Cable stops without ferrules

[crowe-molybdenum]

Im building myself a new road frame ( I think number 10? bike ~50) , with external cables for the derailleurs (plural) and (rim) brakes.

…and Im left wondering; why do I use cable stops (for shift and brake cables) that take a ferrule to fit the cable?

I think for me it’s tradition… so id like to know why others do (or if they don’t, show me where!) . Im trying to think of good reasons and seem to be coming up with lots of ‘maybes’?

Is it for a slightly soft transition at the end of the cable before it hits a hard “support” edge? Is it to allow some angular slop? Are there different standards of cable housing OD i’ve never come across? ( ive only ever seen “4mm” which seems to measure 4.15-4.20 and “5mm” which at 4.90-5.05mm)
is it to stop creaking (plastic) or something to do with lubrication/friction (chrome/brass)?

couldn’t we make nicer stops, (smaller, lighter, lower profile, more durable, less heat etc, which I see as good things but I understand this may not be universally true…) if they were a snug fit right on the cable housing?

p.s. im imagining they have a nice little internal radius on the open end.

[JoeNation]

Ferrules are there to protect the end of the cables, stop them fraying and to make sure they have a smooth square end where they fit into the cable stop. Will pre-existing (ie decades-old) technology, this was vital as cables were rubbish and stops were made of cast iron to massive tolerances. More modern materials and practices have helped, but ferrules have persisted. But if you can make a nicely-machined or 3D printed stop with decent tolerances, it would do all the work the ferrule does anyway. My only question is, why? What’s the benefit?

[Daniel_Y]

@crowe-molybdenum

couldn’t we make nicer stops, (smaller, lighter, lower profile, more durable, less heat etc, which I see as good things but I understand this may not be universally true…) if they were a snug fit right on the cable housing?

That is a good question. It would shrink the size of the cable ends quite a bit. Without the cable ends, you can get a REALLY sleek-looking setup, with the cables running close to the tubes.

My guess is similar to JoeNation, the cable end allows for reinforcement and standardization of housing. There is quite a bit of variability of “4mm” shift housing. I have measured 4.1-4.3mm

Shimano recommends using these styles of ends (see below) whenever possible. I could see that being an argument for cable ends.

[rudgas]

There are also “sealed” cable ends which include one (or more?) Silicone O-rings on the inside to keep the dirt out.

[DEVLINCC]

Dazza at Llewellyn design his Limpet brake cable stops to take a plain cable hosuing. Makes for a very neeat look. The socket is also fairly deep which helps stabilise the housing. Interestingly he uses a cap on the gear housing. Never asked him why. though…

http://www.llewellynbikes.com/FramebuilderSupplies.html

[crowe-molybdenum]

@crowe-molybdenum

smaller, lighter, lower profile, more durable, less heat

In my eyes, for the reasons I mentioned above? The excitement about getting them a bit lower profile is especially genuine. But less heat and more durable also pretty ideal.

Interesting points about the o-ring and little-extended-sleeve shimano style ferrule models, but honestly those things aren’t a big deal for me. I lube cables going in and then leave them alone until they need replacing. Which doesn’t seem to really ever come around.

I like the Idea of reasonably deep; I’ll take a look at Daryl’s offerings, and unless I have a drastic change of heart, or some great reason for using ferrules comes to light before I’m in front of the lathe, I’ll make a set and see how they go.

[manzanitacycles]

Rene Herse Cycles sells their tiny housing stops for brake housing without ferrules.

[Daniel_Y]

nice!

Better delete the ferrule and strip the outer rubber cover of the housing, so the steel of the cable housing fits directly into the frame’s cable stop.

Has anyone used these bosses before? It looks like a pretty cool idea. I wonder if you can do the same with shift cables.

[manzanitacycles]

I’m guessing you can’t have a slot in the stop if you use housing in which the steel strands run parallel with the cable, like in shifter housing or compressionless brake housing. Those strands would end up poking through the slot.

I haven’t used the Rene Herse stops because they don’t look very deep and supportive. Seems like the housing might end up crooked or kinked without an extra guide ahead of the stop to help it go in straight. You can even see in one of their product photos how the rear brake line needs a guide up front and then it leaves the rear stop at a weird angle.

Maybe that kink doesn’t affect cable friction, but it looks like it might.

