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Hammerschmidt on ISCG adapter.... Here we go!

Delimeat

Delimeat

Monkey
Feb 3, 2009
195
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This is a X-Post from the Tech forum, I figure it will see more action here. I'm sure some of you out there have a frame w/o ISCG tabs so it may relate.

So I have this here Hammerschmidt sitting about and would love to go ahead and bolt it onto which ever frame I eventually decide on. One problem though: My top few picks (Trek Remedy or Giant Reign) don't have ISCG tabs on them. The boys at SRAM have made quite the hullabaloo about mounting up their H.S. cranks correctly and only on approved bikes, which I respect, but don't fully believe. The main issue they seem to be concerned about is rotation of the back plate, either from cable tension or hits from below. Having run guides long before any ISCG standard was around, I call B.S. on the first worry, I don't see cable tension pulling hard enough to rotate the back plate/ISCG adapter. As for hitting the guard, there is no boomerang to catch and rotate so I see it just glancing off objects.

SRAM also insists upon a faced surface on the ISCG tabs, which makes sense. I have a few different ISCG adapters I could use, all are perfectly flat. After I face the BB shell there is no reason why it wouldn't be just as flat and square as built in tabs.

So what are your opinions? Has anyone out there used a ISCG adapter to install their Hammerschmidt? I guess the disclaimer would be to say that I am really not all that worried about cutting something up, or coming to the conclusion that it won't work, as the bits are somewhat disposable.

Ideas, opinions, experience w/ this project?
 
Acadian

Acadian

Born Again Newbie
Sep 5, 2001
714
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if you don't have permanent ISCG tabs on your bike you cannot use a HammerSchmidt.

end of story.

if you insist on using one - you'll have to find someone to weld ISCG tabs on your frame. but you'll have to make sure they are welded on to spec (a clocking tool should have been included with your HS)
 
jonKranked

jonKranked

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Nov 10, 2005
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Acadian said:
if you don't have permanent ISCG tabs on your bike you cannot use a HammerSchmidt.

end of story.

if you insist on using one - you'll have to find someone to weld ISCG tabs on your frame. but you'll have to make sure they are welded on to spec (a clocking tool should have been included with your HS)
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Yup. Its not that you need just ISCG mounts to run the HS, you need permanently fixed ISCG mounts - ie welded on or machined into the bb tube. You're right, the cable tension isn't what will cause this, neither will an impact. You need the ISCG tabs to be fixed because the internal mechanism of the HS relies on it. The inner half of the gear system needs to be fixed in place, otherwise there will be no power output to your drivetrain.

Are you familiar with centerlock rotors? Using a HS without a permanently welded/fixed ISCG tab would be like grinding off the centerlock splines on the rotor. Sure, you could mount it, but when you hit your brakes it would just spin in place and not stop you.
 
BrooklynMachine

BrooklynMachine

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Sep 1, 2007
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jonKranked said:
You need the ISCG tabs to be fixed because the internal mechanism of the HS relies on it. The inner half of the gear system needs to be fixed in place, otherwise there will be no power output to your drivetrain.
Click to expand...
That's it in a nutshell. The ISCG adapter will probably torque loose and spin.
That said, give it a twirl just to prove us wrong/right...it's winter, right:busted:
The tech manuals are, indeed, very fussy about clocking and tab clearances.
We've become very fussy about wanting to use the schmidt so we made it happen by lasering and welding our own mount:


Do it if you can make it happen and you don't mind a little weight. The shifting performance is incredible/instant/intuitive/smooth/usable/etc...
 
w00dy

w00dy

In heaven there is no beer
Jun 18, 2004
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The cable and housing both mount to the unit. Cable tension won't be a factor.

A hit might rotate it, but only a little bit. It should keep working no matter what angle it is mounted at.

It may spin the adapter when you are in overdrive mode. This spinning would be in the direction that unthreads the BB cup. If your adapter interferes with the frame enough to halt that rotation you're in the money. You could also try to lash it to the frame in some way. Maybe use a long bolt on one of the mounts and use the extra length to tie it to the frame somehow. I don't know what frame you will be using, so I can't get any more specific than that. All you need to do is block it from spinning around the BB. Think of a coaster brake hub. You need to make something that works like that torque arm on the non-drive side.
 
E

Evil Sylvain

Monkey
Feb 27, 2006
181
1
Montreal, QC, Canada
BrooklynMachine said:
Isn't the schlumpf torque arm/BB/drive all integrated? The Schmidt uses a more or less normal BB design with a bolt on drive system that is separate to the mounting/operation of the BB. The schlumpf torque arm seems more in place to keep the BB from spinning in the shell.
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You are most probably right looking in greater details at the pictures on their site and considering that their new offering, specifically for MTB, needs ISCG tabs and is similar to the HS with the exception that shifting is done with a heel tap as with the rest of their products.
http://www.seed-your-ideas.com/Triebwerk/en/index.html

 
jonKranked

jonKranked

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Jonny5 said:
Huh? It said "BB has no flange, so there is no way to capture an iscg adapter", the bb shell doesn't need to capture anything.
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My bad, I misinterpreted what was said. I thought he was referring to the bb shell and the fact that there is no stop to make an ISCG adapter stationary.
 
