From the Workbench: At-Home Fork Installation

Installing a new fork, to some, can seem like a daunting task. There are a lot of specialty tools needed, there are a lot of steps, and anytime you take a hacksaw to a bike part means wherever you cut is forever. Often, those specialty tools are expensive, too. But, with more and more manufacturers making these tools less expensive, such as the Birzman Crown Race Removal Tool we use in this feature, owning these pieces of hardware is becoming less a burden to the home mechanic’s wallet. With that in mind, in this tutorial we’ll go through the step-by-step process of pulling your current fork, sizing your new fork’s steerer tube, installing and removing crown races, and how to mount up your shiny new fork. Oh, and we’ll clue you in on all the tools required to do the job properly, too.

Tools Needed

Hex Keys (aka Allen Wrenches)
Torx Keys
Hacksaw
Threadless Saw Guide
Threadless Nut Setting Tool
Crown Race Setting Tool
Insert for Setting Crown Race 1.5” (only required if you have 1.5” crown race)
Crown Race Removal Tool
File
Dead Blow Hammer
Tape Measure or Ruler
Shock Pump
Diagonal Pliers
Torque Wrench
Clam Disc Brake Gap Indicator (optional)
14mm Combination Wrench (may not be needed depending on your crown race removal tool)
Sharpie
Rubber Band (optional)
Toe-Strap (optional)

Parts Needed

Fork (Duh)
Threadless “Star” Nut
Zip Tie (only if your fork uses one to secure the front brake hose)

Removing Current Fork

Completely removing your old fork requires a number of steps, including removal of the front wheel, front brake, stem and handlebars. We’ll walk you through each one.

Step One - Removing Front Wheel

This step will be slightly different for everyone depending on your specific fork and axle interface. For us, removing the front axle required a 6mm allen wrench. First we loosen the non-drive side a bit before we remove the axle from the drive side, again using a 6mm allen.

Once the wheel can be dropped from the fork, put it to the side and put the axle back in the fork to keep it from getting lost.

Step Two - Removing Front Brake

Depending on your caliper mounting bolts, you’ll either need a 5mm allen wrench or a T-25 torx. If your brakes are using washers and an adapter, be careful not to lose them in this step. Unscrew the caliper mounting bolts to remove the caliper.

As you can see in the photos above, we made sure to keep both the washers and adapter together while removing the caliper. A handy trick is to use a rubber band to hold them all in place. This is also helpful later on when it comes time to install the caliper on the new fork. We also suggest putting in a clean pad-spacer in case of any accidental lever pulls. If you don’t have one handy, a piece of cardboard can be used.

Different forks use different means to secure the front brake hose to the lowers. Some use a zip tie, some use a little bracket that is held on by a small bolt that requires a 2.5mm allen wrench, and some just use a bracket that snaps on, requiring no tools to remove.

In our case, we needed a 2.5mm allen wrench to remove the bracket. After your caliper and hose have been removed, there’s no need to remove the lever from the bars and the assembly can just hang for the remainder of the job.

Step Three - Removing Stem And Handlebars

Chances are, you won’t have to separate your bars and stem for this install, so leave them together. Your stem, however, will have to be removed. But, before you go in there loosening bolts, if you were smart enough to grab a toe-strap before diving into this, we have another little tip that will make this step a bit easier.

Put the strap under the lower crown and back up around your top tube. Doing so will prevent your fork from unexpectedly dropping during removal, preventing any damage the adjustment knobs or the lowers themselves. Since we were working on a dual crown fork, we didn't need to add the strap until just before we just before we removed the top crown.

Grab the appropriate allen wrench, in our case it was a 5mm. Locate your stem mounting bolts and start loosening them. If you have a direct mount stem like we do since we’re working on a dual crown fork, you can completely remove the stem and let your bars and stem hang until it’s time to install them on your new fork. If you have a non-direct mount stem, which single crown forks use, the top cap will prevent your stem from being removed. We’ll cover that now.

Step Four - Removing Fork

If you don’t have a toe-strap holding your fork on like we recommend, take care not to let your fork just drop out of your head tube for this step. Using a 4mm or 5mm allen wrench, start loosening your top cap bolt while holding the fork from underneath the lower crown (we recommend doing this even if you have the toe-strap). For you dual crown users, the top crown will still be preventing your fork from dropping so don’t worry about holding the fork at this point.

Completely remove the top cap, top cap bolt and any spacers that may be on top of your stem // top crown . Single crowners, at this point you can remove your bar and stem and carefully lower the fork out of the frame and skip ahead past this next bit where we go over how to remove the top crown of a dual crown fork.

If you’re working on a dual crown fork, you’ll need to remove the top crown at this point. Using either a 4mm or 5mm allen wrench, start loosening the top clamp bolts until there’s little resistance. They do not have to be removed. It may take some persuading to get the crown off, so don’t get flustered and forget that the fork could drop out off the bike during this process (toe-strap for the win if you used it). Carefully lower the fork out of the head tube.

Single crown users, jump back in here. Now that we have access to the headset, use the opportunity to do a quick clean-up and re-grease. Pop the bearing out if you can, wipe away the dirty grease from both the headset cups and the bearing themselves and set aside. Apply new grease to the headset cups.

