thomsbrain

When setting corner balance, can pre-load and shock height adjusters be used interchangeably to achieve the same result in corner weight change?

My intuition has been that a given change in either will have the same result (more pre-load or more shock length). Since they affect static ride height equally, they must affect static corner weight equally, right?

I could see extreme dynamic corner weight being affected differently, when a heavily pre-loaded corner is at max extension and doesn't have enough load to move the shock yet, versus a longer shock with little pre-load that can still move easily.

Thoughts?

s2000Junky

I would stick to one or the other myself preferably, rather then mix the methods, so pick one and be consistent. But this is with the idea that pre load and shock length are all equal and balanced to start with, which chances are they are not really 100%. So at the end of the day it probably wont matter to the degree 1/8'-/1/4" typical amounts. More pre load on one corner wile compensating with shorter shock length compared to longer shock length on the apposing corner with less pre load is what id prefer to avoid. So again, id pick one facet to be equal, and use the other to adjust corner balance, wont matter which as far as achieving the weight balance, but handling/bump dynamics I could see being effected with mismatching methods on the same "axle"/end of the car.

Running a different shock length or pre load front to back is fine if desired to accomplish something, but side to side would be strange/inconsistent unless you were doing oval track racing or something lopsided lol

snitm

You don't want to alter preload (and get closer to needlessly hitting the bump stop) to achieve corner balance. You should stick with the shock height adjustment. Preload is very specific for the particular shock's spring rates and travel vs bump stop.

freetors

IMO, if you have both shock length and preload adjustment available to you, then you should always set up the the shock length to suit your desired wheel travel range, ie you set the chock length to control where you want full droop and full bump to be. This will usually dictated by interferences with things like fenders etc. Next, you should set your preload on all four wheels such that you get to the ride height that you want. Also to keep in mind while doing this is the relationship of how much bump travel vs droop travel you'll get.This stuff all requires measuring which most people are too lazy to do. After all that, then you can finally make minor adjustments to the preload at each corner to get you corner weights where you want them.

And I know many, many people will disagree with this but there is no downside to using more preload than just a turn or two like many recommend. If you are sagging through more than 50% of your shocks' travel then you probably need more preload. The only downsides to more preload is slightly greater stress on the spring perches and a greater chance of coil bind (hopefully your springs have more free travel than your dampers). There is no difference in feel or ride quality with greater preload. And please don't be one of those boneheads that runs no preload at all to get a lower ride height. Basically for a given suspension travel, softer springs = more sag = more preload needed.

No.Division

spring preload does nothing to effect spring rates.

thomsbrain

OK, thanks for the input guys. That confirms my thoughts. The context of my question was in regards to the well-documented Ohlins DFV rear and their need for additional preload. I had previously run the necessary preload to center the piston travel at static ride height, which of course is a lot of preload, but I had sufficient shock length adjustment to compensate and ahieve desired ride height. I had a corner balance guy freak out at all the preload and insist it would ruin the corner balance, even though he had headroom on the shock length to adjust corner balance that way and the preload was matched across the axle. He ended up setting it back to "stock" preload and then corner balancing with the shock adjusters from there. I don't have scales of my own to "prove" that the preload wasn't going to screw anything up. This was in the times before SakeBomb came along and added some professional backup to my previously unpopular assertion that the Ohlins rear need a lot of preload unless you get shortened bodies (like SakeBomb now sells).

I'm going to take my existing corner balanced settings and add back my threads of preload and remove equal threads of shock length with the assumption that static corner balance will be unchanged and I'll get back to the correct preload for these Ohlins rears. My corner balance feels great on smooth pavement but big bumps get into the bump stops all the time on the Ohlins at "stock" preload and that can do some unpleasant stuff if you hit them mid-corner.

Apex1.0

Preload is for corner balance. Shock length for ride height. The idea is to maintain ride height and increase corner weight by reducing shock length and increase preload, or vice versa as needed. Preload increases the resistance to initial compression. Preload does not alter the spring rate.

thomsbrain

OK, so that's what I've heard a few people including my corner balance guy say, and I agree that preload both increases resistance to initial compression and does not alter spring rate. But I don't see how that then translates to increasing corner weight if the net loaded shock length hasn't changed. I'm trying to understand what logic folks in that camp are using to arrive at that conclusion.

s2000Junky

It wont, its the ride height change on that corner that transfers the corner weight to the other end of the car. You raise the pass rear, you put more weight on the driver front etc. Its the act of raising or lowering the car that gets you there, not how you get there. Then its just a matter of deciding where you want to effect the damper, the bump side of the stroke or the droop side. you want to aim for balance, so probably what's going to dictate that is where you currently have your ride height/damper stroke set to decide if you want to add/remove compression stroke or droop amount.

s2000Junky

Doesn't make sense. You are effectively canceling them out and not changing corner balance, but rather increasing bump stroke and shortening droop travel wile retaining current ride height.