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Half Step Gearing?

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Half Step Gearing?

Old 05-11-14, 05:23 PM
  #26  
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Originally Posted by iab View Post
When did this become the whole point? It certainly was not the point in the first usage of half step gearing, at least from the race point of view, I don't know about a touring point of view. Typical front rings were 51/48 or 52/49. The back was 14/16/18/20/22. Racers used 6 gears through the 50s, 52/14, 52/16, 52/18, 49/18, 49/20 and finally 49/22.

When did getting 9-10 gears, crossing chaining in the process, become the vogue?
I remember having heard (though I'm not sure if this is accurate or not) that many early front derailleurs couldn't handle a difference of more than four or five teeth, which would have made half-stepping more or less mandatory.
As far as the modern vogue for half-step goes, I think it came about when people started to realize that modern chains are thin and flexible enough that you can easily cross-chain across five cogs with no problem. That probably didn't work so well in the days of yore when chains were stiffer and had protruding rivets. For me, half-step-and-granny is a good way to get a bunch of closely-spaced gears without spreading an old frame to accept more than five speeds in back. Also, I like the shifting--it gives me something to think about while riding.
Plus, of course, it's the vogue.
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Old 05-11-14, 06:16 PM
  #27  
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Most of my bikes that are not set for racing (i.e. riding in large packs of people) are set up as half-step. You simply don't need it for racing. However I vastly prefer it for more lone/small group rides where pace lines are not going to be forming much. I am not a fan of it on mountain bikes. Frankly, modern systems work too well, and chain ring shifts should be less frequent off road.

I have several which are 2x6 (doubles) including my Romic, Dave Moulton, and DiNucci. I get about a 55-60 gear inch spread across the range. I have a low between 36 and 42, and a high between 90 and 100. These are generally lightly-laden bikes, so a granny gear would be nice in some cases, but not required. The RD will be the limiting factor as higher end stuff like DA will not swallow larger than about a 28T rear cog.

As info, I think 7-speed rear ends are the about the practical limit for half-step set-ups. With 7 speeds, you frequently find only 3-teeth difference even with wider range freewheels. It just gets to the point where there is not a big enough difference.

The biggest problem for me is forking out the $$$$$ for appropriate chainrings for Campy and DA on higher-end bikes.
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Old 05-12-14, 12:31 AM
  #28  
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Originally Posted by jonwvara View Post
I remember having heard (though I'm not sure if this is accurate or not) that many early front derailleurs couldn't handle a difference of more than four or five teeth, which would have made half-stepping more or less mandatory...
In many cases, it's the older rear derailers that won't handle larger changes between the front rings, usually when larger freewheels are being used.

Even my old Simplex pushrod derailers with purely horizontal movement handle a 52-36t chainset wonderfully.
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Old 05-12-14, 04:08 AM
  #29  
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Originally Posted by dddd View Post
In many cases, it's the older rear derailers that won't handle larger changes between the front rings, usually when larger freewheels are being used.

Even my old Simplex pushrod derailers with purely horizontal movement handle a 52-36t chainset wonderfully.
I wonder if my remembered source was wrong or my memory was wrong?

EDIT: I found it. In an essay called "Gearing Theory, Sheldon Brown says:

"In the days of 4- and 5-speed freewheels , 8- and 10-speed bikes were commonly set up with chainwheels that were very close in size, for instance, 46/49, or 47/50. When used with typical freewheels of the era, the difference between the two front gears was about half as large as the difference between adjacent gears on the freewheel. (One reason for this was that early front derailers couldn't handle much more than a 3-tooth difference reliably!)"

I wonder where Sheldon got his information about old front derailleurs? Maybe he just read it somewhere.
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Old 05-12-14, 06:58 AM
  #30  
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Interesting discussion. I have avoided the comlexity of gearing for too many years. Now I get it. I have a 3x6 tandem with 13, 15, 17, 20, 24 and 28 in the back. The front was 52/48/28. The middle ring was nearly useless to me. I think it is a half step configuration but the differences were about 8%, hardly noticable for all the double shifing. We took the approach of shifting just the back and when needed, changed to the middle ring. It was near useless, like "didn't it shift" and looking back to see which ring it was on!

