What’s With This Other Rebound Knob on my New Mountain Bike Fork? Set Up and Ride Tips for High and Low Speed Rebound

The high speed and low speed rebound adjustment on Fox's Grip2 damper is a sweet feature that can help you dial your mountain bike fork in for the unique trails and weather conditions you ride in.

I’ve heard the following statement from fellow riders a number of times and have even asked it myself: “What do I do with the second rebound knob on my new mountain bike fork?”

Previous forks came with just one rebound dial that adjusted the low-speed return, while the high speed rebound was set internally at the factory. I recently chatted with a friend, Tyrone Dines, who works as a suspension technician at Fox Europe to get his take on how we can best set up the high and low-speed rebound on a Fox 36 fork with a Grip2 damper. These setting tips should work on other forks with dual rebound adjusters if more companies choose to offer them.

Before we dive into setup and problem-solving, let’s make sure we are all on the same page around what the rebound knobs do. The term rebound indicates the speed at which your fork returns after absorbing an impact, either from rider input or trail features. The low speed rebound knob adjusts the speed your fork will return after absorbing smaller impacts or input. Examples of low-speed inputs are braking forces, a rider pumping the bike through smaller roots and rocks, smaller compressions like berms, and other elements that are dealt with in the first two-thirds of your fork’s travel. The high speed rebound knob controls how quickly your fork will return following larger impacts, like landing a jump, jamming through a rough rock garden, bouncing off of a big root, or any other forces that push your fork deeper into its travel.

To get started setting rebound on the Grip2, Tyrone recommends checking out Fox’s Tuning Guide to dial in the base settings. From there we can adapt the settings to our individual riding styles, bikes, tires, and terrain.

With the sag set properly and compression knobs where you like them, dial in the high-speed and low-speed rebound to Fox’s recommended settings. Then, go ride a trail you know well and see how the bike feels.

Table courtesy of ridefox.com

Tuning and testing rebound settings

Here are some common instances where you might want to click the HS/LS rebound knobs away from the factory-recommended tune. Suspension tunes are as unique as taste buds, and it’s rare that two riders will prefer the exact same feel from their fork. These points are intended to demystify rebound settings a bit, and hopefully help riders find their optimal tune. All of these steps require some patience and persistence. Try a few clicks in one direction and if it feels great, leave it. It’s helpful to remember that you want your bike to feel well balanced for the trails you are riding and that harmony takes time to find.

Tyrone Dines: Consistency is the key in the beginning. Run a trail you know a number of times, don’t make sweeping changes and make notes on your smartphone. It’s important to keep a record of where you’re at in terms of PSI if you run an air fork/shock combo, or spring rate with coil fork/shock combo.

While setting up a new bike I like to keep the base tune on the top tube so I know where I have been and gone. Once the suspension feels dialed this info is typed in a note on my phone for future reference.

My hands and forearms hurt at the end of rough sections and longer trails. 

This issue arises for a number of reasons, including fitness. If you are sure that the culprit is your suspension, the problem may be that your fork is not returning quickly enough to absorb the next bump, instead staying low in the travel, packing* up, and feeling harsh. Try speeding up the LS rebound by a click or two from the factory settings. If the track is truly super rough, with consistent big hits, you can also speed up your HS by a click.

If your fork is already quite fast, your shock may also be too fast, throwing your weight into the handlebars instead of allowing you to remain centered over the bike. If a positive click of HS on the fork doesn’t take care of things, try slowing down the shock by a click. Dines adds that “static sag is the key here. Different bike brands will have recommended settings for the rear suspension, on occasion they may be different to the settings advised by your suspension manufacturer.”

If you max out the rebound settings and things still feel harsh and painful, try starting over with proper sag and factory settings. Lastly, remember that some trails are simply harsher on the hands. Dines suggests another look at the manual in this case. “Regardless of what brand you ride, the base factory settings will give a good starting point. If you’re too far one way or another on either compression or rebound, consult the manual again and check for advice on volume spacers/tokens.”

*Packing: Dines says packing means, “in effect the fork stalls at the point of transition between compression and rebound. Each time the fork compresses, it doesn’t return and you lose travel.”

My front tire is losing traction on flat turns. 

If your front tire is washing in turns and you are confident that your flat cornering technique and tire pressure are dialed, try slowing the LS rebound by a click or two from the factory settings. This will allow your tire to stay planted on the ground for added grip.

