louky

I have been asked to repair a broken derailleur on a 10 speed bike for a homeless organization I have been helping out. Actual 10 speed (2 x 5) schwinn from the 80's. I will have to buy the derailleur. Will this 6-7 speed MB medium cage work for this? The bike has friction shifters. Thanks! Amazon.com : Inkesky RD-TZ31-GS 6/7 Speed Rear Derailleur with Direct Mount, Medium Cage, for Mountain Bike : Sports & Outdoors

Kontact

That could work fine, but check how the derailleur attaches. If you need a hub retained hanger you'll want this one:
https://www.amazon.com/THALOUS-Bicyc...NsaWNrPXRydWU=

Speeds don't matter.

maddog34

will need to know WHICH schwinn you are working on... and it may actually be a 60's or 70's bike, judging by the gear count you provided... Is the bad derailleur a Huret or "Schwinn Approved"? does the bike have an incredibly small Seat Post? Does the frame have Large fillet welds that are rounded in shape? Is the derailleur actually "bad"? or is there some other problem? Is the der. attached to a frame hanger or a hanger held to the bike by the axle nut?

CliffordK

Do you have a local bike co-op? Often they'll have piles of old parts. I'd probably go with a 30 year old chunk of steel over those super cheap Shimano derailleurs.

louky

I measure the seat post at 25mm. The bike is a World Sport. I don't see any name on the RD, here is a pic.

louky

I do have access to a bike co-op, but only on Sundays. I have looked before for RD's. Many of them are incomplete/missing parts and often very worn. They may charge $5 to $10 for a used one and it can end up being a bad gamble for me. These bikes lead a very hard life. The bike I am working on was one I donated to the homeless charity, in perfect working order, about 7 weeks ago. When I picked it up today, the derailleur was broken, Derailleur hanger bent, the seat had been replaced with one that didn't fit properly, the front wheel and tire had been replaced with a 26 x 1 3/8, then obviously the brakes didn't hit the rim so they removed the front brake shoes. In 7 weeks!

louky

That was my main question; can I put the 6-7 RD on a 5 speed freewheel. The RD is a direct mount, I included a pic below.

CliffordK

Sounds frustrating.

An acquaintance's son was in and out of shelters, and needed transportation. So, I spent some time fixing up a bike for him (given to me by his uncle who had then stored under a leaking tarp). Lubing everything, fixing whatever was broken, tuning, etc. Then he apparently didn't like something and perhaps the seat post was loose, so he gave it to the homeless shelter vultures. And hit me up for a second bike (and complained that I didn't have the second bike tuned up quick enough). That second bike eventually was just left locked in front of the library when he tried to move to a city 100 miles away. I barely got it back, and then gave it back to him the next time he was in town. Then it got left in an apartment when he moved out, and is gone. So much for those bikes.

Perhaps there is a way to run a workshop clinic so the people that get the bikes actually learn to do the maintenance, and have some work invested in their bikes, rather than expecting free handouts.

========

I dislike the cheap Shimano derailleurs because they are so flexible that it is impossible to get the derailleur stops set right. I.E. The bike will eat another derailleur next month.

Of course, perhaps that Schwinn got knocked over onto the derailleur and bent the hanger before it lost the derailleur.

You've answered the question whether you need a "claw", or not. Just a regular bolt on derailleur.

Bill Kapaun

With friction shifting, about the only thing that might be a problem is one of the newer >8? speed versions which "might" be too narrow for your relatively "wide" chain.
The other thing as mentioned is the type of mounting.

The RDER you referenced is one of the numerous Shimano counterfeits.
I mean--- Inkesky?

It's which counterfeiter do you trust most to give you an acceptable product?
Kind of makes a bike coop look that much better.

maddog34

that was a Suntour ARX, or something very similar.

If you have a Bike Co-Op or recycler near you, i'd say it would be worth visiting them and asking for an old 5 Speed direct mount Rear derailleur... and almost any direct mount rear der. up to a 7 speed will work... i've put a couple Shimano Mega Range Ders on those bikes before.. the ones with the bigger jockey rollers... and Kontact recommended a better grade than the one you linked earlier... A Co-op is your best bet for a Bargain.. i sell the low end shimano ders for $5.. $10 for old suntours of steel construction...

https://www.ebay.com/itm/25600256220...3ABFBMts6tiYhi

maddog34

wow. there was a rider near me that was as bad on bikes..he was way fast, could jump almost anything, and wheelie for blocks...but he destroyed every bike he owned or stole...He OD'd on heroin and meth at the same time a couple years ago... he'd been thru "treatment" 5 times. Everyone tried to help him, but he would always find a way to screw up again. You could always tell if he'd "worked on" a bike.. the front brakes were removed... on one of his bikes, i once found a rear brake cable TIED to the v-brake clamp arm, and the housing routed directly into the stirrup, no noodle....and to make that mess kinda work, he'd taken the cable housing out of the front top tube cable stop.... YIKES! when i asked if it worked, he grabbed the cable along the top tube and pulled it up.. "Yep, It works!", he proudly proclaimed.

