CaptainSpalding

Hello everyone,

I am starting to rehab a recently acquired Schwinn Twinn tandem. I have a few questions about the cables and housings.

1. The cable housings have no ferrules on the ends. Should there be? It looks mighty strange without them.



2. There's a part floating around loose on the derailleur cable. At first I assumed that it's a guide that is meant to be on the shifter, but it doesn't seem to belong there. It doesn't really fit at all. Have a look:



3. The brake cables are a different size than the derailleur cable. I'm assuming 5 mm and 4 mm respectively. As I browse around on the internet for replacements, I seem only to be able to find a one-size-fits-all tandem brake/derailleur cable with a barrel swage at one end and a disk swage at the other. I suspect that cable will work for the rear brake, but can I use it for the derailleur too?

https://cgi.ebay.com/BICYCLE-CABLE-SC...5#ht_600wt_974

Any clarification you can throw my way would be appreciated!

Velognome 

On my Twinn the braze-on stops acted as ferrules, the floater on the gear cable looks like it belongs to the brake lever. Your LBS should have tandem lenght cables for the derailleur and rear brake. Down tube shifter on a Schwinn Twinn? Perhaps you have something a bit nicer?

JonnyM

What a coincidence, I'm in the middle of a teardown of what looks to be exactly the same model...

Mine's a '65 Schwinn Twinn Deluxe, though it's violet instead of green

My bike appeared to be pretty original and had the exact same cable set up--same floating piece on the derailleur cable and all...

I'm inclined to agree with you that the floating piece is a guide meant to be on the shifter, though I saw no obvious way it'd stay attached.

That cable end unfortunately I believe is specific to a Huret shifter and uses a teeny tiny disc swage, much smaller then for a brake cable. I made the mistake of cutting my original cable in the middle on disassembly--not so sure replacement cables of tandem length are available... I was at Harris Cyclery and they did at least have normal length Huret cables.

My cables also did not have ferrules at the cable stops, really does look like that was how they were built.

My current plan for my Twinn is to mount up a more modern rear mech and mount a thumb-shifter on the handlebar, bypassing the pretty old Huret shifter.

I'll try to post pics of mine when I can, though it's mostly in pieces

By the way, if yours--like mine--has the Schwinn s-7 size rims, I discovered that Harris also stocks whitewall tires to fit. I wasn't able to find them easily anywhere else online.

Good luck with yours, hoping to have mine back on the road soon to get some summer cruisin miles in

Cheers,

Jonathan

CaptainSpalding

Thanks for the replies.

@ Velognome - the shifter is actually on the top tube. It's a quasi-mixte frame. Mine is a Twinn "Deluxe", so I guess that's the nicer part. The differences between the regular Twinn and the Deluxe: black vs. two tone seats, deluxe grips (with the open cell on the top side of the grip to provide cushioning), and of course the 5-speed derailleur.

@ JonnyM

I think I'll omit the floating piece.

Thanks for confirming that there are no ferrules on the cable housings.

I just came across this derailleur cable. Huret compatible, 120" long. Do you think it's appropriate?
https://www.bikeman.com/CA6611.html

My Twinn has S-5 rims. There is only one tire offering that I can find in that size (two if you count blackwall and gumwall as separate types.) The front rim also has a welded repair at the valve stem hole. I've been pondering the idea of having some Sun CR-18 EA.3 rims laced onto the hubs. This would give me more to choose from regarding tires, and would also improve braking on the front wheel. The S-5's are 597mm, and the EA.3's are 590. No biggie.

At this point my plan is to stick with the GT100 derailleur, but I'd be interested in knowing what you come up with as a replacement. I am more immediately concerned with the brakes. I have yet to crack open the Atom hub and check out the drum brake. I have no doubt that I can get better performance out of it than I'm getting now which is, in a word, pathetic. But it's the front brake that concerns me. It flexes a lot under load. I might consider replacing it.

ETA: You might want to have a look at the Sturmey-Archer X-RD8 8-speed gear hub with drum brake. I don't know how it would work out as far as chain line and over-locknut-dimension, but its worth a gander.

I haven't owned a Schwinn since I was 13 years old, and I'm just getting into all the eccentricities and peculiarities of the brand. It's all part of the fun.

I'm going to sort out all the mechanical issues first. I'll enjoy riding it for a while, and then take it apart for a repaint. Keep us updated on your project!

pastorbobnlnh 

The floating piece, a ferrel, on the shifter cable does fit inside the shifter.



You will need to unscrew and disassemble the shifter in order to fit it back into the bottom of the shifter housing. This is relatively easy to do, just note the sequence of each piece as you remove it from the pivot shaft. You can see the same ferrels at the bottom of the shifters on my '65 Schwinn Super Sport.





Hope this is helpful.

JonnyM

@Capt, interesting, it sounds like our bikes are specced a bit differently, do you know what year yours was made? Besides he different wheel size, my rear hub appears to be made by Union, though is also a 5 spd fw with a drum. Very sadly the axle is a bit bent... A local bike shop owner who's been around bikes almost since these were new suggested I try to take the bend out with a hammer. I'm half tempted to try. The good news is that at least when I test rode the bike, my rear brake seemed to have almost-maybe adequate power...

Money no object I was also considering a Sturmey drum brake igh and a big 90mm drum in front. Money, however is a relatively large object I have the same concerns about the front brake, and in fact started a thread soliciting ideas--my front caliper already had bent arms. As a start I've replaced it with a cheapie modern cruiser caliper, will try that out and go from there.

That cable however looks very promising, good find!

@Pastorbob, thanks for the photos of the shifter assembled properly! Clearly I'll have to take another look at mine.

CaptainSpalding

@ Bob:
Thanks very much for that piece of advice. I went right outside to check it out. I was able to get the ferrule back into position by just partially unscrewing the thumbscrew. That revealed the small protrusion on the inner piece of the shifter that captures the ferrule.

@ Jonny
My Twinn is a '72. Atom rear hub. Straightening an axle with a hammer? As long as it's steel and solid rather than hollow, I'd sure give it a try.

I'm starting to lean toward the Sturmey in the rear. Not only for the sake of having a new drum brake, but also for the gearing. I live in a hillside home and at my age I need all the help I can get. I just measured the dropout spacing, and it looks like the Sturmey will drop right in. As far as the chain line, on the Sturmey page for the X-RD8 rear hub, it says this:
I know that the fractions refer to the chain, and I know what dish is on a rear wheel. It the "flat" that I don't get. Does that mean no dish? How can there be no dish if there's a sprocket? 46mm is pretty close to perfect, if I'm measuring the chain of the outer rear chainwheel correctly.

Drum brake in front? Hmm. It's a really heavy bike, and I'm no lightweight. I worry that drums front and rear might not be enough. I'd do it in a heartbeat if it weren't a tandem.

ETA: I just spoke to the wheel builder at my LBS. He thinks drums front and rear are perfectly adequate for a tandem. I'm sooo tempted . . .

JonnyM

@Capt, I think I may try straightening out that axle--the nutty part of that suggestion was to hammer on it while it was installed in the hub... May not do it that way if I can disassemble the thing.

I'm pretty sure flat vs dished refers to two different types of driver cogs, but I could be wrong.

I've similarly heard that the new Sturmey drums are pretty strong once broken in and that the 90 mm drum is very strong.