Suspension bottom out means your car springs have fully compressed and reached maximum travel – causing them to come in contact with the bump stop and produce abrupt clunking noise.
At high speed, this can cause severe damages to the springs, steering, exhaust pipes and your car oil sump.
Let’s discuss a little more about the damages of bottoming out and what you could do to prevent it. Especially if you have lowered your car.
There are two types of bottoming out when it comes to a car. First is where your springs fully compress and collapse into one another. This is usually caused by low quality springs with very low spring load – that come from buying cheap eBay coilovers or springs.
When spring bottoming out happens, you could damage the springs, shocks and the steering component. Bottom out hard enough and you probably have to replace your springs and go for a realignment.
The other type of bottoming out is when the underside of your car scratches against the road surface. This could happen if your car is riding too low or if you have too much load (full passengers with heavy baggage in the boot and full gas tank).
When this bottoming out happens, you could damage various parts in the underside of your car. Things like bumper, oil sump, muffler or exhaust system. If you bottom out at low speed, it should be fine. But if you bottom out at high speed, I recommend checking the underside of your car. Did any of the above crack or left hanging?
So is it bad? Definitely! If you have suspension bottom out, then you should look to replace your car springs for better quality ones. If you have the typical car bottoming out, then you should worry only if it happens at high speed.
If you want to replace your springs, then consider lowering springs instead of stock. They lower your car to give you that aggressive look, improve handling and still keep your car daily comfortable to drive. I have an article here where I talk about the things to look at when buying lowering springs. Best Lowering Springs: Which To Get And What To Look For?
What Causes Bottoming Out?
Here are the top common reasons to bottoming out your car:
- Spring load is too low. Low spring load means it does not take much weight to fully compress your car springs. Which means you will probably bottom out on every road bump when carrying two other passengers.
- Car ride is too low. Low ride height is cool and all. But it wouldn’t be fun to drive if you scrape against the pavement on every driveway or bottom out on every road bump you encounter. Lower your car but lower it right! 1 to 1.5” drop is enough.
- Too much load in the car. Don’t underestimate the weight of 4 other passengers, a fully loaded trunk and full tank of gas. Even stock cars could bottom out from this. Let alone lowered cars. Slow down on the bump if you know you are carrying a lot of load.
Another point to note is that shocks don’t cause bottoming out. It’s typically the spring that’s at fault. Shocks only control the movement after the springs have compressed – it makes sure your car does not bounce uncontrollably after every bump.
How To Prevent Suspension Bottom Out?
Here’s the checklist to make sure you won’t bottom out ever again!
- Don’t get low quality springs. You don’t have to get the top-of-the-line springs. Just avoid getting the cheapest ones. Manufacturers usually do not advertise the spring load of their springs. And this is because it shouldn’t be a concern to most drivers. If you consistently bottom out your springs, then consider replacing it.
- Don’t go too low on ride height. You shouldn’t go too low on your ride height. Not only will it be stiffer, it will also cause bottoming out issues. I recommend only lower your car to a max of 1.5”. I cover ride height in a later section, so read on 🙂
- Go slow on speed bumps. Not only will you reduce the chances of bottoming out, if you go slow, you likely won’t cause any big damages even if bottoming out happens.
- Remove unnecessary load. Do you have any unnecessary items in the trunk? If you do, remove them! Not only will they increase the chance of bottoming out, they will also reduce your fuel efficiency. More load = more power required to work!
Recommended Height For Lowered Cars
If you want to lower your car without much bottoming out, I recommend only lowering your car for 1” to 1.5”. The final ride height should be around 12.5” front and 13” rear. This is just a rough figure for you to keep in mind.
The rear height should be slightly higher than the front. This is because the rear could have more load than the front. Think extra passengers, gas tank and load in the trunk. So we need the higher ride to compensate for the extra load.
I cover much more about car height in this article. Things like how to measure your ride height, best ways to lower your car and whether or not lowering your car is worth it. Check it out! How Much Should I Lower My Car?