CliffordK

I don't know what is on the bike. My friction bike has campy shifters and an Ultegra (6500?) Rear Derailleur. I've used it for anywhere from 5 speed rear to 9 speed rear (which is a little tricky as one has to adjust for full 180 degrees of movement of the shifter). While the barrels of the Campy shifters aren't large, they do support 180 degrees of movement.

Bill Kapaun

Does anybody else?

maddog34

the Suntour ARX equipped World sports used a Suntour Friction Shifter pair mounted to the stem by the heaviest Boat Anchor clamp system ever invented.

I can't recall ever successfully removing one.. the large philips head screws tend to weld themselves to the captured nut I imagine that they thread into....

WizardOfBoz

Maddog, the outward appearance you mentioned - of a "fillet weld" has more complexity than one can see in the joint.

[boring pedantic lecture]

In the early days of bicycles, the tubes were heat-treated and could not be welded without messing up the strength provided by the heat treat. So tubes were fillet brazed. In welding, the surfaces to be joined actually fuse. In the old days, blacksmiths would heat the heck ouf the parts and then hammer them together. The parts never melted, but they did fuse into one piece. This is called forge welding. You can do it on wrought iron, which has low carbon. Harder to do on higher carbon (which provides higher strength) tubing. Starting in the 1880s, we figured out how to separate gases and to make electrical devices. So arc and flame welding started to grow.

When you add a couple percent carbon to pure iron (ferrite) you get cast iron. If you can get the carbon content down below 1.86% you get steel. Most steel in bridges and stuff are less than 0.3% carbon. At that carbon content its less brittle and can easily be welded. Between 0.35% and 1.86%, you can harden steel using heat treatement. Heat it put to really hot (white hot) then quench it in water, brine, or oil. Then you temper it so that it's not brittle and has a little ductility. It will give a little before it breaks. The point is the state of steel is very dependent upon it's heat treatment history. So welding heat will mess up heat-treated carbon steel. Other elements impact welding as well (e.g. Molybdenum and Manganese, which both are in some good bike tubes)

Brazing (and soldering, which is brazing at lower temperatures) is joining two or more surfaces with a filler that flows between the parts and solidifies. The temperatures are much lower than arc or flame welding. Before lugs were used, one would fillet braze tubes together. Doing that brazing is a job that demands a REALLY good skill set, and so fillets were seen on some really good bikes. The results looked like the joints on Schwinn Varsities I think thats's why Schwinn wanted the Varsity joints to look like fillet brazed frames. In fact, those varsities were fabricated by welding together stamped steel parts and, while the setup of the punchs and presses and automatic welding machines was pretty impressive the joints created were heavy and rather artless. The frames were heavy. Whereas the true fillet brazed joints were the product of superbly talented frame brazers. See Sheldon Brown's treatise on Schwinns fillet brazed frames. I have one, a Superior from 1976, and it is an awesomely nice ride.

So the points I wanted to make were
1) Older Schwinn frames, and some that Schwinn make into the 1970s, were fillet brazed, not welded, and these were very high quality bikes indeed.
2) Schwinn's brazing folks were as good as there was in the world. This extended to there brazed lug frames capability.
3) Many of the consumer grade Schwinn bikes that looked fillet brazed were stamped parts welded together. Even schwinn tubes in bkes like the varsity were strips of steel rolled up and welded.
4) If you are interested, soldering and brazing differ by the temperature of the melting point of the filler material. Above 450°C, its brazing, below that, soldering.

[/boring pedantic lecture]

maddog34

dude.
did your self described "/boring pedantic lecture" help anyone wanting to fix an old schwinn for some homeless person? No.
would someone fixing a bike for homeless folks give a rat's pahtooty if a frame is slathered with too much brass or too much welding rod to make it look fancier? No.

and i've both brazed and soldered thousands of parts... and more like tens of thousands of solder joints.... and then, there's all the welds, including Cast Iron, sheet metal, stainless, chrome moly, and several tons of good old 1010 hot rolled steel... tig, mig, stick, oxy/acetylene.. been there, done that.... and a lot of machining ops along the way...

