Topping and Bottoming Out Explained

I've tried typing the question a few different ways in google and am not finding a good explanation (or at least one I can understand) on what it means when your suspension tops out or bottoms out. I feel like there is an obvious and simple answer to this, but I'm not getting it.

Mainly, my concern is how adjusting pre-load on a coilover will make the suspension more prone to topping out. But really, I'd like a better understanding of both, what it feels like and the cause and effect of each.

A video, article or just an explanation here would be greatly appreciated. Thank you for any help with this.

 

This photo might help a little, to understand with a visual. Basically topping out, means the shock cannot extend any further. This is common for some who "crank down" the preload nut to get a taller lift. Bottoming out the shock is similar, just on full compression. Coil bind can also occur on a coilover not properly setup.

Our spring rates article will also be helpful:
https://accutuneoffroad.com/articles/coilover-spring-rates-for-toyota-tacoma-4runner/

 

Thank you for the diagram and the article.

 

This is one of the best descriptions i have seen yet for "preload". That said, the use of the term preload here is a misnomer. As an engineer, that would mean further compressing the spring, which, as stated, is not the the case.

 

Preload is the right term and you are in fact compressing the spring to an initial (pre) state. Before you apply preload, when you put the coilover in the suspension, ithe spring has to compress X inches to support the weight of the vehicle. By applying preload, you are compressing the spring an initial amount, say 1/2X. When you put it in the suspension system the vehicle weight still compresses the spring to X, however since you've already put in 1/2X of compression on the spring, the vehicle only compresses the spring the extra 1/2X. Since you haven't changed the eye-to-eye distance of the coilover the suspension sits higher in its travel resulting in a "lift".

Where coilovers and preload get a bad name for being a stiff ride is with stance boys and girls that add X preload, so their suspension doesn't actually end up compressing the spring at all.

 

Hello Folks.

I think I feel my shocks topping out when going over speed bumps/patholes a bit too fast. Its like a “thud” and feels like I’m running out of downtravel.

Running 2887 OME coils and nitro charger softvalved shocks. 2” lift

Been driving like this for about a year, it’s not a huge deal but I don’t think it should do that.

Does anyone have any ideas what’s happening here? It’s my first lifted 4x4 so I’m still learning about all this.

TIA

 

I have the exact setup and problem as Junkhead. Super loud and jarring on road bumps and potholes. Topping out going over humps offroad too. Ive got smittybilt steel cable winch and coastal high clearance bumper. I do have light truck tires but i dont think they can cause this stiff of a ride. They were fine with my stock suspension Most people seem happy with this setup. Not sure whats up. Any ideas??

 

While on the ground measure hub to fender. Then lift the truck from the frame until the wheel is off the ground and re-measure. Compare and that is how much travel you have.

 

Junk head, is that water or is your shock blown?