Last week I purchase a 46 tooth middle ring. The difference is now 11.5%. I like it! I still avoid the dual shifting but when the hill gets a little steeper and we just need a little more cadence, moving to the middle ring works great! I have a 7spd that wil work on the bike too. The 7spd is a 13, 16, 17, 19, 21, 24, 30. This will still give me a ~11.5% differnece across al 7 speeds with a net gain of 2 gear inches on the bottom end. not much but better and may make a difference for us on the steeper hills.
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Old 05-12-14, 08:23 AM
  #31  
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Originally Posted by SJX426 View Post
Last week I purchase a 46 tooth middle ring. The difference is now 11.5%. I like it! I still avoid the dual shifting but when the hill gets a little steeper and we just need a little more cadence, moving to the middle ring works great!
With your 14-28 FW both the 48 and 46 middle rings are half-step w.r.t. the 52, and the 48 actually places the middle-ring ratios closer to the midpoints between the big-ring ratios. But as you've discovered, (1) when the rear ratios are close enough together you really don't need those mid-points; (2) if the big and middle rings are too close together the ratio change is too small to be significant. With your reasonably close FW the big-to-middle shift is more of a convenient range-shifter for you.

IIRC, our tandem FW is 14-17-21-25-30. (The body is stamped "tandem", perhaps meaning stronger pawls.) Our rings were 52-40-30 but after a year of riding (about the same time I found the current FW) I changed to 52-38-28. This gives good 1.5-step shifts between both ring pairs. We spend maybe 2/3rds our time on the middle ring and most of the rest on the big ring. However I do use the crossover feature occasionally, especially between the big and middle, when one FW position is too high and the other is too low. The double shift is pretty easy. But if the rear shifts were tighter I probably wouldn't do it as often.
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Old 05-12-14, 08:45 AM
  #32  
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Originally Posted by dddd View Post
Even my old Simplex pushrod derailers with purely horizontal movement handle a 52-36t chainset wonderfully.
My UO8 came that way and it worked well enough.

The combination that always amuses me is 52-49 rings, presumably used with a 14-24 5-spd FW. (The crank I got with the Masi, which I assume was original but perhaps wasn't, had 52-49.) That half-step is so small it doesn't do anything. Of course old LBS guys explain that it was a half-step - sure, but to what purpose? With that small a half-step, then full-steps must have been pretty small too. If the FW was 14-24 6-spd the shifting would seem to be even more ridiculous - a real fine-fine-fine-tuning of cadence. But I guess that mattered to some.
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Old 05-12-14, 08:45 AM
  #33  
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@jimmuller, thanks for the explanation. I am still balled up over the numbers. The riding is the proof. I debated on a 46 or 44. I understood 10% change was desirable and with an 11% change between large and middle, it made sense. Even with the <10 mile run yesterday, I discovered that I like the middle ring for most of the time, using only the large for down hills. This works out very well. What was a nice improvement was the low range where I didn't need to go to the small ring (28) because the middle ring (46)/ larger cog (20 or 24) was a high enough ratio to get over the small incline that I was previously using something like a 28/20. This was accomplished by simply moving from the large ring to the middle instead of moving all the way to the 28 or moving sooner to the 46 and simply moving to larger cogs. The ~5 inch difference between the 48 and 46 was enough to bring a surprised smile!

Need to spend more time analyzing this setup. After 30+ years, I need to get my head wrapped around these relationships. I had trouble with trig too, along with calculus, Diffyque (differential equations) was not so bad! Go figure. Oh that’s what I need to do!