PS.. my Trek is Silver Soldered.(see avatar)
and soldering temps can vary dramatically by solder types/compositions.
where's a face palm symbol when you need one?

i just wanted get a handle on the age of the bike and what model it is, if possible.
Mission accomplished... and then some... i guess you were too busy typing for no reason to notice, huh? or is that lecture copy/paste?
on second thought... please ignore the questions.

i'm here to answer questions posed by people requesting help in regard to their bicycle problems.... why are you here?
wait... Answer that to yourself, ok?

and then..there's the metallurgical differences between Soldering and Brazing... two completely different actions.. but they look very similar to the uneducated, eh? I learned about those differences at age 15... IE: a very long time ago... Solder is just a fancy hot glue for metals.

and just for the record...i've also done forge welding.... forging horse shoe nails together at first... smaller is harder... we made hundreds of "roach clips" to sell to deadheads at Grateful Dead concert tailgate parties... sales were brisk! The split and twisted, then forge welded, Fire Poker handles took some practice... try that some time. $500 a set, 4 tools..1977.. .randomly peen the shafts for a better appearance... the base of the stand was 4 horse shoes.. it looked like a clover leaf, so i convinced Tom to let me add a stem.. He continued that addition.

JoeTBM 

That is actually a 12 speed (2x6) looking at the picture in post #5

Shoot me your address via PM and I'll drop a few in the mail to you

..........Also trying to get this thread back on topic. Some of you go so far off the topic that the thread gets derailed

One more thing, the amazon ad you linked now says "unavailable". If you want a new one, try this ad https://www.ebay.com/itm/19540614069...ampid%3APL_CLK Under $14 each if you buy 4 or more

WizardOfBoz

@maddog34 you have more (way more) experience welding, brazing and soldering than me and probably than 99.99% of the folks on this forum. Which makes your use of the incorrect term "fillet weld" puzzling.

I merely wrote to point out that at lot of the old schwinns were not fillet welded but rather were fabricated from stamped parts. See Sheldon Brown's discussion here.

Also that Schwinn made some very good fillet brazed frames over the year. See Sheldon Brown's discussion here.

My writeup was not to criticize or to teach you anything about bikes or welding (I doubt I could) but rather to make others aware that most older frames were brazed, not welded. The writeup was in the same spirit as Sheldon Brown's writeups. Now, you can say that my boring pedantic writeup was not as good as Sheldon's, or that it was indeed boring or pedantic. Fair enough. But questioning my motives seems a bit overboard. Have you questioned the motive of Sheldon's writeups?

I suspect that you mistakenly took my writeup as a criticism of you personally. It was not. But given your username, I note that you may have some degree of self awareness. Mad dog indeed. I assure you that I have immense respect for people who can fabricate stuff out of metal. I grew up working in a machine shop (doing all the scut jobs like grinding flashing from castings - yuk).

PS The definition of brazing and soldering is the same: joining two or more surfaces using a meltable compound and usually flux, and without melting the metal in the parts to be joined. The technical difference is that brazing is when that meltable compound (braze) melts above 450°C. Soldering is then the compound (solder) melts below 450°C. There is, as you put it, a difference in metallurgy to get those different melting points. Brazing is generally much stronger, but also requires a really skilled person to do it. For this reason, bicycles are not soldered, they are brazed. Often with silver-bearing braze, which ends up being really strong. Unfortunately the term "silver soldered" is mistakenly used a lot. Should be "silver-brazed".

maddog34

for the record.. soldering and brazing only share one characteristic in real world application.. both heat up the WORKPIECES... Solder is a fancy metallic Hot glue. it sticks to the existing imperfections found on all materials.. the heat assists the solder to flow into those defects before it cools and ceases to flow.("Cold Solder Joints" can be easily peeled away.)... Brazing is done at a temperature sufficient to open up the molecular structure of the work, which allows the molten brass to actually ENTER THAT FRESHLY OPENED STRUCTURE....the work piece is never brought to a "puddle" as in welding, so the two materials never alloy, but they INTERTWINE, effectively locking them together. Solder holds like two palms pressed together... Brazing is more like interlocked fingers holding on for dear life. Flux helps limit air from getting in the way, and also helps remove filth. See: Welding Slag.

you choose simpler definitions.. i look at the reasons and effects. We both get it done.
PS..i immediately scrap 60's/70's fillet brazed Schwinns with no regrets or hesitations. i also disposed of a pile of 50-ish 22" road tires. 8 years in my stock, and not one sold...they were leftovers from a schwinn dealer that closed in the nid 80's.. someone gave them to me... he'd not sold any, either. I paid for two schwinns in my long life.. one was bought for the Dura-Ace 7400 Group it wore.. the other was a police auction buy.. an old blue stingray that i rode for two years.. the low gearing made it very quick off the line... it also made me learn to spin at 140+ cadences with my huge diameter legs.... i put worn out knobbies on it..the center baldness rolled fast, the edge knobs kept me on line on dirt trails.

the last World Sport i had here got rebuilt then sat in the racks for THREE YEARS unsold... i scrapped two matching his/her Schwinn Travelers not long after that. Nothing below a LeTour II will be rebuilt in my shop, unless a customer pre-pays for the work... although my heart has a big soft spot for fastbacks and crates...

and my nickname comes from a drinking bet when i was a teen. I won, but the other side never paid up... the bikers (Harleys, Whiskey, Drugs, Stinking Clothes-types) liked it just fine. (also, See: ODF Trail #38, Tillamook Burn, Oregon)

and sheldon was doing what you now try to claim to have not been doing. :-PdPdPd

WizardOfBoz

Ignorance is best served by reticence to speak or write.

