After discussing various methods of applying suspension to a road/cyclocross bike, and narrowing down the options, I’ll be going over the installation of Redshift Sports’ ShockStop suspension stem.
REMOVING THE OLD STEM
Swapping is relatively straightforward as the ShockStop is so similar to a normal stem. All you need are a 3 mm and 4 mm hex key, plus your torque wrench, and some grease and carbon assembly paste. I also had some painter’s tape and a black marker on hand.
To start, remove all accessories from your handlebar. The stem swap introduces the risk of your handlebar angle changing. One thing you can do to help keep your handlebar angle constant is to take some painter’s tape (or masking tape) and wrap it around the center clamping area of the handlebar, then use a marker to make a reference line. I make this line against the forward edge of the stem, behind its faceplate.
Once you’ve marked up your handlebar angle, loosen the top cap bolt and the pinch bolts holding the stem fast to the steerer tube. Remove the top cap, plus any spacers that sat between it and the stem.
Next, loosen the clamp bolts on the stem’s faceplate.
With the clamp bolts loose, remove the faceplate and be ready to catch the handlebars. Mine are still fully cabled up, so I just let them rest on the leading edge of my front fender, where the tension of the cables will help lend some support.
Return the faceplate and insert its clamp bolts into the stem, securing them so everything doesn’t fall out. You can now slide the old stem off the fork’s steerer tube.
INSTALLING THE SHOCKSTOP STEM
Loosen the ShockStop’s clamp bolts and remove the faceplate. All six of the ShockStop’s bolts have lock washers; take care not to lose them.
Remove the orange warning label.
You will see the innards of the ShockStop. These are the two pre-installed elastomers and the preload wedge in the middle, secured by a 3 mm hex bolt.
Clean off the old grease on the fork’s steerer tube, smear a light coat of fresh grease, then slide the ShockStop stem on. It was unusually tight, and I found it best to totally remove the pinch bolts first.
Reinstall the top cap and any spacers. Tighten the top cap bolt just enough to remove any headset looseness, then tighten up the pinch bolts the same way. Final torque comes later.
As we’ve already seen, it comes with two elastomers pre-installed, both secured by the pre-load wedge. For a closer look, we will loosen the pre-load wedge with the 3 mm hex key.
Removing the pre-load wedge gives access to the elastomers and exposes more of the ShockStop’s design. When the stem is in action and moving its pivot, any installed elastomers are basically compressed against the upper walls of the stem and the inner cross, plus the pre-load wedge.
Redshift supplies each ShockStop stem with five elastomer options, color-coded to a specific durometer, or hardness rating. The options range from 50A to 90A in 10A increments. When used with a drop handlebar, two of them are supposed to go in the stem. (As it turns out, the pre-installed combination is 70 + 60.)
Redshift recommends using combinations of them against your body weight, although you can experiment should you want more or less stiffness. Part of my evaluation will take this tuning ability into account. For now, I followed the included table and installed the 80A + 70A combination.
Make sure the little removal loops sit against the inner walls of the stem. The instructions will also tell you to apply some weight on top of the stem as you wind in the pre-load wedge bolt with a 3 mm hex key. This ensures the bolt goes in straight and avoids cross-threading.
The pre-load wedge bolt is the critical point of failure on the ShockStop. If it breaks, you will be left with no way to replace elastomers. It takes about 30 turns to fully snug up, and a very low 2.5 Nm to tighten properly. Using medium-strength thread locker on this bolt is a good idea if you plan on using the ShockStop for riding on gravel.
Once the elastomers and pre-load wedge are in, you can reinstall your handlebars and snug up the faceplate using its four bolts. Some carbon assembly paste on the clamping area of the handlebars and the stem faceplate will help increase friction and decrease the required torque.
Line up the mark you made on the handlebar with the stem, break out the torque wrench, and alternately tighten the faceplate bolts in a criss-cross pattern until you crank them up to 5 Nm. Align your stem with your front wheel and proceed with adjusting your headset and applying final torque on the pinch bolts.
Normally, most riders would be finished at this point, but the utility mount requires a few more steps.
INSTALLING THE UTILITY MOUNT
You will have to replace two of the faceplate bolts with longer ones that come with the utility mount. These have lock washers of their own, so make sure you don’t lose them either.
Thread the longer bolts through the holes on the utility mount, through the faceplate, and into the ShockStop stem. Once you figure out how you want the utility mount installed, tighten them until snug.
Due to the shape of the utility mount, it’s almost impossible to use a bulky torque wrench on its bolts. The next best thing you can do is to use the torque wrench on the bolts that don’t involve the utility mount, while estimating the torque on the utility mount bolts by feel. Maintain a consistent gap between the stem and its faceplate, top and bottom. A 2 mm hex key makes a good feeler gauge.
After headset adjustment, final torque on pinch bolts, and reinstalling all my accessory mounts, this is the end result. I wanted central mounting for my Volt 1200 front light, while freeing a bit more room on my handlebars. Working around interference, I repositioned the out-front mount and speed sensor for my Cat Eye Micro Wireless cyclocomputer over to the left. I also repeated the stem install because I was already riding my old stem at -6 degrees. Time for some riding impressions.