SunTour Rachet Bar Ends shifting a Modern RD - Need to Trim??

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John Hawrylak

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Nov 27, 2022, 7:21:33 PM11/27/22
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IF I use my 1975 Suntour Bar End Ratcheted shifters with a modern Shimano RD (Deroe M531) and a Shimano 7 speed HG cassette, and modern Shimano shifter cables/housings,  WILL the RD shift each gear going from the smallest cog to the largest cog, WITHOUT the need to ‘trim’ the RD after each shift, especially when moving up in the large cogs????

Secondary question:  If the SunTours would work without trimming, do they enough pull for a 7 speed cassette???

 I have been using 8 speed Shimano Ultegra bar ends (BS-64) with a HG-50 7 speed cassette and like it, 1 click, 1 shift, no need to trim.  Been curious about going back to using the SunTours rachets if the modern RD eliminates the need to “trim”.  Would like to know if others have tried it and what the results are with respect to trimming.

 Note,  NOT looking for a debate on Index vs Friction.  I think index is better, but I have trouble burying those nice SunTour bar ends & maybe I can use them if the RD eliminates trimming.  YMMV and that’s great, diversity is good.

 

John Hawrylak

Woodstown NJ

Nick A.

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Nov 27, 2022, 7:38:27 PM11/27/22
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I'm currently running Suntour bar-ends with an otherwise Shimano 2x9 speed system. And yes, it occasionally requires trimming. Most of the cassette needs 2 clicks, but a couple require 3. Hope that's helpful.

DavidP

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Nov 27, 2022, 8:18:49 PM11/27/22
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Hi John,

The RD will not eliminate the need to trim - best to think of RDs as "dumb" with any/all indexing done by the shifter. If you switch to friction shifters there is no indexing; the clicking of the ratchet mechanism may coincide with some indexed positions but will usually not be consistent (as the above response said - sometimes 2, sometimes 3 clicks per shift). To get 1 click per shift you'll need an indexed shifter compatible with the indexing of the cassette.

-Dave

Scott Luly

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Nov 27, 2022, 9:43:17 PM11/27/22
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John:

I'll attempt to add to the valuable information Dave and Nick have shared...

When thinking about compatibility with shifters, RDs, and cassettes; keep in mind the RD does whatever the shifter (index, ratchet, or friction) tells it to do, hence the "dummy" comment. So you can for the most part eliminate the RD from your compatibility question.

Your Shimano 8 speed shifter works with your Shimano 7 speed cassette because the "indexing" in the shifter is matched with the spacing between the cassette cogs; hence one click, one shift. So when you click a shift the shifter pulls the cable an amount that causes the RD to move (inboard or outboard) an amount equivalent to the distance between the cogs of the cassette. On a Shimano 8 speed cassette the distance between cogs is 4.8 mm, so each time you shift with a Shimano 8 speed indexed shifter the RD is going to move 4.8 mm inboard or outboard. Shimano 9 speed cassettes have the cogs spaced 4.34 mm apart. You can see the problem if you were to use, for example, a Shimano 9 speed indexed shifter with an 8 speed cassette (one shift would move RD 4.34 mm, not the needed 4.8 mm between 8 speed cassette cogs) Your 8 speed shifter works on the 7 speed cassette because a limit screw on the RD doesn't allow it to move the full distance into the 8th position and the distance between cogs on a 7 speed cassette are the same as 8 speed: 4.8 mm. Indexing (space between cogs) is the same between Shimano 7 and 8 speed, so they play well together. If you were to use a cassette from a different manufacturer in which the distance between cogs was different from that of a Shimano cassette, then you'd likely run into a compatibility issue with your 8 speed shifter/non-Shimano cassette (assuming cog spacing was different from an 8 speed Shimano cassette).

One can almost look at a friction shifter as allowing infinite adjustment. Riders that are good with them almost develop an indexing in their head/hand feel then fine tune after a shift. No indexing to a friction shifter so you can run a friction shifter with any make/speed cassette. Just have to find the sweet spot yourself.

