Mountain Bike Reviews Forum banner

Possible to 'glue' add-on cable stops to frame?

23K views 39 replies 15 participants last post by  crazy8  
#1 ·
I've got a SS frame with only a single set of cable stops -- for the rear disc brake. I'd like to convert it to an IGH (Internally Geared Hub) so I need additional cable stops. Would it be possible to epoxy cable stops onto a frame? I had in mind a 2-part epoxy readily available in stores or even the less available body panel adhesive used in automotive body repair work. Thanks in advance.
 
#2 ·
you would need to remove the paint first and sand the metal. maybe JB weld would work. but i think to glue them on you need to make new ones or braze them onto a piece of some sort of metal. to give more area for adhesion. or you could clamp em on. if you made new ones or brazed em like i said before.
 
#4 ·
smilinsteve said:
I can't see glue being more than a temporary solution.
First, where would you get the cable stops? If your frame is steel or aluminum, have someone tack weld them on for you.
Could you do without the stops and run your cable in housing the whole way? Use Electrical ties to secure the housing?
that would just create weak points. i think bonding or clamping would be better.
 
#6 ·
Sometimes said:
I've got a SS frame with only a single set of cable stops -- for the rear disc brake. I'd like to convert it to an IGH (Internally Geared Hub) so I need additional cable stops. Would it be possible to epoxy cable stops onto a frame? I had in mind a 2-part epoxy readily available in stores or even the less available body panel adhesive used in automotive body repair work. Thanks in advance.
You do not need stops for an IG hub, just guides. I would just tape the full length housing in place.
 
#8 ·
Glue them since there really isn't any stress on the boss itself. All the stresses are on the housing itself. All the boss has to do is support the weight of the housing. I did something like this back in the '90s when I wanted to run an IGH on an aluminum frame. Sure brazing would be cleaner and all that, but epoxy will work fine. I believe I used JB Weld and closed loop TT housing guides.
 
#9 ·
#10 ·
themanmonkey said:
Glue them since there really isn't any stress on the boss itself. All the stresses are on the housing itself. All the boss has to do is support the weight of the housing.
If the cable housing is perfectly straight, than this is true. However, if there are any curves in the cable housing, than there is indeed a very significant load on the housing stops. A simple way to prove it is to take an existing housing out of the stop and try to see how well shifting (or braking) works. It might work a little, but it won't work well.

The reason for this is as tension is applied to the cable inside the housing, it tries to straighten out the housing (remember, the shortest distance between two points is straight line). Fixing the ends of the housing makes all "straightening" forces internal and maintains the tension in the cable. I guess that year as a brake cable engineer in detroit finally paid off..... :thumbsup:
 
#11 ·
RoyDean that's all nice in theory, but have you actually done it? I've done it and it worked fine. Even the highest tension from a Nexus hub didn't pull anything loose and the nexus has the hardest pull of any IGH I've ever played with. I spent many years working at the shop that did these kinds of things in Seattle. Now a days you need to talk to Val or Aaron. Your year as a brake cable engineer doesn't really apply to shift cables on a bicycle as the forces involved are magnitudes smaller.
 
#12 ·
I was thinking RoyDean was right on the money, as clearly there are significant forces on your cable stop. Take your housing out of the stop and hold it as you squeeze your brake for example.
To resist that, you must have used some pretty good glue. Even so, eventually that stop would get banged by something or hit when you lay your bike down, and pop off. But maybe that epoxy is tougher than I thought.
 
#13 ·
There is a huge difference between a housing stop that works to interrupt the cable housing (i.e. as is common w/ road bike rear brakes) and a cable guide that simply holds a full length cable in place, especially if shift cable is involved.

SIS shift cables work by transmitting cable position and not tension as their main function. Yes, there is some residual tension on a shift cable but as themanmonkey pointed out, it is a tiny, tiny fraction of the tension forces generated in a brake cable.
 
#14 ·
lol this is a little ghetto but, thought i would share anyways, because i found the simple idea funny.

braze the stops onto hose clamps. they can form around odd shaped tubing.
 
#17 ·
smilinsteve said:
I was thinking RoyDean was right on the money, as clearly there are significant forces on your cable stop. Take your housing out of the stop and hold it as you squeeze your brake for example.
To resist that, you must have used some pretty good glue. Even so, eventually that stop would get banged by something or hit when you lay your bike down, and pop off. But maybe that epoxy is tougher than I thought.
What forces are you talking about WE"RE NOT TALKING ABOUT BRAKES, or cable housing stops . We're talking about an IGH (internally geared hub) where the stresses from one end of the cable to the other are at most a couple of pounds. Distribute that stress over the 6' of housing with 90% of those stresses at the end points and you have almost no stress at the housing supports.

Also there are plenty of strong glue out there used to hold things to cars and airplanes and other high stress applications. In this case JB Weld will be fine though. If you doubt any of this look at the stick-on housing guides used to run the disc brake housing line.
 
#18 ·
Whoa, there, cowboy. I'm talking about STOPS, not guides (reread my post, and the OP's). I agree, that a cable housing guide sees VERY LITTLE load. However, when cable STOPS are used with cable housings that are curved, the resultant force on the cable stops can be as high as 100% of the tension in the cable.

So sure, if using cable stops with a cable tension of just a couple of pounds, the loading on the stops is will be low, but for brake or standard derailleur shifting, thats simply not the case. I realize that may not be the case for the OP, as he wants to us an IG hub, but he has to be sure that his cable STOP solution is capable of handling 100% of the pull tension of the cable (to be sure that there will be no failures). That's all I'm getting at.
 
#20 ·
I see where you're coming from. Most folks have no idea about the difference between stops and guides and every IGH is designed for a full run of housing. This is the kind of thing I have to explain multiple times to customers regularly. That's where I'm coming from.

That said for an IGH using stops would be fine too. Most of the SRAM and Sturmey hubs have at most 1 lb. or pressure at high tension and the Shimano hubs might be as high as 5 lbs., but I'd guess closer to 3. Even under load (which IGHs don't really do very well) it's maybe 15-20% higher. Even Gorilla glue should hold up to those pressures using stops.

Again, if we were talking about brakes and stops I'd say no way, but we're not. Any mention about brakes is an apples to oranges comparison. Of course in the end the OP should just try it with glue. If the stops pull off then there is the proof in the proverbial pudding. Lots of folks talk about things they want to do, but few actually get beyond the thinking to the doing stage. We all can sit here and theorize, but until someone actually does something we won't really know.
 
#22 ·
Actually hold on a minute I just had a thought. I've worked on thousands of CF frames with glued on stops over the years with very few problems. I have seen a few pop off over the years, but it's quite rare. I think that would be the proof in the pudding I was talking about. It all comes down to finding the right glue.

(sorry to monopolize the thread)
 
#26 ·
smilinsteve said:
The best solution is still the clamp-on stop in post #9.
No, not at all, because IG hubs do not need frame mounted housing stops at all. The housing runs full length from the shifter to the stop on the hub itself.

Using that clamp on stop only complicates an otherwise simple setup.