happycheapskate

Thank you for the information, Ruffinit!

I understand the concept now, and I like it. My first couple of road bicycles had very high 2x cranksets (53/42 example) with road racing clusters. I liked the close ratios, but they were terrible for anything but racing, since there was no way to just chug up hills or carry packages.

Duplicate gears don't really annoy me too much. I usually drive my bicycles in whatever chainring they are in, plus the cog I want, though I do shift strategically for hills or mountain bike obstacles.

Re DOWN TUBE SHIFTERS. Those things are awesome for townie bikes and ultralight set ups, but I tired of them long ago when I started mountain biking. I have since customized mountain bike "pods" for the drops on my road bike, like this. I like the XT style ones better though, they have a thumb trigger and a index finger trigger, instead of 2 thumb buttons.

Have you guys ever tried Low-Normal rear derailleurs? If you can find a Shimano XT Low-Normal 8 or 9 speed rear derailleur, it should work with 5,6,7,8,9 speeds using compatible shifter and cogs! It will go toward the "granniest" cassette/freewheel gear when you shift. They take a while to get used to, but are very nice, as they shift automatically, as soon as the optimal ramped surface meets the chain.

Barrettscv 

I've been planning a modern 2x10 drivetrain with half step gearing using the Sram Apex ten speed 11-32 cassette.

I have a 46 & 38 130 bcd Sram Cyclocross crank. If I was to install a 43 as the small chainring, I could have very good half-step gearing across a broad range. I think TA makes a 43 chainring that accepts a 10 speed chain.

It would be helpfull in windy conditions to stay on cadence. 15% jumps in cadence with a 11-32 Ten speed cassette can be annoying, the half step provides a 7% change in cadence, much better.

Michael

ciocc_cat

Frank Berto's great articles in Bicycling magazine became my gearing "bible". I frequently referred to his "Build Your Own Super Tourer" and "All About Twelve Speeds" articles, the later becoming the basis for my current "crossover" (no double-shift) gearing on my Ciocc.

ewmyers

I have a 1984 Univega Gran Turismo which I thought had half step gearing, but after reading this thread and putting the numbers through Sheldon Brown Gear Calculator, I discovered that really isn't the case at all:



I had tried using it as a half step but it didn't feel like the steps were anywhere near equal, and now I see that's because they aren't! Does anyone have any recommendations on the best course to make this gearing more usable, either half step or not. I tend to stay on the middle chain ring, occasionally use the smaller chain ring, and pretty much never use the larger one, so I've even considered replacing the outer one with a chain guard :-P I'd rather not do that though.

-Eric

Barrettscv 

You could have a true half-step & a granny gearing if you put a 50 or 49t chainring on the outer position. You could also replace the crankset with a 48 & 34t double from Velo Orange.

sailorbenjamin

28/24=1.17
24/21=1.14
21/18=1.17
18/16=1.13
16/14=1.14
That's fairly consistent with an average difference of 1.15. The rings should be half that difference, 1.075. Keeping the 46 you'd want a 49.45 (46x1.075). Rounding to the nearest integer gives you a 49, though a 50 is pretty close.

Peter_B

It seems to me that your riding preference is to ride on a middle chainring as much as possible, and shift down when you get on a steeper grade, and maybe shift up on a big downhill. Half step plus granny gearing isn't suited for that gearing/riding preference. With half step plus granny gearing you would be shifting up and down on the middle and large chainrings in combo with the freewheel, in order to use the right gear for your regular riding (plus shift down to the small chainring for steeper hills). Your riding preference can be effected with double chainrings of 28-48. Maybe you don't "need" a triple and would prefer to save some weight and simplify? If you change your triple to half step plus granny gear, you "should" be front shifting a lot to utilize your gears, but if your preference is to leave it on one front chainring as much as possible, then maybe you don't want a triple?

MrEss

I've been planning out a half-step plus granny for the Atala (I know, I know, that's so wrong for an Italian bike). Shimano makes a 11-30 8-speed cassette with nearly perfect 15% spacing.

With something like a 24/42/45 triple, that goes down to 22 gear inches with perfect 7% spacing from 38 to 110 gear inches. With brifters I don't think the extra shifting will be a problem at all. Can't wait to get it built up.

ewmyers

There are plenty of times where I'd rather be in a gear halfway between two options using only my middle chainring, but the current gearing configuration just doesn't have it. I'd say the double chainring idea of minimal front shifting would be more appealing if I had more than 6 options on the freewheel, but I would happily do the front shifting for a working half step. I think I'll try to find a better chainring such as Barrettscv and sailorbenjamin suggested.

-Eric

Sixty Fiver

I just swapped the wheels on my touring bike to a more original set of Sansin high flange hubs and Araya rims and am using a 7 speed mega range with a 28/36/48 up front.

I had a half step ready to go but when I ran the numbers I saw that I have a 19/21 speed bike with one gear overlapping 3 times and in two places it is a gearing I would never select, and the mega ranges offers a tighter 6 speed with 2 step changes from 14-24 and that 34 tooth bailout.

Will play with this for a while as it looks ideal... will probably spend most of my time cruising with the 48 and the 14/16/18, can climb most things with the 36 and have full range across the block whileI will reserve the 28 for extreme climbs and could make that smaller without creating any more serious overlap.

