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.

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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.

The deflection diaries, part 1: Adding suspension to a road bike?

If you ride a mountain bike, chances are you are familiar with having some form of suspension – at least on the fork legs. Traditionally, however, road bikes with drop handlebars rarely use suspension at all. Short of double-wrapping bar tape and fitting wider tires, how do manufacturers bake comfort into their road bikes?

FRAME MATERIAL

A custom titanium bike made by Triton Cycles. The simple, round tube shaping is reminiscent of how steel bicycle frames were (and still are) made.

Up to the mid-1980s, almost all road bicycles were made of steel, and for good reason. Despite its weight and susceptibility to corrosion, steel delivers a characteristic springiness to its ride quality that helps absorb bumps and keeps a rider fresh over long distances, which is why it’s still a favorite of bicycle tourers.

The later introduction of titanium addresses the corrosion and cuts weight, but is otherwise essentially a “twin” frame material to steel. It has never seen widespread adoption, though, because of its reputation for being hard on its tooling and finicky with welding…both factors driving up its price.

6061 aluminum alloy is one of the most common materials used in bicycle frames.

Due to the expense of titanium and professional cycling’s desire to drop the weight of steel, aluminum came into prominence. Early frames, however, were infamous for a harsh ride. Manufacturers later learned to manipulate it into frame tubes vastly different from the simple round ones of steel bicycles using a couple of favored tricks. Double- or triple-butted aluminum frame tubes have multiple wall thicknesses along their length, allowing comfort to be tuned and weight reduced, while hydroforming shapes the tubes during manufacture to maximize the material’s more meager strength. While current aluminum frames ride better than ever, very few bicycles use the material on fork blades.

My friend Michael Nera riding his white Giant Defy Advanced – a carbon fiber endurance road bike.

The concept of “tuning” the frame material peaked with carbon fiber composites. In addition to tube shaping and butting, the properties of a carbon fiber frame are dictated by the types of carbon fiber ply used, and their subsequent layup. High modulus carbon fiber is good for stiffness per unit weight, but bad for comfort; lower modulus carbon fiber is usually applied to places where either greater flex or a lower price point are desired. With these layups a closely guarded secret, the scope of tuning a bicycle frame is much wider.

GAPS AND GIVE

Manipulating the material itself to create a suspension effect can only get you so far, though, as competitors of the annual cobblestoned cycling races Paris-Roubaix and the Tour of Flanders can attest to.

The Lynskey Pro Cross titanium bike I test-rode in 2016 used a fork stolen from a Specialized Roubaix SL4. Midway up its blades are Zertz elastomer inserts.

Specialized tore out the rule book with its Roubaix endurance road bike. In early iterations, the Roubaix introduced gaps cut into its seat stays and fork blades, filled with elastomer inserts. In a clever bit of marketing, Specialized called the system “Zertz,” making it look like the elastomers doing the job. In reality, the subtle flex created by the gaps they sat in did the lion’s share of the work.

Other manufacturers have taken notice. Notably, Italian manufacturer Wilier injected elastomers into a linkage built into the rear triangle of its new Cento10NDR endurance road bike, which can be swapped for a different density to tune the ride. Another Italian maker, Pinarello, made a damper out of the elastomers themselves with their Dogma K8-S.

MECHANICAL FLEX

Trek first introduced its IsoSpeed Decoupler on its Domane endurance road bike, which induces more leaf spring effect by decoupling the seat tube from the rest of the bike. Photo courtesy CyclingTips; click for review.

Trek went about introducing comfort a different way via the so-called “IsoSpeed Decoupler” on their Domane road bikes. A bearing pivot helps isolate the seat tube from the rest of the bike, helping it flex more freely and making it act like a leaf spring. It was so successful that they even engineered it into the Madone, their aero bike, in a novel “nested seat post” implementation.

Later incarnations of the Domane introduce the IsoSpeed Decoupler tech up front, which is a pivot at the steerer tube and headset area, in order to balance the front end with the bike’s plush-riding rear.

SHORT-TRAVEL SUSPENSION

Cannondale’s Slate gravel bike uses a Lefty Oliver suspension fork with a scant 30 mm of travel. Photo courtesy CyclingTips; click for their review of the bike.

Somewhere along the way, the engineers at Cannondale must have thought “why not try something from the mountain bike world?” when they set about designing their gravel bike, the Slate, released in 2015. Coupling with larger-volume 650B tires was a modified version of their Lefty suspension fork, dubbed the Oliver.

Beyond the funny looks, the Slate stoked the adoption of suspension for an otherwise rigid cyclocross or gravel bike. Fox retooled one of its forks into a short-travel “AX” unit, while Lauf got into the game with its Grit fork as well, using glass-fiber leaf springs that shed weight over a traditional damper unit.

Instead of hydraulic pistons, Lauf’s Grit suspension fork uses 12 glass-fiber leaf springs for vibration absorption. Photo courtesy BikeRadar; click for their review.

Where your typical mountain bike will yield anywhere from 100 to 160 mm of suspension travel up front, those adopted by road and gravel cyclists are typically limited to 30 mm.

One downside to this design is it’s susceptible to a phenomenon called “pedal bob.” Under high pedaling loads, the suspension can squish with each pedal stroke, sapping power. On mountain bike forks and similar, this is dealt with by actuating a mechanical suspension lockout, but this also adds a layer of complexity.

SUSPENSION UP TOP?

During my 2016 visit to Singapore’s Ubi Vertex, the Specialized store had the 2017 Roubaix lineup with FutureShock front and center.

With the Roubaix refreshed for 2017, Specialized retired the Zertz system and dabbled with suspension of its own. They went their own way and put it higher up, above the head tube.

The result is a needle-bearing suspension cartridge within the fork’s hollow steerer tube, dubbed “FutureShock.” A couple of springs provides the 20 mm of suspension, and Specialized gives you three options of upper spring for tuning firmness. Because this design suspends only the weight of the handlebars and nothing else, the company says it is resistant to pedal bob and other undesired effects.

The FutureShock suspension cartridge rules out a traditional star-fangled nut or compression plug for headset adjustment, so that procedure relies on grub screws on the sides of the Roubaix’s head tube. Photo courtesy CyclingTips; click for review.

FutureShock isn’t without its problems, either. As the cartridge occupies the space where a star-fangled nut or a compression plug would sit for headset adjustment, that procedure is done via a couple of grub screws, which some reviews say don’t like to keep their tightness.