Lombard

Shifting is very light almost like butter. If it were any less tension, it wouldn't spring back!

cxwrench

The cable can only be under as much tension as the derailleur spring creates. It's always the same really. When the derailleur is in any gear other than high (small cog) the spring force is always the same. The shifter just holds it in different positions to correspond with the different cogs. Unless you have a TON of housing here and some really awful housing routing the 'tension' on the cable doesn't change.

prj71

What I'm saying is that cable housing that is too short can kink and bind the cable creating even more friction/resistance vs. just the resistance of the derailleur spring. A tight loop where the cable enters the derailleur is more likely to cause the issues that some of you speak of.

Lombard

Wrong. No tight loops or excessive housing on either of my bikes that has this issue with the STI shifters. cxwrench has been a bike mechanic for at least 3 decades. I think he knows what he's talking about.

Koyote

Pffft! Why would an experienced professional mechanic know anything about it? prj71 can diagnose your problem (and mine, and many other people's) without even seeing our bikes!

cxwrench

Wrong.

Lombard

For something like this to create the problem you say, it would drastically affect shifting performance. Nobody here has complained about shifting performance.

prj71

No. I'm not wrong.

https://www.parktool.com/en-us/blog/...-cable-housing

https://bike.bikegremlin.com/8622/housing-routing/

I'll let you know what mileage mine breaks...if at all.

Koyote

cxwrench

You arguing this point is like someone bringing a spoon to a gunfight.

trailangel

I made a mistake and CXWrench corrected me.. in a nice way. I think his ban should be over......

prj71

And you claiming that shifter cables need to be replaced once a year is a load of horse manure. I mentioned it to some friends biking last night. They laughed and laughed and laughed...

cxwrench

And what is it you and they do for a living? You don't learn about bicycles just because you ride them. Sounds like your friends knowledge is as limited as yours. I build, service, and repair hundreds if not thousands of bikes every year. I've been doing so for nearly 30 years. This includes shop, pro team, national team, and world cup experience. Don't make me embarrass you.

prj71

Mechanical engineer for 30+ years. Been working on my own bikes since I was a teenager. Haven't worked on as many bikes as you over the years...but they are simple machines and not that difficult.

Lombard

Or a lemon to a knife fight:

cxwrench

'Engineer'...classic. "I'm an engineer, to save time let's just assume I'm never wrong". This is the way you operate, right?

DangerousDanR

I'm not going to say that it's impossible that the cables need replacement annually. I was part of the team on an industrial machine where the scanner data cable replacement was a monthly scheduled item due to fatigue.

But there needs to be a very good reason why shifter cables need annual replacement. Like coating them in mud on a daily basis. If it is true, it doesn't speak to me of a well designed product.

And I can say that the Campagnolo Record mechanical group on my Ritchey solo breakaway has not had the cables replaced in the four years since I built it up. Maybe one year of normal use on it and it is just fine.

If they really need cable replacement once a year and you think that is unacceptable, just get Di2 or SRAM wireless, or if they will fit the cockpit, EPS. I know, big bucks there.

cxwrench

I've said it time and time again...it's NOT THE CABLES that really need replacing (unless they're fatiguing and fraying inside the shifter) it's the HOUSING wear that causes deterioration in shifting performance. If you think it's the cables that are the problem and you just replace them it shows just how little you know. If you ride 4-5 days a week you would be doing yourself a favor if you replaced both on an annual basis.
Not well designed? How much better do you think you could do? Let's hear it.

DangerousDanR

Ok. I'll bite. Housing wear? There is an inner sheath, the steel structural linear strands of the housing, and the outer case, which on most of the cables I have seen looks to be vinyl but I haven't actually checked.

As a system, the inner sheath is there to limit the friction. The steel structural stranded linear housing is aligned parallel to the direction of pull and should not wear, but the outer case could stretch which would definitely degrade shifting.

I know that Jagwire sells housing with a kevlar braid covering the stranded structural part of the housing.That should reduce the degradation of the housing. There are also housings made of multiple segments like the Nokon housing.

