If Rotor Uno can do it, why can't Shimano or SRAM!

[NetworkMan]

Concentrating the close ratios at the high end may make sense (though this Rotor example is pretty extreme) because drag varies with the square of the speed. That means significant changes of power output cause only small differences in speed when already going fast. So you want closer ratios there to match your desired level of exertion to a comfortable cadence.

When climbing, power and speed have a more linear relationship. So wider ratios still allow close matching of effort to cadence.

An exception is racing when climbing must be done at the pace of the group, i.e. you may be on the limit at whatever speed is dictated. Then you may want close ratios even at low speeds. Another exception is headwinds.

If I were Mr. Shimano I'd imagine I'd keep more people happy more of the time with a uniform geometric progression and bye and large that's what they do I think. The headwind effect I've certainly encountered which of course is more non-linear than the climbing effect.

[Samuel D]

It depends how steep the hill is or equally, how small the inner chainring is. On a 30t inner (E.G. a Dura-Ace 7800 triple had that) I can see how those last 3 sprockets at 23-27-32 would feel like they have big gaps, but on a 22t inner they wouldn't feel like as big of a jump.

I don’t follow the reasoning. The gap between 27T and 32T remains the same as a percentage whatever the chainring. Do you mean that a 22T chainring would obviate the need to ever use the gappy end of the cassette? If so that raises other doubts.

[Manc33]

I guess it is always the same percentages. What I meant was, if you're on a smaller chainring you are probably going up a hill steep enough that you want the next sprocket to be a bigger jump.

Where that Uno cassette starts spreading out more is exactly where you'd want it spreading out more.

All Shimano/SRAM have to do is make the thing, no one has to buy it, but I certainly would. Even at £280 people are buying the Uno cassette, perhaps not because of the ratio's though, the thing weighs nothing and seems to have no center to it at all - despite it being claimed to fit on a Shimano freehub.

It's because of them always splitting people into 2 camps of road and MTB that such a cassette doesn't exist IMO. Or maybe making one cassette that covers both flat roads and hills is beyond them, I dunno.

[Samuel D]

Campagnonlo’s choice of ratios for their two new 12-speed cassettes seems fairly sensible to me except for the 11T start, now inescapable across the industry unless you get the even sillier 10T:

11-12-13-14-15-16-17-19-21-23-26-29T
11-12-13-14-15-16-17-19-22-25-28-32T

What do you make of those, Manc33? Maybe there’s some Super Record in your future.

[NetworkMan]

I guess it is always the same percentages. What I meant was, if you're on a smaller chainring you are probably going up a hill steep enough that you want the next sprocket to be a bigger jump.

What about a 150 watt rider like me trying to ride into a 20-30 mph headwind, possibly up a hill?

[NetworkMan]

Campagnonlo’s choice of ratios for their two new 12-speed cassettes seems fairly sensible to me except for the 11T start, now inescapable across the industry unless you get the even sillier 10T:

11-12-13-14-15-16-17-19-21-23-26-29T
11-12-13-14-15-16-17-19-22-25-28-32T

What do you make of those, Manc33? Maybe there’s some Super Record in your future.

Any chance of getting rid if those stupid 10T, 11T and 12T inefficient cogs has now gone; they have to be there to justify the existence of 10?, 11 and 12 speed cassettes.

[peetee]

I do wonder how many punters have 'upgraded' from 8 to 9, 9 to 10, or 10 to 11 (or all of these) in search of that elusive 'perfect' cruising or climbing ratio only to find it's not available regardless of which cassette or crankset they use.

[bgnukem]

For me, loads of one-tooth gaps towards the top of the cassette are a waste of time and I just find myself double-shifting to get a worthwhile increase or reduction in the gearing.

I use 12-14-16-18-21-24-28 on all my bikes and just vary the chainring sizes to get the range of gearing I need, with a triple chainset (Oh, how unfashionable!). Only use 7 sprockets regardless of the number of 'speeds' to try to obtain a decent chainline.

Perfect ratios are in the eye of the beholder....

[peetee]

I use 12-14-16-18-21-24-28 on all my bikes and just vary the chainring sizes to get the range of gearing I need, with a triple chainset (Oh, how unfashionable!). Only use 7 sprockets regardless of the number of 'speeds' to try to obtain a decent chainline..

I am still using this on my mountain bike along with 24/38/46 chainrings. It's only just seeing some proper action again after, ooh, 15 years or so lying idle. I am far from the rider I used to be but having given it a couple of difficult rides recently I have to say it doesn't feel lacking in any way.
I, on the other hand...

[roubaixtuesday]

11T sprockets are great for fun on a high speed descent, or if you want to apply a little power on a slower descent without spinning.

Not essential, but on a compact double I'd keep the 11T rather than a 32T any day.

[The utility cyclist]

Concentrating the close ratios at the high end may make sense (though this Rotor example is pretty extreme) because drag varies with the square of the speed. That means significant changes of power output cause only small differences in speed when already going fast. So you want closer ratios there to match your desired level of exertion to a comfortable cadence.

When climbing, power and speed have a more linear relationship. So wider ratios still allow close matching of effort to cadence.