Getting the relationship of differences to actual experience is the challenge for me. The numbers make sense to a degree, but how do I relate that to how well I can maintain an optimum range of cadence for a give incline (+ or -) and what is the optimum usage of gear changes? Changing gears downhill is not an issue. Skipping is easy! It’s the climb that is the challenge.
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Old 05-12-14, 11:55 AM
  #34  
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With only enough space for a five-speed freewheel on my old 700c Phil wheelset, I solved the problem of having "tight" enough gearing and wide overall spread by using a 52-36t with a 13-24t 5s freewheel.
That's 13-15-17-20-24t btw.

This freewheel's gaps are just tight enough for me to stay on top of my spin in fast company, and whenever I have to shift the chainrings, I "double-shift" one step in back to keep the shift increment in the same "tight" range as my freewheel's ratio gaps.
So instead of "half-step", my chainrings are "double-step".

This yields a total of 7 sequential gear ratios, not too much playing with the shift levers, reasonably tight gearing increments and a wide overall spread giving a low (36-24t) ratio equivalent to 39-26t or 42-28t, which is enough for me.
And, with the 52-13t, I can spin it all the way up to 47mph on the downhill stretches.

I was quite happy to get myself in synch with this shifting strategy, sufficient to maintain very nearly my normal pace on the faster rides.
The 5s freewheel definitely gets noticed in a world of 10 and 11s cassettes.

I agree with Jim about those "third-step" 50-47t chainrings, I usually lose enough speed while downshifting those that it feels like I might have actually upshifted by the time I resume spirited pedaling!

My race weapon, so equipped (chainrings are original, and the original Simplex derailers are still hanging in there after some 3k of my own miles):

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Old 05-12-14, 05:25 PM
  #35  
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Unlike some posters in this thread, a 6-8% half-step in the cruising range is ideal for me. Not saying it should suit everyone though.
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Old 05-12-14, 05:35 PM
  #36  
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I've got a 1/2 step and granny on my tandem, but i'm sure i'm not using the set-up properly. I just shift front and rear until if feels right.
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Old 05-12-14, 05:44 PM
  #37  
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Originally Posted by dddd View Post
That's 13-15-17-20-24t btw.
A classic combo if there ever was one! I rocked one of those for years, Atom flavour, on my Moto GJ, before I upgraded it to a single step plus granny combo (sporting an Suntour Ultra corncob), and said goodbye to chain skating into the bargain!

You're certainly one for taking every opportunity to embarrass your crabon-fiber mounted, brifter equipped cycling brethren.
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Old 05-12-14, 05:50 PM
  #38  
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Originally Posted by old's'cool View Post
Unlike some posters in this thread, a 6-8% half-step in the cruising range is ideal for me. Not saying it should suit everyone though.
A lot of riders agree with this. ^^

I think that as the terrain gets more into the "rolling hills", that the others of us tire of shifting so often, and where such small increments of gear change become un-noticeable.

In this age of near-instant bar-mounted shifting, smaller gear ratio increments become more practical, but for me, here, I find almost no use for small increments even when struggling to keep pace with the fast crowd.

The gearing setup I described above actually is nearly as good as I could ask for in my foothills region. I use modern 9s chain over Uniglide cogs, so the "double-shift" is relatively quick, painless and consistent.
A modern 10s STI drivetrain, like on my Orbea, affords a significant but small advantage I would say, not that the 10-Lb reduction has anything to do with it(?)...

Setting up my bikes with such a forward rider position (as shown above, using larger frame sizes) makes for such a quick and effortless transition between seated and standing so as to negate much of the drawback of wider gear spacing, by allowing efficient use of a wider range of pedaling cadence.
That it also offers aero benefits is just icing on the cake.

Here's another one, only fitted with a 7s 13-30t freewheel, and now using 54-44t chainrings in place of the pictured 54-48t half-step.
No need for any double shifting here, but again, a more-forward rider position often affords more pedaling cadence flexibility by allowing a quicker transition from sitting to standing, especially while climbing:


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Old 05-12-14, 06:39 PM
  #39  
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Originally Posted by old's'cool View Post
A classic combo if there ever was one! I rocked one of those for years, Atom flavour, on my Moto GJ, before I upgraded it to a single step plus granny combo (sporting an Suntour Ultra corncob), and said goodbye to chain skating into the bargain!
You're certainly one for taking every opportunity to embarrass your crabon-fiber mounted, brifter equipped cycling brethren.

