flanders

I thought Öhlins used Lesjöfors?

YCW

They mainly use Eibach (it actually still says it on the spring on some of them). Or at least that's what I assumed based on all the coilovers they had on display at their trade shows, and what the engineers were telling me about their relationship with them.

I could be wrong though

Chuck S

Since you're making this a "101" how 'bout a few definitions and explanation of the spring tester readings. I'm completely at a loss here, don't intend to mess with my springs, bur remain curious.

1. What is a 10K spring? 10,000 what?

2. What do the 557 and 574 readings from the tester show? For example 557 somethings = 10,000 somethings in what units of measure?

-- Chuck

B serious

10K is a shorthand way to type 10kg/mm.

This equates to ~560LB/IN

Car Analogy

So its just like inches vs cm, SAE vs metric. Different units to measure the same thing.

Spring rate is how much weight it takes to move the spring how far. A straight rate spring (a spring that is not progressive) will need to add that much more weight to move it that far.

So if its a 500 lb/inch, it will take 500 lbs to compress it that first inch. It will take another 500 to compress another inch (1k lb total). And so on. By contrast, if its a progressive spring, it keeps taking more and more weight to move it an additional increment of distance, as it gets stronger the more its compressed.

Our cars stock have a corner weight in the neighborhood of 750lbs. However that weight operates on the spring with the leverage of the control arm. Ots the so called Motion Ratio that quantities how much leverage there is (for every inch of motion at the wheel, how much motion at the spring. Its really just a lever with 750 lbs on the end, a pivot point, and a spring somewhere in between).

Stock our springs are around 260-310 lb/inch, depending on year (and around 350-380 for CR).

Springs should be matched to tires, among other things. More traction can produce more load, which produces more roll, etc. Stiffer springs are desirable to control body motions if higher traction tires are fitted and their abilities utilized.

Also, the spring, motion ratio, and weight combination defines a Natural Frequency, how 'bouny' the setup is. Cars wanting boaty, pillowy plushness will aim for lower NF. Cars with sporting intent higher NF.

So when designing waht spring rate to use they would take all of these things, and more, into account.

Shredwick

Any chance you have more than one of each spring to test? It would be interesting to see the variation across a population rather than one of each.

YCW

Yeah, once I get the chance, I'll run more tests. Got quite a few used ones as well. Will be interesting to see what results those give

alSpeed2k

Hmmm, I don't remember where I saw it, but I know Ohlins had Eibachs (perhaps it was right on the springs themselves?). My coils are off the car but packed away, next time I pull them out I will have a look.

YCW

I know that Lesjofors make springs for Ohlins for a lot of their oem stuff, but I don't know if they make any for their aftermarket stuff (the engineers didn't event mention Lesjofors at the trade shows; only Eibach)

postwarart

Subbed! Especially interested in what data you get about the stock s2k springs.