justinzane

Perhaps I'm just showing off my ignorance, but, here goes... My understanding is that the difference in compatibility between different cassette / rear derailer / right shifter sets -- for example Shimano 9 speed, 10 speed road, 10 speed MTB, 11 speed road, etc. -- is the amount of distance between shift points. By shift points, I refer to both cog-to-cog cassette spacing and gear-to-gear cable travel. The former is only related to the latter by designed ratio, one of SRAMs marketing gimmicks IIRC.

Now, it seems to me that it should be mechanically simple to adjust the amount that the end of the rear derailer cable travels for a given pull on a brifter lever. I assume that this is not common simply as a planned obsolescence profit generator. Sheldon Brown mentioned the alternative cable attachment method that alters ratio slightly for one particular mismatch. So, my question is, what else is available in this regard?

Are there small maker brifters that can be adjusted to a variety of pull/release travel distances? Are there intermediate -- within the cable run between shifter and derailer -- mechanical devices that are available? Or, are there reasonable easy to construct mechanisms for the bike hacker with limited metalworking equipment?

Sorry if this is a repeat, but most of what I read on the subject relates to specific pairs of components, i.e. ErgoPower 10 + Dura-Ace 10 or whatever. I'm trying to get at whether there is a more generally applicable solution that will allow one to upgrade components over a period of time without having to buy a whole groupset at once.

FBinNY 

Variable cable pull is easy to imagine in theory, but not so easy in practice. The cable winds onto a drum, so all that's necessary is to change the drum diameter, according to the desired cable travel. this is far easier than trying to vary the click spacing. OTOH, when you look at it, varying the drum diameter isn't all that simple in practice, though it could probably be designed to be so.

bradtx

justinzane, It maybe possible with electronic shifting, but it seems impractical with mechanical shifting. Even Sheldon Brown's advice to anchor a shift cable to the opposite side of the screw is a bit iffy.

Brad

Dave Mayer

The wisdom you seek is here:

Shimergo | CTC

Indexing bicycle drivetrains are simple machines. Despite this, only a small minority of avid cyclists (and even shop mechanics) ever really figure out the relationships between shifters (cable pull), derailleurs (mechanical advantage) and cassettes (cog spacing). If you read the CTC article, and truly understand it, then you have what you need -for life.

I am not aware of shifters that feature the ability to vary the cable pull. There are some hack solutions out there for adjusting derailleur mechanical advantage (such as the alternative cable pull trick). Or modifying the shifter cable pull. These can work fine. Most of my bikes feature a mix of derailleurs and shifters that strictly not 'manufacturer recommended'. For example, I use Campy 10-speed Ergo levers with the older generation of Campy indexing derailleurs. This allows me to run Shimano 10-speed cassettes and hubs. Cheaper and far more available than the Campy equivalents. Works perfectly every time.

Understanding indexed shifting at a deep level will allow you access these optimal solutions. And avoid endless frustration working on kludge solutions that will never be compatible.

Wisdom here comes from understanding the numbers. If you know the cable pull of the shifter, the mechanical advantage of the derailleur, and the cog spacing of the cassette, and you run the math, and it should work, then it will work. For me, this approach has never failed.

I have no respect for hack mechanics who suggest that: "perhaps you should just try a Suntour derailleur with Shimano 8-speed shifters on a 9-speed cassette and see if it works". This demonstrates that the mechanic does not have a clue what they are doing, and they are wasting everyone's time.

It all starts with accurate numbers, and then running the math.

Good luck.

justinzane

According to the wikibook, to get all the basic Shimano and Campy RDs to work, having the ability to have a base barrel with nested shims that alter the diameter for each RD type would look something like this:


[TABLE]
[TR]
[TD="align: left"]Cyl. Thickness[/TD]
[TD="align: left"]Nested Dia.[/TD]
[TD="align: left"]15° Travel[/TD]
[TD="align: left"]1:1.7 Travel[/TD]
[/TR]
[TR]
[TD="align: right"]10.34[/TD]
[TD="align: right"]10.34[/TD]
[TD="align: right"]1.35[/TD]
[TD="align: right"]2.30[/TD]
[/TR]
[TR]
[TD="align: right"]0.45[/TD]
[TD="align: right"]11.24[/TD]
[TD="align: right"]1.47[/TD]
[TD="align: right"]2.50[/TD]
[/TR]
[TR]
[TD="align: right"]0.68[/TD]
[TD="align: right"]12.59[/TD]
[TD="align: right"]1.65[/TD]
[TD="align: right"]2.80[/TD]
[/TR]
[TR]
[TD="align: right"]0.23[/TD]
[TD="align: right"]13.04[/TD]
[TD="align: right"]1.71[/TD]
[TD="align: right"]2.90[/TD]
[/TR]
[TR]
[TD="align: right"]0.91[/TD]
[TD="align: right"]14.85[/TD]
[TD="align: right"]1.94[/TD]
[TD="align: right"]3.30[/TD]
[/TR]
[TR]
[TD="align: right"]0.21[/TD]
[TD="align: right"]15.26[/TD]
[TD="align: right"]2.00[/TD]
[TD="align: right"]3.40[/TD]
[/TR]
[TR]
[TD="align: right"]0.25[/TD]
[TD="align: right"]15.75[/TD]
[TD="align: right"]2.06[/TD]
[TD="align: right"]3.50[/TD]
[/TR]
[/TABLE]