[crowe-molybdenum]

I agree about the above offering not looking very supportive, being so short, but if it’s a tight fit and it’s steel on steel, maybe it’s actually better than usual?

wether or not that kink may be a problem; it’s not how I’d like my bikes to look. Whatever solution I come to, I’ll be making them snug and tight enough to avoid that… But it’s nice to know it works well enough as seen for them to at-least continue selling them.

I personally tend to ignore the slot so /could/ strip the outer plastic for gear and brake; (I don’t use the slot, if something needs doing I’ll want to pull the cable out anyway…)

How I feel about stripping the outer plastic off, I’m not 100% sure;

my knee-jerk reaction says no, it adds a step, potentially shoehorns the frame into needing one brand/era of housing, without modification and it creates a finicky transition zone of trimmed cable-housing-housing that needs to be kept very slightly longer than the stop is deep, but cannot be zero for an ideal setup. Also does brake cable housing compress more without the plastic? Potential for ‘annoyingness’ there feels high.

my practical brain says I’ve already used the arguments for doing it to justify what I’m already proposing…

I want to say I feel like, maybe the plastic shielding will do some of the transition work the ferrule would have done, just tidier? But probably I’m just making it all up at that point.

I’ll test run the options in the workshop next week and post up some images.

Untill then I’m away from the workshop and still all ears. Thanks for the ongoing conversation!

[Daniel_Y]

@crowe-molybdenum

I personally tend to ignore the slot so /could/ strip the outer plastic for gear and brake; (I don’t use the slot, if something needs doing I’ll want to pull the cable out anyway…)

How I feel about stripping the outer plastic off, I’m not 100% sure;

I agree with both these statements. I think the cable slots are a bit redundant. Compared to modern bikes, re-doing externally routed cables is pretty easy, even if you need to pull the cable all the way out!

Also, stripping the plastic seems a step too far to me as well.

You convinced me! I will also try to 3D print some “no cable end” cable stops for a road bike build I am working on.

[crowe-molybdenum]

Got on the lathe today,

here’s a couple of ferrule-less BRAKE (yes, definitely brake) cable stops, 11.5mm long, 6.8mm OD, 4.80mm ID with a pretty generous ~( 0.4mm) flat filed on the tube-facing side. the “wall” at the end is 2.5mm thick.

specifically, the bore (with my tiniest “small hole bore gauge” ) actually measures 4.80mm and Im confident in that measurement +/- 0.02. the housing is just a little tighter than what I would call “perfectly snug” ; its tight. after a few times in and out the housing seems to have compressed and is then a firm snug fit. im using Shimano housing, im not sure how to identify it beyond that it is black, and says Shimano, in tiny black text every 15cm or so.

the interior, housing-facing-surface (the inside of “the wall”) has been cut flat with a square-ground twist drill.

the through hole for the cable is drilled with a 2mm twist drill. I flipped these in a three jaw chuck to spot and drill the through hole, which isn’t best practice, but its a good chuck, and the 2mm hole is oodles of room for the cable, even if its not bang on. I did this because I wanted to watch the 2mm bit going in, now ive done it twice id push it through blind from the bottom of the cable bore, after centre drilling with a terrifyingly small centre drill down the housing bore

I don’t have a boring bar that small, or a 4.85mm drill, and I’m actually pretty happy that this is workable enough for now without bringing the bore out a smidgen. so ill pop these on a bike (on the top tube this time, I promise, finally got a silver soldering setup sorted in the new workshop yesterday) and see how they go longer term. this bikes not going to see proper paint for a while, so no harm no foul if I have to swap them out.

a stop, note the flat on top keeps the housing snug up against the tube,

here is another new stop VS a brake (definitely brake, despite its location) cable stop I made using the same 1mm wall thickness, with the bore for housing simply drilled with a 6mm twist drill, i’ve tried to orient the flat as it would sit for fair comparison, the green stop has a similar flat.

I welcome your thoughts.

[crowe-molybdenum]

here are a couple of GEAR cable stops I managed to turn earlier this afternoon.

same as above, but a 4.20mm bore, a 0.8mm wall, and a 2mm “end wall”. this time id say 4.20 is perfect snug fit, slight press in by hand.

same flat, and again, same comparison. obviously the gear ferrule is way thicker than the brake ferrule, so the downsizing here is notably more prominent.

same barely branded Shimano housing.

ill have them on a bike before next week is out!