We’ve talked about highly anticipated products before. Hardly anything has had us biting our collective nails as much as Truvativ HammerSchmidt. That’s the beauty of the bike industry — once we think we’ve seen the best and brightest, and that technology has taken us to the top, along comes a new model year and a slew of hot new products. Thankfully, some schools around the country, and the world for that matter, are graduating industrious and enterprising designers and engineers. HammerSchmidt is the first of its kind to hit the beaches here in the states, one of a group of at least three separate gearbox cranksets being talked about in the industry. “No way, Schlumpf has had one for sale for some time now,” you might be yelling at us, but who the hell has ever heard of Schlumpf? None of the people we ride with, nobody we know, and who knows…any U.S. distributors? Bionicon and Nicolai have the B-Boxx in the works, but what have they got…a nice drawing, an entertaining and informative website, and a few handmade prototypes? Enter the global powerhouse of SRAM. They have displayed that sometimes it pays to have vast resources to draw from in order to develop great ideas into actual production componentry.
Truvativ HammerSchmidt has changed the way we think about front derailleurs. We don’t need ‘em. We made up our minds about three seconds into our test ride across the shop floor. In that miniscule space of distance and time, we shifted the HammerSchmidt a multitude of times. Wow! You want a crisp shift up or down? You got it, says SRAM. No need to soft pedal as we wait for a traditional front derailleur to force the chain to climb up onto the next bigger chainring. Ramps, pins, notches, and custom tuned tooth shapes are no longer necessary to bandage the proverbial broken arm that is what the front derailleur/multiple chainrings seem to be now. No matter the crank cadence (or direction), HammerSchmidt shifts. You can shift while coasting or standing still. Hell, you can shift while pedaling backwards!
We’d heard lots of rumors about this thing. Until we rode it at Interbike Dirt Demo, we could only speculate as to how it worked. While we were impressed after riding it in Bootleg Canyon, it was still a bit of a mystery. Actually, as we like to comment on the occasional perplexing issue here at the Competitive Cyclist service area, “it’s a mystery wrapped in a riddle.” HammerSchmidt sure was. The best way to understand it, we found, was to unwrap the package. As soon as we got one in our hands, we were dying to take it apart. Of course we couldn’t as we needed to get some images of it for our website. A late night delivery from the photographer ensured that we could tear into promptly on day two.
Tear down on the Truvativ HammerSchmidt was actually quite easy. At Competitive Cyclist, we’re pretty fortunate to be able to get our hands on hard-to-get new products. Sometimes what that means though, is that we get pre-production stuff. In the case of our HammerSchmidt, we got in it a plain brown box with only the necessary parts. Since Truvativ hasn’t got the production units for the aftermarket ready, that also includes the packaging and literature, so we were in our own little wilderness. We went for it anyway. Our curiosity to see the inside of the HammerSchmidt was too much to bear. Disassembly took less than ten minutes with no prior knowledge of the unit. We used simple hand tools hanging right here on our workbench.
Upon inspection of the guts, it became apparent how simple it really is. HammerSchmidt is one of those things that seems complex, but really is not. In simple terms, it’s just a planetary gearbox. A planetary gearset has three components, a sun gear with teeth on its outer diameter, planet gears that have teeth on their outer diameter that revolve around it, and an annulus or annular gear that has teeth on its inner diameter. All these gears mesh together. In the low gear, the planetary assembly rotates as one unit and the crank delivers a 1:1 drive ratio. Our HammerSchmidt came with a 24 tooth chainring on it. It is also available with a 22 tooth chainring. It spins freely like any other crank, as none of the internal parts are in action until the rider selects for the overdrive. In overdrive, the planetary gearset is activated when the rider pushes the small thumb paddle on the shifter, releasing cable to the lever on the inboard side of the backing plate. This in turn frees three pawls, attached to the backing plate, that “catch” the inside of the sun gear. As the rider pedals, the planet gears, which are attached to the four bolts on the crank, rotate around the now fixed sun gear and drive the annular ring, to which the chainring is attached, at a 1.6:1 drive ratio. This effectively turns the 24 tooth ring on our HammerSchmidt into a 38 tooth chainring.
