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Yep definitely. But the spring rate and ability to adjust ride height to a specific point needs to be considered as well. On my car with 13kg/mm springs F + R I am just able to get to the rear ride height I was after, because I also have 12mm J's Racing rear roll center adjusters, which offset the knuckle up 12mm (which also lowers the ride height). If I was running stiffer springs like 16kg/mm or so and wanted to achieve the same ride height, I would height more roll center adjustment or lower mounts like this that allow for more ride height adjustment. 13kg/mm springs work very well for me with my setup. I have them at just a little more than 0mm preload and the compression travel is more than acceptable.
Where did you end up? Somewhere between 12.4 and 13.0" from arch to wheel center?
In regards to running more preload than recommended by Ohlins, how much bouncier is the car? It seems like a trade off between: low ride height/optimal damper piston position/preload (stored energy in springs, which may upset the car over bumps, etc)
In regards to running more preload than recommended by Ohlins, how much bouncier is the car? It seems like a trade off between: low ride height/optimal damper piston position/preload (stored energy in springs, which may upset the car over bumps, etc)
Originally Posted by noodels
Its less bouncy than the 25kg bumpstops.
Exactly! It actually doesn't add any bounciness once the car is on the ground a preloaded spring behaves just like a non preloaded spring, the preload simply changes the resting position of the spring. The only spot where you are likely to notice the difference is entering driveways and places you need lots of rebound travel
I was trying to figure out the rear suspension settings on my Ohlins DFV dampers and if I could achieve my desired preload (and in turn bump travel) and ride height using the standard DFV mount or if it would be necessary to purchase Sakebomb's rear lower mounts. I used the following information/equations:
So to keep Ohlins recommended ride height, the max preload you can add (with bottoming out the lower mounts) is the following:
2 + (420-410) = 12mm preload
Therefore, if you are using the chart in the original post, Sakebomb is telling you they do not recommend keeping Ohlins recommended ride height using the stock 8 kg/mm springs and lower mounts.
Now let's see how much you would need to raise/lower the ride height from Ohlins recommendation to get preload you desire with bottomed out rear mounts:
H = (P - 12) / 0.578
Hs = H - 25
H - Change in ride height from Ohlins recommendation (+ is higher and - is lower) [mm]
Hs - Change in ride height from stock suspension (+ is higher and - is lower) [mm]
P - Desired preload [mm]
Or rearranging that equation if you know the height you want, you can find the maximum possible preload:
P = 0.578 * H + 12
For example, if I wanted 16mm preload:
H = (16 - 12) / 0.578 = 6.9mm
Hs = 6.9 - 25 = -18.1mm
In plain terms, that would mean I would be at 6.9mm higher than Ohlins recommended ride height or 18.1mm lower than stock.
Hopefully this helps people dial in their Ohlins DFV suspension settings and figure out if they need aftermarket rear lower mounts to achieve their desired preload and ride height.
I guess how is this information any different than what is on the chart, the chart gives ride height drop at x preload and even does it for multiple spring rates
Nothing different, just shows the math and logic behind the chart. The values may be a little different though. I was unaware of this thread and sent a message to Sakebomb and they asked for me to post this information in here. I was in process of making a spreadsheet with bump travel and other factors so I can finalize my rear suspension.settings.
My Preload would be 18 maxed out and keeping at Ohlins 25mm lower spec ride height.
Bottom bracket would have hit the bottom of full range of adjustment at above.
15mm preload at the moment and have 2 full turns left<1 turn is 1.5mm>
I went for 15 for future adjustments if needed.
8kg.
12-16-2016, 10:46 AM
