I removed an old sedis chain from an old Peugeot UO8, after thorough cleaning, I notice plenty of cracks, need a replacement chain, I am kind of a layman as far as sizing goes, went to fleabay etc not sure on the sizing, what do I need? the chain is 4 feet 5 inches long , came off a 10 speed French bike, what am I looking for as far as sizing ? or what kind of chain would fit? thanks

As far as length goes, your Peugeot has a long chain, but a new chain is usually 114 or 116 links and you may need to shorten it slightly.

Get your link count first before buying a chain, just to be sure. Links can be removed carefully with a bench grinder if you have one, or you or a shop can shorten as needed using a bike chain tool.
The link count includes inner and outer links, so always an even number!

Many modern chains come with a tool-free connecting link, but not Shimano's chains.

You can probably use an modern "8-speed"-width chain on your Peugeot, and a KMC Z-series chain could be as little as $10 retail and has a tool-free quick-link included.

For heavier use and longer mileage, KMC or SRAM have better chains in the same width, and both come with quick links.

sedis was absorbed by SRAM .. new chain? 3/32" wide covers everything up to 8 speed..

brand relatively unimportant .. you probably need a new freewheel too ..

Another can of worms here, since the Peugeot's hub and freewheel might be French-threaded in this case.

A modern English-threaded freewheel will usually spin right onto a French-threaded hub, but the strength of the connection is quite compromised.

Many have gotten away with this, but I was at least hopeful that the 8s chain might work well with the bike's original freewheel.
Sometimes a modern chain will "skate" or have a false-neutral effect when used on an old French or Italian freewheel, so best to be prepared for that possibility.

Possible also that this UO8 may have had an English-threaded rear hub put on at some point, if the wheel has ever been replaced.

I've stocked up on Sram PC 870s

Still have a stock of Sedis but I'll try one on my main ride this spring. It's supposed to be top of the bunch and that's a relatively good price.

A chain tool costs very little. Much less than a bench grinder.

The design of the SRAM PC48, PC58, & PC68 chains is similar to the old Sedisport and Sedis Delta chains. They've been out of production for a while but you can sometimes find them around. If I couldn't get one of those I'd try a SRAM PC850 or PC870.

For a replacement freewheel, if there are any shops in your area that sell used bikes exclusively you could check with them to find out if they have any French Atom or Maillard freewheels for sale. I'd be inclined to try one of those before getting a Shimano part.

Does a better job, too...

Another vote for any modern SRAM "8-speed" chain. Try it first before assuming you need a new freewheel, although you may find it skips in the smallest cog, if a previous owner did a lot of riding in small-small crosschain, as many "shiftless" people seem to like to do.

I have a couple of French thread freewheels I've serviced. PM me if interested.

The later and current versions of SRAM 8s chain are wider on the inside, such that they can better resist any tendency to skate over an old freewheel, and also prevent sluggish shifting up to the big ring. Really, these are better than older versions with the straight, beveled sideplates (and that only work better with 7-speed Accushift systems which have excessive overshift movement).

The OP should be careful to verify if a French freewheel purchase is or is not French-threaded, since perhaps half of them are not, and any stamped markings may be cryptic.
French freewheel threading is something that is never a good thing to have to deal with imo.

doubt that includes removing the wear on the cog teeth, that takes a Time Machine..

Cog tooth wear is an overrated nonsensical urban myth created by the modern bike industry and local shops to make you purchase expensive 9, 10, and now 11 speed cassettes, more frequently than needed. We're led to believe that good steel cogs can wear out in a few thousand miles. I'd contend, that under normal conditions (not MTB mud and dirt racing), if cleaned off the bike (and the chain receives the same good care) on an annual basis, vintage freewheel cogs can last for tens of thousands of miles.



Think about your car for a moment. Even a wonderfully modern engine and drive train, which is superbly sealed against the elements and environment, is supposed to have its oil changed every 5000-10,000 miles. Therefore removing and cleaning the chain, freewheel/cassette and chainrings once a year or every 1000-2000 miles makes the most sense in order to preserve your investment, but unfortunately doesn't happen.

