted (for height) but the rear shocks were not adjusted to match.

Sounds like my shocks are approx. 15mm too long, which is keeping the shocks outside of their operating range. My shop will adjust (shorten) them this week, but Ohlins was extremely confident that we identified my issue and that comfort was in my near future. Here’s hoping . . .

My shop is installing an Evolve airbox at the same time. I’m more excited about the Ohlins adjustment.

PSA Request: Does anyone know the stock rear ride height on 18s and OE suspension? This will help me do some math to shorten the shocks more accurately.

Where did you buy them from? I bought them from 3ddm and he had the shocks preloaded in the right position. Car does feel a bit jittery I would say. I wonder what number you come up with. Measure the threads from top to bottom on the rear shock when your done.


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[repoman89]

Interesting, as far as I know there wasn't anything in the install instructions about rear shock length, so I didn't do anything with mine either. Bought from Barry at 3DM though so he might have set them appropriately. I'm also running higher ride heights than most, something like 13.75/13.25 f/r.

[Slideways]

I spoke to Ohlins today. They confirmed what I/we suspected—the springs were adjusted (for height) but the rear shocks were not adjusted to match.

Sounds like my shocks are approx. 15mm too long, which is keeping the shocks outside of their operating range. My shop will adjust (shorten) them this week, but Ohlins was extremely confident that we identified my issue and that comfort was in my near future. Here’s hoping . . .

My shop is installing an Evolve airbox at the same time. I’m more excited about the Ohlins adjustment.

PSA Request: Does anyone know the stock rear ride height on 18s and OE suspension? This will help me do some math to shorten the shocks more accurately.

Why were the rear dampers lengths adjusted from the factory setting? Out of the box, they are the correct length to match the spring perch length they recommend in the install manual - it is something like 220mm IIRC. The preload is just enough to keep the spring from coming loose under full droop. When you raise the rear ride height by lengthening the spring perch collar, that will create even more preload. Not sure how shortening the shock is the right answer.

[LSB4Me]

I was told—by Ohlins—that the rear shock length is set for a 20mm drop. Going lower than that, they said, necessitates shortening the shock to maintain shock stroke and keep the rears off the bump stops.

As I began to describe my driving dynamics, the guy (Brian) at Ohlins cut me off as he knew what was going on. In his words, I have all droop; no bump. This makes complete sense to me. I will report back.

Anyone know the stock rear ride height?

[Tbonem3]

Never heard of adjusting the height or droop or a rear damper for this car, at least not off the shelf stups. How do you adjust the length of the rear shock? AFAIK, you can adjust rebound and/or comp, and you can adjust the ride height with the spring perch. Then you bolt in the stock. Please describe or show a pic/video!

I think stock rear is at 14" and most go to 13" which is a 25mm drop. If you go to 13.2" that's a 20mm drop as they suggest, assuming 14" even is stock rear (I think front was 14.5")

I also don't understand the "all droop, no bump" unless he was just exaggerating. All droop is where the car is up in the air and the wheel is hanging down as far as the shock will let it. That'd be like a 18" rear ride height lol. I'm just not understanding.

[LSB4Me]

The sensation I’m getting from the rear is that I have no “up” travel. As if the rear shock is choked up to the point of not being able to dampen correctly—or at all, in my case. The Ohlins instructions talk about adjusting the rear shock length, but they don’t do a good job of explaining when/why, imo. The conversation yesterday put it into perspective. Apparently, this is an Ohlins feature. We’ll see what happens when I shorten the shock, thereby taking the shock out of its near-full compression at rest and giving the shock a chance to help absorb impacts.

Ohlins said they have a shop car running 13” ride height in the rear. That’s my ride height. They said their car rides like a dream.

By “all droop; no bump”, he was referring to the movement available to the shock. It can only release down, but any up travel runs me into the bump stop.

If the rear stock height is 14”, I will only shorten the shock 10mm.

[Tbonem3]

What are you at now? 13" is lower than what Ohlins told you is bump stop territory, yet the car drives like a "dream" which is why I always take a grain of salt with anything anyone says. I'll assume that car in the shop doesn't have 3mm thick racp/subframe plates that lower the subframe, or has the cmp corrective bushings.

[Epsilon]

My Ohlins setup out of the box is currently 13" in the rear with 19s as another data point.

[Tbonem3]

My Ohlins setup out of the box is currently 13" in the rear with 19s as another data point.

Just for more perspective, where did you put the rear spring adjuster at? All the way down, somewhere in the middle, all the way up?

[LSB4Me]

I had my shop shorten the rear shocks by 10mm. They said a few mm shorter would have been problematic.

I am happy to report that I immediately noticed more travel in the rear. Playing with settings now to finalize the setup, but it’s pretty clear that I was running into the bump stops on any/every road undulation. FWIW, I am running 13” rear ride height with 275/35/18 PS4S and 35psi.

[Tbonem3]

You're running 13" in the rear NOW, so before you were almost down to 12.5"? Yes, that was your problem. I think the confusion has been you referring to the shocks, but it's not the shocks, it's the springs on their perches that are adjusted up and down for ride height. Ohlins or whoever telling you about the shocks' range weren't quite telling the truth (or whole truth) - it's not the shocks, it's your roll center/susp geometry that's the issue being too low.

I doubt there's any adjustment to the dampers themselves besides the rebound (and consequential comp).

If you have subframe plates, and don't have the corrective CMP bushings, you should probably go up to 13.125" to compensate for the lowered subframe.

[Obioban]

Never heard of adjusting the height or droop or a rear damper for this car, at least not off the shelf stups. How do you adjust the length of the rear shock? AFAIK, you can adjust rebound and/or comp, and you can adjust the ride height with the spring perch. Then you bolt in the stock. Please describe or show a pic/video!

I think stock rear is at 14" and most go to 13" which is a 25mm drop. If you go to 13.2" that's a 20mm drop as they suggest, assuming 14" even is stock rear (I think front was 14.5")

I also don't understand the "all droop, no bump" unless he was just exaggerating. All droop is where the car is up in the air and the wheel is hanging down as far as the shock will let it. That'd be like a 18" rear ride height lol. I'm just not understanding.

The Ohlins' rear shock is adjustable length, so you can set ride height and bump/droop independently. The shock body itself is threaded, it screws into the bottom yellow part, and there's a locking collar:



It's pretty great, actually. Lets you dial in front ride height to optimize for bump/droop, and set rear ride height by optimizing for rake, then setting rear bump/droop from there.

[repoman89]

There is definitely an adjustment to the shocks too. They have a threaded insert and locking ring to set the length. Easy to see in pics: https://www.ohlins.com/product/road-...2001-2005-e46/

[Obioban]

Front tire clearance is a huge PITA with the Ohlins. I ended up using a front beehive spring that was short enough that I could get the spring perch above the front tire (along with camber plates that moved the upper spring point as high as possible), which allowed me to run normal wheel/tire offsets with large tires (and not have to compromise my car with huge amounts of camber). It took a ton of trial and error to get it dialed in, and ended up clearing by 1-2mm.


I think the Ohlins are one of the best setups for this car once you get them working, but getting them working up front (with track sized tires and not stupid camber) is a HUGE PITA compared to... anything else I've run. Really, you should go in knowing that a 245 is the biggest tires you'll run up front (fine for cars that don't see track use) or that you're in for a fight... or offset/camber compromises.