An exception is racing when climbing must be done at the pace of the group, i.e. you may be on the limit at whatever speed is dictated. Then you may want close ratios even at low speeds. Another exception is headwinds.

This is why the Aqua Blue team hated the 1x system they were riding and did relatively poorly comparatively speaking to their previous year, the team ditched it at season end as a 'bad un'

Even so I still don't want too big a jump when in the lower gears because you're often exerting yourself or in the lower gears because you're really fatigued (at the end of a ride where the same bit of route would be a much higher gear if you were fresh), if you're touring with a load not having the bigger jumps in the lower gears is also important IMO, particularly when you're transitioning from gradients both up and down so that you can keep in your sweet spot cadence wise, too big a jump in the lower gears when you might be struggling and/or with a load and that can make things even harder.
This is why the triple road drive-train is so important IMO as well as the original question as to why Shimano et al can't fathom that most people need easier/more logical ratios in the cassettes than they currently produce (and have done so for decades). 1x particularly is just illogical all round as a 'solution', dinner plate cassettes and rear derailleurs that look like something out of a science fiction film really don't do it for me at all, even 2x has its limitations even with the 'sub' compact. A 28/36 combo is just slightly lower than 24/30, there's a significant difference in the ratio jumps at the lower end between a 36T and a 30T low end cassette.

I wouldn't mind this on a 12 speed, 11/12/13/14/15/16/17-19-21-24-27-30, if it was a purely touring/audax rig with steep/lots of climbing I'd be fine with 52/39/24

[bgnukem]

Having just spent a week riding a Pinarello around the mountains of Spain with the obligatory 50/34 chainset and 12-28 cassette I would have killed for a triple.

Hills were a slog, massive difference between rings meant changing up at the front almost invariably meant changing down at the rear, and top gear was still pretty low for the long descents while hours were spent slogging up hills in a bottom gear which was way too high for anything steeper than about 8% (especially in 30°C+), and a lousy chainline to boot!

What was ever wrong with triple chainrings!!??

[peetee]

Having just spent a week riding a Pinarello around the mountains of Spain with the obligatory 50/34 chainset and 12-28 cassette I would have killed for a triple.

Hills were a slog, massive difference between rings meant changing up at the front almost invariably meant changing down at the rear, and top gear was still pretty low for the long descents while hours were spent slogging up hills in a bottom gear which was way too high for anything steeper than about 8% (especially in 30°C+), and a lousy chainline to boot!

What was ever wrong with triple chainrings!!??

The pro's don't use them. That might not gel with our educated, experienced, impartial take on cycling kit but for the majority of punters image is a big consideration.
Most of them believe steel frames are old hat too. But, as a memorable narrator would say, that's another story.

hammygpshouse_grande.jpg (17.69 KiB) Viewed 309 times

[Manc33]

11-12-13-14-15-16-17-19-22-25-28-32T
What do you make of those, Manc33? Maybe there’s some Super Record in your future.

Bliss.

Having just spent a week riding a Pinarello around the mountains of Spain with the obligatory 50/34 chainset and 12-28 cassette I would have killed for a triple.

Hills were a slog, massive difference between rings meant changing up at the front almost invariably meant changing down at the rear, and top gear was still pretty low for the long descents while hours were spent slogging up hills in a bottom gear which was way too high for anything steeper than about 8% (especially in 30°C+), and a lousy chainline to boot!

What was ever wrong with triple chainrings!!??

I couldn't agree more. The first road bike I got had a triple with a 30t inner and 25t low sprocket. I rode it to the foot of Snake Pass and didn't get much further than the pub on the left just before the hill starts (Glossop side) before realising there's no chance I am going to get up it. I ended up turning around soon after.

Then, I spent ages trying all different chainring and cassette combinations. The best setup I managed on that bike that seemed to cover absolutely everything was a 52-38-24 triple with a 11-32t cassette (on 9-speed). For even lower gearing there's 34t and 36t cassettes too but the inner chainring can't go smaller than 24t.

Indeed why not have a triple, here's a thought - pretend the inner isn't there and you have a double, right?

What's the weight of an aluminium 24th inner anyway, hardly anything. The only other issue might be that the rear mech can't cope with the overall capacity but thats just a case of remembering not to use the smaller half of the cassette on the inner chainring. Are people scared of getting laughed at with an inner, really sheesh.

[The utility cyclist]

Well you can go smaller than a 24 but you'd need a different chainset than the std 110/74 bcd, I think current MTB chainsets go down to a 22, you used to be able to get the smaller 94/58mm BCD chainsets some years back that went down to a 20, I had bought the chainring but never did get around to buying the chainset and finding nice ones is very hard and they usually come up fairly spendy.
There's an average condition Middleburn crankset on fleabay for £130 but a complete chainset from an old Lava dome can be had for £30 and there's the odd one or two 20T ring on there too.

It's anther of those manufacturer led things, many people actually need a 20T inner, many people want nice smooth jumps between the ratios, most people don't want very expensive/very large cassette sprockets and needing an even bigger rear capacity RD, the manufacturers go with what costs them less to roduce and selling stuff at a higher price because there is little to no option to get the gearing you want and thus means coercing people into ever more gears to fill the voids between the sprockets.