The ratchets move the shift cable in little bits (and the RD in little bits) I believe (I've never ran them. Someone, please, correct me if I'm wrong). So each click moves the shift cable a certain amount that in turn moves the RD a certain amount. You'd have to do some research to find out how much the RD moves with each click of your 1975s and then do some math. You know, at least with your Shimano 7 speed cassette, the cogs are spaced 4.8 mm apart. How much does the 1975 shifter move the RD each click? For perfect shifting on the 7 speed (or 8) cassette, the clicks (one, two, or three)/RD movement would have to add up to intervals of 4.8 mm. I doubt that's going to be the case, but fortunately there's a little wiggle room short of perfect that will obtain satisfactory shifting. At least there is more wiggle room with 4.8 mm spacing than there is with 4.34 mm (Shimano 9 speed casette).
I guess one could look at ratchet shifting as being somewhere between indexing (one click, one shift) and friction (infinite adjustment) shifting.

Your research task: find out how much RD moves with each ratchet of your 1975s. Then you'll be able to better assess compatibility with different cassettes of any maker/speed, as long as you get the respective cog spacing. For the compatibility issue you are inquiring about, the RD isn't really part of the puzzle, so eliminate it.

Sheldon Brown's website has that level of trivia: cog spacing, indexing values. And hopefully it has ratcheting values. You might find your answer there.

Good luck! And, please, report back!

Scott in Big Sky Country



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Joe Bernard

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Nov 27, 2022, 11:23:52 PM11/27/22
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Scott has covered this completely so I'll just add this from my experience with various ratcheting style shifters: I've never noticed the specific number of clicks per cog, what I have noticed is the ratchet feature makes the "I have to move the lever this much to get a clean shift" action easier to nail. I can't explain why it helps me, but I always had better luck with them than pure friction levers. 

Scott Luly

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Nov 28, 2022, 9:28:52 AM11/28/22
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Clarification/correction to my previous post on this thread.

John:

I previously stated cog spacing for 7 and 8 speed Shimano cassettes is the same at 4.8 mm. In fact, Shimano 7 and 8 speed cassettes have different spacing.

Correction: cog spacing for Shimano 7 speed cassettes is 5 mm and for 8 speed is 4.8 mm.

Check out this dandy spacing chart on Sheldon Brown's website: https://www.sheldonbrown.com/cribsheet-spacing.html

I bet your 1975 shifters work just fine with the 7 speed cassette, since your ratchet shifters are more like a friction shifter than an index shifter, allowing you a bit of fine tune/trim after a gear shift to find the chain's happy spot on cog. And the little extra spacing between cogs should favor you being able to find a sweet spot once a shift is made.

Happy shifting,

Scott in terrible roads Montana






Bill Schairer

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Nov 28, 2022, 9:34:51 AM11/28/22
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John,
Suntour ratchet shifters will pull enough for your seven speed cassette.  I have used them up to 10 speed.

My take on trimming is that the modern chains and cassettes are the main factor in nearly eliminating the need to trim.  Muscle memory will take care of most of the rest.  I rotate regularly between 4 different bikes (two Suntour ratchet bar-ends and two downtube) all in friction mode so my muscle memory gets kinda messed up moving from one bike to another but it usually does not take long for me to get in sync. If stick with one for a while, trimming is generally not an issue.  I rode my Atlantis this past summer on a two month tour shifting a 9 speed 12-36 cassette with a Suntour ratchet bar end-shifter and honestly don't remember trimming but I'm sure I did from time to time.  I have also heard plenty of indexed systems that sure could've used some trimming.  I've also found that shifting up the cassette can be smoother if I make the shift under more power than in the old days. Sometimes I think that if Shimano had done the chain and cog engineering first, there might have been little need to do the shifter engineering for indexing. 

For whatever it is worth, I shift a LOT, I think more than most that I've ridden with who use indexed.

Bill S
San Diego

Patrick Moore

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Nov 28, 2022, 12:36:09 PM11/28/22
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I use Suntour barcons to pull an 8-speed Dura Ace rd across 10 cogs with an 11 speed chain; no problem at all.

To shift across the 10 cogs takes just a bit more than 90 degrees of lever movement; I'm confident they would shift 11 without problem.