A 13-24t Atom freewheel is a very rare find around here, especially one with French threading!

I set aside my Gitane TDF's 14-28t 5-speed freewheel for a 14-16-19-22-26t Cyclo64 with French threading for the Gitane's Tipo hub.

The Cyclo64 freewheel is also a gem since it plays nice with an HG70 chain. My chainrings here are now 52-40t, but obviously no rider-forward position on this one and no large frame, but I've had some intense fun riding it. Allow me to blow this one up a little. Behold, the the "Green Hornet":

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Old 05-12-14, 08:21 PM
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Originally Posted by dddd View Post
Allow me to blow this one up a little. Behold, the the "Green Hornet":

Nothing subtle about that!
Originally Posted by dddd View Post
A 13-24t Atom freewheel is a very rare find around here, especially one with French threading!
I aSSume my 78 Moto (i.e. Normandy/Atom rear hub thereof) has English threading since it came with a Suntour freewheel and has accepted any number of Suntour freewheels in the mean time, so I also aSSume that the Atom freewheel I swapped in had English threading. At least I can say there was no snarling and gnashing of teeth involved in its installation and removal.
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Old 05-14-14, 01:56 AM
  #41  
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Originally Posted by jimmuller View Post
if the big and middle rings are too close together the ratio change is too small to be significant.
last night I was messing around with half step gearing and set up a crankset with 48t and 45t rings. changing rings was hardly noticeable but the middle ring being so close to the size of the big ring caused problems with the front derailleur striking the middle ring unless i raised the FD higher than I normally would
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Old 05-14-14, 04:07 AM
  #42  
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Originally Posted by frantik View Post
last night I was messing around with half step gearing and set up a crankset with 48t and 45t rings. changing rings was hardly noticeable but the middle ring being so close to the size of the big ring caused problems with the front derailleur striking the middle ring unless i raised the FD higher than I normally would
Yes, that derailleur problem is not uncommon. A difference of 4 or 5 teeth often works better, though that may require a different freewheel and pair of chainrings. It can get pretty frustrating at times.
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Old 05-14-14, 04:37 AM
  #43  
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Originally Posted by frantik View Post
last night I was messing around with half step gearing and set up a crankset with 48t and 45t rings. changing rings was hardly noticeable but the middle ring being so close to the size of the big ring caused problems with the front derailleur striking the middle ring unless i raised the FD higher than I normally would
When I installed the 46 for the 48, I was able to lower the FD by about 1/8". Huge improvement in shifting. In order to accommodate the granny, Tandems typically get a MTB FD that has the inner plate lower than the outer.
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Old 05-14-14, 06:34 PM
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Originally Posted by SJX426 View Post
In order to accommodate the granny, Tandems typically get a MTB FD that has the inner plate lower than the outer.
As a aside, such MTB FDs do NOT play nicely with closely spaced middle & larger chainrings. The inner plate tends to foul on the middle chainring when shifting to the upper chainring, unless the derailleur is set abnormally high, which may impair shifting in general, and/or cause the bottom of the cage to foul the chain when on the granny chainring.
With a half-step plus granny combo, you'd rather have a proper road touring intent triple FD, or one of the many double FDs that can make the stretch to triple service.
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Old 05-15-14, 06:32 AM
  #45  
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Originally Posted by Lascauxcaveman View Post
I'm going off the top of my head (bike is up on the shelf right now). It might have been 50-45 or 52-48. All I remember is thinking "Is that it?" whilst shifting from big to middle ring.
Biggest problem with HS or HS+G (outside of finding the parts to build a good one today) is the rider. Same with true Alpines. Frank Berto said in his great "Upgrading Your Bicycle" book, if lab rats can learn to run mazes, cyclists can learn to shift Alpines.