In building radios, oscilloscopes, and guitar amplifiers I learned that it is critical to heat a joint to be soldered and let the joint melt the solder. This avoids a cold joint. So no, in soldering, as in brazing, one should heat the faces to be joined. And if you are having your solder puddle and fail to adhere, you are probably not preheating the joint properly. My advice is to not do much electronics work without more instruction and practice.

As a registered professional mechanical engineer, I'm somewhat familiar with the processes you speak of. But I don't get to define my own facts or definitions. "The American Welding Society (AWS) defines brazing as a group of joining processes that produce coalescence of materials by heating them to the brazing temperature and by using a filler metal (solder) having a liquidus above 840°F (450°C) and below the solidus of the base metals. Soldering has the same AWS definition as brazing, except that the filler metal used has a liquidus below 840°F (450°C) and below the solidus of the base metals. Soldering can be considered the low-temperature cousin to brazing." Or, from the AWS site, "The AWS defines soldering as a joining process that takes place below 840° F and brazing as a similar process that occurs above 840° F" In practice most soldering is done way below the limit temp, and most brazing is done at signficiantly higher temperatures. So the strength of the filler is different as well and brazing is much stronger than soldering. But soldering can be done on more than metals. Some vacuum tubes, for example, have metal and ceramic joints that are joined by soldering.

Interestingly, in earning PhD in Chemical Engineering, the idea that filler and substrate molecules intertwine but do not fuse was never explained. How does that work? If true, you should write it up and submit it to the Nobel committee - you may have a new phenomenon. I thought that it both cases it was simple molecular adhesion, and in both filler metal is distributed and retained between the closely fitted faying surfaces of the joint is by capillary action.

That's not what flux does either. Flux helps reduce surface tension and also penetrates the surface oxide layer on the part (not in the air). Flux means flow. Flux helps the filler flow.

maddog34

THIS post will be my last response to you...ever.


PS.. i was an audio tech for 10 years, and have assembled a 24x4x2 Mixing console, and a host of Outboard gear, along with hundreds fresh Mic and speaker cords, and a few PA snakes... then there are the hundreds of Trailers wired, Cars and tractors repaired, accessories installed, and a long list of other PA gear... my first electronics assembly was a DynaKit... it powered my Bass rig well. Good bye... your phD just earned you an honor. You are now blocked, "Doc" While you were busy dreaming, imagining, and supposing, i was actually doing... and just completed yet another bike for sale. Time for you to move on to supposing someone else is less skilled than you.

louky

Ok guys, I went throught my own junk box and found the below pictured RD. Is this a possibility? Since JoeTBM astutely observed that the rear on this bike is actually has 6 gears, I may now need to ask the question backwards to my original. Will a 5 gear RD work with a 6 gear freewheel? Will the pictured derailleur work on this bike?

maddog34

Nice find!!! worth a try! the wrap (ability to take up slack in the chain) might be a bit shy, but there are too many variables to sort out here... mount it up and see how it works!

WizardOfBoz

Oh, thank goodness.

WizardOfBoz

Ok, that's a 6 speed cog. If this is the original freewheel then this World Sport is from 84 to 89 (prior to 84 the freewheels were 5 speed, and in 90 it was seven speed). The pic does not match Shimano derailleurs used in 86 and 87. And in 89, an indexed rd was used. Given all this, it’s a Sun Tour AR short cage derailleur. You can see the AR on the pic. That means the bike is an 84 or 85.

You were asking if a specific derailleur would work. It was a long-cage derailleur, which could handle a lot bigger freewheel than you've got, but might work. You might need a longer chain though. Replacing the Sun Tour with a vintage AR would be expensive and I sense you want a low-cost, good option. You could try a used Shimano 600 SIS but even these are in the 30 dollar range. But by the time Shimano had SIS, their quality was approaching those early Sun Tours.

How about a new Shimano Tourney? 16 bucks and compatible with all Shimano shift systems and 6-7 speed cogs. It has a long cage but would work fine as long as you have enough chain. It appeals to me more than the Inkesky shifter you listed, and is the same price.
https://www.amazon.com/Shimano-Tourn...A1E5K32CINJQSZ

If you want a short cage (the only advantages I see would be less chain slap/slop, and you might get away with the original chain) then a short cage shimano is ten bucks more:
https://www.amazon.com/Shimano-derai.../dp/B08B3TD9QG


As far as being behind the times, I worked for seven years in a Schwinn shop but this was before the World Sports. I'm with you.