You have to learn the shifting technique: shift crisply and confidently (and get a "sense" of how far to move the lever for each cog jump) and the chain moves obediently and quietly. Shift hesitantly, weakly, shyly, and you get mis-shifts and rattle.

Overshifts: no, at least not with my rd, cogs (more-or-less in-series Hyperglide, 13-25 10 sp): IME, HG cogs shift better in friction than straight-tooth cogs. 

IME, the Barcons work better than the first edition Silvers. They pull more cable for a given lever movement -- iow, less MA -- but I find shifting easier with them compared to the first gen Silvers. I have not used 2nd gen Silvers.

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Eliot Balogh

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Nov 28, 2022, 12:36:23 PM11/28/22
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While were on the subject. I have some Riv Silver 2 shifters. I can’t seem to get the tension right. They’re either stiffer than I’d like or they slip. New housing and cables. Any tips?

Ben Adrian

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Nov 28, 2022, 1:36:50 PM11/28/22
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I have a nutty setup at the moment:
Silver 1 shifters
R7000 105 rear derailleur (yes, this is modern 11 speed which has a lower cable pull ratio)
11-32 8 speed cassette
9 speed chain

In general, it works really well. I have has some issues "finding" the larger cogs. When shifting from small to the 6th or 7th cogs, it sometimes either doesn't go enough, or goes too much. I make up for it by intentionally shifting too far and then trimming it back down. A bit tiresome, but I'm okay with it for the simplicity of the setup.

Also, since this RD has a 1.4 cable pull ratio rathe than a 1.7 of the 9 speed and earlier RDs, it sould have finer movement. I believe that I have experienced this. The R7000 is definitely more forgiving than the RD-6500 that I had on previously. Thought if I want to go back to my indezed shifters, I know this RD won't work.

Cheers!
Ben

Ted Durant

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Nov 29, 2022, 9:04:58 AM11/29/22
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On Sunday, November 27, 2022 at 8:43:17 PM UTC-6 Scott wrote:
Your research task: find out how much RD moves with each ratchet of your 1975s. Then you'll be able to better assess compatibility with different cassettes of any maker/speed, as long as you get the respective cog spacing. 

I spent an inordinate amount of time on this topic and put together a spreadsheet (naturally). I found 25 clicks on my SunTour BarCons, and 25mm of total cable pull, so each click is 1.0mm. 

Rear derailer ratio, the amount of horizontal movement per mm of cable movement, varies pretty widely, from 1.1 (Shimano 11 mtn, SRAM 7-9 Mtn) (I did this before 12 and 13 speed...) to 1.90 (SunTour).

The SunTour BarCon has a pretty small barrel, and 25mm isn't enough cable pull for a low-ratio derailer across a large number of cogs. For example, a Shimano 11-speed MTB derailer needs 36mm of cable pull.

If you want to dial it in, a Campy newer 9-speed derailer with a matching cassette needs 3.03mm of cable pull (3 BarCon clicks) for each cog. Or, combine a Shimano 10 or 11 speed derailer with a SunTour freewheel and you'll use right around 2mm (2 clicks) per cog.

There aren't many combo's that line up with even 1 mm clicks.

Ted Durant
Milwaukee, WI USA

Scott Luly

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Nov 29, 2022, 12:54:11 PM11/29/22
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Ted:

Very interesting and insightful...I learned a lot from your post! It appears RD ratio is a critical variable that really deepens the analysis one would have to do bench top to get a feel for how a certain combo of bits would work in theory before trying. Personally, I think I'd be more inclined to just install the bits and see how they work before undergoing that much analysis, but it's educational to at least better understand how bits function together and the interplay between different parts of a system.

Thanks for sharing!

Scott in frozen ground Montana

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Ted Durant

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Nov 29, 2022, 1:14:55 PM11/29/22
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On Tuesday, November 29, 2022 at 11:54:11 AM UTC-6 Scott wrote:
... It appears RD ratio is a critical variable that really deepens the analysis one would have to do bench top to get a feel for how a certain combo of bits would work in theory before trying. Personally, I think I'd be more inclined to just install the bits and see how they work before undergoing that much analysis, but it's educational to at least better understand how bits function together and the interplay between different parts of a system.

