sysrq

About to try out half-step gearing. Since there are some mechanical and dimensional issues regarding to 45t chainring to get 7% steps between gears, I'm starting to think about putting on 46t chainring which would result in 10% gear steps for coarse finetuning when shifting from 42t to 46t. This should be better than 14-17% steps between14, 16, 18, 21, 24, 28, 34 cogs when using rear derailleur alone. Downshifting would require double shifting which results in loss of momentum anyway.
This would also result in 11% and 10% step between 34t and 28t cog for better cadence during climbing, instead of 7% and 13% which would otherwise not be noticable. On the other hand there would be no even progression on the top end for building up and maintaining speed. Probably will have to just try it out since preference for specific gear steps and cadence is considered to be highly individual thing which depends on a muscular ability, terrain, etc..

CliffordK

Hmmpf.... I've always done it the opposite. Traditional gearing of as many single step gears as possible.

So, say 53/34 up front, and something pretty tight in the back. 11/25? I reduce overlap some, but I do end up double-shifting whenever I have to shift the front derailleur.

Anyway, I'd make a spreadsheet and put in all of your teeth and try to figure out the gearing jumps.



Whew, alternating from a 2% change to a 12% or 14% change. To me, that wouldn't have a large benefit.

skidder

A few other things to consider: How about the terrain along your commute route (hills, dirt paths, asphalt &/or concrete?), and the normal weather patterns for the area; any prevailing winds to deal with at the beginning or end of your workday? What type of load would you be carrying (clothes, lunch, workboots, etc)? What size of tires/wheels you rolling on?

Steve B.

Agree with skidder, weather/winds and hills are a factor.

My bike commute is mostly flat, I've one long 1/2 mile climb of about 250 ft (a bridge) but other then that flat. My older system had about 7% jumps between gears on a 39 ring (mostly) and a 12-23 spd. cassette. I was in the 13-14-15-16 about all the time, never used the big or small rings (triple. New bike has me on about 5% jumps with a 46 ring and 16-17-18-19-20 cogs available. Gives me the gears to deal with strong headwinds, which I encounter frequently along the beach in Queens, NYC.

tomato coupe

It looks like a 42/46 front combo works better for the 28-34 shift, but a 42/45 combo works better everywhere else.

CliffordK

Ahhh, thanks, I think I had interpreted the post wrong.

I'm not sure one would really feel a 1t difference in the half steps, so not a huge difference between 42/45 & 42/46. Nontheless, choose the gearing combination that is best for the gears that one is most commonly in. So, pick out the gears that one is in the most (14 to 21?), then choose the gearing that works best for those gears. Also consider how it impacts the top end or the bottom end of the range.

You mentioned 14T. Is this a cassette or a freewheel? Are we ignoring a few sprockets?

sysrq

It's a 70km or a 40 mile commute with one half flat and the other half with 3-8% grade rolling hills. Prevailing winds: either light tailwind or strong crosswind.

Koyote

It'd be a lot simpler to commute on a single-speed bike.

sysrq

Agreed, with a single speed you need a chain tensioner in a place of a derailleur, after that you change your sprockets before each ride depending on your mood.

Koyote

You don't necessarily need a chain tensioner (depends on the bike) and with grades of only 3-8% you shouldn't need to swap cogs.

My larger point is that the kvetching about gearing jumps is...well, it's just kvetching. Some of the guys I see at our area gravel races are on SS bikes -- for 60+ mile events that usually include 20%+ climbs. I couldn't do that, but I do commute on a SS, and my commute is shorter than yours but includes steeper climbs. And shoot, I'm an old man. If you've got a bunch of gear choices, the details aren't really that important, are they?

tomato coupe

To some people, the details are important. What you do when you ride is not necessarily relevant.

sysrq

Komoot satnav shows them as 3-8% grades, but they are fairly long up to 1-2 miles and feel steep.

livedarklions

I'm old enough to have grown up on 3 speeds. To this day, I care about range, but don't care much about size of jumps between them. It's usually just a bigger number of gear combos I rarely use.

livedarklions

If you ask whether something is too much anything, as OP did here, what other than our riding experience do we have to offer?

I don't think anyone rational finds all details important, so the real question is whether gear step size is an important detail for a commuter or not.

martianone

IMHO- there is little difference between 42 and 45/46.
for commuting suggest getting rid of the FD, go with the 1x7 and 44 chainring.
rode a cross check lots of km with 12-36 and 44.
our current beach bikes are 1x7 with 44 - while terrain is fairly flat, some bridges are pretty steep.
if terrain was very hilly, would consider 38 t chain ring.
1xN is pragmatic for commuting.

Koyote

If the OP didn't want people's opinions, he/she shouldn't have started a thread.

Ditto.

Yep.


This. Why bother with two chainrings if they're so close together?

woodcraft

Rolling hills with small gearing steps is a PIA, in my opinion.

I got a wheelset recently that came with a small-ish cassette.

It requires shifting through the whole thing to get over the hill, rather than a few cogs on the bigger cassettes that I've become used to.

It seems pointless to have to front shift while going uphill for a change of ~5 rpm.

