I installed Bilstein 5100's on my 09 platinum today and drove about 30 miles on a gravel highway that I drive regularly. The highway is built on permafrost and is really bad with washboard and big dips this time of year. I usually can safely drive 60-70 mph on it without losing control or having the back end kick out at all. After installing these shocks I could barely go 50 and even at that speed it was a scary ride. It went almost right sideways a couple times. Even on pavement they were a little squirrelly on stutter bumps. Can anyone else with these shocks comment on wether they might just need to be broken or maybe these just aren't the right shocks for this kind of terrain? Thanks

 

Strange, that's how my stock shocks acted and with the Bilsteins it got better.

I know they do break in after a bit.

 

I have a 2014 xlt for a work vehicle and I was driving it around with blown out shocks for a while. It was pretty dangerous on the washboard but this is worse.

 

Never Liked Bilsteins, weak welds on the lower mounts... Yikes

 

Mine are holding up just fine as are the other thousands and thousands out there. Lol

A few breakages and people freak.

They are one of the best shocks on the market but not sure what's going on with OPs! Mine are great at speed over rough roads, they ride a but stiffer than the stock squishy ones but more controlled.

 

Bilsteins will break in slightly. You might have to adjust tire pressure as they are a bit firmer than stock.

 

My off-road control was much better with the 5100s

 

Love mine. Much better control and handling . I crawl all over our moutains with them.

 

I've had mine on for almost 10k miles now. In that time I have only been on 1 washboard road and my tail was swaying also but in any other circumstance they run great. Try tossing 200lb in the the back and see how that helps.

 

I don't have these for my F-150 but I did have some for my 2008 Tacoma...but they should be basically the same thing only bigger. Someone please correct me if I'm wrong. Since they're adjustable with that ring and "cup" to hold the spring it's possible to install that "cup" upside down. If that's the case then you're spring is under more compression than intended and will result in an extremely rough ride like the OP is describing.

I'm wondering if that's what the problem might be. I know back when I had my Tacoma the guys who inadvertently installed their 5100's incorrectly had complaints exactly like what the OP is experiencing. Worth looking into anyway...hope this helps.