corrado33

We've run into a consistent problem with old 10 speed bikes at our local coop. The bikes come in with rusted to crap chains and we have to replace them. Unfortunately, the new chains (even 5,6,7 speed ones) simply don't work. They slip and they don't shift well, even when the freewheel/chainrings aren't worn. The ones we use are the Z50 chains.

Does anybody know a good source for the old style of "10 speed" chain? Or, do you know how to make the old 10 speeds work with modern chains? This isn't just on one bike. It's not just with one freewheel, this is with many bikes over many months. All of the old 10 speed (and 12 speed) bikes have this problem when you replace the chain.

And yes, I understand that a worn chain leads to a worn cog which will skip with a new chain. I promise all of these cogs aren't worn.

rhenning

KMC 3/32 chain from Walmart. Roger

Homebrew01

Maybe you're spoiled with modern drivetrains, and the old clunkers you're fixing just can't be any better ??

corrado33

No not at all! These bikes ride great when you have a decent OLD chain on there. When you put a modern chain on them they're practically unridable. The chain will jump in the smaller cogs generally and often it'll get stuck between cogs/chainrings.

dsbrantjr

New chains will often not work well on worn cogs; if this is the problem I do not think any new chain will work well.

bikemig 

+ 1. New chains work fine with old 5 speed freewheels if the freewheel is not too worn.

SBinNYC

I've encountered the same problem using new freewheels and chains. My solution has been to buy NOS freewheels and chains. That's a good solution for me because I'm in my mid 70's. It's likely I'll run out before the supply of NOS does.

Here's my take on what's happening.

First, all the "new" freewheels are hyperglide or ultraglide compatible. That means their cogs have shifting gates to make shifting easier. The new chains are designed to work with hyperglide and ultraglide. Their side profiles are slightly different to catch the cog's gates.

This works fine for an indexed shifter. It's a disaster for a friction shifter.

An indexed shifter places the derailleur in the same lateral position for each cog to a very tight tolerance. If the derailleur is off that lateral position, the cog gates will catch and try to initiate a shift. That's the reason for the fine cable adjustment and the necessity for making certain the hanger is also aligned to a tight tolerance.

A friction shifter depends on a large tolerance of the derailleur's lateral position to stay in gear. The reason a large tolerance is necessary is because the friction shifter cannot repeat the derailleur lateral position with any degree of repeatibility. The friction shifting technique is to overshift and then correct. The overshift forces the derailleur into another cog. Overshifting is necessary because the chain won't otherwise derail. The correction gets the derailleur lateral position into the wide range necessary to keep the derailleur in the new gear.

These two philosophies are contradictory. The only way I see out of this predicament is to figure out a way to loosen the tolerance required to keep the derailleur in gear. One possibility is the lateral float on the upper jockey wheel. There is no float for derailleurs designed for friction shifters. I'd try swapping out top jockey wheels to test the hypothesis. If there's any merit, I see the least expensive solution for a bike coop would be to get slightly longer bushings for the top jockey wheel.

ypsetihw

+1 these are under $10 and work perfectly. it's the cogs that are worn - new chains on old freewheels almost always skip in my experience.

fietsbob

New 5 speed freewheels are still Produced , for repair of old Bicycles.

3alarmer 

KMC X8.93 Chains w/ Missing Link, Bag of 5, 6-8 Speed, Silver/Gray

...these work very well for me on every 5, 6, 7, or 8 cluster I've ever tried one on. Assuming it's not worn out. They work better on ramped cogs, but they still seem to do OK (about as well as you can expect) on the straight toothed ones.

You do have to cut the chain length correctly on your first try. If you make it too short, you need extra quick links to rejoin some links.

3alarmer 

...based on considerable practical experience here, I would have to voice some skepticism. Friction shifters work fine with ramped cogs, and if you use indexed cable housings for them, you can cut down considerably on the need for overshifting. As always, YMMV.

ThermionicScott 

+2. My favored SRAM PC-850s work great on 5-speed freewheels. I'd be suspicious of any drivetrain parts that come to me with a rusted chain.