Drew Eckhardt 

4.761% is too close going from 21 to 22T (although Lance Armstrong used 21-22-23 large cogs on the l'Alpe d'Huez time trial stage)
5.000% is fine going from 20 to 21T.
11.76% is excessive on flat ground going from 17 to 19T
13.04% is fine climbing shifting from 23T to 26T

Since getting my first decent paying job allowing me to buy what I want, I've ridden road bikes with one tooth jumps through the 19 cog because I really don't like a 17-19 gap; achieving an acceptable low gear with a larger starting cog (13T) and/or triple crank (a 21T large cog paired with a 30 granny ring yields a low like 39x27 or 42x29).

I rode a 14-15-16-17-18-19-20-21-22-23 straight block for 2400 miles as an experiment when upgrading to 10 cogs allowed that option.

Adding the 22 cog between 21 and 23 didn't make a difference.

The 20 between 19 and 21 was a bit better, but not worth the shifting hassle skipping another cog changing rings.

Climbing it's less important. 23 to 26 (13%) feels fine.

I rode the next 25,000 miles with 13-14-15-16-17-18-19-21-23-26.

I speculate gear spacing sensitivity comes from power requirements on flat ground increasing with the cube of cadence, while they're approximately linear on hills.

Although people think overlapping gears are a waste, wide rings and a tight cassette were a bad combination when I tried that. After Campagnolo discontinued my beloved 13–14-15-16-17-18-19-21 8 speed sprockets and I wore out my 50-40-30 big ring, I switched to 50–34x13–23 9 cogs sharing the same range and spacing. I shifted the front derailleur ten times more. Any time I sped up over 18 MPH in 34x14 for more than a brief small-ring sprint I shifted five cogs to 50x19. Any time I slowed down below 16 MPH in 50x21 I shifted five cogs the other way to 34x15. Electronic shifting with one touch going to the next gear on the other ring would mitigate that.

Your mileage will vary. The pro peloton generally added gears in the middle until we got to 9 cogs 12-13-14-15-16-17-19-21-23. Progressing to 10 some added an 18, some an 11 or 25. Most riders are content without the 18 cog, although with Campagnolo dropping it in the move to 12 cogs they've noted there's a significant minority which don't like the omission. I'd pay more for old 10 speed from 2000 with 17-18-19 cogs than new 2020 12 without, but fortunately have spare parts so I won't have to.

sysrq

With the rise of wide range cassettes people are forced to seek out something which would reduce the steps between the gears, so half-step gearing combines quick shifting with wide steps for highly variable terrain with close ratio spacing for fine tuning on straight sections.

DaveSSS 

Half step was relevant in the day of 6 speed freewheels, but totally unnecessary these days. An 11 or 12 speed cassette has all the small steps you'll ever need.

big chainring 

I used a half step gearing with 49/52 and 15-24. Really liked it. Front shift is quick so double shifts are a snap. The progression of gears proposed by OP would lend itself well to commuting.

Drew Eckhardt 

It doesn't.

No one makes a 12 speed cassette with 17-18-19 cogs.

The big three companies with nice shift ramps don't make 11 speed cassettes with 13 starting cogs, so a final cog larger than 25T means an unacceptable gap. Miche sells loose cogs, although I learned my lesson about indexed shifting not working well with mismatched shift features following a Campagnolo 13A cog with a 14B instead of the correctly timed 14A.

A 46-36-26 triple would work nicely with 12-25 11 speed, although a 36 ring is too small for a 130mm BCD, no one makes nice 110/74mm BCD cranks, and finding a used Stronglight Fission Triple is impossible.

New 3x11 Campagnolo Ultrashift levers are also an issue, although some of us have them in our NOS parts bin.

sysrq

I'm restricted to 42t as a smallest chainring in the front so I have no other choice but to opt for wide range cassette with wide spacing between the cogs. Half-step gearing is the most popular way to mitigate that while enabling faster shifting on the hills with rear derailleur.
Shifting from 28t to 34t which is 21% doesn't feel fine, but 20% is unnoticeable.

sysrq

12 speed chain might not be as strong, so half-step mitigates that as well + excessively dished rear wheel.

Drew Eckhardt 

42-39 x 11-13-15-17-19-21-23-25-27-30-34 11 cogs

would provide the same tight spacing as

46-36 x 12-13-14-15-16-17-18-19-21-23-25 11 cogs

but with a low like 36x31.

Swapping the 36 for a 34 would yield an inadequate small ring sprinting gear eschewing the fully cross-chained combination, and with an 11T starting cog preserving acceptable spacing you'd be down to

46-34 x 11-13-13-14-15-16-17-18-19-21-23 11 cogs

with a smallest gear like 39x26 - two short of the 42-39x11-34 half step configuration.

Historically ring changes were relatively slow; although with aggressively shaped pins, ramps, and shift forks this is no longer an issue.

46-36-26 x 12-13-14-15-16-17-18-19-21-23-25 11 cogs

would be the best of all worlds, but is no longer an option you can buy brand new.

Bike designs are periodic, like ovalized rings. It's time for a half step electronic road double gruppo.