After a thorough, on-bench inspection of all of its internal workings, we put the HammerSchmidt back together in roughly five minutes. If we add our tear down time to our assembly time, which included cleaning and re-lubricating all the gizmos, total time for a normal servicing would be less than twenty minutes. We were ready for some frame prep and install.
Our test mule for this project was an ’06 Turner RFX. The folks at SRAM have been emphasizing the need to ensure that the ISCG tabs and bottom bracket shell are faced properly so that the HammerSchmidt backing plate sits squarely relative to the bottom bracket spindle axis. We presume that any gross misalignment here could cause problems with the pawls operating correctly inside the sun gear to make the shift between low and high gear. On our test bike, it was necessary to face the drive side of the bottom bracket shell to make it flush with the ISCG tabs. The tabs on our bike were very slightly off plane. It was an interesting experiment to see if it would work or not. It did, and we were relieved because we had to remove a small amount of material from the drive side of the swingarm yoke to make clearance for the HammerSchmidt backing plate. We love a good project, but files and sandpaper may not be something that many folks like to use on their pride and joy. So be aware that until manufacturers make statements about HammerSchmidt compatibility, any guesses about simplicity of the installation would be just that, guesses.
The complete Truvativ HammerSchmidt Freeride version that we tested tipped the scales at 1940 grams with the shifter. We replaced a single ring setup that included an XT crank and bottom bracket, a 36-tooth e.13 chainring, and an e.13 SRS single ring tensioner and polycarbonate bashguard. Admittedly, our old parts tickled the scales at 1260 grams, but the XT crank isn’t a straight comparison to the Holzfeller-level HammerSchmidt Freeride setup. We gained 680 grams with the swap to HammerSchmidt. But with that extra beef, we also gained a climbing gear and a bigger top gear for fast downhills. We’re sure that the weight differences would be less if we had replaced a comparable dual ring setup with a front derailleur and bashguard. In fact, Truvativ’s published weights for the Holzfeller front setup with two chainrings, a bashguard, and front derailleur, is only 11 grams less than the Freeride HammerSchmidt. The security that the HammerSchmidt provides for the chain, the massive increase in ground clearance, and a nice chainline all the time are things that make a slight increase in weight a favorable trade-off.
For the weight conscious or someone who isn’t hucking 25 foot cliffs on their mountain bike (not that we are either), the All-Mountain version of the HammerSchmidt might be a better choice. While still no favorite with the weight weenies, the All-Mountain HammerSchmidt weighs in at 1623 grams. That’s 162 grams less than the advertised 1785 grams of the Freeride version. Be aware that our aforementioned weight measurement for the freeride HammerSchmidt included the shifter. SRAM’s weights are for the crankset, bottom bracket, and all necessary hardware but do not include the shifter. While 162 grams may not sound like much, saving weight is saving weight. We’re sure that the All-Mountain HammerSchmidt can handle a beating as well as anything we normally ride. The All-Mountain version has a lower Q-factor than the Freeride crank, at 169mm and 177mm respectively. For comparison, a Truvativ Stylo has a Q-factor of 176.5mm. We didn’t feel like we were doing the splits aboard the Freeride version, but the wider Q-factor was something that we noticed. Having a single front chainring, both versions allow the use of a short cage rear derailleur and fewer links in the chain, and that would help even out the addition of the HammerSchmidt in place of a typical dual ring/bashguard setup. Given the intended purpose of the HammerSchmidt, we feel like it is awesome for those kinds of riders who prefer riding gnarly, technical trails. The increase in ground clearance, both at the crank and with a short cage rear derailleur, increases our confidence when we tackle boulder laden trails and rocky ledges. We know we won’t blow anything up and end up walking out of the woods.
Out on the trail, at least for the first ride, we were continuously surprised by the quickness of the HammerSchmidt shifts, both up and down. With a traditional system, upshifts to larger chainrings usually happen pretty slowly by comparison. Once we became used to it, we were able to shift at will, under any power load, anytime we wanted. Imagine riding a new trail and bombing down a hill at speed only to find a sharp blind corner with a steep short climb directly after. This situation is tailor-made for the HammerSchmidt. To maintain speed, it would be ideal to grind into the climb right out of the corner. With a traditional front derailleur system, you’d need to soft pedal for a bit to get the downshift. We can only hope that you keep your chains clean, otherwise the dreaded chainsuck might occur.
