F-Sport Shocks and Springs still Stiff/Super Firm - Lexus IS Forum
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post #1 of 4 (permalink) Old 05-03-2014, 05:17 AM Thread Starter
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F-Sport Shocks and Springs still Stiff/Super Firm

Some Help

Had it for 2 weeks already installed, in my taste its still kinda stiff not the stock ride I had, maybe out of 100% stock feel it was reduced to 75%, I trimmed the front bump stops since shocks are shorter to allow more suspension travel. It improved the ride I bit but still stiff. What can I do before replacing them. Wait a little while to allow the shocks and springs to "Settle" "beak-in" if there is there such a thing?or cut the rear bump stops to 1/4

Spring rates are near as stock and up to 7kg at final rate but it seems still firm, and near other lowering spring rates

F-Sport Springs
Front = 6.6kg/mm
Rear = 7.0kg/mm

If I change the springs whats the best in terms of comfortable ride and stock feel, even if it reduces cornering performance.

Many Thanks
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post #2 of 4 (permalink) Old 05-03-2014, 01:38 PM
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Any "performance" suspension is going to ride a little bit more stiff then factory regardless of all the reviews you read. From personal experience even though i have never owned them personally the F-sports had the best ride i had ever been on vs factory. H&R which i have owned were probably second. Next to doing that your only real other option that i can think of off the top of my head is to get a set of coils and do a custom spring rate setup.

As far as settling goes if they have been installed for 2 weeks they are more then settled. I personally have never seen settling take more then about 20 miles.

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post #3 of 4 (permalink) Old 05-03-2014, 07:06 PM Thread Starter
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install was great no squeaks or clunks its just the firmness of the ride, Is it the progressive nature of the springs? Because at good roads with a few dips and waves the ride is GREAT but at paved cemented roads its REALLY STIFF.

Thats why I'm thinking of

F - 6 kg/mm
R - 6.3/kgmm
Swift Springs which has the closest to stock
F - 4.6kg/mm
R - 5.2kg/mm

Or go the Coil-over Route with Tein Comfort Sport.

Or the F-sport shocks are making the ride stiff together with the F-Sport Spring because it is a more performance oriented setup?

Last edited by turtleboy; 05-03-2014 at 11:49 PM.
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post #4 of 4 (permalink) Old 06-18-2014, 07:16 PM
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I was thinking about swapping out my OEM suspension for an F-Sport suspension and I was told not to by my service advisor. He strongly recommended against it. From what I hear, the closest match to stock are the Swift Springs.
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