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Old 02-07-12, 08:23 PM   #1
tuxfan212
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New Derailleur for Schwinn Varsity

I have an old Schwinn Varsity 10spd(June 1970) that I got for free, replaced cables, tires, innertubes, bar wraps, etc. Here is the problem though. The spring in the old Schwinn Approved rear derailleur is too weak to keep enough pressure on the chain. I can ride it fine in the second highest gear but when I shift the rear to go into 10th it will still ride but the chain slips. I figured it would be easier to just buy a cheap vintage derailleur to replace it with.

I know it has to be for a 5spd cassette and I think it has to be long cage? I might consider getting indexed bar end or thumb shifters (of which I will need proper cabling, right now just using crappy Bell cables from walmart). Also, it has to look crappy. I know its a weird request but its a college town and I have seen many bikes that have been stripped of parts while still chained up... So something inexpensive, that will actually shift, and is preferably old or cheasy looking. Any suggestions?
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Old 02-07-12, 09:17 PM   #2
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As I understand your description of the problem, you're not saying that the lower loop is sagging, but that the chain is slipping over the top of the sprocket when you apply power.

If I read you right, it has nothing to do with your RD, and everything to do with the wear age of the chain and sprocket. As chains wear the pitch increases and the sprocket wears in such a way to allow a "stretched" chain to climb outward on the teeth until it's riding high enough to slip forward if pulled hard enough.

You can confirm my theory by putting enough tension on the chain to pull out slack then measuring 12" of chain with a ruler. Since the chain is 1/2" pitch, every pin should line up on a 1/2" mark of the ruler. As the chain wears the play at the pins increases allowing the links to move apart (imagine a freight train pulling out and stretching as each car takes the slack out of the couplers). The error accumulates at each pin, and the rough guideline is that if the chain is stretched much over 1% or 1/8" over 12 it's toast, and in all likelihood so is the freewheel.

If the chain isn't stretched beyond 1%, other possibilities include the chain wanting lubrication, or the RD being slightly mis-adjusted in high (cable and/or high gear limit adjustment).

Start with the chain, that will tell you where to go next.
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Old 02-07-12, 09:25 PM   #3
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As I understand your description of the problem, you're not saying that the lower loop is sagging, but that the chain is slipping over the top of the sprocket when you apply power.

If I read you right, it has nothing to do with your RD, and everything to do with the wear age of the chain and sprocket. As chains wear the pitch increases and the sprocket wears in such a way to allow a "stretched" chain to climb outward on the teeth until it's riding high enough to slip forward if pulled hard enough.

You can confirm my theory by putting enough tension on the chain to pull out slack then measuring 12" of chain with a ruler. Since the chain is 1/2" pitch, every pin should line up on a 1/2" mark of the ruler. As the chain wears the play at the pins increases allowing the links to move apart (imagine a freight train pulling out and stretching as each car takes the slack out of the couplers). The error accumulates at each pin, and the rough guideline is that if the chain is stretched much over 1% or 1/8" over 12 it's toast, and in all likelihood so is the freewheel.

If the chain isn't stretched beyond 1%, other possibilities include the chain wanting lubrication, or the RD being slightly mis-adjusted in high (cable and/or high gear limit adjustment).

Start with the chain, that will tell you where to go next.
The chain is brand new. I am not an expert but the sprocket appears to have very little wear as the bicycle was almost never ridden. I have tried every adjustment I can find. I can say that the tension on the chain is very loose in top gear. So loose that the chain actually has visible slack at the bottom. I am sure the spring is just old and not holding the same pressure it used to.

You can technically still ride it in top gear... Just with any power every few seconds the chain will slip. The chain is the correct length and I even tried a chain with one less link and that didnt work.
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Old 02-07-12, 09:32 PM   #4
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" I am sure the spring is just old and not holding the same pressure it used to."

Not too sure about that. Old spring doesn't equal weak spring. If it did, then none of my really old vintage bikes would shift right or brake properly.

It could be that the new chain doesn't work right because the rear cogs are worn. They might look fine but what are you comparing them to? Personally, on a used bike I would tend to want a new freewheel with a new chain. A new freewheel is pretty cheap. Just my opinion.
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Old 02-07-12, 09:37 PM   #5
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If the old chain was badly worn, the freewheel is likewise toast. Search the forum for "new chain slips on old cassette" and you'll see this situation is classic. A new freewheel is the only solution.

