Bicycle Mechanics - MTB Brake handles (mechanical)

I bought some brakes by AVID and have been using a 4mm OD cable housing.
The part of the brake handle (I will callit a nipple) where the cable housing goes into
is allot looser then the OD of the cable housing.

I dont understand why the ID of this nipple is so much larger than the OD of the cable housing.
Should I wrap some ducttape aorund the cable housing for a snugger fit inside this nipple or threaded
barrel whatever you call it?

Should I use a ferrule at the end of the cable housing, even though it is inside the threaded barrel?

Thanks for any clarification.

All of the brake housing that I've ever seen had a 5mm OD.

Take a close look at the cut end of your cable housing. Do you see a lot of wire ends? If so, you have shift housing not brake housing.

You put a lot more tension on a brake cable than you do shifting. If you use shift housing for brakes, it is very likely to break out at one of the bends.

Typical brake cable housing is 5mm outer diameter, which is the only diameter I've seen it in. (Though I'm not doubting the existence of 4mm housing, just never seen it). I've seen shift cable housing in 4mm and 5mm.

Don't mean to be insulting, but ensure first that you re using brake housing and not shift housing; there is a difference. Using brake housing for shift cables may affect performance, but using shift housing for brake cables can jeopardize your safety.

Also, whatever the housing outer diameter, I believe you still need a ferrule on the end of the housing before it goes into the barrel adjuster of the brake lever. 4mm and 5mm inner-diameter ferrules have the same outer diameter.

Yes I have brake housing, I MEANT to say 5mm OD. Anyway the brake housing cable is still
way loose inside the barrel adjuster.
Is it supposed to be like that?

But are you using a ferrule?

Ferrule = the little silver slip on metal piece that goes onto the end of the housing to help support the cut end.

Also the "nipple" on the lever is called the barrel adjuster since they are almost all setup with threading to be able to adjust the final lever position when you pull the lever.

I just looked at the Avid levers on my wife's bike. There's considerable free play between the cable adjuster and the ferrule on the brake cable. It's more free play than the Shimano levers, about the same as the Tektro levers, and less than SRAM levers. (I've got a garage full o' bikes.) 5mm cables on all of them. Not a problem on any of these bikes.

Yes, you should use a ferrule. It will allow the adjuster to turn more easily.

Some ferrules have so much play, you can use a ferrule within a ferrule to take up the clearance...

Yes I have brake housing, I MEANT to say 5mm OD. Anyway the brake housing cable is still
way loose inside the barrel adjuster.
Is it supposed to be like that?

Would you rather it be tight and have to pry the housing ferrule out if there is corrosion.

thanks
you guys are right. The freeplay between the barrel adjuster and the ferrule is to facilitate turning the barrel. However, I tend to think it is excessive in the Avid Levers so I will wrap a some electrical tape to make it slightly more snug.

Thanks for the help.