None of this is a concern for riders with the HammerSchmidt. As stated earlier, in the low gear, the HammerSchmidt pedals like any other crank. We appreciated that since we were grinding up to the top of the mountain when we were in the low gear. Where we once had a single ring on our RFX and long steep climbs were tough, if not impossible, we suddenly had a manageable climbing gear. Once over the top of the hill, we jammed it into overdrive and hammered back down. When it is in overdrive, the HammerSchmidt exhibits minor mechanical drag. This is due to the drag within the planetary gearset as the planet gears roll around the sun gear and overdrive the annular ring. Some of the noticeable drag is partly due to the three pawls on the sun gear dragging on the inside of the annular ring. While this may sound unbearable to those who haven’t ridden it yet, trust that we think it is worth it. The drag is enough to be noticeable, but we found it disappears out on the trail. The rougher the trail, the better.
We always try to be at the forefront of new technology so that we may take advantage of emerging sectors of the market. With this in mind, we get excited about new stuff like this. However, there will always be an air of skepticism until we get to ride these new products. With the HammerSchmidt, we had high expectations. It performed flawlessly. There has never been a faster front shift. No way. We’ve ridden it up hills and down, through the mud, muck, and rain, and we’ve jumped it off rocks and ledges. We’ve had it at our dirt jump park and shifted mid-jump, in the air. Truvativ HammerSchmidt does everything it was designed to do with sturdy assurance.
We wonder, who might be our potential customer for this great new product? Those of us who rode it, want one. That is, except for the cross country guys. Admittedly, they’re a bunch of weight weenies, so the HammerScmidt in either version is about as appealing to them as lead grips. But those of us who’ve thrown away our big rings and dream about Whistler, Megavalanche, or someday nailing a barspin 360, want one in a bad way. So the obvious transition would be from a traditional front derailleur/ dual ring setup. A move to the HammerSchmidt wouldn’t gain that much weight, and would provide the security of a single ring. The chain is nestled down in a protected trough on the HammerSchmidt. The guide on top of the unit keeps it from flying off and becoming derailed. That rider would also have more ground clearance for extremely technical, rocky trails.
We think that it would also be awesome on our dirt jumper/urban bikes too. Imagine this. We ride when we can, where we can. When we have daylight in the evenings after work, we ride the dirt jumps and trails around town. This time of year, when it’s dark at 5:00 pm, we end up riding street in the downtown Little Rock area. The riding is a little different. Instead of sprinting into or between jumps at speed, our street riding is sometimes more like a trials session. For the trials type stunts, it would be great to have a gear lower than what we normally have on our bikes to facilitate pedal kicks over obstacles. We could run a HammerSchmidt to increase our ground clearance, and if we geared the rear hub accordingly, we could have a low gear suitable for our street sessions and a high gear for riding to the next session spot or for hammering down on the trails or at the dirt jump park. Two gears, one great crankset, and loads of fun!
It must be noted that the HammerSchmidt uses its own bottom bracket. It is not compatible with any other b.b. system on the market. Truvativ uses an external bearing and cup on the left side of the crank and an ISIS style double row bearing on the right side. The ISIS system on the right side must be used because of the width of the planetary assembly. We remember some horrific battles with frozen and mangled ISIS bottom bracket bearings in the past. Looking back, most of those disasters were examples of serious neglect. However, we’ll keep our eyes on those double drive-side bearings. We haven’t experienced any negative issues with them up to this point. SRAM sells a HammerSchmidt specific shifter as well. The X.0 version has an anvil logo etched onto the big thumb paddle. It is a left side specific shifter, so anyone looking to install a HammerSchmidt on their rear-brake only dirt jump rig with the idea of keeping the left side of the bar clean will have to improvise something. We can only speculate, but maybe a Gripshifter or Poploc would work? All it has to do is pull cable right? We’d love to hear about any experiments.
SRAM is here to stay. They’ve placed themselves in the heap, maybe even at the top. Their commitment to refining existing bike technology to better our mountain biking experience is something that we’re very appreciative of here at Competitive Cyclist. Truvativ HammerSchmidt, in our minds, is a revolution. It won’t change the whole world, but it might change some of ours.