I think he was very optimistic.

I have an old book which discusses gearing, written by a math teacher/avid cyclist in the '70s. Rather than try to compute some new HS and HS+G arrangements, I'll just quote some for y'all to peruse. Which ones are actually feasible depends on our personal capabilities in scrounging and scraping up old useable hardware. Unless it happens Pastor Bob can build the freewheel ...
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Old 05-15-14, 08:16 AM
  #46  
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Originally Posted by Road Fan View Post
Frank Berto said in his great "Upgrading Your Bicycle" book, if lab rats can learn to run mazes, cyclists can learn to shift Alpines.

I think he was very optimistic.
My UO8 came from the factory with 52-36 rings and 14-16-19-22-26 FW, which produces a 2 1/2-step crossover. As I understand it this what is meant by Alpine; well, the Peugeot catalog called it Alpine gearing. I could use it as a crossover system, but there were few reasons to. The cogs were close enough together that the in-between ratios weren't needed. If I (or the generic "you") needed one of those ratios, the road might change and the opportunity be gone before I ever got the shift finished! Instead, the front shift was a by-golly-go-into-LOW range shifter, so that's how I used it.

But the real reason I (or "you") don't do crossover shifting with an Alpine is that at least for a 5-spd FW there are only two mid-point ratios available on each ring anyway, and one of each is an extreme cross-chain combination. There just weren't many useful gears available!

Back to half-step utility, it was suggested a page or so ago that you actually shift most on the rear, and the front is just for fine-tuning so a very small front change is okay, that you really didn't use the front to get in-between ratios. It seems to me that that is exactly what "fine-tuning" does, gets a ratio better than the one you just got and better than the one you just left. Which is to say, one in between the two.

It also seems to me that if you find your front shift beneficial even if it is just a small change, then you'd do it more often, not less. Road grade, wind, and similar things that affect speed or your pedal load a small amount occur more frequently than things which affect your load a lot. Of course around here the load changes a lot quite often, but that just make small shifts less useful so that a larger front shift is more desirable anyway.

All of which is to say a half-step makes sense (to me) only if the cogs are far enough apart to make the front shift useful.
But what do I know?
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Old 05-15-14, 10:07 AM
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That's interesting about the origins of the "alpine" wording, which I am supposing was the antithesis of existing half-step and mid-step (like a PX10's 52-45t) cranksets of the time (1960's).

I have in the past also read of 42-52t with 14-28t referred to as "alpine" gearing, so I think it was a broad term. Probably perfect for the American entry-level market.

The 2-1/2-step chainrings make sense in that one can "back shift" the rear derailer one or two steps depending on terrain and whether the rider is upshifting or downshifting.

Your 14-26t sounds like a 1960's cog stack(?).

I've noticed that this 52-36t combination has made a recent comeback, marketed as new "racing compact" or "mid-compact", LOL.
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Old 05-15-14, 10:59 AM
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As someone who has ONLY ridden a geared bike with HS+G gearing (and using barcons), I find the shifting and fine-tuning of gears to be incredibly intuitive. I think of the RD as the "defining" mechanism, and the FD as the "fine-tuning" mechanism. Of course, it makes it easy when you're using barcons to push down with your palm, or flick up with your fingers, rather than reaching down and flipping left and right on a DT shifter.

For me, it's the crossover gearing I can't seem to wrap my head around...
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Old 05-15-14, 11:56 AM
  #49  
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Originally Posted by dddd View Post
...mid-step (like a PX10's 52-45t) cranksets of the time (1960's).

I have in the past also read of 42-52t with 14-28t referred to as "alpine" gearing, so I think it was a broad term.
Px10's had 52-45? That's a curious set. I can see no ideal cog set for that but perhaps that doesn't matter. A corncob FW won't require in-between gears, I wouldn't think.
You may be right about the terminology. Back in the old days I never saw "Alpine" mentioned anywhere except in the Peugeot catalogs.

