Hammerschmidt

7 04 2010

My last post I talked about the idea of putting a Rohloff in my Santa Cruz Nomad.  That idea has stalled because of the performance issues associated with adding a significant amount of unsprung weight to the rear wheel.  Another thought is to add a Hammerschmidt 2 speed BB to the Nomad and swap in a short cage rear derailleur.

The Hamerschmidt is a 2 speed BB made by Truvativ.  It gives you a direct drive lower range and an over drive range that is 1.6 times the lower range.  The All Mountain version I’d be interested in would be like having a 24T granny and a 38T middle ring.  Shifting is instantaneous and can happen at any time – under load or while coasting.  I often find myself jumping back and forth between my two front rings [big ring replaced by a bash guard] as I go from steep uphill to steep downhill.

Hammerschmidt internals...

This has the following benefits:

  • no extra weight at the rear wheel
  • shorter derailleur and less chain to slap and move around
  • impossible to throw chain on front rings
  • instant front gear changes when coasting or under load
  • no extra drag in low range when climbing [BB running at 1:1]
  • weatherproof front shifts
  • access to all 9 cogs at rear all the time due to better chain line
  • very good clearance for obstacles
  • small amount of extra weight [200grams or so] is sprung on main frame of bike

The downsides are:

  • not cheap @ $900cdn+ for the All Mountain version
  • Nomad not optimized for running in 24T ring all the time
  • still have a rear derailleur
  • rear end of drivetrain not weatherproof
  • requires ISCG 03 or 05 tabs to mount HS

Photo: Pinkbike

I tried out a Santa Cruz Driver 8 with Hammerschmidt at Bow Cycle and I was impressed.  It shifts so fast you can respond to whatever the trail throws at you without having to pedal or wait for the chain to get sorted.

Hammerschmidt Info:

Photo: HS on Bliz2z' SC Nomad


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12 responses

7 04 2010
Zyzzyx

Ooooh… that is a tasty piece of equipment. If I was still seriously using the Heckler I’d consider it for that. I too, long ago, took off the big ring for clearance. That, and I just wasn’t using it.

7 04 2010
thelazyrando

One thing I should have posted was the HS uses ISCG tabs to hold the BB in place so it will only work with recent all mountain/freeride/DH bikes. I also think the older Hecklers really had a lot of suspension – chain feedback in the granny so the HS would compromise the ride quite a bit. It’s not really even ideal for the Nomad mk2, but on the latest generation of VPP bikes SC has reduced granny feedback on the suspension a ton which makes it at least a possibility.

I think in the next 2-3 years you will see some of the higher end FS bikes have their systems redesigned to be optimized in the 24T for HS and maybe see HS go to bigger rings like 26T or 28T to reduce this effect and make more bikes compatible.

7 04 2010
Scott

Now what would be really fun, for some serious digger action is Rohloff + Hammerschmidt! Heavy as hell, expensive as hell, but 28 all-internal gears!

Scott

7 04 2010
thelazyrando

If we are talking dream bike stuff I’d like to have a CF Nomad with a Rohloff in the frame and just a single fixed cog out back and a second short chain to the cranks.

400% + gear range and all the extra weight inside the frame.

Something like this, but an all mtn 6″ travel reasonably light beast:

http://farm5.static.flickr.com/4024/4500221419_39771de933_o.jpg

http://farm3.static.flickr.com/2684/4500856564_d91f924d40_o.jpg

7 04 2010
Scott

That’s incredible! If I had any gravity skills whatsoever, and alot of cash, I’d have one!

Scott

7 04 2010
thelazyrando

I doubt we’ll ever see a production bike like that, but I am hoping SRAM will come out with a lightweight 4 or 6 speed IGH for MTBs to use with the HS. You don’t need 28 gears, but 8 to 12 nicely spaced gears would rock!

7 04 2010
Scott

Agreed. I would jump on that system over my Rohloff, probably.

How’s things?

Scott

7 04 2010
thelazyrando

I’m doing well. Trying to organize and sort and reduce my stuff. Living in one spot for 3-4yrs lets you accumulate a lot of stuff.

7 04 2010
thelazyrando

How are things at your end?

7 04 2010
Scott

Good. Stitching like mad…it’s a good mad though.

7 04 2010
thelazyrando

Being doing something you care about is a good thing….=-)

14 09 2010
Santa Cruz Nomad + Hammerschmidt Review [Lite] « The Lazy Randonneur

[...] related posts: (automatically generated)HammerschmidtHammerschmidt without ISCG Tabs…Santa Cruz NomadSanta Cruz Bicycles Demo Day at Phil’s July [...]

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