Cycling UK Forum

Some years ago I bought some plastic gear cable ferrules which had a brass insert and "O" ring seal within them. The brass insert kept the end of the gear cable outer nicely square in the ferrule and prevented any strands from working their way through the end of the ferrule, which ruins accurate gear shifting. The sealing "O" ring prevents dirt and water entering the cable. This type of ferrule is much better than a simple plastic ferrule and also some of the metal ferrules, which have a hole in the end that is too big, allowing some strands of the outer cable to get through, ruining gear shifting.
I've used them all and now need to find another supply, can anyone help please, or at least tell me what make is of this type?

Most sealed plastic ferrules will have a metal insert in addition to the rubber seal. eg Shimano sp40 caps. Jagwire, bbb, elvedes all make good aluminum caps with rubber seal, plus many other manufacturers. They're all a fair bit more expensive than bog standard plastic with no insert, but I've seen loads of cheap all-plastic ferrules punched through by gear outer strands. Personally I find that having all ferrules sealed in a cable run introduces too much friction, I prefer to have one sealed on the most exposed part and just decent reinforced but un-sealed on the other ends.

Thanks for the reply with your suggestions.
I've been messaging various suppliers to ask specifically if their sealed gear cable ferrules include a brass insert, but I am yet to receive an answer that is helpful. I've found a Jagwire plastic gear ferrule that shows a brass insert with a sealing rubber O ring, but everywhere states these are unavailable, maybe they are discontinued. These is also a Jagwire alloy gear cable ferrule which is sealed, but the insert is nylon, not brass, so it kind of defeats the object of a metal ferrule by putting a plastic insert into it.
The ferrules I've been asking suppliers about are the Shimano sealed plastic gear cable ferrules, product code Y6Z298010. I think these ferrules include the brass insert (something has to hold the sealing O ring in place), but as I say I've not had a helpful answer yet. Even the Shimano website doesn't say anything about the insert, only that they are sealed, and there doesn't seem to be an facility to ask a question of them.
Does anyone know if these Shimano sealed plastic gear cable ferrules, product code Y6Z298010, include a brass insert?

Uberbike sell aluminum gear (and brake)end caps with brass insert in 4 and 5mm I.d.

https://www.uberbikecomponents.com/view ... rules-Gold

Shimano sp40 caps come in sealed and un-sealed varieties. The sealed ones have an o-ring set into a chunk of white plastic pressed into the cap (not brass as I originally thought). I think that the plastic insert is a different type of tough plastic because I've never had any problems with steel strands partly or wholly pushing through these ones. These sealed variety have a divot on the end and two flats on the cap.

Minutes before Gregory posted this ^, I headed off to the garage to check for metal inserts in Shimano ferrules:

This is one from the used box (you can tell it's a sealed one by the four bands around the outside): And this is what it looks like when sliced in half. As Gregory says, a hard white plastic insert (that my Stanley knife went through) and the rubber o ring that makes it 'sealed':
I find they work well but the sealed end is only required for the cable runs that end somewhere wet or dirty.

Thanks for your replies, that's very useful.
I think what I probably had years ago were the Jagwire plastic ones with the brass insert an seal. I am actually less concerned about the seal than the "hard" internal end for the cut cable to press up against without any danger of it poking a few strands through the end of the ferrule. I always finish the cut ends of my cable outers using a bench grinder to square them off properly - no different length strands and no sharp strand ends.
Thanks for the pictures of the internals of the sealed Shimano ferrule. The plastic insert holding the seal must be a harder type than the ferrule itself, its good to hear that you've never had any "push through" problems with these. Incidentally I've never had any strands push through a ferrule, maybe that's because I always square off the ends of the cable. I'm sure that these ferrules will be good enough. I'm less keen on alloy ferrules because of the eventual galvanic corrosion between the ferrule and the cable end and, in my case, the steel frame cable stops.
Thanks again for your help.

I don’t have a bench grinder but I’ve never felt the need to ‘dress’ the cut ends of gear cable. Spiral wound brake cable is a different matter. Do you pre bend the cable when grinding it, as presumably the strands that follow the inside of the curve will be the ones that protrude once installed? I have looked to do this when cutting though I’m not convinced it has ever been successful or beneficial.

I just had a measure up of some cheap plastic ferrules - internal diameter 4.3 to 4.4mm and gear cable outer - external diameter 4.2,
inner cable diameter 1.2mm. I see on ebay (or elsewhere no doubt) miniature brass M1.6 washers with an OD of 3.5mm as used by model makers which might do the job, £4.95 for 20.
https://www.ebay.co.uk/itm/141476696041 ... BM8MD-zYBi

Yes, I do pre-bend the cables when squaring off the ends with a bench grinder, with particular attention to the short outer cable adjacent to the rear derailleur, which has a sharper bend than the other sections. The grinding must be done very slowly to prevent the heat generated from melting the inner sleeve and closing it - I always have a large darning needle ready to open out the inner sleeve if it melts closed. Maybe the slight closing of the inner sleeve acts as a sort of seal to keep dirt out.

you can tell it's a sealed one by the four bands around the outside

Good Tip - thanks !

I had a look at the link for the washers: the ones with an OD of 3.5mm have an ID of 1.7mm. I suspect that an ID of 1,7mm would allow a few strands of the gear cable outer to poke through alongside the inner cable. The M1.2 ID of 1.3mm would be mores suitable, but its OD is only 3.0mm, so would rattle around in the ferrule, or would it, wouldn't it be centred in the ferrule by the inner cable?
Maybe this is the solution, thanks for the info.

simonineaston wrote: ↑12 May 2023, 8:52am

you can tell it's a sealed one by the four bands around the outside

Good Tip - thanks !

Me too. I'm still confused by gear cables with 4mm or 5mm outers. What's the current recommendation. Are 4mm casings replacing 5mm ones. Both sizes seem to be around. Working on older bikes 5mm is commonplace, are new machines extensively 4mm now.

rjb wrote: ↑12 May 2023, 9:02am Me too. I'm still confused by gear cables with 4mm or 5mm outers. What's the current recommendation. Are 4mm casings replacing 5mm ones. Both sizes seem to be around. Working on older bikes 5mm is commonplace, are new machines extensively 4mm now.

5mm gear outers are quite a bit less flexible than 4mm, I much prefer the latter for that reason. 5mm brake outer isn't as stiff being spiral wound but of course is not suitable for shifting on modern systems.

Some years ago I used 5mm spiral wound brake outer cable on my 10 speed shimano 105 gear cables - I know it's said it is not suitable, but the shifting was just as good as with 4mm parallel strand gear cable outer!

Andy61 wrote: ↑13 May 2023, 9:08am Some years ago I used 5mm spiral wound brake outer cable on my 10 speed shimano 105 gear cables - I know it's said it is not suitable, but the shifting was just as good as with 4mm parallel strand gear cable outer!

That's interesting!