The deflection diaries, part 4: Redshift Sports ShockStop stem review

After whittling down the various methods of adding suspension to a road bike to just Redshift Sports’ ShockStop suspension stem, then installing it onto Hyro’s fork steerer tube…how does it feel out in the real world?

STATIC IMPRESSIONS

I was half-expecting it to be a floppy mess, with lots of unintended movement every which way, but the ShockStop moves in an arc in only one axis (up and down) with zero lateral slop. The only uncontrolled movement you’ll feel is when it has no elastomers in it – which then highlights the smoothness of the pivot bearings. It might have gained 80 g over a rigid stem of the same length, but that weight went into areas that mattered.

The whole deal with the pre-load wedge, and the need to press your weight on the stem before screwing it in – that was a little strange but simple enough to follow. I found you could release the weight once 2/3 of the bolt’s length is in, after about 20 turns clockwise.

The utility mount is also nicely made. It gives you an extra floating section of 25.4 mm handlebar to mount stuff to – perfect for moving bulky items like my Cat Eye Volt 1200 front light to free up space on a narrow drop handlebar. Its shape does mean it’s impossible to use a torque wrench on it unless you have some sort of extension…and even then, it would have to go in at an angle, which isn’t ideal for hex-key-driven fasteners. I think the original design of the utility mount was more torque-wrench-friendly. 

ON THE TURBO TRAINER

Thus equipped, hooking up Hyro to the turbo trainer and mashing my pedals off, it’s surprising how very little happens up front. The only real indication that there’s something different is when cranking up the watts while out of the saddle, and only while on the hoods…and only if you’re consciously looking for it. I noticed a non-dramatic bit of deflection or sag at the stem, unless I was shoving all my weight into the brake hoods, where it deflected all of 1 cm downwards – and rebounded immediately.

Clearly, this thing needed a proper road test.

ON SHORT RIDES

Spins around the block, and around Makati CBD, over a route of concrete roads with humps and other irregularities, revealed still no lateral slop or torsion in the stem. Sprinting, riding out of the saddle, changing hand positions – it all felt pretty natural to me. Attacking humps and road acne at moderate speed, the feeling up front was that of running a slightly softer front tire, despite having an actual pressure of 85 psi.

How would it feel on long rides over the varied streets of Parañaque, Taguig, Muntinlupa, and Bacoor?

ON LONG SUNDAY MORNING RIDES

Riding from my house to Daang Reyna took up the first 25 kilometers, and I didn’t really notice anything different – at least not with the 80A + 70A combo installed, which is recommended for my weight. Continuing the ride with time trial efforts around the Daang Reyna loop, though, had my palms and hands go numb every time I approached the Palazzo Verde U-turn and slowed from 40 km/h. I thought this elastomer combination was a little too stiff, but repeated visits with other combos yielded the same hand numbness, so that might be down to Daang Reyna itself. Impressively though, there wasn’t any undesired front-end “dive” under braking. Numbed fingers aside, I was able to retain as much control as I could, without having to fight with a sagging stem.

Tuning Hyro’s ride feel with other elastomer combos yielded interesting results.

  • The pre-installed 70A + 60A combo was way too soft and had insufficient damping. I could tell without riding that it wasn’t for me and I swapped it out straight away.
  • The 80A + 50A combo is listed as the next step in increased stiffness, but felt similar to the 70A + 60A combo. The static sag is noticeable, although not disconcerting. I could feel the stem moving through its travel when I yanked on the bars via the brake hoods, though.
  • Finally I tried the 80A + 60A combo. This is what I’m currently on, and was my Goldilocks setup for a good long while. Going over a “washboard” of closely-set speed bumps, there was enough compliance left in the ShockStop, but the elastomers tightened up the damping and reduced the static sag to a more natural amount. That said, it seems like this combo has broken in and there is now a bit more movement, so I’m considering a return to the 80A + 70A combo.

The 80A + 60A elastomer combo. The deformation on the 80A elastomer is from the pre-load wedge.

Even with the mushier elastomer combos, it’s impressive how little the ShockStop affects handling. The stem will provide 1-2 cm of actual squish in the handlebars, but I didn’t really notice it unless I unweighted the handlebars quickly, or deliberately pulled up on them as in a bunnyhop. It simply let me get on with my riding, in the saddle or out of it, with no unpleasant pogo-stick sensations.

