It is bad to bottom out a mountain bike suspension when you regularly hit the end of its travel in too harsh a fashion. The regularity of your suspension reaching the limit of its travel is a good indicator of your suspension being too soft (bottoming out regularly) or too hard (rarely bottoming out).
Your suspension should bottom out at least once every ride in a manner that is not damaging to your frame or the actual suspension. Ideally, you should hardly feel it when your mountain bike bottoms out.
When your mountain bike’s suspension bottoms out and you can feel it via stress being transmitted to your frame, and brutally regarding your suspension, it is considered bad for your bike. A good bottom out will be when your suspension reaches full travel, and you hardly feel it.
Most modern mountain bikes are all equipped with a suspension system. The purpose of a mountain bike’s suspension is to dampen the roughness of the riding terrain, providing the user with a smoother, controlled ride.
This article will explore why bottoming out too frequently is bad for the bike’s suspension. Alternatively, rarely bottoming out is also an indicator that you are not getting the most out of your bike’s travel.
When Is It Bad To Bottom Out A Mountain Bike Suspension?
When your mountain bike’s suspension is set up correctly, it will bottom out when taking big hits on the trail, typically when you are performing jumps downhill. It is all about the quality of the bottom out.
If your suspension is regularly hitting its travel, sending stressful shocks through your bike’s frame, followed by harsh full-blown hits to your shocks that can damage it, it’s a bottom out that is bad.
If your bike is frequently bottoming out, it could be that you require more significant shocks or that your suspension is not set up correctly. It may also be a sign that you need a bigger mountain bike.
Without going into too much detail, let us list the components that you can check out with regards to your suspension setup, if and when your bike is bottoming out all the time:
Setting Your Sag
The amount of travel your suspension moves by adding your weight (body, riding gear, and pack) to the bike is referred to as sag. The sag factor puts the suspension into an active state, allowing it to react in both directions, also keeping your tire glued to the dirt. You should set your sag while you are positioning yourself on the bike in your actual riding position.
Set your fork and shock compression dampening to Open/Descend settings and climb on the bike. Make sure to dress in your usual riding gear, including the water bottles and the hydration kit on your back—everything you would include in a regular ride out.
Have a friend assist you with balancing your bike and move the O-rings for you. Once you are in position, bounce the bike around a few times without holding the brakes, then settle in a neutral riding position.
Once you are satisfied with your position, hold it steady while your friend moves the O-rings down the canisters/lowers, then slowly lean over and climb off the bike. Do not hop off the bike, as this could compress the suspension and move the rings further down.
Remember that the sag will differ from a sitting position to a standing position. It’s important to mimic your dominant riding position that you mostly use on the track you are setting up to ride.
Mark Fitzsimmons, Fox Racing Shox’s Race Program Manager and pro athlete suspension tuner, advises the following when setting up your bike’s sag:
- Downhill Bike: Set your sag in a standing attack position.
- Enduro/Trail Bike: Set the sag in a standing position for bike park riding and a seated position for everyday riding.
- Cross County Bike: Set the sag in a seated position
How Much Sag Is Correct?
Eric Porter, a professional racer in XC/DH/DS/DJ, says that “Most bikes feel good between 20-30% sag, I like 25-30% most of the time” and “If you are doing a ton of climbing, you may like it closer to 20%.”
Generally speaking, your sag should be somewhere between 15-40%, ultimately your bike should feel right to you while still getting all the maximum travel available on most rides.
Modern shocks and forks suspensions have numerous settings that can be adjusted as the terrain changes. From the open, trail, descend, pedal, climb, lock, the options vary from manufacturer to manufacturer. Having the suspension set at the correct setting when encountering different conditions around the trail is vitally important for them to do the job that they were designed to do.
The fully open position is the shock’s neutral setting; set in this mode, it will perform how the engineers designed it to work. The pedal setting should be used to move up a non-technical climb or a flat smooth surface when you need a firmer platform.
Not having the suspension in the correct setting will also feel like you are bottoming out heavily. For example, if your bike is in the pedal setting and you hit more diverse terrain, roots, rocks, sharp-edged objects, you as the driver and bike will absorb the shocks and bumps instead of your suspension. Your suspension setting could also play a part in your bike bottoming out.
When it comes to the fork setting, it is advised that you set it with less sag than the back shock. The fork is in charge of absorbing impact as well as keeping the front end under control. It has to prevent diving in and floating over the small stuff to maintain traction. Set it too low, and it will dive under braking. The trick is to run the fork high in its travel, allowing for a platform and ready for any rough stuff.
Manitou’s Eric Porter on this topic “I’ve heard before that you should bottom out once or twice a ride, that’s how you know you are set up the right way. I don’t believe that necessarily; I think you should bottom out only when you think you should if that makes sense.
If you’re riding a medium rough trail and aren’t smashing everything, you probably won’t use all of your travel, really.
I want it there when I really need it, not just when every big rock comes along. Forks are so tunable now that you can really set your compression dampening to keep you from smashing the bottom, the Manitou Mattoc even has HBO adjust built-in, which stands for Hydraulic Bottom Out, and you can tune how the last inch of travel feels and keep yourself from ever feeling a harsh bottom out.”
If you what to know when it is time to lock your suspensions, I encourage you to read this article!
Adjust Air Volume
After setting the sag correctly, your suspension setting is on point, but still, your bike is bottoming out. It may be that you are running on the incorrect air pressure. Adjusting the air pressure can help with sorting out your suspension issues.
Eric Porter on air pressure “If your suspension feels too linear, then it’s time to adjust the volume. In the end, you want to be using all your travel without having a hard bottom out. It’s great to hit something big, have it feel smooth, and then look down and see that you used everything that you had, but it didn’t smash the bottom.
Reducing the volume with a spacer can also make it feel more supportive, so if you like to pop off lips and roots and whatever, less volume can help because it will ramp up more as you compress it.”
If you what to know the advantages of hydraulic disk brakes over mechanical ones, I encourage you to read this article!
To bottom out with your mountain bike is normal. It shows that you are using all of your bike’s travel and getting the most out of your suspension. The quality of the bottom out is what is vitally important. Hitting significant obstacles and having it feel smooth without smashing the bottom is considered a good bottom out.
When you and the bike’s frame absorb the shock when bottoming out, it is a clear indicator that your suspension setup is not fine-tuned to your specific needs. The shock and fork suspension should absorb the bumps and shocks that hitting hard objects will produce, and you should hardly notice it.
Setting up or correcting some suspension settings could help you sort out the quality of your bottom outs.
I started mountain biking many years ago to improve my overall health state. After my first ride, I fell in love with the sport. Now I spend dozens of hours a week researching and training to compete in local XC and Enduro events.