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Discussion Starter #1
So, if you don't know the '00 900S has a different rear brake setup than its non 'S' sister. On the S, the caliper bracket is actually able to pivot a bit, and is braced by a rod that runs below the swing arm, and attaches by where the lower set of bolts for the stock rearsets are.

The non 'S' bikes mount is basically bolted onto the swing arm and doesn't have the ability to pivot when the suspension compresses, like the 'S'

But, after all that - What good is that pivot ability? It's gotta serve some performance purpose (in theory).. or else why do it. But, the local gang's knocked skulls and can't really figure out any great gains from this more complicated set up. Does anyone know?

This all stems from my desire to use an Ex-box, and realizing I can't with that linkage in place on my 900S

So, techo-gurus - educate me please.
 

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The setup on your 900S is a 'floating' caliper mount.

It applies the braking force directly to the engine/frame, rather than to the swingarm.

This should make it much less prone to braking-induced wheel hop.
 

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Discussion Starter #3
Ah, yes.. now it makes sence. My first tought was more along the lines of the caliper to wheel orientation... but that didn't make sence.

But, having the forces applied to to the frame vs. the swing arm.. that I get.

Thanks!
 

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Aha! Makes sense. Sort-of. The force on the swing arm is mostly horizontal, so I'm not sure how much wheel hop would occur.

Two other considerations regarding importance. SSS bikes don't have this, and most of us don't use the rear brake much, if at all.

So I'd say go for the X-box. Check your right swing arm. The non-floating model (like my '99 M900 City) has a boss about 3" ahead of the axle to hold a retaining bolt. The part number of the non floating caliper mount is not readily visible, but I'll check again more closely once I clean off the mud from last night's ride.
 

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With the non-floating setup, brake torque is applied directly to the swingarm, which tries to lift the rear wheel off the ground.
If the brake is applied sharply, the rear wheel can get air, and it will lock, or come very close to locking.
Braking torque then drops quite a bit, and it comes back down, locked.
Braking torque goes up sharply, and the hopping cycle continues... :(

With the full-floating setup, there's no torque applied to the swingarm, so it should be much more hop-resistant.
 

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I wrestled with this myself as I was drooling (literally) over the exbox a few months ago. Kept the existing brake set-up and put on some sweet Arrow highmounts instead. Still not sure it was the right thing or that I'll ever notice the difference in braking, but I figured it was just part of the old school charm of the bike.

FWIW if you still want the exbox ducman851 had one of the non-floating caliper mounts he was willing to trade for the floating variety, and you'll see them on ebay every once in a while. Both work on the aluminum swingarm we've got.
 

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Just remember, that they only work on the older 17mm rear axles from 2001 (except for S4) and older bikes.

And the steel swingarms have a caliper fixing rod welded to the inside of them, where as the aluminum swingarms have either the fixing rod (on the swing arm mounted brake carriers) or the brake line guide (on the "S" floating caliper model) which is bolted to the swingarm and can be swapped for either part.

In a nutshell if you've got a steel swingarm, you'll have to cut off the little rod that sticks out the inside of the swingarm on the right side and then make some type of brake line guide/carrier.

Personally, my bike came with the fixed and I wanted the floating (I had one on my downhill bike and loved it). So I got all the parts and did this swap myself. So this is all FHE.

HTH
 

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Here's a pic (from ducman851) of the inside of the swingarm. You need the "peg" that's in front of the axle and inserts into the swingarm to fit a non-floating caliper bracket.
 

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Discussion Starter #9
Yeah. I looked up the schematics on bikebandit. There's a couple other small parts I'd need to convert from the floater, to non. Doesn't seem like a big deal... just an added hook.
 

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I'm in the process of swapping in an alloy SA and need this "peg" that is mentioned in this thread. Does anyone have one of these floating around that they could take some dimensions off of for me? Or, perhaps sell to me?

Thanks
 

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Arms are used to find the elusive "correct" level of rear end squat by appling the forces to a different part of the swingarm. Whenever you like it or not is more personal preference.
 

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Can anyone tell me if this pin that is pictured screws into the SA (as in the arm is threaded), or if it bolts in (the arm is just a through-hole)?

I'm just now getting back to doing this swap and I'm still trying to find this pin. The only one I have found is off a S4 and screws into the SA... problem is... my 900S SA doesn't have any threads... there's a bolt from the outside that would need to screw into the pin to keep it in place and I just can't find this type around.


Thanks.
 
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