VERDICT

So the ShockStop stem is a little heavier and quite a bit pricier than a normal rigid stem of aluminum alloy. It’s nowhere near the price of a carbon stem though.

Then again, it can introduce front-end riding comfort to any bike with a 1-1/8″ (1.125″) threadless steerer tube; its stiffness can be tuned to your liking; and it can do its job without resorting to any other engineering compromises. There’s not much that can touch it, in my opinion. The only thing I’ve seen most similar to it is the TranzX AntiShock suspension stem, which also uses a single-pivot design. However, it involves a two-piece steerer tube clamp, and comes in a slightly greater range of lengths (as short as 80 mm), but no +30-degree option.

People have taken their ShockStop stems riding in the cold, and have reported no adverse effects on the elastomers. Redshift says the elastomers will last 3-5 years in normal operation; if you need extras, they can sell you a full set of five for a small fee.

Given how well the ShockStop works on the ridiculousness of Philippine road surfaces, I am seriously impressed. Highly recommended.

Advertisements

The deflection diaries, part 3: Installing the ShockStop stem

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.

Redshift Sports ShockStop stem up top, Giant’s stock stem at the bottom. The ShockStop has its faceplate removed.

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.

Utility mount installed on the top faceplate bolts while hanging down. You can install it with the bar section curled upward.

Utility mount installed on the bottom faceplate bolts while hanging down. This is what I ended up as a final setup.

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.

ShockStop stem and utility mount installed and accessory mounts remounted. Note the out-front mount for my computer is on the “wrong” side now.

The deflection diaries, part 2: Aftermarket solutions

Previously I wrote about the various tricks manufacturers use to bake comfort into their road bikes, and I finished with Specialized introducing the FutureShock suspension cartridge on refreshed versions of its Roubaix and Diverge bikes. With that system, only the rider’s weight on the handlebars is suspended.

I purposely left it for last.

In 2015, a little American company called Redshift Sports opened a crowdfunding campaign on Kickstarter for their ShockStop suspension stem. This was almost two years prior to Specialized announcing the FutureShock, and almost thirty years after Girvin attempted a similar product. So when the 2017 version of the Roubaix came out, it served as validation of the concept behind Redshift’s product – from one of the big legal bullies of the bike industry, no less. Better yet, unlike the many prior attempts to add suspension to a stem, the ShockStop is 95% a normal stem, so it should be usable with any bike with a threadless fork steerer tube 1-1/8″ (1.125″) in diameter, without any funny compromises such as grub screws for headset bearing adjustment or expectations of unrealistic suspension travel.

Crowdfunding was a success, and you can now purchase the ShockStop stem via retail channels. I spotted a good deal on it, bundling a dedicated utility mount, so I decided to try it out.

This is the shortest 90 mm version with +/-6 degrees of rise. It’s offered in 10 mm length increments up to 120 mm, and it is also available in a 100 mm variant with a +30 degree rise, which you’re not supposed to install inverted.

It includes five wedge-shaped elastomers; two are installed by default.

The stem itself is almost disappointingly stealthy, finished in matte black with some polished logo accents. Only the pivots on the sides and the slightly disjointed look of the steerer tube end give anything away.

What’s remarkable about the boxy ShockStop is it feels really beefy, with no play or looseness when off the bike. Since the Girvin FlexStem dabbled in the concept in 1987, materials and construction methods have improved considerably, and expectations have been scaled back. It’s not one for the weight weenies though. Reviews out there rate this stem at 255 g, which is roughly 80 g heavier than a conventional stem of the same length, but lighter than either a more complicated StaFast suspension stem (367 g) or Cannondale’s Lefty Oliver suspension fork (1195 g on its own, or +800 g vs a typical rigid carbon fork).

Behind that orange warning label, you can barely make out the pre-installed 70A and 80A elastomers and the preload wedge keeping them in place.

All the exterior bolts are turned by a 4 mm hex key, and have knurling and split lock washers on them. Be careful you don’t drop the bolts, as the lock washers have a knack for flying off into hard-to-find nooks and crannies after hitting the floor.

The stem rise and length show up on top when it’s at the inverted -6 degree position.

The 5 Nm torque figure is shown when the stem is at the +6 degree rise position.

Pinch bolts are also tightened to 5 Nm.

The utility mount bundled with the ShockStop has the two longer bolts needed to attach through the stem’s faceplate. It’s similar to the Minoura Space Grip, which gives you an additional section of “handlebar” to hang accessories off from.

Does it work as advertised? Stay tuned.