Exactly! It's not like I used a super-accurate digital measuring device to come up with the numbers. When you're talking .1 mm, you can understand why it's hard to make a cable-shifting indexed system work reliably on tightly packed gears. I was able to confirm on the road my spreadsheet prediction that a Shimano 9-speed lever can work with a SunTour rear derailer and a Shimano 8-speed cassette.

John Hawrylak

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Nov 29, 2022, 3:36:34 PM11/29/22
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Ted

Thanks very much for the detailed explanation and 25mm of cable pull for the SunTour barcons

Did you measure the RD ratio's or are they a published value somewhere??

Do you happen to know the ratio for a Shimano Deore M-591-SGS??  I have this with a Shimano 9sp road cassette (4.34mm cog spacing).   The RD ratio would have to greater than 1.39 for the SunTour barcon 25mm travel to shift the 8 cog spacings on the 9 speed cassette   (8 * 4.34)/25 = 1.39

John Hawrylak
Woodstown NJ

Ted Durant

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Nov 29, 2022, 4:00:33 PM11/29/22
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On Tuesday, November 29, 2022 at 2:36:34 PM UTC-6 John Hawrylak wrote:
Did you measure the RD ratio's or are they a published value somewhere??
I have seen some published, but my memory is that I measured them from the total distance between cogs and the total amount of cable pulled.
 
 Do you happen to know the ratio for a Shimano Deore M-591-SGS??  I have this with a Shimano 9sp road cassette (4.34mm cog spacing).   
Classic Shimano 6-7-8-9 (and 10 Road) derailers are 1.72.
 
The RD ratio would have to greater than 1.39 for the SunTour barcon 25mm travel to shift the 8 cog spacings on the 9 speed cassette   (8 * 4.34)/25 = 1.39
Well, I have Shimano 9 at 4.35, not 4.34, but otherwise I concur :-) My spreadsheet says you need 20.2mm of cable pull to shift a Shimano 9-sp derailer across a Shimano 9-sp cog set, so BarCons should have plenty of capacity. Just don't try to put a SRAM road derailer on that setup - you'll be a couple mm short.  

Newer derailers are using lower actuation ratios so that more cable pull is required for each shift, so that there is more room for error. So, any derailer that pre-dates the 11-speed era, other than SRAM "Exact Actuation" will probably be a good match with BarCons.

Scott Luly

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Nov 29, 2022, 4:13:24 PM11/29/22
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John:

How about using your 9 speed cassette as an 8 speed by adjusting out lowest or highest gear with a limit screw, assuming you can so without one of those gears?


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John Hawrylak

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Nov 29, 2022, 5:44:40 PM11/29/22
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Scott

Thanks for the suggestion.  Others have stated the barcons have enough pull for Shimano 9 speed and the M591 is definitely 9 speed.   Also, I am quite happy with my drivetrain choices for the 650B-38's I'm using
12-36 Shimano CS-HG-400,  12-14-16-18-21-24-28-32-36
46-36-26 triple gives me a gear range of 101 to 19
and more importantly I try to shift the rings to maintain the sideways chain stretch to <= 0.020% except for the Small-Large 28-36 combo at 0.040%.

I use cogs 1 thru 5 on the Large ring, shift to Middle using cogs 3 thru 6, shift to Inner ring using cogs using cogs 5 thru 9.   The ring/cog setup puts my cruising range (5 to 78 gi) on the Large & Middle ring, but I have not noticed any problems with the ring/cog shift to do it.

So overall, very happy with the drivetrain selection and 8 speed maynot work as well.  I looked at 10 spee, but did not see an improvement over 9.

John Hawrylak
Woodstown NJ 

John Hawrylak

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Nov 29, 2022, 5:50:38 PM11/29/22
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Ted

thanks for the confirmation on the barcons with Shimano 9 speed.  Looks like the Shimano 9sp Rd's have a ratio of about 1.72.

I got the 4.34mm cog spacing from the Shimano exploded view drawing of a 2.56mm spacer and 1.78mm cog for a 9 speed cassette.