Originally Posted by dddd View Post
Your 14-26t sounds like a 1960's cog stack(?).
1972, IIRC. Back then it was only bike or catalog I ever saw with gearing like that. Perhaps it was holdover.

Originally Posted by bear_a_bug View Post
For me, it's the crossover gearing I can't seem to wrap my head around...
It's really quite simple, especially with a half-step, easy but less so with a 1 1/2-step. In practice it is more or less a form of fine-tuning.

Here is a 2x6 half-step gear arrangement, named half-step because a front shift is half of what a single-cog shift on the rear would be. Cogs are numbered from large (1st) to small (6th). A 2x5 would work exactly the same way. Note that I didn't say how big the steps are. With a wide-range FW the steps are large so the half-step will be too. If the FW is a corncob, the half-step must be correspondingly smaller too or it won't be a consistent half-step at all.

......1.....2.....3.....4.....5.....6..........large ring
...1.....2.....3.....4.....5.....6..............small ring

Suppose you are on large-3 and you need to shift down "just a little". You'd shift the front to obtain the ratio in between large-3 and large-2. A key point about this is that the front shift went in the direction you wanted to go, i.e. down a little. Of course this assumes the steps on the rear are large enough that going an entire rear cog's worth is a bit too much so that the in-between ratio really is a better choice. Otherwise you'd just shift the rear and live with it, which you might do anyway if the terrain is going to change again quickly or if the shifting is difficult.

Likewise if you were on small-3 and wanted to shift up a little, you'd shift the front up. As in the previous example, the front takes you in the direction you want to go. Easy-peasy.

But suppose you were on large-3 and wanted to shift up. If you shift the front it takes you the wrong way, down. So you then shift the rear one step in the direction you want to go. The front took you half a step in the wrong direction but the rear shift took you a whole step in the right direction, so the net gain is half a step in the right direction.

The same logic applies when you are on the small ring. If you want to go down but you're already on the small ring, then shifting the front will take you higher, i.e. the wrong direction. So you shift the rear too downward, for a net gain of minus one half.

Now, you could think of that double-shift sequence as just shifting the rear first, and finding that it overshot you then fine-tune with the front in the opposite direction. The difference is that when you shift the rear first (conceptually or in practice) you don't "know" whether the front will help or hurt! You could shift the rear, realize that it overshot, then discover that the front shift would only take it further in the same direction. But if you are aware of what ring you are on you'll know what to do. Even better, if the front takes you in the right direction, up or down, that's all you need to do, no rear shifting necessary.

The 1 1/2-step is a little different in practice. I use double shfting on our tandem fairly often, on a solo bike less so, whenever I'd prefer a gear in between what the rear will give me. It's worth the trouble if I think I'll be in that gear for a while. It's also worth the trouble if the terrain is changing to be consistently faster or slower so that the other ring is going to be better for a while, regardless of the in-between gears. But if I'll be double-shifting to the other ring only to get off it again in 30 seconds, I'll just live with whatever the FW provides. And of course, with a 1 1/2-step the total gear range is obtained via wider rings and tighter FW, so the need for those in-between ratios is lessened anyway.
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Old 05-15-14, 12:32 PM
  #50  
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I don't have a lot of experience with 1/2-step gearing (only one bike among my keepers, the Nishiki Competition), but I have to say that I am not a fan. I like the evenly spaced set-up of half-step gearing usually provides, but not at the expense of having to use the FD so much. A RD shifts more quickly and precisely than a FD, plus you don't have to worry about gradual wear on the chromes FD cages, and it handles shifting better under load, and it is a lot less likely to result in a dropped chain. Thus, I'd much rather do most of my shifting with the RD. I'd speculate that ~80-85% of my shifting on a typical road bike is done with the RD, versus ~50-55% on my half-step bike. Just one man's preference.
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