Holly Hammer Schmitt!! Batman!

Norm

Mayor McCheese
Team MTBNJ Halter's
How does it actually work? I see only 1 ring in the pics and no real description of how the ratio gain is achieved.
 

pinkshirtphotos

Active Member
i had the great idea ohhh yay turn my ss into a 2 speed with keeping chain tension. the down falls to the hammer. you NEED isg tabs on your frame, the adapters wont work! That means no isg tabs no work. Second you have to use the provided BB, and that bb is an internal bb on the driveside and external bb on the non diveside! You need 2 bb tools to install, what a headache for the diy noobs. Truvativ says to "bring it into your local truvativ shop after 100 hours of use too look for wear in the pauls" So wait that means they are saying it will start to wear out at 100 hours! That is less than a season for some people. The hammer schmitt is a good idea but i think ill wait.
 

Norm

Mayor McCheese
Team MTBNJ Halter's
Do you classify to ride in the SS class if you have one of these? I'm thinking not.
 

bonefishjake

Strong like bull, smart like tractor
Team MTBNJ Halter's
i had the great idea ohhh yay turn my ss into a 2 speed with keeping chain tension. the down falls to the hammer. you NEED isg tabs on your frame, the adapters wont work! That means no isg tabs no work. Second you have to use the provided BB, and that bb is an internal bb on the driveside and external bb on the non diveside! You need 2 bb tools to install, what a headache for the diy noobs. Truvativ says to "bring it into your local truvativ shop after 100 hours of use too look for wear in the pauls" So wait that means they are saying it will start to wear out at 100 hours! That is less than a season for some people. The hammer schmitt is a good idea but i think ill wait.

no, they are NOT saying that it will wear out after 100 hours you mo-mo. i'm assuming that this thing is similar to other planetary gear setups (uh, yeah) which require servicing after X hours. i couldn't tell you a thing about the driveside/non-driveside tabs/eternal BB whatever. what i can tell you is that in general, these systems are super reliable. gen1 may have quirks but once they get it dialed in...
 

Nathan Crisman

New Member
How does it actually work? I see only 1 ring in the pics and no real description of how the ratio gain is achieved.

Planetary gear set, same as what's in every automatic trans in automobiles since the 1940s. A planetary gear set consists of a Ring gear (outside), A Sun gear (inside center), and a set of Planetary gears that fit between the Sun and Ring. The ring gear has teeth facing the inside, the sun has teeth facing outside. The Planet gears are connected together with a carrier brace.

Your crank arms are bolted to and turn the outside gear, the ring gear. The normal chain rides on a single toothed gear that is connected via center shaft tothe SUN gear. When the carrier brace is locked to either the sun or ring gear...the whole mess is one solid block, thus a 1:1 ratio of input (ring gear rpm) to output (sun gear rpm). If the brace is unlocked you get a gear ratio determined by teeth count with the ring gear driving the planets, and the planets driving the sun.

This system would seem great because the chain never has to move and there are no teeth engaging/disengaging to make a ratio shift.

Simple mechanics, but I would think 5 internal gear surfaces would eat up some power compared to a single chain/ring. Then again, this seems designed for a downhill situation where power efficiency isn't quite as important as reliability.
 
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Glancing Aft

Active Member
The mechanics of this as Nathan Crisman describes it make it seem very similar to those late night informersial "automatic transmission" bikes that you see on TV. I know those are in the rear hub instead of the front ring but really what's so revolutionary about this?
 
T

Timekiller

Guest
you NEED isg tabs on your frame, the adapters wont work!

Why don't you think an adapter will not work? Besides SRAM is marketing to AM/FR which most bikes in that catagory have ISCG tabs.

Truvativ says to "bring it into your local truvativ shop after 100 hours of use too look for wear in the pauls" So wait that means they are saying it will start to wear out at 100 hours!

As someone else stated... same as an old archer hub. They do need service, but it does not mean they will break after 100 hrs.



With that being said... I personally think the device is an interesting design. I would also go as far to say that it is a "gimmicky" device, and you would never see one on my bike. I have absolutely no problems with my 1x9 setup, and so far I have never needed an 'overdrive' gear.

Personally I would really like to see the effort this technology put into hubs. (capable of FR/DH/AM duties) I know Rolhoff is out there, but I would see much greater benefit in rear internal gearing.. possibly an internal geared cassette! A beefed up shimano nexus, sram spectro, or Sturmey-Archer :p
 

Norm

Mayor McCheese
Team MTBNJ Halter's
The mechanics of this as Nathan Crisman describes it make it seem very similar to those late night informersial "automatic transmission" bikes that you see on TV. I know those are in the rear hub instead of the front ring but really what's so revolutionary about this?

It goes to 11?

The more I think about it the more it seems it will indeed be more DH friendly. When you add weight plus the loss in the transmission, is this practical for true XC? I think that's why they name it overdrive, to give the impression that this is something you use at lower rpm and higher rolling speed. At least that's what it feels like.

Maybe this does have a place in the SS realm, where it will lock for uphill (little/no loss) and open up on the flats and downhill (loss is less important). On a geared bike I don't see this as having an advantage over traditional front rings.
 
T

Timekiller

Guest
...what's so revolutionary about this?

You are absolutely correct, there is nothing new about the technology, just a minor twist in the 'use' of the design. Thats good old fashioned marketing for ya.

Its funny too how sram has been hyping the launch of the hammerschmidt for the past few months. Top secret and all. They would even let people try out the device on trainers, blindfolded, for 2 minutes. Funny stuff really.. :rolleyes:
 

pinkshirtphotos

Active Member
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ok ok guys the only reason im crying like a 2 year old is because i want one on my 29er really bad. and it wont work with an e-bb. and who makes a 29er with isg tabs AND horizontal dropouts?
 
T

Timekiller

Guest
ok ok guys the only reason im crying like a 2 year old is because i want one on my 29er really bad. and it wont work with an e-bb. and who makes a 29er with isg tabs AND horizontal dropouts?

I could make you one... why don't you get a set of tabs welded on a frame. Its an easy job.

Also, most of the time, mfg put disclaimers like that to avoid insurance problems if the product were to fail.
 

Panhead

Well-Known Member
ok ok guys the only reason im crying like a 2 year old is because i want one on my 29er really bad. and it wont work with an e-bb

People who ride S/S 29er's don't cry like 2 year olds. How automatic is it if you still need a shifter? I'm sticking to my 1X1 and 3X9's.
 

MixMastaMM

Team Bulldog Rider
what's so revolutionary about this?

Has anyone else done it for a bike? No.

The mechanics of this as Nathan Crisman describes it make it seem very similar to those late night informersial "automatic transmission" bikes that you see on TV. I know those are in the rear hub instead of the front ring

All of those bikes still have a normal cassette, they just have something that will move the rear derailleur based off of the speed of the rear wheel. I remember one design had weights in the spokes that would slide in on the spokes. This moved the spokes and the derailleur was connected to the spokes via the plastic "over shift" protector. There was also a design that had a fly wheel that would spin and move the derailleur.

Is it new technology? No. Is it a lot of marketing? Yes. Does it make me want one for my Moment? Yes.

CVT transmissions in cars followed the same path. CVTs have been used in 4 wheelers and snowmobiles since they were invented. Now cars with them are the slickest thing since sliced bread.
 
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