John Hawrylak
Woodstown NJ

Patrick Moore

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Nov 30, 2022, 12:12:00 PM11/30/22
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Ted's remark raises an interesting question. I for one didn't think that so very closely spaced cogs might require fine tolerances that exceed the everyday capabilities of shift-by-cable systems, what with friction changing with wear and dirt.

So, question: Is it generally true that above 10 speeds or perhaps 11 cable systems don't work very well, or at least, shifting quality degrades quickly compared to systems with fewer cogs and wider tolerances?

I recall using a Cyclo Benelux pullchain rd* to shift 2 cogs hacked onto a SA AW driver; to take an extreme case, I can't imagine that rd indexing 4 cogs let alone 12. It did index 2: all t'way for'ard and all t'way backward. (Kidding.)

So, again, to sum up: do 12 and 13 speed systems require and lock you in to electric shifting?

That is a question, not an implicit value judgment.


On Tue, Nov 29, 2022 at 11:14 AM Ted Durant <tedd...@gmail.com> wrote:
... 

Patrick Moore

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Nov 30, 2022, 12:12:01 PM11/30/22
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Forgot the asterisk:

* This was a pushrod rear derailleur with the cage attached to a spiral spring encircling a shaft along which the cage traveled. The spring held the derailleur close to the hub and the cable via pullchain pulled the derailleur outward along the shaft. The shaft was a weak point for contamination and binding, tho' with just 2 cogs the action was a doddle. I have no idea what this rd was doing in the shop where I found it, since at the time and place the (really) latest and greatest were cheap Indian clones of the Raleigh Sport with single speed drivetrains.


This is close to the one I had if not the exact model:

image.png

Ted Durant

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Nov 30, 2022, 12:33:44 PM11/30/22
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On Wednesday, November 30, 2022 at 11:12:00 AM UTC-6 Patrick Moore wrote:
So, question: Is it generally true that above 10 speeds or perhaps 11 cable systems don't work very well, or at least, shifting quality degrades quickly compared to systems with fewer cogs and wider tolerances?

My experience with 11 speed so far (SRAM Force brifters, derailer, and cog, with a few different chains) is about 10k km, in not terribly challenging environmental conditions. The biggest detractor to shifting performance has been chain wear. The SRAM 11sp chain I first used wore very quickly (as in a few thousand km) and it really degraded the shifting.  Subsequent YBN chain seems to be wearing better. I just bought a new one and cleaned it and bathed it in Silca super secret wax, so we'll see what that does for longevity. It certainly makes it clean and quiet, once the initial excess is worn off. I have not experienced any issues with cables getting full of junk, even after a lengthy 2-day session on crushed gravel trails. 

I also have a recent experience with a Campy 9-speed setup. I had a hawk take me out by trying to fly between my front wheel and frame. I went down on my right side and bent the derailer hanger a bit. Let me tell you, that sure ruined the indexing!

Ben Adrian

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Nov 30, 2022, 12:40:55 PM11/30/22
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Campy Ekar is machanical only and has 13 speeds. I've heard nothing but good reviews (also, how high price comments). My guess is that they just have a lot of cable pull and the derailleur is a lower ratio than other mechanicals.

There's also the Ratio Technology retro-fit kit that turns SRAM 10 or 11 speed mechanical into a 12 speed with their SRAM MTB mechanical standard, so one can run road shifters up front and mechanical 12speed MTB in the back. I've also heard good things about this.

I think the problems mainly come when people try to make a 1.7:1 ratio derailleur (like Shimano 7-8-9 speeds) work on higher numbers of cogs. 

Patrick Moore

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Dec 5, 2022, 2:46:25 PM12/5/22
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Ben and Ted: So 11+ does not require electricity. Thanks, good to know, even if only for academic reasons. 

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Ted Durant

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Dec 6, 2022, 10:26:35 AM12/6/22
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On Monday, December 5, 2022 at 1:46:25 PM UTC-6 Patrick Moore wrote:
Ben and Ted: So 11+ does not require electricity. Thanks, good to know, even if only for academic reasons. 

My experience with SRAM 11 speed has been good. SRAM was the first to advertise a lower actuation ratio - "Exact Actuation" - which increases the amount of cable pull for a given amount of derailer travel. That allows more room for error in the cables. 
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