saving4one

I was going to put my OHLINS together this weekend, and I have only checked to make sure all the parts were accounted for and read the directions (still in the original packaging). I am wondering if I can set the spring pre-load on the bench, or do the coil-overs need to be installed on the car? I have researched quite a bit and it looks like Gernby set spring pre-load with the OHLINS on the car while others seemed to set with them off. Also how do the adjuster knobs come off the ends to put the top-hats, spacer bushing, nuts, etc. on? I'm asking because I haven't even unwrapped anything. Thanks!

gptoyz

Here's a pretty good article surprisingly from megan

You sort of ignore this if you have helper springs
http://www.meganracing.com/new/tech/...ing%20pre-load

as far as the adjuster 2 methods that i know of removing the adjuster:
#1 set screw, look around for a little hole on the adjuster, insert allen wrench and release the tension, then pull straight up
#2 adjuster = fancy allen that is just held in place by friction, pull straight up (KW style)

can you post a pic of your shock?

thomsbrain

The adjuster knobs simply twist off and on by hand, grabbing the lower portion of the knob. No tools needed, though you can use an adjustable wrench if you need extra leverage to loosen them.

For spring pre-load, if you are using Ohlin's recommended settings, the pre-load is so slight that you can easily set it while the shock is off the car. The Ohlins recommended pre-load for the front is very close to ideal. For rear, Ohlins aren't even in the ballpark, which is what Gernby is describing. If you are setting the rear pre-load to the actual ideal location, you will need a lot of pre-load and it will likely be easier to set it with the shock held in place by being mounted to the car.

andrewhake

Other measurements in the rear done by SHG_Mike in the rear with the DFVs say differently. He removed the springs and put the rear through it's range of travel. The shock doesn't come in contact with the bump stop until the wheel is fully tucked into the wheel well. I still don't see where you have measured the rear to have no travel at Ohlins recommended settings. Other measurements definitely say otherwise. He has small RCAs on his car but there was clearly more than enough travel in the shock with or without RCAs before it would bottom out.

saving4one

Thank you for the comments guys. Thomsbrain, they just pull off? I was wondering if by twisting them you would change the setting 'click'. Again I haven't even fiddled with them yet. Andrew, I have been following both SHG_Mike and your build threads (and other dfv posts) so I think I am going to go by the OHLINS recommended specs, and bench set them after measuring. I want to get them all set up and then take them to where I work and make some foam molded packaging so the day I send them in for service I'll be all set.

thomsbrain

They twist off from the little half-nut under the gold part. Yes, taking them on and off will likely cause some changes to the adjustment in the process. After you put them back on, you'll want to turn them to full-stiff and then back down to your preferred setting (which you should do any time you change settings).

Andrew, as I've said, I got my measurements by installing the shocks and included springs at the recommended settings with the dust boot off and putting the car on the ground. Bump stop contact.

It's not rocket science. If you have an 8K spring at the rear with essentially no preload (2 mm is just enough to keep the spring seated), an S2000 will compress that spring by a little less than 2.3 inches, with variance for corner weight, etc. Gernby calculated 2.2", which is probably due to slight differences in how we rounded numbers or our corner weights. The Ohlins have 2" of total travel on the rear before engaging the bum stops. What's 2" minus 2.3"? Bump stop contact.

I'm not going to comment on measurements made by someone who has changed his suspension geometry, nor speculate on what "fully tucked" means.

On the rear 8K spring, I calculate the ideal amount of preload as 30 mm (Ohlins only recommends 2). Gernby calculated 29.5 mm as ideal. So there's two guys who know how to use a calculator and a spreadsheet, working totally independently, and coming up with the same result.

Both the math and the actual physically observed behavior of the spring and shock support the need for big pre-load on the rear of this travel-limited shock. Even Urge Designs said this about the DFV:

I will say that on Laguna Seca (a very smooth track), I found the DFV to work very well... when set with proper rear spring pre-load. So again, I really like my DFV. Just please, everyone, do yourself a favor and set the preload right.

saving4one

thomsbrain, thank you for the input. I wonder why the OHLINS instructions would state the 2mm pre-load? Wouldn't they have done testing on their own product? This seems like a huge error on their part if what you and gernby have found is correct? Andrew did you set up your shocks yourself? And if not, do you know what your installer used for pre-load? I have read several posts on this subject and many have gone with the factory recommended pre-load. I wonder if they are just un-aware of the travel they have?

andy_intel

I have read a few of your posts on this preload issue, thomsbrain - and while I haven't noticed any crazy behaviour from my own car, it is cause for concern that Ohlins would release a product with a fairly fundamental problem. I mean, it's not like they're all that cheap either!

You mention using about 30mm preload in order to have a reasonable amount of bump travel? Can you tell us if there is enough range in height adjustment to compensate, for example on a car that is 20-25mm lower than standard. Thanks for helping to bring this issue to light - it excites me that these coilovers could be even better than they already feel with just a little tweaking!

saving4one

I just remembered, Andrew went with different springs. I'll have to ask/check what SHG_Mike set his pre-load at.

andrewhake

And I am saying that your measurements are different that others who have also measured. It isn't rocket science indeed. Did your DFVs have the top rubber piece between the spring and top hat?