Prepping New Fork For Install

There are a few things that need to be done to a new fork before it’s ready to be installed on a bike. The steerer tube must be cut to the proper length, a threadless “star” nut must be installed, and your lower crown race has to be removed from your old fork.

Step One - Removing Crown Race From Old Fork

There are a couple ways to go about this, but the safest and proper way is to use a crown race removal tool and that’s what we’re going to cover. Note which way is “up” on the crown race before removal. Bring the tool down on your crown race. Carefully start bringing the wedges in towards the steerer tube making sure they line up between the top crown and the crown race. Our Birzman crown race removal tool requires the use of 14mm combination wrench in order to start bringing the wedges in towards the steerer tube. The wedges will start lifting the crown race away from the crown as you tighten them down.

Once you have a bit of purchase on the crown race, you can flip the fork over and use a dead blow hammer to start tapping the crown race remover to separate the race from the fork. In our case, we were able to skip this step as tightening the tool alone popped the race right off. It’s worth noting, if you have a dual crown fork you might have to bring the lower crown up a bit on the stanchions to get the proper angle to set the crown race tool in order to prevent damage to the crown. You’ll likely have to do this in step two, anyways.

Step Two - Measuring And Cutting The Steerer Tube

Since we just pulled a fork off with the proper length steerer tube, we can use that to measure where we’ll make the cut on the new one. Using a tape measure, measure the how long the steerer tube is from the crown, up. We’ll touch on how to measure your steerer if you don’t have an old one to use at the end of this section.

With a sharpie and the tape measure, mark where you’ll be making the cut on the new steerer tube using the measurement you made on the old fork. If you have a vice, put your hacksaw guide in it. If you don’t, figure out a way to safely hold the fork steady in the following step.

Slide the steerer into the hacksaw guide, making sure the portion of steerer that will remain on the fork is the side that’s clamped on and not the piece you’ll be removing. This prevents your fork from falling out of the guide after the cut is made. Line the guide up with the mark you made in the previous step. If you’re working on a dual crown fork, you’ll likely have to move the lower crown up in the stanchions to avoid damaging them when you cut. Even if your fork has lower crown “min” and “max” markings, we recommend you measure the distance between the seals and the crown and noting it for when you reset them.

Hopefully you were precise with your measuring because there’s no going back after this. If in doubt, remove the fork and re-measure. If you’re sure, put the hacksaw in the guide making sure it lines up with your mark and go to town.

After you’ve made the cut and removed the fork from the hacksaw guide, you’ll have to de-burr it using a file, both the inner-diameter and outer-diameter of the steerer tube. For you dual crown users, remember to line up and re-clamp your lower crown making sure you set them at the proper height and your stanchions are even. You’ll be banging the fork around in the next couple steps and you don’t want the crown sliding off.

Step Three - Installing The Threadless Nut

Grab your threadless nut install tool and a new threadless nut (please don’t try to reuse your old one). Place the threadless nut on the guide inside the tool with the angle of the nut flanges pointing towards the tool (some tools require threading the nut on). Holding the nut in place, bring the tool over the steerer tube and slide the sheath down around the top of the tube.

Using one hand to hold the fork from UNDER the lower crown, give the top of the tool a good whack with a dead blow hammer. Keep whacking until the tool bottoms out. This will set your threadless nut the proper depth in your steerer tube.

Step Four - Installing The Crown Race

Time for more whacking! Take your crown race and slide it over the steerer tube, making sure it’s not upside down. If you have a 1.5” crown race, place the 1.5” adapter over the steerer tube and then finally the crown race setter. Again, holding the fork from UNDER the lower crown, give it a few good whacks with the dead blow.

You’ll hear a distinct change in the sound of the whack when the race is set, and it sometimes takes a few whacks. Pull off the tools when you think the crown race has set and make sure there is no gap between the race and the crown all the way around. If so, your fork is all prepped for install.

If you don’t have an old fork to measure, first install the crown race like we just went over above. You’ll have to basically assemble the front end, using the headset, any stem spacers you intend on running, and your headset or top crown (depending on fork type) to find your needed length of steerer tube. You’ll want enough steerer so that there is enough length to at least make it COMPLETELY though your top crown or stem. Make your mark with the sharpie then pull it all apart again and make the cut. We HIGHLY recommend overestimating the amount of steerer tube you’ll need so you have ample room to move your stem and spacers around until you figure out your preferred bar height. You can always cut off the excess if you desire after a couple rides and dialing in the bike, but never cut short enough that the steerer tube doesn’t make it all the way through the crown or stem. Notice how we said that twice? It’s important.

Installing The Fork And Controls

Now it’s time to get your bike back together and rolling again. As you’d expect, this process is basically the reversal of the fork removal steps. We’ll walk you through getting the new fork on, adjusting your headset properly and getting your cockpit back in one piece, as well as how to get your caliper back on without rubbing.

Step One

The first thing you’re going to have to do is get the lower race and headset bearing ready for install. Apply some grease to both the race and the lower headset cup. Slide the lower bearing over the steerer tube making sure the bearing is oriented the right way. Grease the top cup and drop into the top bearing in.

