Cassette steps/gaps
 

Ever since SRAM overcame their inability to perfect front shifting by giving us the "1x" drivetrain, I've seen a proliferation of ridiculous cassettes out there. Things with large cogs that look like chainrings themselves.

The gaps between gears must be just cadence-shatteringly and knee-wrenchingly huge. At least as bad as my Alfine 8, which has its place for certain conditions, but the gaps alone prevent me from ever trying to employ it in the name of efficiency and speed.

Maybe I'm just old and old fashioned now, but it seems like there's been a big shift in the notion of proper, or even "ideal" cassette spacing. I've long felt that a bike with sub-10% gaps in back just smoothed everything out, and kept me efficient on the ride, to the point where I once put a triple on a bike just so I could really tighten up the cassette, and not to deal with hills, but with howling winds.

What do the BF masses now consider acceptable for gaps in this new drivetrain age? And yes, I realize that rider preference and riding conditions are widely varied, but we have a forum just to field these kinds of obscure discussions.

a straight block freewheel or cassette has cogs increasing in size by 1 tooth at a time. a straight line.
going lower the diameters increase in a parabolic curve, to have each gap bigger than the last

IGH have been engineered to increase as a % over the next smallest gear ratio,
so difference is less, closer together as you shift downward..

Basic Math is a weak subject, these days, it seems.

To tighten up the gaps at higher end on your IGH, add a second chainring 1/2 the % difference .

1 tooth steps isn't a straight line at all. If it forms a curve that gets steeper as the number of teeth gets fewer.

Basic math.

This would be a partial fix - Alfine 8 has very uneven gaps between gears.

+1. 52-42 with 13-14-15-16-17-19-21 is more than I need in flat terrain. In fact, a 39-49 would be enough.

I'm not a big fan of pie plate cassettes either, but have you actually looked at the gear ratio steps? When you have 11 sprockets to play with you can have fairly close ratios AND low gears:

11-32: 11,12,13,14,15,17,19,22,25,28,32

That's essentially a very close ratio 8 speed followed by 3 more cogs going all the way to a rather low 32.

Seems like you oldsters should be able to remember when your bike had a 14-17-20-24-28 (or even better, 14-17-21-26-32 like on our Schwinn Suburban) block on it and you just rode it happily. ;)

My memory isn't what it used to be... but I remember my first geared bike was a 3 speed 16-18-20 with a 48 in front, Super Champion derailleur. :50:

I put a couple thousand miles on a Shimano 11/42 this spring. Interesting cassette. Jumps are a bit large, but not killers.

IRD actually makes an 11 speed wide range cassette with smaller gaps for the smaller sprockets... at least adding the 12T back in.

https://store.interlocracing.com/bllica.html

I don't know if one really needs the 42T, but I've been experimenting with wide range and escape gearing for pulling cargo, and probably loaded touring.=

For unloaded riding, even climbing, I use a much more aggressive cassette, and prefer to stand a bit on hills.

To borrow the term from Di2, it is called synchronized shifting. Dump the FD and a multishift in the RD up--easy to do with Campag mechanical, or automatically on Di2.

I was daydreaming about an Alfine 11 Di2 drivetrain...then looked at the 13%-29% gaps in Alfine 11 and though....well maybe for 12 speed.

I don't even need a 42 on a MTB. Not even close to that. Who the hell needs that on a road bike?

Front and rear are different, although there are some people who advocate half step shifting on the front.

When one throws the front derailleur, one can often compensate with a double shift the rear to find one's optimum gearing.

For fietsbob: apparently both math and reading comprehension are in short supply these days, since this thread was not about the IGH, but the IGH was used as a comparison for some of the really super wide cassettes. It's also an apt comparison:

SRAM 11 speed 11-42: 18% 15% 13% 12% 16% 14% 12% 14% 13% 17%

Alfine 8: 24% 15% 17% 17% 22% 16% 14% (And, incidentally, those progressions are all over the place.)

Compared to,

Shimano 10 speed 12-25: 8% 8% 7% 7% 6% 12% 11% 10% 9%

Also, I'm not talking about straight 1 tooth progressions. As the cogs get larger, to keep the percentage jumps even you have to go to 2 tooth.

I think it depends on the usage. for MTB I am fine with wider gaps. Nothing I have seen put out there, even the 10-42 and 11-50 11 speed cassettes, have any gaps that concern me. In fact, I have always felt that up until now, mtb cassettes were too closely spaced, and I would have much preferred wider gaps and a wider overall range. IMO, 9 speed could have been offered in 11-42.

Riding pavement is a little different. I don't mind wider gaps at the very bottom and top, but around where I am usually cruising on flats or gentle hills, I want it tighter.

I am not sure about dirt and gravel roads. I have not tried a wide-spaced cassette there.

Why compare an 11-42 to a 12-25? You would also have to have radically different chainrings to get a comparable gear range. In this case, if you were comparing 1X drivetrain to a 2x with those cassettes, your 11x42 with a 50t chainwheel would be the equivalent of a 12-25 with a 53x30 crank. You can't even use a 50x30 crank.

Not talking about gear range here. We're talking about the gaps, and how people are achieving the ranges of double and triple cranks with massive gaps in the cassette.

Specifically, about the fact that gaps like that were once frowned upon, but now people are running pie-plate sized rear cogs everywhere.

The gaps have been cited, on multiple occasions, as a drawback in the Alfine 8. Yet, here we are with cassettes.

If one had a vintage 2x5 drivetrain compared to a modern 1x10 drivetrain, it would be pretty easy to create equivalent gearing. In fact, since the old 2x5 drivetrains were problematic for cross chaining, and had gearing overlap, the 1x10 would likely be better.

Well, you're probably right there. I'm not old enough for 2x5. I'm just old enough that the addition of more gears was seemingly always tilted towards narrowing the gaps while the range marginally increased, but still taking up most of the range work with the crank.

Now we've apparently given up on the advances in cranks and FDs. (Thanks, SRAM?)

Honestly though, with gaps that big, I'll just run an IGH if I'm looking for simplicity or cleanliness in a drivetrain. And since I'll only tolerate my IGH gaps for more casual riding...

Most of these are seen in the mountain and gravel side. Cadence jumps matter less and speed differences matter less when not in a paceline.

Well, that's a good perspective. I'm not really a MTB guy, so hadn't thought of that angle.

I did, however, see the ridiculous cassettes and 1x cranks on a recent "gravel" ride. Really silly there, in my opinion.

But you don't have to have gaps - they only occur when you have the most extreme gearing range. Which is how it always has been.

If you were to make apple to apple comparisons your outrage would likely subside.

Good one! :lol:
With the Nuvinci N380 and N330 you can have gapless, continuously variable ratio adjustments, and with their "Harmony" system you can even skip the shifting and never break your cadence...you just won't have the efficiency of a traditional gear and chain system.

FWIW, after 30 years of manual transmissions I bought my first CVT-automatic and love it. No matter what speed I set the cruise on, the engine drops to the lowest RPM possible. And unlike my wife's 5-speed automatic's sudden gear changes and gear hunts, my Rogue CVT merely "adjusts".

I would love to try a CVT bike...

Get a modern Vespa!

Oh wait... wrong kind of bike =)


New bicycle will have 32:36 max gearing... I may be able to tackle Indian Hill (10-12%) without my knees killing me.