At least three times now I have been stranded with a busted shifter cable.
The problem is I have a massive hill at the end of my ride and I just can't get up it without the ability to shift to the biggest ring.
I guess it must happen once a season.
So my cables are never more than a year old.
I do live in hilly New Hampshire so maybe it is just that I shift more than someone in Kansas.
I have ultegra shifters and derailleurs.
These are the ones I have been buying at Amazon (they get good reviews):

https://amzn.to/1wncylR


Can someone link to something that might be better?

Thanks

I have had good success with Jagwire and Shimano cables. The key features that I look for are die-drawn stainless inner wires and lined housings. I avoid coated inner wires due to perceived installation and longevity (coating peeling/shredding) concerns, so no experience there. I replace inners and outers together.

Several Amazon product reviews mention that the shifter housing is not compressionless and may be problematic for indexed shifting. Not sure how that would contribute to your cable breaking.
Where does it break?

Would think that any Jagwire cable/housing would work better.

I also use jagwire cable and housing, and have been happy with them.

It breaks right at the head in the shifter. Usually about an 1/8 of an inch long when I pull it out.

It likely starts fraying long before it breaks and often manifests as sluggish shifting or suddenly needing frequent adjustment. More frequent inspection and timely replacement might save you getting stranded.

Something ain't right. Is the cable rubbing against something causing it to fray ? A bit of inner housing wire maybe ?
Is it routed wrong in the shifter , making it bend too much ?

It's not the cable, nor are you doing anything wrong.

The problem is that you live in New Hampshire. (or any hilly area where you shift often).

Cables fray and break at the lever because of metal fatigue. Shifting winds and unwinds the wire onto the lever drum. That constant back and forth flexing work hardens the steel, making it brittle and eventually the strands start to break. It's the same as when you bend a paper clip back and forth until it snaps, though slower (thankfully).

Since it's the bending that's the issue, how often you bend the wire by shifting determines it's life expectancy.

All cables that wind on pulleys or drums have a service life and in critical applications like elevators, they're replaced on a schedule to prevent failure.

Bike use is too variable to set a single standard for replacement, but you seem to have a sense of what to expect and might opt to waste a few bucks a year in early replacement to avoid the inconvenience of walking the hills.

OR, cut a 2" or so length from a direct pull spoke (no bend) and carry it with a hex key. If a cable breaks the spoke can be dropped through the barrel adjuster and secured to the inch bolt to hold the RD in the gear of your choice. With most RDs the barrel adjuster will allow manual shifting between a few gears, and the ft derailleur can cover the rest (sort of).

I strongly suggest you buy Shimano or Jagwire cable AND housing. Those Bell sets are galvanized inner wires and, most likely non-lined housing and their only attraction is they are cheap. Spend more and get better ones.

Amazon sells both Shimano and Jagwire cable sets and bulk housing and innner cables:
Amazon.com : Shimano Road Shift Cable and Housing Set (Black) : Bike Shift Cables And Housing : Sports & Outdoors
https://www.amazon.com/Jagwire-Hyper-...hift+cable+kit

Pay the extra couple of bucks.

I agree with all that has been said.
If you have external cables on your bike, you can shift to the largest cog (ring usually refers to the front, not rear cogs), then while pulling on the cable shift down all the way with the right shifter. You can then pull the cable out of one of the cable stops and push it so you can see the last several inches of cable coming out of the shifter (as you do when changing cables, but don't disconnect from the derailleur). If there is any fraying, time to change the cable.
It takes less time to do than to explain.

It's a good idea to have spare cables, brake pads, chain, tires & tubes on hand so when they need replacing, you don't have to wait.

Low compression housing is steel wires standing on their ends a number of them in a circle. around the liner sleeve.

a die drawn cable, the finished cable is pulled through a hole, slightly smaller than the cable itself.

this flattens the cable surface, making it smoother.

brand neutral .. Indexed shifters depend on low friction and low compression .. to work as designed..

the cables in 1st post just offer low price.

Those Bell fix kits are only appropriate for getting Wal-Mart level kids bikes back in usable condition. If you are on a budget, any bike shop will have bulk cables (usually Jagwire or similar basic stainless cables) and bulk housing you can buy by the foot. My LBS throws in the cable ends and ferrules but other shops might charge you an extra buck or two. Even these basic cables and housings are a couple steps up from the Bell fix kits and you will notice much smoother and sharper shifting and less mushy braking. Remember that, unlike the Bell kits, there will be a difference between the shift and brake housings so don't get them mixed up.

You can also buy Jagwire or Shimano kits to re-cable your whole bike. Some get pricey for the ultimate in smooth performance, but most riders are happy with the mid-priced cables. As I said, if you have been happy with the Bell cables, even the entry level bulk LBS cables will put a smile on your face. If better cables with new housings keep breaking at the same place, look for a problem in routing or the shifter.

You don't want to use cheap shift cables like that. If you want to save money just replace cables and housing on an as-needed basis which is

- Less frequent for the left shifter than right
- Less frequent for the housing than the cable

Note that you can secure the cable with something like a bottle cage bolt and lock your rear derailleur into a more favorable gear.

Also note that cables usually don't fail without warning. Once the first strands fray shifting to smaller cogs gets a little sluggish. While you might get acceptable performance by reducing cable tension, you really want to look into the root cause because it could be a bent hanger that also gets your rear derailleur too close to the spokes.

Irrelevant. Cable and housing life are functions of how much you shift.

I shift like I have ADHD and usually fray rear cable strands within 4000 miles which is less than a year. One (Campagnolo like I usually use) cable only made it 2000 miles for some reason.

We have a customer who use to break 2 or 3 cables a year. After a few years we finally trained him to have his cables replaced every 3 or 4 months. he hasn't been stranded since.

Some context- he rides 8K-10K miles a year in VT and the Finger lakes of NY, he's big and from what we see of the rest of his bike he rides in all conditions and jam shifts as needed.

We are finding that the new cable routing of the current STI shifters seem to be less fatiguing on the cable then the old external casing versions.

When I do service assessments I pull the rear der's casing loop off the chain stay stop and push the inner cable out of the lever (old version routing) and look at the first half inch of cable. If there's any doubt I suggest a replacement. $5 vs being stranded in high gear and a possible lever replacement... Andy.

I use a tiny bit of grease on the button end of shift cables because I've heard it will keep, or at least delay, that from happening.

So do I, primarily to keep them from corroding into place. If it helps prolong their service life, so much the better.