Carefully bring the fork back up to the frame so that the steerer tube goes through the head tube. You can use your free hand to hold the top headset bearing in to prevent the steerer tube from knocking it out if you want. With the fork completely through the head tube and the bearing in place, keep holding the fork there with one hand and slide the top race over the steerer with the other. If you like spacers under your stem or top crown, now is the time to install those, too.

Step Two

Now it’s time to put on either the top crown or the stem, depending on what kind of fork you’re using. Dual crown users, make sure you place your cables and hoses between the head tube and stanchions before you install the top crown. Once the crown or stem in place, add any additional spacers that are needed so that there is at least a 2mm gap between the top of your steerer tube and the top of the spacer. This gap will be used to pre-load your headset bearings in the following step. You can now put your top cap and top cap bolt on and finger tighten the bolt. Don't forget to grease the top cap bolt. There is no need to tighten your top crown bolts or stem bolts at this time.

Step Three

With everything back where it’s supposed to be, for the most part, let’s go over how to adjust your headset properly. Take a 4mm or 5mm allen wrench and start snugging down that top cap bolt, making sure there’s no binding or weird resistance as you go. Your top crown or stem cannot be tightened during this process. You’ll want to tighten this bolt until your headset rotates smoothly without resistance or any grinding feeling, but snug enough that there’s no play in your headset. A good check, if you have enough spacers under your stem or top crown, is to hold the spacers with one hand and turn your headset // fork with the other. If the spacers spin, your headset is likely too loose. If they don't spin and do move with the headset and you don't feel any binding, your headset should be good. Once you get your bars back on and finish the repair, it's worth grabbing the front brake and gently pushing on back and forth on the bars to see if you feel any play or hear any noise. If you do, loosen your stem or top crown and try again.

Step Four

If you’re running a dual crown fork, you can now put your direct mount stem with bars back onto the top crown. Both crown bolts and stem bolts should be checked with a torque wrench.

Tighten all stem and crown bolts to spec, using the required allen bit (this goes for both single and dual crown forks). If you’re using a traditional stem and not a direct mount, you’ll have to align the stem and fork by eye as best as possible by eye before tightening. Torque spec will also vary so be sure to check.

If you were wondering why we were using a multi-tool and not a torque wrench on our crown bolts above, wonder no more. We're using the Birzman M-Torque 4, which is a 5Nm multi-tool.

Step Five

Now it’s time to re-install your brake caliper to the new fork. Proper hose routing is in front of the fork arch and in-between the wheel and the lowers (unless you're running a reverse arch fork). Making sure your hose isn’t twisted in a way that causes some weird angle in the brake line, use a 5mm allen wrench or T-25 Torx (depending on brake) to start threading into the lowers.

You don’t need to snug them down at this point, and once the bolts are partially in you can snip the rubber band. Leave the caliper loose at this point. Our fork uses a snap-on style bracket to secure the hose to the lowers and keep it away from the wheel. Your fork may require a zip tie or using a 2.5mm allen wrench to secure the hose.

Bring your wheel up into the fork, you may need to jiggle the caliper a little to get the rotor in. Once the wheel is completely in the drop-outs, secure the axle in properly. Our fork required a 6mm allen wrench to tighten the axle and a 4mm allen wrench to tighten the pinch bolt.

Step Six

To align your caliper properly, there are a few different ways. But, no matter which way you do it, you’ll need either a 5mm allen wrench or a T-25 Torx to tighten the bolts. To center the caliper, you can eyeball it while you snug down the bolts, making sure both pads are evenly spaced around the disc. You can grab the front brake lever so the pads make contact with the rotor and snug the bolts down.

We used Birzman’s clam tool, which is thin spacer that goes around your rotor. To align the caliper, put the tool over the rotor and while holding it, slowly rotate the wheel so that the tool slides into the caliper. The spacer takes up the room between the pads and the rotor, effectively centering the caliper. Snug down the bolts, remove the clam and we’re done.

A quick tip no matter which way you go about this step is to always “sneak-up” on the bolts. What we mean by “sneak-up” is slowly tighten each caliper bolt a little bit at a time. This helps prevent the caliper from shifting as you tighten the bolts up.

Step Seven (Air-Sprung Forks Only)

If you’ve just installed an air-sprung fork, it’s always recommended to check the air pressure and make the necessary adjustments before hitting the trail. Remove the air spring cap, which in our case was located on top of the left stanchion. Attach your shock pump and set pressure to the manufacturer's recommendation for your specific body weight. The recommended pressure may not be exactly where you should be, but it’s a good baseline to start setting the fork up. Detach the pump and put the cap back on. We’re almost done.

Wrap It Up

Before hitting the trail it’s always a good idea to check your work. We like to do a “touch every bolt” check before we ever pull a bike out of the stand. With a torque wrench and the various bits required for your specific bike, check all the bolts to make sure they’re all tightened to spec. It doesn’t hurt, or take much longer to check the bolts on the entire bike, as well.

Once you’re sure the bike is good to go, you’re ready to hit the trail. Get out there and enjoy that new fork.