Morning all,
I continue to work on rehabbing my 1973 LeJeune TDF. Next up is changing out the original Sedis chain for the SRAM PC-870 which was suggested by several members as the go-to replacement for my bike.....I have the Park master link tool to help with the supplied sram master link that came with the chain. I also have the link removal tool which will help,remove the old chain. I have read quite a lot about the chaining out process. I'm not sure how many links are in the original change. I thought I would remove the old chain, count the number of links and be sure the pc 870 had the same number. If not, (remembering that the master link counts as one link) assure myself that the new chain has exactly the same number of links as the old. Clean the freewheel and chain rings, lube each link on the new chain and reinstall. Making sure the freewheel is lube also. The bike has new shifters and cable housings and has been tuned up. Since then the shifting has gone downhill a little. Part of that is rider error I'm sur , but all the other symptoms indicative of the need for a new chain are evident. Others suggested the time was ripe for a new chain. I believe they are right. I'm just asking if I'm going about it in the correct way.

Your help is always appreciated as I become more adept at the bike maintenance regimen. On an interesting side note, as I continue working on the Le Jeune, I have also started reviving my wife's 1993 Schwinn Cross Fit. Recently saw my daughter, and she has the 1990’s Trek 8?? Antelope man bike that I'm probably going to start redoing soon. In several month's time I've gone from not riding bikes at all to working on redoing three bikes, building a workshop to do this work, building a bike stand to save my back, and actually still riding some during this warm winter....I guess it doesn't get much better than this!

Thanks,

The 'Rsterman

+1 I don't recall reading your other thread, did you check the existing chain for wear? Are you sure the shifting issue is the chain vs the RD adjustment/ freewheel wear? Sorry if I am repeating what has been discussed.

I always wrap the chain around the large rear cog and around the large front chainring without going through the derailleurs. I over lap two complete links then use a missing link connector. Right or wrong it always works perfect.

No need to count links . If you are content with the length of your old chain , lay both chains side by side on a flat surface and remove the appropriate number of links .

Sounds like you've landed on your hobby of choice. You're in good company!

Probably okay to use the old chain as reference if you've owned the bike a long time and it works fine through all the gears. Problem arises however with these vintage bikes where some hack did it wrong before, or links have been removed over the years, or cog/chainring sizes have been changed beyond the chain's capacity.

I like this video for guiding you through the process of sizing a new chain. His process looks at limits for being too short as well as too long. You'll see he uses a 2 inch hook which is easily made with a piece of coat hanger. I've followed this on several installations with no issues at all.

https://m.youtube.com/watch?v=ELsKrgTt0oY

This works for me, as well. Also, the master link only counts as 1/2 link. One complete link is one set of inner plates and one set of outer plates.

Success. Period.

Use Sheldon Brown's guide on chain length. I never count links.

I mount the chain and hold it while it's on the small front/small rear, make sure the RD is not compromised or rubbing, and that's it.
you are much better off using Sheldon Brown's guide, seriously.

The only problem I see is if your freewheel and/or chain rings are worn to where it doesn't matter what chain you use.

I don't believe anyone has mentioned yet, you don't need to lube a new SRAM chain. It is perfectly lubed out of the package.

Can you post a picture of the freewheel or tell us the brand?

Cleaning the sprockets on the freewheel is an excellent idea. Clean the chainrings as well!

This is a tried and true method, and I've used it plenty of times, most often when in a hurry. But it has the following flaws.

It assumes you are currently using the largest rear cog you EVER plan to use. This can be a big issue with a road rear derailleur that isn't close to its range. But then you get older and now your rear cassettes have grown more teeth.

For wide range gearing, as in an MTB 2x or especially an MTB 1x with say a 10-42 range, it doesn't work as well as the method [MENTION=108582]RobbieTunes[/MENTION] brought up, which is to make sure the small small is still usable and clear.

However, since you should always change your chain when replacing your cassette/freewheel, this should never be a problem if you check the size at each chain replacement.

Comparing new chain to old assumes that the old chain was the correct length to begin with. I'm not saying that the OP's original chain wasn't the correct length. It's good to understand how to determine the correct length of a new chain.

this.

in addition, you'll never be able to lube it as well as when it was new.

in your op, you also mention lubing the freewheel. only lube the threads of the freewheel and threads of the hub where the two meet. the freewheel cogs should be dry and clean.

My last trip to the LBS yielded 2 new tubes/tires, cables/housings for brakes as well as shifters, and a tuneup all around which I assume includes adjusting front/rear derailleurs if need be...actually by "shift problems" I was suggesting that there was sometime chain noises after a shift.....which is probably more a product of my learning th nuances of the bike and the shift were not accurate/crisp enough to begin with.....small movements of the shift levers makes the noise go away......but there have been skips between teeth at times.....I have been led to believe they are usually a product of a worn out chain.........the friend who gave me the bike was the original owner.......he related to me that the chain has never been replaced....I used the Sloan method and measured the chain over 24 links......it was almost an 1/8 of an inch past the accepted tolerances.......There are pictures of the chain rings and the freewheel in two other C/V threads......both of the threads refer to 1973 Le Jeune TDF......another thread or two are in C/V What's It Worth forum, and they refer to 1973 Le Jeune TDF also.....after I get the old chain removed, I'll post some additional pics of the chain rings and freewheel as well......I have been told that they are in good shape by several members of this forum......I have been listening to everyone's ideas because I am a total neophyte at this bike stuff.....and I appreciate all comments/help.....

I used the Small to Small Method.



The only time i use the Large to Large method is on Mountain bikes with triple chainrings and long cage derailleurs. Also, when using the Large to Large method always run the chain thru the rear derailleur pulleys pull tight, then add 2 links. I don't know what Sheldon was thinking......

Hmm. Some good advice here but it is always good to adhere to a few basic principles.. First:
Good question. I tried riding the Le Champion I'm slowly building up with the original Sedis. Just took it around the block, got only 3/4ths of the way and the chain broke. Examination showed that maybe one quarter of the outer side plates had significant cracks. There is no way that chain would have survived a "real" ride. So do check yours.

Re using the big-big combination, be aware that you may never intend to do so but you might do it accidentally when shifting in a situation that requires one smidge more concentration than you have available. The consequences of too short a chain can be disastrous, catastrophic, dangerous (you get the idea). The point being, you shouldn't plan for the probability of something bad happening. You should plan for accommodating the severity of the consequences of the worst possible result. (That's the right approach for dealing with so many of life's, or the world's, hazards but a lot of people don't seem to understand that.)

I select chain size by putting the chain on big-big with the chain broken. Then I pull the loose ends together (and get my hands dirty) until the RD is almost pulled tight, then count how many links to add or remove. It helps to start with a chain longer than necessary. You also have to allow for the extra length needed for the chain to ride over the teeth during a shift, so you can't make it absolutely as short as the RD seems to allow. After connecting the loose ends I shift to small-small. If the RD can't take up that much chain, the the RD can't handle it and must be replaced with a long-cage RD. Then I try the big-small and small-big combinations.