Truvativ's new Hammerschmidt drivetrain system

Hammerschmidt drivetrain system (SRAM)

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After months of online teasers, rumours and speculation SRAM (the people behind the Truvativ brand) have finally shown their hand and unveiled their new all-mountain and freeride drivetrain system which has the potential to change the future of gear shifting.

BikeRadar contributor Callum Jelley is at the Crankworx freeride mountain bike festival in Whistler, where the Hammerschmidt has just been launched. He’s been lucky enough to test the new drive system, so here’s his take on it…

An idea first proposed to SRAM's advanced design group over two and a half years ago, the Hammerschmidt has been a challenge from the start; to create a front chainset with the security of a single ring chain device system along with the versatility of a dual ring setup all in a neat little package fit for everyone from the all-mountain warrior to the downhill racer. 

The Hammerschmidt is a very difficult thing to describe as it is truly innovative and this is why SRAM market it as ‘magic mechanics’. 

Based around either a 22 or 24-tooth single ring, the system can be ridden in either a 1:1 ratio or what SRAM term 'overdrive'. 1:1 is used when the system is engaged and you are just pedalling a normal single ring. When you shift into ‘overdrive’ you turn the chainring 1.6 times with one revolution of the crank giving you effectively a 14-tooth jump in chain ring size. 

So you have the choice of a 22-36 or 24-38 tooth setup.  What this all really means is that you now get the convenience of a dual ring chainset without the need for a front derailleur and with no worries of the chain popping off at crucial moments, all encased in a sleek well protected package. 

The chain is encased in a sleek well protected package

The detail

The Hammerschmidt is available for both all-mountain and freeride-specific use. The all mountain version is based on the Truvativ Stylo with 170mm and 175mm crank lengths. The freeride version is inspired by the Truvativ Holzfeller, coming in 165, 170 and 175mm size options.

Hammerschmidt has its own shifter and a bottom bracket that will be specific to either the all mountain or freeride model.  The single ring offers superior chain management and also allows full access to the rear cassette meaning you never have to worry about crossing up your gears. Based around a small ring, it also allows you to run a downhill style setup, ie shorter chain and shorter cage rear derailleur further decreasing chain noise and derailleur exposure to roots, rocks and other trail objects. 

The freeride crankarm in all its glory

The Hammerschmidt mounts onto ISCG 03 and ISCG 05-equipped frames but SRAM have specified that they must be up to a certain strength and in the correct position which will push frame builders to stop welding them on as somewhat of an afterthought.  This ultimately means that the Hammerschmidt will start as a piece of original equipment rather than an after market product.

The ride

The ride is a testament to the years of work that have gone into this product.  The shift is instant and solid whether under full load of freewheeling. There is no grinding and no hesitation.  This enables you to concentrate on what you are riding rather than focusing what gear you need to be in for the next technical ascent.  This was extremely prevalent to me as I am a poor technical climber often shifting too late into a section and grinding to a halt. 

Superior ground clearance means less chance of hitting trail obstacles

When riding the Hammerschmidt you don’t have to think about the gear, merely the line you will take and if you get stuck you drop the hammer and you’re into 1:1 ratio (granny ring) and home and dry. 

The rear cassette becomes far more usable too and you find yourself regularly riding in 1:1 as the shift into overdrive is a big one and can feel sluggish on undulating trails.  Ground clearance is supreme and takes some time to get used to as the places you are used to getting caught up on the trail are now easily clearable and even when you do manage to smash it off something, which takes some effort, it shrugs it off just as a regular bash guarded system would. 

It is going to be interesting to see how companies and frame builders respond to the Hammerschmidt.  After years of designing frames and suspension systems around a double or triple ring system, they now have a new challenge to incorporate this new technology, hopefully for all our benefits.

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