Sharp edge chatter bumps

[McCarthy]

23 on 37" BFG's, truck rides awesome. Far and above the old gen 2 I had. Not even on the same playing field.

However, like everything, it needs some improvements. Any recommendations on improving the sharp edged bump compliance? Up here there's sometimes sections 300' long of large, sharp edged deep "potholes"- They're not really potholes so much as undulations from water damage- imagine hundreds of small, sharp whoops that are not evenly spaced, and often affect left and right side of the truck differently, covering the covering the entire road surface in areas.

Only options that work okay is either slowing down to 2 mph and crawling through it, or hitting them at speed, however hitting them at speed makes the ride MUCH more comfortable, it throws the truck sideways and generally tries to send the truck off the road.

The other thing that helps is dropping tire pressures, but i'm not comfortable running them below 25psi as I have wrecked a number of tires from punch flats at lower pressures on big hits in the past.

 

[BoostCreep]

Unfortunately, the Gen 3 on 37 ko2’s with 17” wheels and pressures in the mid 30s is about as good as it’s going to get. The types of road imperfections you’re describing are the hardest thing for a suspension engineer to deal with. When softening things like that it’s less about the spring and damper and more about all the typical things that isolate and eliminate NVH. But on a body on frame pickup truck, you can only do so much.

The Cullinan probably would do pretty well with this type of surface.

Hitting it with some speed will help, it’s possible a shock upgrade may help a bit but there isn’t much for the Gen 3 yet.

 

[McCarthy]

Unfortunately, the Gen 3 on 37 ko2’s with 17” wheels and pressures in the mid 30s is about as good as it’s going to get. The types of road imperfections you’re describing are the hardest thing for a suspension engineer to deal with. When softening things like that it’s less about the spring and damper and more about all the typical things that isolate and eliminate NVH. But on a body on frame pickup truck, you can only do so much.

The Cullinan probably would do pretty well with this type of surface.

Hitting it with some speed will help, it’s possible a shock upgrade may help a bit but there isn’t much for the Gen 3 yet.

Interesting! I hadn't thought of the problem that way.

To me, being basically thrown off the road sounds like a shock setup issue. I would like a king or fox upgraded coil but the research i've done (fairly extensive...) has told me the factory shocks are hard to be improved upon... I wonder if a different spring rate or shock setting (shocks were in Baja mode.) I will try normal and sport next time and see if it changed anything.

 

[taquitos]

If you have high frequency impacts, which is what this sounds like, your rebound speed has to be insanely fast for the wheel to track the ground and compression damping has to be very light. If rebound isn’t fast then you skim over the top and tires are off the ground half the time (makes you fly off the road if you aren’t careful and a curve comes up). If compression isn’t mega soft it’s jarring when you hit the next one. This works terribly it most other scenarios because vehicles rely heavily on damping to keep from bottoming. So shocks are never tuned for that. Lower tire pressure is the best bet. Tires are close to undamped so can deal with this better. Live valve is as close as it’ll get to being able to deal with both super high frequency chatter and single large impacts. Hopefully the Fox aftermarket shocks have live valve on both rebound and compression when they come out. I could see live valve on rebound being useful here.

If impacts are shorter in terms of height then running it in a softer setting might help you out, but it’s more likely a rebound speed thing.

 

[McCarthy]

If you have high frequency impacts, which is what this sounds like, your rebound speed has to be insanely fast for the wheel to track the ground and compression damping has to be very light. If rebound isn’t fast then you skim over the top and tires are off the ground half the time (makes you fly off the road if you aren’t careful and a curve comes up). If compression isn’t mega soft it’s jarring when you hit the next one. This works terribly it most other scenarios because vehicles rely heavily on damping to keep from bottoming. So shocks are never tuned for that. Lower tire pressure is the best bet. Tires are close to undamped so can deal with this better. Live valve is as close as it’ll get to being able to deal with both super high frequency chatter and single large impacts. Hopefully the Fox aftermarket shocks have live valve on both rebound and compression when they come out. I could see live valve on rebound being useful here.

If impacts are shorter in terms of height then running it in a softer setting might help you out, but it’s more likely a rebound speed thing.

They're not actually adjustable outside of the stupid modes in the truck though are they?

Hmm... Other question... IF live valve is working. IF.

 

[taquitos]

They're not actually adjustable outside of the stupid modes in the truck though are they?

Hmm... Other question... IF live valve is working. IF.

Outside of the modes they are not adjustable. You could take them apart and change the shim stack, but not seeing many people do that. I think SDI does for their set up if people want it. Could be worth checking that out if you want more control over the live valve. I don’t think it would solve this though.

If live valve isn’t working it tends to tell you drive modes aren’t available. So unless you are getting an error message it should be working. The cables to the front shocks are kind of exposed though. I have one that got damaged because something knocked it off the clip and it rubbed on the CV axle. Still works though.