As for the slack lower loop, some sag is normal, but if it sags more than 1/2" below the straight line level, that's too much. However it's probably not the spring, but that the Chain is long and the RD cage is hitting the stop. If it were the spring the chain would sag in all the gears to verying degrees.
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Old 02-07-12, 09:40 PM   #6
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Examine the spring that pulls the derailleur arm back. If my memory serves, there are a couple of hooks that the end of the spring attach to. The spring may have come unhooked.

If you decide that you need to replace the derailleur, a Shimano Tourney should serve you well. You'll want the version with the claw that attaches to the rear axle.
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Old 02-07-12, 09:56 PM   #7
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If the old chain was badly worn, the freewheel is likewise toast. Search the forum for "new chain slips on old cassette" and you'll see this situation is classic. A new freewheel is the only solution.

As for the slack lower loop, some sag is normal, but if it sags more than 1/2" below the straight line level, that's too much. However it's probably not the spring, but that the Chain is long and the RD cage is hitting the stop. If it were the spring the chain would sag in all the gears to verying degrees.
The old chain actually seemed to be in fine condition. This thing was litterally never ridden... The gentlemen who gave it to me was the original owner and this bike was 100% original including tires and brakes... I had just broken the old chain when I removed it as I didnt have the proper tools for that type of chain.
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Old 02-07-12, 10:11 PM   #8
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Examine the spring that pulls the derailleur arm back. If my memory serves, there are a couple of hooks that the end of the spring attach to. The spring may have come unhooked.

If you decide that you need to replace the derailleur, a Shimano Tourney should serve you well. You'll want the version with the claw that attaches to the rear axle.
There is 2 hooks on mine. Tried both of them. The second tighter one allowed me to go into 2nd to top gear without the chain slipping. Thinking about converting it to a single speed. I never actually shift it but I will be moving again in about 6 months to a more hilly area. Not sure yet.
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Old 02-07-12, 10:24 PM   #9
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I agree with the other comments that this sounds much more like a worn out small cog. If the original owner tended to just leave the chain always on the small (14 tooth) cog, then this can wear out rather quickly. I've had bikes using a short-cage derailleur where the chain would hang completely slack in some ring/cog combinations and this still didn't cause any problem with skipping. OTOH, putting a new chain on a worn cog will frequently result in just the type of skipping that you describe.

If you still want to replace the derailleur, then just about any cheap one will do - it doesn't have to be specified as for 5 cogs since the derailleur doesn't really care about the number of them. But indexed shifters do care about the number and spacing of the cogs - so replacing your current friction shifters with new indexed ones would also require other components to be replaced and is unlikely to be worthwhile.

Here's a reasonably cheap derailleur that should work better than the old Huret you probably have now (but again, I doubt that this is your problem):
http://www.nashbar.com/bikes/Product...200545__202435
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Old 02-07-12, 10:31 PM   #10
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Varsitys are good candidates for putting a 3 speed IG hub wheel into.
make derailleurs go away.
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Old 02-07-12, 11:12 PM   #11
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+100

A chain that skips over the sprockets is NOT a RD issue. Putting a Dura-Ace RD on would not solve your problem. It is either a RD adjustment issue or (as everyone has said) the cogs on the freewheel are worn out. If it only skips in the smallest cog the high limit screw might be turned in too much.

If the RD shifts smoothly through all 5 cogs it is NOT to blame.
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Old 02-08-12, 09:39 AM   #12
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Ok, I see the logic in buying a new freewheel with good cogs.

My question is which one to buy? I might hold off on it until I can take my bike up to the new area and see if I really need it to have multiple gears or if I can just convert it to single speed.
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Old 02-08-12, 09:59 AM   #13
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The chain is brand new. I am not an expert but the sprocket appears to have very little wear as the bicycle was almost never ridden.
Maybe you are a lot smarter than me. I have worked on hundreds of bikes in the last few years, and I rarely can tell if a freewheel is worn out visually. I take it for a ride, up a steep hill, mashing the gears (high gear= small rear sprocket). If it skips, its done.

Perhaps a quarter of the freewheels I see are worn out. Freewheels only cost me $9, so its not really a big deal.

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Old 02-08-12, 11:52 AM   #14
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Have you properly sized the new chain?

http://www.parktool.com/blog/repair-...ir-and-service
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Old 02-08-12, 01:48 PM   #15
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Maybe you are a lot smarter than me. I have worked on hundreds of bikes in the last few years, and I rarely can tell if a freewheel is worn out visually. I take it for a ride, up a steep hill, mashing the gears (high gear= small rear sprocket). If it skips, its done.

