ShannonM

Especially in the cruising range?

The freewheel I'm riding now has 16-18-20, and I'm thinking that I like that way better than the 15-17-19-21 that I always had before. The even-numbered gears make my legs happy, and I don't miss the 21.

This is as between a 14-16-18-20-23-26 and a 13-15-17-19-21-23-26, but I wonder if it generalizes?

--Shannon

Kapusta

Sort of. I prefer prime-numbered cogs, and they are all odd.

subgrade

except 2

Kapusta

True. But I had a hard time mounting the 2 tooth cog.

Melvang

A 2 tooth cog wouldn't work for obvious reasons.

Litespud

dont think it makes any difference. There’s nothing inherently better about even sprockets, the ratios just work better for you, your chainrings, your terrain, your riding style and strength. However, change any one thing slightly - the gradient, headwind, how you’re feeling on the day, whatever, and that 13 may become more ideal than the 14. Change your chainring by 1-2 teeth and you might find that different sprockets now make your legs happy. I will say that my 14 is my most comfortable “cruising” sprocket, but that’s only because that gives me 7 teeth per leg, and 7 is an auspicious number in some cultures, so both my knees feel equally lucky on the 14. Change to a 15 and there is an inherent imbalance in the good joint fortune.....🤔

JohnDThompson 

The only place where it might make a difference is on a fixed gear bike, where, as @Kapusta notes, prime numbers are preferred to maximize the number of skid patches to prolong tire life.

Kapusta

Well of course not. 2 is not a perfect square.

rydabent

Like so many ideas, I would bet that if you were given two bikes, and the sprockets and gears were covered up you couldnt tell the difference.

AdkMtnMonster

...and these reasons are...?

Drew Eckhardt 

I like my 13-14-15-16-17-18-19-21 cogs and was happy to add 23 and 26 tooth sprockets with the move to 9 then 10.

Missing odd or even cogs in the 13-19 range yield more shifting with gears that are't quite right.

I put a few thousand miles on a 14-15-16-17-18-19-20-21-22-23 straight block. While the 20 was noticeable, it wasn't better than having another on either end or not having an extra cog to skip over when changing rings. The 22 was superfluous.

Your mileage will vary.

ClydeClydeson

This sounds more like an issue with OCD than with actual bicycle function.

fietsbob

I have the 16t on my Rohloff , the default one the hubs ship with..

pdlamb

I remember reading an essay (in Buycycling?) 15-20 years ago that waxed poetic about a 16 tooth cog. I haven't come up with a reason to move that out of the "senseless fixation" mental file. (Put on a 17 tooth instead, crank it up to the same cadence, and you'll go 6% faster!)

79pmooney

You can go prime number up front and use any cog you please.

ofajen

Actually, you’ll be slower at the same cadence running a 17 tooth cog, since this number goes in the denominator of the gear inch calculation.

Switching to a 15 is what you are thinking of as a faster gear.

For example, I used to ride 42/17 SS and it was too slow (66.7 gear inches) for cruising, so these days I’m running 42/16 (70.9 gear inches).

I have nothing against odd numbers, but I suspect 42/15 (75.6 gear inches) would be a bit too much up the hills, at least at present.

Otto

70sSanO

If even tooth is better, then I’ve hit the mother load.

Went from 13-15-17... to 14-16-18-20-24-28-34 with 30-38-48 chainrings.

My only concern is the crank is a triple.

John

pdlamb

Oops, you're right.

canklecat

Probably depends on your chainrings. This gear calculator gives a visual guide to how minor changes in chainrings and cogs can affect the perceived steps across the gear range.

I'm picky about gear steps so when I plan to tackle a long ride with more climbing on my old school 7-speed bike I may swap small chainrings from 42 to 39 or 38. But I have to coordinate it with with freewheel or cassette as well, because the gear steps are very different between my usual 13-28 freewheel, and my other rear wheel with freehub and 12-28 cassette. The problem usually isn't the smaller cogs, which tend to be closely spaced, but the bigger cogs for climbing. A 24 to 28 cog jump can be really awkward and there are a couple of Shimano freewheels and cassettes I won't use anymore because of the awkward steps. I prefer the steps of some SunRace freewheels, and SunRace and MicroShift cassettes. Probably wouldn't matter so much if I upgraded to 10 speed but I still use old school stuff on my old steel bike.

Also I can't use any freewheel or cassette that has a 14T smallest cog on my '89 Ironman. It'll cause the chain to rub the drive side chainstay. The smallest cog needs to be 13 teeth or fewer. Just a quirk of that bike design, which was designed for 1980s era triathlon time trials. I suppose they figured anyone who needed a 14T smallest cog should be riding a different bike.

c_m_shooter

I can't count them once the pedals start turning, so I have no idea.

JohnDThompson 

Yes, a prime number chainring will always result in skid patches equal to the number of teeth on the rear sprocket. But it seems many modern cranks only offer even number tooth count rings.

N.B. I have several vintage 144mm BCD 47 tooth rings in my stash…

crankholio

Not with that attitude.

ofajen

I’ve noticed that trend toward even number chainring count. That’s ok on geared bikes I suppose but for SS/FG it’s nice to have more selection. For instance, if I want something a bit higher than my 42/16, I’d like to be able to try 43/16 as well as 42/15.

Otto

Reynolds 

If I had to choose a single all around gear for flat terrain, it would be 42/16.

brunes83

I'm not sure why having an even number of teeth as opposed to an odd number would matter. I understand that more teeth is generally easier. But having a cog with 11-13-15-17-etc. shouldn't really be different than a cog with 10-12-14-16- etc. except where the last gears on the ends will have one extra/less tooth and that could make a slight difference I supposed.