If I find I am spinning out my 85 gear inches I will swap in a 50 tooth ring and still won't have any grievous overlap.

Sixty Fiver

If you look at my post above... the 14-34 mega range has steps of 14, 16, 18, 20, 22, 24, 34 which are 2 steps through 6 whereas the 14-28 has some 3 and 4 step changes at the lower end.

It is an easy upgrade to move from 6 to 7 and I am a big fan of these m-range freewheels and cassettes.

rhm

'58 Lenton Grand Prix with Cyclo Benelux derailleurs.

46-49 chain rings shifted with the lever operated derailleur.

original 14-16-18-20 freewheel has been replaced with a 14-28 freewheel for various reasons. The Benelux derailleur won't shift to the smallest cog, which is no surprise and, really, no great loss.

sailorbenjamin

Well, here's my shot at this game. It's a Williams/Raleigh 46/49 crank with a 36 32 28 24 21 18 16 14 12 cassette. The ratios aren't as close as I'd like but they're not bad. I've also got a 34 30 26 23 20 17 15 13 11 cassette and I think I can do a little better if I mix and match cogs but I need to think that over some more.
I did a little more wright up on this thing here;https://www.bikeforums.net/showthread...n-a-531-Falcon!

Captain Blight

that crank is Beeeeeeyooooootiful! Why doesn't Shimano make next year's Ultegra look like that? Why? WHYYYY?!?!?!


<<Here's what I got: 46/50 with 30/24/21/19/17/15/13 for 14 unduplicated gears. Strongly considering ditching the Mighty Tour crankset for something I can set up with a bailout ring, no matter how pretty the Sugino is.

And it will never be as pretty as the Williams, no; not if it were ever so.

Bianchigirll 

I am sure this has been explained in the previous pages but I have a few questions. I am seriously considering building a bike with a realish 1/2 step gearing. on most of normal road bikes I run a 42/52-3 and a cassette/FW something like 12-21/23ish. I normally use the 42 most of the time.

would a 42/48 ctrank and 12-25 be acceptable or should I use something like a 48/52 and a 13-30 cassette? i doubt I will really get to use this bike as an actual long distance/Randonneurer bike but I want to atleast try and build a true half step.

and one of the great things about bikes is I can easily change back to a normal 42/52 bike

sailorbenjamin

Try the online gear calculator. Punch in both gear combo options and then punch in your current set up and see how the new sets compare to the gears you use most on your current set.
https://sheldonbrown.com/gears/
How many cogs are on your freewheel? 42/48 seems like a big jump but if the numbers are good then they are good.

Bianchigirll 

I am going to use a a 7spd. 42/48 is only 6teeth is a half step much closer? 45/48 maybe?

I'll try the calculator. the bike is currently a blank slate, so this is still in the hypothetical arena

Sixty Fiver

Your chain is far too short...

I should send you a Shimano 14-34 5 speed so that you can fully appreciate what half step gearing is supposed to accomplish

Half step gearing works best with wide range 4-6 speed freewheels and is almost redundant with wide range 8-9 speed cassettes and impractical with a close range 8-9 speed as the gearing steps in the rear are already so very close.

sailorbenjamin

Your chain is far too short...

Yeah. I've got the extra links. It's just that these 9 speed pins aren't reusable and this chain is really supposed to be on this other bike I've got.

I should send you a Shimano 14-34 5 speed so that you can fully appreciate what half step gearing is supposed to accomplish

I've got one of those on my Trek now. The thing came stock with a 45/50 and this 6 speed freewheel that had nothing to do with half stepping. I don't know why Trek bothered with that thing. The rest of the bike seems so well thought out. I haven't had a chance to try it out since the weather cleared but this afternoon I'll be on it for a while.

Half step gearing works best with wide range 4-6 speed freewheels and is almost redundant with wide range 8-9 speed cassettes and impractical with a close range 8-9 speed as the gearing steps in the rear are already so very close.

Turns out the steps on this cassette are about the same as for a 14-24 5 speed which is what the crankset was designed for. So I can stay in the middle gears and it's the same but I can keep downshifting when I get to a hill.

sailorbenjamin

Hmm. How do you copy the gear chart into a reply?

Sierra

Screen Shot.

Hit the PrtSc(Print Screen) button which saves the screen image into the buffer.
Open MS Paint and paste the image into it.
Save as a Jpeg and you have it to attach to your post.

big chainring 

Oops, never mind.

JohnDThompson 

Nice bike. It needs a Campy Gran Turisimo rear derailleur, though...

sailorbenjamin

Oh, like this.

While the steps seem close on the 9 speed, they average a 14.75% difference so they're actually a little wide for the 46/49 with a 6.5% difference.
It does seem a little finicky for the rolling hills around here. I'm always fiddling with the shifters. But I'd be doing the same with the old freewheel, I'd just run out of gears sooner.

sailorbenjamin

So, I finally got around to getting My Trek out today. It's an '82 612 (or 614, I forget). This is the freewheel the brochure says it came with from the factory but it doesn't make any sense to me.

I replaced it with this Suntour Perfect that's just about perfect for it;

The 45/50 seems a lot less fussy than the 46/49. I'm still monkeying with it a lot but that might just be cause I'm new to this half step thing. Then again, maybe the terrain around here is just not right for half stepping.
Hey, Sixty Fiver, what are the other gears on that 14-34?