# Educate me about ferrules



## winstonc (Nov 18, 2002)

I finally finished recabling my bike. It's always a lot harder than it seems like it should be. Anyway, I have some technical questions about ferrules because I spent way too much time dealing with ferrules that were too big or worse, too small.

For the derailleurs, I started out using some generic bulk cable I had, which has approximately a 4.2mm outer diameter. The 5.0mm (inner diameter) ferrules that I have are way loose, and the 4.0mm ferrules don't want to go on there. (I made all these measurements with vernier calipers).

For the brakes, I used generic 5mm cable, and the 5mm ferrules went on there but were a little bit loose.

I recently used a Campy cable set, and the included ferrules fit just right on the derailleur cables -- they went on with just a little resistance so you know they had a snug fit. But since everything fit nicely and I wasn't fighting with too-tight ferrules, the cabling job was much, much faster.


A couple of questions: 
- Is Shimano 4mm SIS cable really <4.0mm in diameter, so that it fits the 4mm ferrules? If not, then what size ferrules do you use? 
- Should I just get 5mm derailleur cable?
- Do cables ever fit nicely into the ferrules like on my Campagnolo cable set?


My measurements, in case anyone is interested:
- Generic derailleur cable: 4.2mm OD
- Campagnolo derailleur cable: 4.4mm OD

- Generic brake cable 4.8mm OD
- Campagnolo brake cable: 4.9mm OD

- Generic ferrule: 4.0mm ID
- Campagnolo ferrule: 4.5mm ID
- Generic ferrule: 5.0mm ID


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## Mr. Versatile (Nov 24, 2005)

I'm not familiar with Shimano cables,but I know there's a difference in the cable housing between brakes and derailleurs, especially if you have indexed shifters. The brake housing are wound. The derailleur cables are straight longitudinally. Der. housings have to be stiffer to accommodate the precision demanded by indexed shifting.

Sorry I can't help with the ferrules. I only use Campy, and as you've already said, they fit very well.


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## the Inbred (Feb 28, 2004)

After reading this post, I feel obligated to reply given how much time was put into it...for ferrules. 

with 4mm housing, i use generic 4mm plastic ferrules, and one alu ferrule to go into the RD. they all fit snugly. 

brake ferrules tend to fit a little more loosely. 

in the end, i just slap something on. if it fits, it fits...if it doesn't, it doesn't. regardless, it takes me no more or no less time to replace cables and housing.


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## winstonc (Nov 18, 2002)

the Inbred said:


> After reading this post, I feel obligated to reply given how much time was put into it...for ferrules.
> 
> with 4mm housing, i use generic 4mm plastic ferrules, and one alu ferrule to go into the RD. they all fit snugly.
> 
> ...


I figured that someone would think this is silly... if you had seen how much time I spent trying to get the 4mm ferrules to go on a 4.2mm housing (they go partway on!), the troubles it cause with shifting, and the subsequent recabling, you'd understand. If I had ferrules that had just fit, it would never have occured to me that they can be such a pain if they're not quite right.

In a downtube adjuster barrell, I previously used a 5mm ferrule with the 4.2mm housing, and because the housing moved relative to the ferrule when I turned the handlebars, it eventually sawed through the softer metal of the ferrule and started chewing up the adjuster barrel. And so I had to recable and replace the barrel.


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## SANdave (May 8, 2006)

FWIW, I have the pre-packaged Shimano brake and shifter cable packages. It does say on the package that shifter cables are 4mm outer diameter and 5mm for the brakes. I don't have a vernier to check it though.

They also come with pre-packaged ferrules and all fit snugly against the brake & derailleur cable stops on my frame. Shifter ones are plastic except for the one at the RD. (Rear) brake ones are metal.


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