YMMV.

If the parts are older than you are then they are Classic & Vintage ,

those of us that wear things out by using the bikes , since before you were Born, they're just Parts.

Please elaborate.

I do have one bike which has the majority of components and the frameset which are older than my 1958 birth (1939). Does this mean my 1960s, '70s and '80s bikes are not C&V?

Are you also saying that I just look at my bikes and don't ride them? How did you reach such a conclusion?

I am specifically talking about steel cogs on freewheels. If cared for, cleaned and serviced, under normal and not harsh riding conditions, I'm contending they will last for way longer than the typical LBS BS that they'll throw your way quicker than you can blink, "Replace the chain and the freewheel at the same time. That will be $75. Thank you very much."

I'm saying drivetrain parts Freewheels and chains and chainrings are consumables ..
they wear with normal use

just because you scored an old freewheel and cleaned it up does not necessarily guarantee

you can use it and have it work properly. as if it were New. un less It Actually Is NOS.


want to ride the bike a Lot ?, buy a Freewheel that is cheap and commonly available Now.

save the collectible drivetrain parts for a Bike Concours D Elegance , to show off

then, take it back off, and put the pragmatic stuff back On.

Definitely the freewheel should last through a few chains, as long as the rider uses different cogs!

That does add up to many thousands of miles in good conditions.

Nice photo of that Cyclo64, 14-26t freewheel!

That is perhaps the best score I can think of for a sporting, French-threaded bike. These even work wonderfully with HG70 chain, and it really made my TDF into a performance sleeper.
I also found a 40t ring for the Mod93 crankset, and thus I fear no hills now.

I dub thy green Frog bike 'Kermit'

Within our local peloton, it has been dubbed "The Green Hornet".

I think we just approach the same challenge with a different emphasis. Mine is to clean, service, and reuse. Your's appears to be use until worn out and then toss.

I take your approach on tires, tubes, brake pads and bar wrap. On all other bike components I take the same approach as my Honda service department takes with my Odyssey.

Did you use a cleaner/degreaser like Simple Green? Or other non petroleum product?
I have seen that cleaner kill chains if soaked overnight in it.

I use an IGH bike for the most part, now, anyhow .. AW3 cogs are Cheap..

Have an RB1 hanging around .. Just not all that Practical day-to-day..

I've seen many chains that developed cracks simply from extended outdoor exposure.

But alkali-based cleaners can do the same thing in a matter of perhaps days.

As far as freewheels being consumables, yes, but there are no modern freewheels to fit French-threaded wheel hubs.
The newest of them are perhaps 33 years old!

Thankfully, those Cyclo64 freewheels seem generally robust, with my only concern upon rebuilding mine (in order to shim the bearings a little tighter) was that the lockring/cone might loosen.
So, with my basic wire-loop style Park pin tool, I cleaned the threads and applied Loctite to the threads upon final tightening.

And should the tall, thick teeth on one of these older freewheels develop enough "hook" to cause skipping with a new chain, one can simply put a 1mm bevel up on the driven-side corner of each tooth of the affected sprocket. The previous "failure-to-engage" and resultant slipping is usually remedied this way, for many thousands of additional riding miles.
I do this regularly, in under 5 minutes (and with the freewheel still installed on the bike), using a Dremel with a 3/8"-diameter stone wheel.
I've made the mad dash U-turn back home when riding a new-old bike that immediately showed the skipping problem, and the fix took no longer than it sometimes takes me to find my windbreaker after heading out with one layer too few. I'll then go right back out on the road and make the ride start with still a minute to spare, and with no skipping.

I implore riders not to discard freewheels that have less-common threading and/or desirable mid-range ratios, just because one or two cogs skip under load with a new chain.
They aren't making any more of these!
Shimano UG, Suntour and especially Cyclo w/French threading, these are the best-friction-shifting gems that will only get scarcer and more expensive.