Truvativ engineers aim to obsolete the front derailleur
Previewed: Unveiling Truvativ's Hammerschmidt
Text and photos: Alan Davis
Since spring, we've been subject to a barrage of ambiguous ads and various clandestine activity from the folks at Truvativ all in the name of Hammerschmidt. Thankfully the veil of secrecy has been officially lifted and Truvativ is publicly revealing its secret product.
The freeride version of Hammerschmidt
Hammerschmidt is a crank and bottom bracket combination with an integrated planetary drive mechanism. It’s essentially a two-speed crankset. It gives the reliability of a single-ring system with chainguide and the gear range of a two-ring system, plus improved shifting. At first glance it looks shockingly small, with just a single 22 or 24-tooth ring.
Such a small front ring yields incredible ground clearance and, when combined with the 1.6x multiplication factor of the planetary mechanism inside, you get an approximate 36 or 38 tooth high gear. These 22x36 or 24x38 gear combinations are already standard on many all-mountain and freeride bikes so these numbers should be familiar to riders.
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Truvativ developed two Hammerschmidt models. One is an all-mountain build comparable to Stylo cranks while the other freeride build uses cranks along the lines of the venerable Holzfeller. An included shifter looks remarkably similar to a SRAM X.0 model, but has only two positions.
There are several advantages to a single-ring, planetary-drive crankset. Riders can shift gears under incredible torque loads, while the cranks are stationary, or while pedaling backward. During the official unveiling, SRAM spokesman Greg Herbold was quick to point out that he could even shift while airborne. And shifting is more instantaneous than conventional derailleur systems—the gear mechanism uses a set of pawls to quickly engage a ramped gear, and they do it faster and more reliably than a conventional chain with a row of lifting ramps.
Here's the shifter, aside from the anvil emblem on the paddle it looks just like an X.0 shifter
What's a planetary gear look like anyway? Here are the two halves of the mechanism. The crank arm with planet gears and locking pawls on the left and the sun gear on the right.
Watch an introduction to Hammerschmidt video HERE.
What do you think of the Hammerschmidt? Leave a comment below.
Good Idea, adapting Auto trans tech from cars. All that metal might have a slight weight penalty for racers but this obviously not aimed at the XTR crowd. Time will tell for durability and I would expect a few bugs/teething problems with the first two runs. Still though, I gotta have it!!
Posted Wed Aug13, 2008, 2:35 AM — By photo-john
That is f-ing sweet. Gimme.
Posted Wed Aug13, 2008, 5:21 AM — By Olly
Very interesting indeed. Obviously it'll need to be reliable and *very* well sealed if it's going to survive a typical british winter (mmm, gritty).
The only slight downer is the ISCG requirement, good excuse for a new bike though :D
Posted Wed Aug13, 2008, 8:51 AM — By Interested
Hammerschmidt + belt drive + economical Rohloff = bombproof
I would be all over the theoretical XC model, for sure. Far more exciting than external bottom brackets ever were.
Posted Wed Aug13, 2008, 4:56 PM — By jeremy
When can I get one? Sign me up!Not afraid of change that is long overdue in the bike industry!
Lots of suspension designs pedal poorly and offer lots of pedal kickback when pedaling in the granny gear. I'm not sure I want to be permanently stuck there as far as the chain tension/suspension effect is concerned, regardless of the gear ratio.
Posted Wed Aug13, 2008, 10:50 PM — By Peter
that looks sick I want one. It looks like its sortof like the honda bike transmision
Posted Thu Aug14, 2008, 7:44 PM — By Axle
I have been fantasizing about something like this for a long time. High and low gearing, just like my 4x4 truck- it's about fucking time. But if it relies on the 9 speed system, I am not going to buy it. I am pedaling around a heavy bike (40 lbs) and I don't really need 27 gears. I just need a super low gear for climbing, a downhill gear, and a few gears in between. This used to be known as 8 speed, and it was way more reliable and durable than 9 speed. Unfortunately, it was impossible to buy a 8 speed setup with a nice 34 tooth cassette. 9 speed chains, narrow as they are, wear out way faster, need much more adjustment to say shifting smoothly, and and are way easier to break or kink than stout 8 speed chains. Small front rings wear out fast, and if I still have to buy a new $100 cassette and $30 chain every year, I don't see myself switching to this system. But it is a step in the right direction. Go back to fatter chains, while maintaining the super low gearing, and I am totally sold.
Posted Fri Aug15, 2008, 3:47 PM — By gregb406
I assume the chainrings are replaceable and either 22 or 24 teeth. I wonder if a few other sizes will be available, because either of those would be too low for a Rohloff hub.
Posted Sat Aug16, 2008, 1:24 AM — By Dan
Looks pretty sweet, though the necessity of ISCG tabs mean we're all on the hook to buy new frames, too. Bummer. Maybe the likes of Dave Weagle can come up with a reliable retrofit kit?
Posted Sun Aug17, 2008, 4:50 AM — By Webitor
Axle - It doesn't have anything to do with 8 or 9 speed rear shifting. It's only the front gearing. You can run it 7,8 or 9 speed or single speed or with a rohloff, although each of those systems will have its own advantages and disadvantages in different environments.
Greg - For starters the chainrings are 22 and 24, I have a feeling other sizes will be available in the future. The current FR and AM designs completely capture the chain though and so they will have some sort of tooth limit because of the chain guide/bash guard design.
Posted Tue Aug19, 2008, 10:25 PM — By Evan
I want one for my townie with an 8-speed Nexus hub. Now that would be sweet. The design looks like it would be very commuter-friendly.
Posted Mon Aug25, 2008, 6:34 AM — By adders from Sillygrin
this unit replaces a 22T & 36T from a standard 9speed set up.
it wouldn't make sense to use it with a rohlof as you get a full range of ratios (over 14gears) just like a 27speed set up but with with a single front ring.
The application is a replacement for duplex 9 speed front - leaving the 9 speed cassette and rear mech which SRAM already manufacture.
it does however open the door for rohloff to develope a new unit with fewer ratios that you could use WITH this system to multiply up to your 27speed equivalent - but then why have 2 levers & cables which rohloff already have a 1 lever, 1 cable solution which does the job. Hmmm could be a betamax/VHS showdown on the horizon...
Posted Tue Aug26, 2008, 11:50 AM — By JaKeefer
HammerSchmidt + improved version of shimano's 8 speed alpine rear hub = potential greatness...
Posted Wed Aug27, 2008, 11:45 PM — By Jerome
looks interesting, agree might require a larger (but still small!) ring to work for many folks' purposes
seems would also mean shorter caged derailleurs could be used, thanks to no chain slack from front shifts
Posted Thu Aug28, 2008, 11:29 PM — By Tim
Looks cool. Immediately I think of BMX. It looks like the only thing that limits the size of the front sprocket is the chain guide piece. It might require a custom sprocket, but if you were running a single speed in the back you wouldn't need a chain guide. Being able to shift under load and have that 1:1.6 ratio would change everything.
For all those commuters who are lamenting being neglected during the debut of this thing, you should know that your product has already existed for some time made by Schlumpf Innovations (http://www.schlumpf.ch/md_engl.htm). And it's way cooler anyways because it dumps the cable and shifter. Ride on.
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