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4xBoy

4xBoy

Turbo Monkey
Jun 20, 2006
7,043
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Minneapolis
jonKranked said:
My bad, I misinterpreted what was said. I thought he was referring to the bb shell and the fact that there is no stop to make an ISCG adapter stationary.
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That's what I meant, for some reason I thought it was the same as the old isis style on the drive side with no flange.

:imstupid:
 
buildyourown

buildyourown

Turbo Monkey
Feb 9, 2004
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South Seattle
I don't see why it wouldn't work. I understand that the bolts are what counteract the planetary, but if you got the BB cup tight enough, it would work. I'm sure SRAM is concerned that it won't work perfectly and will tarnish the brand, but I say it's worth a try.
It would at least work well enough to be rideable around the block.
 
Delimeat

Delimeat

Monkey
Feb 3, 2009
195
0
Canada
Thanks for the replies.

First things first: within the next few days I will mount the H.S. up to a random non-ISCG tabbed bike using just an adapter. I'll go for a spin, see what happens and report back.

If it rotates, there should be a simple way to cure the issue. I like the idea of the braze-on front der. mount, depending on the bike that may be a clean way to anchor the back plate. Another option could be to install two ISCG adapters, one on each side of the BB shell, with a long connecting member between them. Using the SRAM clocking tool to line the adapter up it looks like the connecter would rest snugly against the down tube and hold things in place. It would be ugly I'm sure, but would also hold it put.
 
D

davep

Turbo Monkey
Jan 7, 2005
3,276
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seattle
When I was running a bb mount guide on my Fly (no ISCG tabs) it would rotate when hit hard. I was able to solve the problem by putting some green (bearing retaining compound) loctite (make sure you clean of all oil residue) on the all the contacting faces (bb face, cup inner face, and both sides of the guide)....and then tightening the sh1t out of the drive side cup.....
 
DirtyMike

DirtyMike

Turbo Fluffer
Aug 8, 2005
14,437
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davep said:
When I was running a bb mount guide on my Fly (no ISCG tabs) it would rotate when hit hard. I was able to solve the problem by putting some green (bearing retaining compound) loctite (make sure you clean of all oil residue) on the all the contacting faces (bb face, cup inner face, and both sides of the guide)....and then tightening the sh1t out of the drive side cup.....
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MRP was working on a BB mounted "Taco" Style BB mounted three ring Bash guard, never heard much more about the non ISCG style than I did from them at Interbike, but when I was talking to them about it, they were talking about basically giving the arm some teeth were it interfaced with the BB, just enough for it to grab, and also using a little bit of a sleeve retainer to go along with.




To the OP, I am sure it can be done, the trick here with doing this though, would be making sure the ISCG tabs would be flush with the BB shell. Probably just need to get the right adapter that is made flush against itself already. You could prbably score the side that meats the BB, and use some sleeve retainer and have it work just fine.


I had also heard rumor Truvativ was working on a style of HS that is made for non ISCG bikes as well.
 
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D

davep

Turbo Monkey
Jan 7, 2005
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seattle
Yea, I would think that a bit of knurling on the contact surfaces could help for sure, especially if they were sharp and hardened....
 
Delimeat

Delimeat

Monkey
Feb 3, 2009
195
0
Canada
So it's on a bike via an ISCG '03 adapter, a nice rootbeer colored C'dale Prophet. The Prophet uses a 68 mm shell, so when I use my adapter it works out to a 73 mm shell. Bikes that have a 73 mm shell may have some issues if you used an ISCG adapter, as the Truvativ BB setup requires the proper width to keep things spinning properly.

The ISCG adapter I used has a flush outer face (as most do) which made things easy. I did need to remove some material for the cable anchor bolt to clear, 5 mins with a saw and file did the job. Total install time was about 25 mins or so and was easier than setting up a triple crankset and front der, especially those fu*king E-type disaster's. The Prophet is not my ride, but those out there that own them may be in luck as the E-type anchor bolt on the Prophet's (and some other rigs) seat tube could easily be made into a anchor point.

This followup is a bit premature as I have no dirt time on it yet, but I have bombed around town doing my best to cause trouble. A few ****ty 4 and 5 foot drops and lots of hard pedaling have not moved it yet. Sure would be nice if it never did move...
 
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