Now, I only threw the core, 2nd, 3rd and last rings into the image, but the rest are similar. Since they are nested and very infrequently changed, the shims do not have to have any significant strength themselves which should make manufacture easy.

Manufacturers can easily mass produce pistons, rings and valves that work at vastly higher temperatures, pressures and duty cycles than anything on a bike. I truly fail to see why this is difficult, other than protecting profit associated with brand image and expense.

justinzane

There is no "electronic" shifting. All that the Campy and Shimano "electronic" systems are are amazingly marked-up micro controllers, battery packs, stepper motors and simplistic sensors. They make the RaspberryPi look like a supercomputer and they are electrically operated mechanical devices at heart. Any modifications to these electro-mechanical shifters would be simpler as a purely mechanical system. And, I've seen both Shimano and Campy trying to wall these overpriced doodads off from their other high-end lines.

Sorry to be rude. Being an electronics and software guy professionally, seeing things that are so abusively over marketed to leverage the ignorance of potential customers is like watching someone be mugged.

Wilfred Laurier

didnt campagnolo used to make downtube shifters
with replaceable plates
that control the angle of shifter movement between gears?

fietsbob

Rohloff with a rotary shift sequence is easier to (3rd party) make a servo motor AboutUsPage. Melbourne Australia.

Di2 Alfine 11 speed is passing thru several marketing layers , each needs to pay its expenses thru markups .. Utopia is nowhere..

HillRider

Look up Jtek's Shiftmate. They accomplish a lot of what you are asking about.

FBinNY 

You've asked and answered your own question, so since you don't need my input I'm out.

justinzane

ShimErgo... That's the article I had in the way-back of my brain apparently. I've read it.

Your right that that is what I am looking for; but more universal. What I want is a brifter than can be adjusted, not on the fly, in the shop, so that when one goes from a formerly affordable 7 speed to an affordable now 9 to an affordable in a couple of years 11 speed cassette/derailer one does not have to throw away or sell at a loss a perfectly fine set of brifters that one's hands know by instinct.

Imagine for a moment someone with a car hobby... They have an old car that they love and have painted, chomed, etc. They decide to replace the 4 cylinder engine with a rebuilt 6. They do not have to change the transmission to accomplish this. They could instead decide to replace the 5 speed manual with a 6 speed. The engine stays the same. The two changes are not integrally linked. Or a gamer who decides to upgrade his GPU (graphics card). She can keep her CPU, RAM, everything else; and then later upgrade another component.

Make sense?

Bill Kapaun

Why is brain surgery so expensive when everybody's brain is made of the same stuff?
RIP OFF!

HillRider

Have you actually done an engine or transmission swap on an old car? It's vastly more complicated and costly than you suggest and certainly not something done "on the fly". Changing the indexing disc in a brifter or changing an entire brifter is trivial by comparison.

darkhorse75

Don't look very ergonomic but you could always get some of these.morphos

AnkleWork

You sure do know a lot about transmissions . . . and how to make electromechanical systems durable, reliable, efficient, and cheap.

gregjones

Two questions:

1: Might the OP be attempting to use a SRAM derailleur with Shimano shifters (or some other mismatch)?

2: Would the ShiftMate not solve this problem.

Or, this one.

LesterOfPuppets

In MTB land I run 7,8 and 9 speed cassette+shifters combos with the same 8 speed Shimano Derailleur. 10-speed is another realm, though.


In roadie land, I swap out Sachs, Sram and Shimano 7-speed cassettes/freewheels on a bike with the same 7-speed shifters and derailleurs.

If running 6,7,8,9 speed MTB stuff, only a few tricky combos you have to worry about, really. You just gotta know that Sram MTB rear derailleurs require numbered Sram shifters and that solves well over half your problems right there.