Perhaps a quarter of the freewheels I see are worn out. Freewheels only cost me $9, so its not really a big deal.
No, you guys are probably right. I am comparing all of these to the severely worn one that I had on an old Mt.climber roadmaster bike.

Where do you get a freewheel for my bike and which one do I need? I really do not know.
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Old 02-08-12, 01:49 PM   #16
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Have you properly sized the new chain?

http://www.parktool.com/blog/repair-...ir-and-service
I sized it based on the old original chain. It should be right.
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Old 02-08-12, 03:10 PM   #17
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It shouldn't skip either, but it does!
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Old 02-08-12, 03:31 PM   #18
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I sized it based on the old original chain. It should be right.
What if the prior owner did it wrong? Copying what was there assumes what was there was "right". Getting chain length correct is super easy, Sheldon Brown site details the method.

As far as a freewheel, I assume you have a 5 speed. I would just take the wheel to your favorite LBS, have them remove the old one, and install a new one. There are dozens of different freewheel tools out there (lack of a standard). So unless you plan to work on this particular freewheel again, the tool will be a one time use (replacement freewheel will use a different style tool!!). I have a drawer full of freewheel tools, and still am not close to having them all.
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Old 02-08-12, 04:01 PM   #19
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No, you guys are probably right. I am comparing all of these to the severely worn one that I had on an old Mt.climber roadmaster bike.

Where do you get a freewheel for my bike and which one do I need? I really do not know.
Unless you opt for the gold plated version free wheels are in my experience inexpensive and an LBS will put it on for not much cost. That solution will get your bike back on the road the fastest.
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Old 02-08-12, 05:46 PM   #20
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if you get a new freewheel why not upgrade to a 6 or 7 speed? with friction shifters you would not have to change them, ans your RD should have enough adjustment to cover 6, possibly 7 gears in back
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Old 02-08-12, 08:30 PM   #21
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Unless you opt for the gold plated version free wheels are in my experience inexpensive and an LBS will put it on for not much cost. That solution will get your bike back on the road the fastest.
I am thinking I might just do that. I live out in the sticks a bit where I am so the LBS is 40 minutes away. Probably have to make a special trip...

Also, to the other poster. I want less gears not more... Thinking I might convert it to a single speed after I move this summer. I want to try out the new terrain (more hilly) before I commit to that though.
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Old 02-09-12, 10:40 AM   #22
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I am thinking I might just do that. I live out in the sticks a bit where I am so the LBS is 40 minutes away. Probably have to make a special trip...

Also, to the other poster. I want less gears not more... Thinking I might convert it to a single speed after I move this summer. I want to try out the new terrain (more hilly) before I commit to that though.
With a 5 speed derailleur you have a built-in single speed....just don't shift! To go single you will have to swap out the double chain wheel too.

My brother rode the heck out of a Varsity that had a double chainwheel shifted by reaching down and moving a lever on the seat tube. Archaic by the really nice brifters and thumb shifters of today but it worked.
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Old 02-09-12, 05:05 PM   #23
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if you get a new freewheel why not upgrade to a 6 or 7 speed? with friction shifters you would not have to change them, ans your RD should have enough adjustment to cover 6, possibly 7 gears in back
Because the spacing will be wrong. Those old 5 speed Schwinn hubs are not spaced for 6/7 speed freewheels. You could always squeeze in a wider rear wheel, but that means additional $$.

Yes, to below, while Suntour Ultra 6 is an option, they tend to go high, really high. Even nice used ones go pretty high. And gearing is pretty limited due to a lack of supply.

Last edited by wrk101; 02-09-12 at 05:28 PM.
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Old 02-09-12, 05:16 PM   #24
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Because the spacing will be wrong. Those old 5 speed Schwinn hubs are not spaced for 6/7 speed freewheels. You could always squeeze in a wider rear wheel, but that means additional $$.
he could go use a Ultra-6 freewheel if he can find them. These use 7s spacing to pack 6 sprockets onto a freewheel the width of a 5s. they were a popular upgrade for 120mm hubs back in the early days of 7 speed. But he cannot go to a standard 6s or 7s without 126mm OLD minimum.
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Old 02-10-12, 08:41 AM   #25
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I took it down to the LBS to change the freewheel. Waiting to go pick it up. I also had them take a look at the derailleur to see what they thought... I would have just changed it myself but with classes right now I just didn't have the time...

Yeah it is a single speed if I don't shift it. Problem is every once in a while I will hit my knee on the shifter. Just nitpicking really.
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