Bicycle Mechanics - rivet chainstay cable stop unsafe?

I stopped by the local bike shop looking for one of these. First they had never heard of them, and then proceeded to tell me that drilling a couple small holes in the chainstay would dangerously weaken the frame. I asked how they fixed frames when the stop is damaged and apparently they just replace the frame. I was going to attach one of these to a Nashbar Touring frame, which has fairly large diameter chainstays. I need a stop further from the dropouts to support cabling a Nexus hub if I don't want to run the cable housing the whole way with zip ties. Is this dangerous?


http://www.cycle-frames.com/bicycle-frame-tubing/images/P/NOV_ALBK_CSST_RIV_NEWPIC-06.jpg

I wouldn't do it. Zipties are fine for me....

Probably won't seriously weaken the frame till the rust starts but I wouldn't do it.

It's aluminum so it's not going to rust.

If the stays are generous in size as you say then go for it. Just go find the smaller 3/32 pop rivets instead of using screws. The metal will be too thin to get screws tight enough.

Canondale, and I'm sure others too, used to rivet their stops to the tubes and the old frame I have with the riveted stops is still doing just fine.

You could even do a variation on this guide idea that I sketched up for someone else. It's not a stop as such but you may be able to modify the design to suit your needs if the plastic one looks too kludgey on the stay.

Thought Nexus hubs had a strut that was in the axle nutstack to terminate the shift cable against?

But Yea setting 2 pop rivets to hold the new cable stop on will be fine,
after all the holes you drill will be filled by expanding the Pop rivet.

I'd use a stainless steel pop rivet rather than an aluminum one, for long term durability, after all you will put some shear forces on the rivets, each time you shift the gears.

running the cable housing all the way does keep crud from getting in the space between the housing and cable.

There's plenty of reserve strength in the stay, and a couple of rivet holes aren't going to present structural problems. The only thing I suggest is to take a Q-tip and spread a dab of grease on the walls of the drilled holes so they aren't starting points for oxidation. Alternatively, you can wick something like BoeShield under the fitting when finished.

If you're a belt and suspenders guy like myself you might consider using a drop of super glue under the fitting so you have strength above that provided by the pop rivets alone.

Why not this (http://www.sjscycles.co.uk/product-Unbranded-Gear-Cable-Stop--Chainstay-Fitting--Chrome-18470.htm) instead? No nasty drilling needed:
http://www.sjscycles.co.uk/images/products/18470gear_l.jpg

Rivet Aluminum, clamp steel.

Why not epoxy the stop on to the chain stay instead? or do both. The epoxy bond and the stop itself could act as a reinforcement in the area you are drilling and riveting. Also, make sure you "ease" off (file smooth, round off) any sharp edges resulting from the drillng as those could act as "stress risers" where cracks can start. You might need tiny jeweler's files to do so.
Anyway, IMO, unless you have the sprinting wattage of Cadell Evans, you cannot break those stays after drilling for such. but make sure anyway that you drill the smallest holes that could work with the rivets, tkae your time and don't accidentally go through to the other side of the stay.

Chombi

Why not this (http://www.sjscycles.co.uk/product-Unbranded-Gear-Cable-Stop--Chainstay-Fitting--Chrome-18470.htm) instead? No nasty drilling needed:
http://www.sjscycles.co.uk/images/products/18470gear_l.jpg

I have been looking at those too, but I haven't found any reference to the size, this frame has larger chainstay tubes than I have seen before and they aren't exactly round, and of course the bike shop I went to didn't have those either, although they knew they existed.

Thought Nexus hubs had a strut that was in the axle nutstack to terminate the shift cable against?



It does, but the other end of the cable housing has to butt up against something too, which could be the shifter itself, but I thought it would be cleaner to run housing from the shifter to the downtube cable stop, and run bare cable under the bottom bracket to a stop there. And it gives me a place to put an adjuster, which the bar end shifter I am using does not have.

Thanks

If you're a belt and suspenders guy like myself you might consider using a drop of super glue under the fitting so you have strength above that provided by the pop rivets alone.

I'll do that, if I glue it first, I am sure to drill the holes in the right place.

Those clamp on ones John suggests would work but to my sensibilities they just look way too ugly for words.

When you consider how many frames were made in the past and are still made now with expand in place "brazeons" drilling for two small rivets is not a big deal. Bedding them with a glue such as CA or epoxy isn't a bad idea either but too many things can happen over time for me to trust a glue only situation unless the brackets have wings that wrap around to increase the surface area of the bond and make the stops look like old tyme lugs. Add to that the requirement to sand or otherwise remove the paint in the joint area and it just seems like more work than drilling for rivets. But for just bedding the stops so they can't wiggle around just scuffing the paint right under that area by masking off the surrounding area will form enough of a bond for just bedding things down. If you sand the spot through to the metal then that's a bonus.


Chombi, in this case there's no requirement to ease the corners. Stress risers come from cracks in the metal. A raised burr from drilling a hole just does not qualify as a point that will stress into a crack.

Problem Solvers makes a stick on cable guide that works without compromising the frame tubing.
http://www.ebikestop.com/problem_solvers_stick_on_hydraulic__housing_guide_bag_of_5-BR4120.php
It's held up after over a year and 3100 miles on my Fuji Touring frame and Nexus hub.
Other than that, I use zip ties at the down tube and between the stick on guide and the bottom bracket.
Under the bottom bracket, the stock cable guide groove was widened, using a Dremel tool to shape it to fit the housing.
I did compromise the frame in a way. I drilled out the down tube brazed on cable stop so full housing could run through it. I installed an inline cable adjuster just below the braze on.

Does anyone know an online source where these can be purchased? I have been to 4 shops in town without success. I only found one site online Nova Cycles Supply and they want $5 to handle the small order and $15 shipping, which brings the cost to purchase a couple cables stops ($2.25 each) almost $25. I guess they don't like dealing with little people...

most shops do not stock frame building supplies. when I was doing my Nexus project last year I thought I was going to need a FD hanger and my shop ordered me two from QBP ( one make a great keyfob now).

post over in the frame builders section maybe some hobbiest has one lying about.

my cable routing was difficult too as my frame used a "highwire" cable routing style.

Keep in mind that there's a big difference in the load that a cable GUIDE vs a cable STOP will see. With the stop having to resist the considerable cable pressure of the derrailleur system and not creep is not an easy thing to expect of a little tab of adhesive even if it's backed up with a zip tie. The first post talked about a cable STOP and now the focus seems to be on mere GUIDES. Be sure you're not confusing the two since your OP mentioned not wanting to use full length cables.

Right I am definitely looking for a rivet on cable stop for a shifter cable.

They rivet everything on newer carbon bikes. Aluminum rivets are very strong. Ive used them for all kinds of non bike load bearing applications. Keep in mind that generally the rivet does not fail. The sheet good that is riveted typically fails first by elongation/distortion. Stainless steel rivets are a poor choice with aluminum. Corrosion is a big problem between those two metals. I have had plenty of problems with stainless rivets on aluminum sailboat spars(masts/booms). Riveting is actually the preferred manner of fastening when dealing with thinner wall thicknesses. Keep in mind the aluminum skin every airplane(Boeing/AirBus) is help on by rivets. If you are really concerned you can throw a dab of epoxy resin between the frame and your cable stop. You need to scuff both the frame and stop with 80 grit sand paper for a good epoxy adhesion. This is called the "glue & screws approach". The fastener(ie nail, screw, staple, rivet) holds the the two materials in contact until the glue cures.

This is really a no brainier.