Also, be sure to check the rear shock sag point, and rebound (see packing note above) to make sure the rear is not squatting too much and causing the bike to understeer.

The fork feels sluggish, and it is difficult to pop off of trail features.     

To make your fork feel more lively and “poppy” you will want to speed up the LS rebound by a click or two. If that’s still not doing the trick, try adding 5psi to the air side, and reducing the static sag by a few percent, to give it some extra oomph. If you are looking for even more of a pogo-stick feel on the front end, try adding a volume spacer and reduce the fork’s compression settings by a click to help it reach the rebound circuit faster. Remember that speeding the fork up will sacrifice its ground-hugging grip capabilities, and for some courses, you may have to decide between pop and grip.

I am going to ride steeper trails than usual, and want to set the fork up accordingly. 

For fall line and otherwise wall-shaped tracks, it can help to speed up your LS rebound by a click and slow down the LS on your shock. This will help your fork stay higher in its travel, and keep your weight further toward the rearward balance point that steep inclines demand. If you still feel heavy in the hands on steep stuff, try raising your handlebar as much as you can to compensate for the bike’s forward angle.

Here, Dines adds, “if it’s really steep and gnarly, adding in volume spacers may be required. Don’t forget to adjust the rebound when adding a spacer. This usually means closing the HS and LS, as the return pressure on the circuit will be greater.”

I showed up to a race and it is super muddy. What can I change to ensure maximum traction on wet roots and rocks? 

Apart from lower tire pressure and taller mud spikes, slowing down your LS and HS rebound on slippery tracks will help you keep the bike on your chosen line. There is less concern with the suspension packing when you are riding slower through the mud, so give the dial a few clicks and see how it feels.

I am riding/racing trails that are far more technical than I am used to. How can I set my fork up to better deal with the gnarlier conditions?

Assuming your fitness and bike are on par with the track demands, you can try a few things to better prep your suspension for rockier and rootier trails. If you watch a lot of professional DH and enduro racers on uber-rough tracks, they are consistently pumping off of one obstacle and over another. The best racers move more like a nimble rabbit than a blundering plow. This sort of riding requires higher fork and shock pressures, additional volume spacers, and often slightly faster LS rebound settings.

Again, if you have the muscle to handle a bike that wants to be launched off of everything, experimenting with all three of these variables can help you achieve the true kangaroo style. You will likely want to add some tire pressure and possible foam inserts as your suspension becomes stiffer. Less of your mass and the forces of impact will be absorbed by the stiffened suspension, and once that energy is switched to the tires you will need to fortify them a bit.

The track I am racing has a lot of jumps that land in rock gardens and root mats. What can I do to add control to the front end upon landing?  

First, make sure your suspension is well balanced so that you are not landing front or rear wheel heavy. Then slow down the HS rebound by a click or two. This will allow your bike to smooth out rough landings while it is recovering from the previous drop, rather than launching back toward full extension immediately. This one may seem a little counter-intuitive, but give it a shot. If you don’t dig it you can always speed it back up.

Remember to consider the balance between the front and rear of your bike while making adjustments to the fork.

I am riding flow trails at a bike park and want to get the most out of my suspension. How should I adjust the rebound to make the bike work well on the jumps and berms? 

With purpose-built jumps and berms, balance is key. Making sure that you can launch off of a smooth lip with as much pop as you like, and land with both wheels at the same time will allow you the confidence to play around more in the park. Start with the factory settings to judge how well balanced your fork and shock are. Find a small jump to test your settings on a few times. Once you are hitting the ground with both tires at the same time, speed up the LS rebound until you have the amount of pogo you desire. If there are a lot of jumps in succession you may want to speed up HS rebound a touch as well.

For smoother tracks I also like to add a click of HS and LS compression to my fork and shock to make the bike feel nice and firm when it’s time to pedal.

A final word from Dines: “At the end we all have a different perception of the ‘magic carpet’ feeling, whether it’s the rider who is deceptively fast, but has an uber-supple setting, or the [EWS] rider who mashes the bike through a trail and sets everything on the firm side. Your preference takes a while to get dialed in.”

Do you have HS/LS rebound advice or preferences to add? Please share them with our readers so everyone can shred happily!