Severe tire cupping

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Nov 12, 2021 | 11:45 AM

#16

Paul_R7.3

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Mountain Pass

Joined: Jul 2019

Posts: 199

Likes: 33

From: Northern California

Do you recall if you ran the valve all the way firm and still had cupping with the RS9000s?

Nov 12, 2021 | 11:48 AM

#17

FordTruckNoob

FTE Chapter Leader

Joined: Jan 2005

Posts: 13,111

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From: Henderson, NV

I think I was one or two clicks shy of max firm. I am running different shocks now.

Nov 12, 2021 | 12:26 PM

#18

ScaldedDog

Fleet Mechanic

Joined: Aug 2010

Posts: 1,458

Likes: 156

From: Sedalia, CO

It's a bit of a SWAG, but I suspect the slightly taller shocks are also valved a little firmer, as lifts and bigger tires tend to go together. In any event, I absolutely would not go to double shocks, as the genuine use cases for them are very limited, and likely non-existent on street driven trucks. Get the Bilsteins if you want, but disciplined rotation and correct pressure are a more likely fix for cupping. Don't get me wrong - I love me some PMS, but there are lots better ways to spend money on these 20yo trucks that high end shocks, IMHO.

Mark

Nov 12, 2021 | 12:58 PM

#19

Tugly

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Joined: Jan 2011

Posts: 18,849

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From: Puget Sound

Find somebody who really knows something about front end alignments. Not all adjustments are possible in our era of Superduty, an aftermarket part has to be installed to get it right - I think it's the camber that's the problem.

Stinky (R.I.P.) used to eat tires for breakfast, until I had this work done by an "old-timer". After the work, Stinky never ate another tire (about 2 years) before his demise. Normal wear - yeah. Rotation - no. Cupping - no. 55 PSI to handle the weight of the nose.