I recently replaced my straight handlebars with trekking bars and now want to shorten the first section of cable housing a bit on my brakes and derrailleurs.

I disconnected the front brakes this weekend and was all ready with my (new) cable cutters to tackle the job. I thought I would simply take out the inner cable, slide off a ferrule from the cable housing, cut the housing a bit, put the ferrule back on and re-insert the inner cable. But I was stymied. I cannot figure out how to remove the ferrule from the cable housing. It wouldn't simply pull off. I tried pulling the ferrule off with pliers, but didn't apply too much pressure because I was afraid of damaging the cable housing. Still couldn't get it to budge.

Any thoughts? Are the ferrules not removable? Should I use more pressure with the pliers? Should I just cut that section of the housing off and use new ferrules?

Often not.

I have the opposite problem; these plastic ones on my gear cables are jammed like buggery into my STIs... I've ascertained the only way they're coming out is if I drill them out. I've nearly bust a gut trying to get them out with pliers...

So anyway, try twisting the ferrule off in the direction the strands in the housing go.

If you're trying to get the ferrules off your off-cuts, why are you scared of damaging the housing?

I hadn't cut off a section of the housing yet and didn't want to cut off a section until I knew that I could re-use the ferrule. If I cut off a section of the housing and couldn't get the ferrule off then I would be without my bike until I got a new ferrule. I guess I should go ahead and cut off a section of the housing and try to get the ferrule off using whatever force is necessary. If I'm concerned that I will be without my bike, I should get some spare ferrules on hand.

Maybe they have changed the design over the past couple of years, but I always thought the ferrules were built in to the STI levers... if you managed to stuff another plastic ferrule in there it's gonna be hella tight.

Original style STIs and really skinny housing. But yeah, hella tight.

You can ride your bike without ferrules. Just be careful not to use too much force when shifting to a bigger cog or ring. On brake housing they're not that necessary; they mostly just make using the barrel adjusters easier.

Sti's don't require ferrules for brake housing entry. They DO require however for SHIFT housing. The strands of the housing WILL blow through the stop, if you don't use them.

Not unless you want the shifting to fail after 100km. This is just ********ly bad advice.

When it appears brute force is not the answer, try a bigger hammer.

In this case, grab the ferrule with a pair of pliers and pull. When the ferrule is stuck in the brifter, try a pair of needle-nose pliers.

If it is the housing with the wound steel, you don't need ferrules. They look nice, but it is not a structural component. If it is the indexed specific housing that has the bundled steel wire running the length of the cable, it needs a ferrule.

OEM ferrules are pressed on by machine. They are not designed to be removed.
Ferrules are cheap tho- cut the housing to the length you want,then re-cap them with new ferrules. The LBS should have them. Bike shops buy them in 100's or 500's.
There are 2 different sizes: 4mm and 5mm. 4mm is usually found on modern higher end road and mountain bikes. 5mm is usually speced on mid to low end bikes. The diameters are not interchangeable.
There are also 2 different types of ferrules- Brake and derailleur. The brake ferrules are pressed with a larger diameter hole on the end. The derailleur ferrule is machined and thicker at the end to prevent SIS housing form pulling through. At home, I normally use 5mm derailleur ferrules for everything as it's easier to just keep one around so i don't make a mistake, and the price difference is minimal in the grander scheme of things. Do not use brake ferrules on SIS derailleur housing- the housing pulls through.

I have a feeling that mine were pressed on by machine. Sounds like I need to make a trip to the LBS to pickup 5mm ferrules. Thanks.

Decided to order new cables and housing rather than make a trip to the LBS. When I calculate the cost-benefit of the time for an LBS trip versus the cost of the replacement cables and housing, it is cheaper just to order new housing. Ordered them from velo orange.