Which rear hub?

[SILVERKINGPC]

So check out this Soul Cycles Sturmey 3-disc. with slide-out drops....you can see more of it here...
http://www.ebay.com/itm/Fat-Tire-Be...d-Hydraulic-/271952295372?hash=item3f519eb5cc

 

[Bicycle808]

That's a cool hub, but you'd have to stretch an old Schwinn a whopping 2.35" (60mm) to make that thing fit.... it's built for fat bikes, and measures 170mm between the jam-nuts. You'd want the s-rk3 hub, which is exactly the same but spaced at 135mm, or the rs-rk3, which is the same but with an in-board rotary gear-selector (also spaced at 135mm)...

 

[SILVERKINGPC]

Exactly B808.....The 135 mm disc version may be able to be worked into an old frame. What interested me is how the slide in/out dropout worked with the disc & caliper since the position of the hub axle could move and mis-align the whole enchilada. It would not be an easy task to get the disc itself lined up clean with the caliper if using the 135mm hub in a reverse dropout style frame that was modified to accept it. It would have to be perfect, and when perfect, you may still have chain slop & require the chain tensioner....Hmmmmmm.......still thinking...

 

[Bicycle808]

Paragon (among many others) makes sliders, and Black Cat (among others) makes swingers (Paragon calls their version "rockers").

Sliders above, swingers below:

I've worked with sliders before; had a Redline Monocog Flight with a knock-off of the Paragon slider set-up, works good. Was creaky til I put beefier hardware on it. Very easy to dial-in chain tension without worrying about aligning the caliper.
The swinging/rocking/alternating dropouts look cool, and they'll change the geometry less in terms of chainstay length, but more in terms of BB drop....

You can easily source these dropouts and associated parts if you wanted to retrofit one to an old Schwinn, but you might end up replacing the whole rear triangle, to make sure it's up to dealing with the spread as well as the added torsion brought on by a disc brake....

 

[SILVERKINGPC]

That would do it! That is one good solution to the problem B808. I would prefer, and was wondering whether a more permanent, less-modified solution involving brazing or welding some caliper mount posts directly to the seat or chain stay. It'd be tough. You could: 1.) Bolt the SA135mm disc hub/disc and complete drivetrain into it's final positiong in the frame dropouts. (Chain tensioned) Then: 2.) Fit the caliper over the disc to determine where it needs to be to allow the "backwards" wheel removal. Then fabricate and weld in place a permanent post-style caliper mount in that exact spot. Determining this perfect spot for the caliper would be a trial and error process for sure. Match it in front with a prewar single pivot fork? RAT-a-tat-tat!
Great info on that hardware B808...a much simpler solution to be aware of....

 

[Bicycle808]

As with most things, there's probably a bunch of ways to skin the rear-disc cat.... I'm of the opinion that, if you're gonna do something, you should do it in an obsessive and thorough way. Some might say you ought just do it right, but what fun is there in that? Anyway, if i were gonna try to put a disc kick-back on an old Schwinn, i'd want to replace the rear triangle with some 4130, and i'd choose a diameter that plays nice with whatever dropouts i chose.... which'd probably be Paragon rockers.
http://www.paragonmachineworks.com/cgi-bin/commerce.cgi?preadd=action&key=DS1090

http://www.paragonmachineworks.com/cgi-bin/commerce.cgi?search=action&category=0006
While I was at it, depending on the year/model of Schwinn, i'd be tempted to maybe play with the chainstay angle; possibly change the BB drop if i could if it's one of those low BB Schwinns... not really necessary on a prewar Model C or DX, but tempting on bikes from the 50s. In any case, i'd try to shorten the stays a bit, tighten things up. This is all just fantasy; i haven't welded anything since shop class in 9th grade, so i am not currently able to do it. But i'm tryng to get into a welding class by this time next year....