You can also actuate 7/8/9 speed Shimano road rear derailleurs across shimano or Sram 7/8/9 speed cassettes with Shimano brifters that match the cassette gear count no problemo. They won't do so well with MTB front derailleur/crankset, though.

I think there are far more feasible matches than there are of auto engine/transmission combos from the 90s and aughts.

dsbrantjr

"Manufacturers can easily mass produce pistons, rings and valves..."

Auto manufacturers produce millions of units, bicycle manufacturers thousands or even only hundreds of units. The economies of scale are vastly different.

paulkal

The Modolo Morphos brifters can shift multiple manufactures/speeds.
Shimano 7,8,9,10 speed; Campagnolo 9,10 speed, and also Index 5,6 speed.

morphos

davidad

Shimano is the 800 pound gorilla. It produces 80% of bike components. So it makes millions of units.

Dave Mayer

I get it. There are 3 variables in indexed shifting: the shifter cable pull, the derailleur mechanical advantage, and the cog spacing. You want the ability to modify the cable pull within the shifters.

I am only aware of 2 takes on this, the Modolo Morphos shifters and Campagnolo Ergopower levers, where there is the ability to change the indexing rings. I have never used the Modolo levers, but have read mixed to negative reviews. Campagnolo has changed their shifter internals several times since the introduction of Ergopower in 1991, so you cannot upgrade certain generations of shifters beyond a certain point. I have spent a lot of time digging around in and servicing Ergopower levers, and I know that you cannot upgrade the old 8-speed levers to take a 11 speed indexing ring. I suppose if you'd drop a few hundred thousand bucks on Valentino, he'd be willing to manufacter a custom indexing ring for say: 12 speeds, but short of that, I think you should focus on easier solutions, such as modifying the length of the cable pull after the cable exits the shifters.

Or thinking completely out of the box, I might suggest jumping off of the n+1 cog merry-go-round of planned obsolescence that the bike manufacturers have hoisted on us for the last few decades. 11 speed drivetrain? It is an absurd joke that has gone well past the point of diminishing returns; it is only meant to sell more stuff.

fietsbob

Modolo Tried years ago, to make a brifter to use with Campag and Shimano wheels ..

https://www.google.com/search?q=Modo...w=1663&bih=959

fietsbob

Justinzane, bring a really big line of Credit to the next big Taipei bike Trade show and shop your idea over there

where much of the bike business is concentrated ..



I'm one who got off the marketing more is better band wagon at 7..
which works fine with friction Levers, the pull variation is in my hand.

Darth Lefty 

Two thoughts. First, I think your nested idea wouldn't work; there's stress on these components and you need to vary both pulley diameter and number of clicks, and you are always going to lose in your garage all the outer layers you aren't using. Second, the length of pull is a little more subtle than implied by the Shimergo tables. There's a progression of pull length to try to get linear motion out of the RD which pivots in a circle. The reason C10 shifters work on S8 cassettes and derailleurs is that the 1st and 8th position are controlled by the stop screws on the derailleur and only the second through seventh clicks need to be a reasonably close match. I found this last year when I was studying, but I can't find the link right now... it was an older forum post from pre-Shimano-11. Some of it is out of date about newer hardware, probably.

At the time I was trying to find a way to get brifters to index a NR derailluer - I've gotten over it since then.

justinzane

Yes! Though I do not so much care if it is within the shifter or cable-run. Another gentleperson here suggested I check out JTek and they indeed do have some nice inline pulley systems. From my perspective, where function is 99% and appearance is 1% of the attractiveness of a thing, they work. For the general market, it requires too much hacking, in looks expecially to be common.

I thoroughly agree about the bovine feces bandwagon of ever increasing cog numbers. It seems thoroughly silly to attempt to imitate a CVT by adding gear ratios to infinity (and beyond? ). For the few pros and really gifted amateurs who can train and compete at the high end, there is likely a real benefit. The problem is that the major manufacturers deprecate their lower cog-count parts to force one to either scrounge the LBS/craigslist/ebay or to upgrade.

At my current low level of skill and fitness, a 3x7 is really quite fine, though 8 or 9 on the back would not hurt. I know that I really cannot get added value from 10 or 11 tight spaced gears. I'm not that capable a cyclist at the moment. When looking at bike shops, though, DNP is the only? maker of 11T-## freewheels for older bikes. For cassettes, Bicycle Cassettes - Modern Bike shows:
7sp - 13 choices
8sp - 18
9sp - 49
10sp - 73
11sp - 35.
That looks like one either has to live with ever decreasing choice and stay off the train or throw away good bits every few years to buy new.

Thanks. I appreciate the insight and experience.