I'm having trouble getting some modern cable end caps to fit an 81 Giant frame. Is there a size difference or special cable I need to get?

Cable sizes (I assume you're talking about the inner cable itself, not the housing) have been standardized since before your 1981 frame was made, but brake cables (1.6mm) are larger diameter than derailleur cables (1.2mm). Your LBS should have cable end crimps capable of accommodating various cable diameters up to 2.0mm.

https://www.jensonusa.com/store/sub/1...ng.aspx?s=1590

Don't need cable end cap . . . dab of superglue keeps end of cable from unraveling

No, the outer. It wont fit inside the frame.

For a clear answer a picture would be very helpful.

Is this the housing that you're trying to put into a frame made for internal cable routing? Or are you using a double-ended replacement cable? Or trying to feed the cable through with the end cap in place?

They make caps with a little nipple on the end. If the ones at the LBS have too big a nipple, chuck them up in a drill and hold a file to them while they spin. That will get them in there.

Housing cable ends ??
https://www.jensonusa.com/store/sub/1...ng.aspx?s=1769

I think he's talking about ferules.

This is a bit of a guessing game for lack of a picture, but I suspect he has an old bike with the smaller diameter cable stop braze-ons (as shown below).

The modern standard cable ferules are too large for these, so I just take some scissors and trim 3/16" of plastic off the end of the housing. (The metal inner portion of the cable housing is the right diameter.)

If he's speaking about a cable ferrule on the lead end of an RD cable housing, where it fits into a cable stop on the R chain stay, I understand.

Otherwise, I don't.

What about the brake cable end caps that are metal and coated? I dont want to file them.

Won't fit inside the frame? What part of the frame do they need to fit inside, exactly?

You say sailor's headed in the right direction, but he is talking about ferules (step down ferules specifically), but then you say you're not talking about ferules???

Got a camera?

Are you trying to run an internally routed rear brake cable?

I think he is talking about stepdown ferrels too. "Loose screws" sells them. I don't use cable cap ends. I braze the cable ends. It is permanent and you only have to do it once.

there are 2 sizes: small for derailleur cables and large for brake cables.

it seems silly to have 2 sizes, so i just use the larger ones for all cables. one of those containers is essentially a lifetime supply.

This issue is still not resolving itself. Sorry for the mistake before. I cant get the cable housing ferrule to fit inside the the little parts of the frame that hold the ferrules. I orderd some stepdown ferrules online and they did not work. I dont know what to do short of just running the housing all the way and zip tying everything to the frame

Hmmm, odd. Still no pics, eh? Is this a mountain bike? Which portion of the frame are we talking about? Top tube, downtube, chainstay?

If it's on a top tube, are there three hoops that hold the housing? If so, they'll sometimes be too small to fit ferules through so you'll need to feed bare cable housing through, then place a ferule on either end of the cable housing after feeding it through the three hoops and cutting it to length. Leave the length too long at first until you get things dialed in and you know you can fully turn your bars and that you have your stem height where you want it, etc.

The more details you can supply the quicker an answer can be zeroed in on.

Zip-tied full housing runs should work if you're using new cables/housing and lube the cables with light oil or Tri Flow.

1981 style friction shifters will be more tolerant of full housing runs than newer indexed systems.

EDIT: actually most deraileurs aren't setup to accept a full housing run, so you'll have to terminate the housing run before it reaches the deraileur somehow. But full housing run for the rear brake, no problemo. Every 1981 bike I've seen had a full housing run for the rear brake.

On an interesting side note - 1981 was the first year for Giant bikes!

How about a tangential question while I'm at it -- Where did you get the bike? Do you live in Asia? I'm guessing they were quite rare in my part of the world in 1981. The first one I remember seeing was in 1988.

Step down ferrels are made in 3 or 4 different sizes. Options are to:

1. Post pictures as the cold weather is causing condensation on my crystal ball
2. Use the proper size ferrel
3. Trim back the outer casing Thats how my Merckx is setup
4. Use the proper size cable housing. If you have that super sized 80's diameter stuff it isnt going to work

From Sheldon Brown:

Ferrules
Ferrules are small metal caps, usually nickel-plated brass, which fit over the end of a piece of cable housing. They help keep the housing aligned with the cable stop it fits into. Whenever possible, you should fit a ferrule on each end of a cut piece of housing. Some housing stops/adjusting barrels are too small to fit a ferrule into, so you don't always need to use one. Such stops will generally be a snug enough fit that they will act as a ferrule. The use of ferrules is particularly important with compressionless housing.

Ahhh, Yes! I seem to remember my first Mountainbike having cable stops on the downtube that were sized thusly. It was a Takara, which may very well have been made by Giant.

Memories. Sigh.

You seriously shouldn't bother buying these online. These ferrules comes with every Shimano kit (packaged with the downtube cable bosses), so most shops have a bucket of these somewhere. If you can't find any, let me know via PM and I'll mail you one.

And for those still wondering, this is what he is looking for:

Thats a derailleur ferrel.