So I really don't need to design a better product. It looks to be an off the shelf item. Albeit a costly one. I put Ekar on my commuter / touring / gravel bike. If shifting performance goes down after a year, I will probably start with the braided covered Jagwire housing. The Nokon housing looks nice but it is expensive.

My solution to control cable issues has mostly been to use some form of linear electronic motion system. Linear motors or a rotary to linear gearbox. I think that is what is inside an EPS rear derailleur.

I ride 6-7 days a week in the summer, and an EPS group set doesn't have any issues, and since the cables don't flex all that much, fatigue of the power and control cables is not an issue.

I'm likely going to put an electronic motion rear derailleur on the tandem. Probably a SRAM, since the tandem is the only place I have noticed poor shifter performance.

Lombard

Hmmm. IDK, my 2017 gravel bike has about 6K miles and still has the original Jagwire housings. It's been through multiple cables due to hungry Shimano shifters and I just put a new set of shifters (right shifter broke) and cables on it. Shifting is flawless. Could it be even better if I replaced the housings? I can't imagine I would notice if it were better. It's spot on and never misses a shift.

prj71

2016 Hardtail (Shimano) still has original cable and housing. Shifts perfect.
2018 Fat Bike (SRAM) still has original cable and housing. Shifts perfect.
2019 Hybrid Bike (SRAM) still has original cable and housing. Shifts perfect.
2021 Fat Bike (SRAM) still has original cable and housing. Shifts perfect.
2020 Road Bike (Shimano) still has original cable and housing. Shifts perfect.
2021 Road Bike (Shimano) still has original cable and housing. Shifts perfect.
2020 Full Suspension (SRAM) Mountain bike still has original cable and housing. Shifts perfect.

Annually? That's a lot of housing and cable to change and money spent for something that's working perfectly fine on every bike. Please tell me again why I need to change these annually?

I go through all my bikes and inspect them a few times throughout the year and the bottom line is when there is evidence of wear on cables, housings, shifters or anything...then parts will be replaced. Bike cables (and many other parts on a bike) last until performance isn’t what it should be. How long cables (or any part on a bike) lasts varies depending on MTB or road bike and the conditions the bike is exposed to. How often isn’t necessarily a set time in months, years or miles. The signs will be in how your bike is responding to shifting, braking etc.

Last night I went out and checked the cables on the brifters of both road bikes (Shimano 105) and no signs of the cables fraying.

I'm starting to think that as a bike mechanic (either in business for yourself or working for someone) that you tell people annual replacement in order to make more $$$ for yourself or the shop you work at.

Lombard

To be fair, age of the bikes mean nothing unless the bike is stored exposed to the elements. As KerryIrons says, how long is a piece of string? Mileage on each of these bikes would be a better indicator of what kind of maintenance needs to be done.

Conspiracy theory noted. cxwrench mostly sees bikes that rack up thousands of miles in a year. If you have bikes that only log 500 miles in a year, then every year would be excessive. If 2000 miles or more, cables once a year would be prudent. 5000 miles a year or more and you should probably replace housings as well as inspect under bar tape for handlebar corrosion. You don't want this to happen to you:

cxwrench

^Exactly this^ With that many bikes you're not putting a ton of mileage on any of them (I'd guess there are favorites, but still...) so replacement intervals can be longer time wise. I'm talking about the riders that have one bike they ride all the time. I'd think that would have been obvious to someone as intelligent as an engineer.

Lombard

just remenber that the D students need work too.

prj71

The oldest bike, the 2016 hard tail mountain bike, has over 4000 miles on it right now.

The road bike (the one you indicated that I should be having problems with annually because of notorious cable problems with Shimano shifiters) has around ~2900 miles.

Neither are a problem at the moment so I'll keep riding them as is. The obvious part is that I recognize that I don't need to change my cables and housing on an annual basis based on what some guy on the internet says. And as a bonus I keep more money in bank account.