cassette gear increments

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mig
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cassette gear increments

Postby mig » 15 Mar 2019, 1:31pm

following on from a couple of comments in another thread re. teeth differences in cassettes.

which is more commonly done?

1. changing gear to maintain a preferred pedal cadence.
2. changing gear to speed up/'slow down' (accept a lower speed in given circumstances.)

when i ride gears i change to increase my speed. hence i want a noticeable change of ratio and don't like changing by only 1T. i find it over fussy. i then pedal that higher gear a bit more quickly too.

is that unusual?

*i ride mostly on the flat (ish.)

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foxyrider
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Re: cassette gear increments

Postby foxyrider » 15 Mar 2019, 2:36pm

Yes
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!

Bmblbzzz
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Re: cassette gear increments

Postby Bmblbzzz » 15 Mar 2019, 2:49pm

Do you mean changing gear in order to change road speed or to change cadence?

tatanab
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Re: cassette gear increments

Postby tatanab » 15 Mar 2019, 2:51pm

None of the above.
I like to ride at a fairly constant power input, which probably does not work when climbing. To speed up, pedal faster then change up not change gear first then force the pedals round. Having grown up with only 5 gears at the rear and consequentially large jumps between ratios, I appreciate the extra gears closer together.

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Mick F
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Re: cassette gear increments

Postby Mick F » 15 Mar 2019, 4:49pm

Wot he said.

I pedal at the same power ............. or weight pressing down.
More gears next to each other the better, as far as I'm concerned.

They are called "speeds" as in 8sp or 9sp or 10sp etc. Back in the old days, we had 3sp or 4sp or 5sp.
Mick F. Cornwall

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Oceanic
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Re: cassette gear increments

Postby Oceanic » 15 Mar 2019, 4:59pm

'There is a question of gearing in a performance machine, and now it is possible to have 30 or more gears. Personally I dislike so many gears, since it often takes several clicks to get the gear I actually want, and the more cogs there are on the rear cassette, the more clicking I have to do'

- Graeme Obree (The Obree Way 2018)

BigG
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Re: cassette gear increments

Postby BigG » 15 Mar 2019, 5:42pm

I agree theoretically at least with MickF and try to keep to a constant power input (constant cadence and constant pedal pressure}. However, it feels more natural to me to use a greater pedal pressure when climbing together with, if necessary, a slower cadence. This has the (unintentional) advantage of allowing much wider gear gaps to be used comfortably. For me, any gap less than 10% is not worth the bother and gaps of 13-14% (two teeth) in the most used range is fine. At the bottom end of the gear range when the basic ability to keep riding begins to override any performance considerations, even larger gaps of about 20% are (again for me) quite acceptable.

tatanab
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Re: cassette gear increments

Postby tatanab » 15 Mar 2019, 9:14pm

BigG wrote: However, it feels more natural to me to use a greater pedal pressure when climbing together with, if necessary, a slower cadence.
Agreed, it is my experience too which is why I noted that constant power may not work when climbing - for me at any rate. In the racing world this is a reason that Chris Boardman was difficult to ride with in team timetrials. He really did ride at constant power which meant he slowed going uphill while the rest of the team applied the pressure, and while they used descents to recover he was powering away from them.

For me, any gap less than 10% is not worth the bother and gaps of 13-14% (two teeth) in the most used range is fine. At the bottom end of the gear range when the basic ability to keep riding begins to override any performance considerations, even larger gaps of about 20% are (again for me) quite acceptable.
With a modern plethora of sprockets (10) I use 7-8% difference between gears, with 8 speed a bit more than that. I used to think in terms of gear inches between gears and kept about 10" or so ( a relic of my old 5 speed riding) until I went touring in the Pyrenees with a bottom gear of 24" and a next of 32" - only 8" so works for me I thought. The problem was that at times I could not change up from that 24" inch gear because the percentage change to the 32 was simply too great. I learned to keep gears closer together at the lower end too.

Another nice (for me) thing about having close gearing is that in normal use I might use a particular sprocket, but loaded with camping kit I want something just a little smaller - a one tooth difference in my cruising range gears.

drossall
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Re: cassette gear increments

Postby drossall » 15 Mar 2019, 9:54pm

I'm not sure that there's quite the distinction that the OP is assuming. It's not such a good idea to change gear first and then speed up, because accelerating in a higher gear is harder. In reality though, if you want to go faster, you'll have to pedal faster, unless you change up gears. Generally, you'll pedal a bit faster, and then change up so that you can keep increasing speed without pedalling at an uncomfortable rate.

It's not a matter of pedalling at a fixed rate of course. You're trying to keep pedalling within a range of speeds, and changing to avoid going outside that. What may happen is that some fitter riders pedal faster than average, and are aiming for a narrower range of cadences, so prefer closer ratios. In fact, I'm not fit, but I still like close ratios on the flat, perhaps remembering days gone by when I used them racing. But I'm happy to sacrifice them for wider ratios when riding in the hills, as it's a long time since I could just storm up them.

mattsccm
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Re: cassette gear increments

Postby mattsccm » 15 Mar 2019, 10:47pm

I for one like small gaps. For this reason I don't like the current trend for a single ring on so called gravel bikes . I can live with it on a TT bike where the cassette is straight through.
In fact I wish that the 1 tooth gap existed in the little gears. A subtle change is often wanted when flogging up hill but a bit of a jump isn't important when dropping like a stone. I know that 1 tooth has a greater proportion at the high end of the cassette but it would still be nice not to have 3 teeth changes up around the 28t sprocket at times.

drossall
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Re: cassette gear increments

Postby drossall » 16 Mar 2019, 8:11am

I certainly notice it on my Brompton. It's a six-speed, which is more than average, but a bit more complex than above (three-speed hub by two-speed derailleur). Regardless, and even though it's better geared than most Bromptons, the jump from four to five, which are my most-used, is just that bit wider than I'd like.

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Mick F
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Re: cassette gear increments

Postby Mick F » 16 Mar 2019, 9:02am

I know it's not possible, but imagine a gearbox on a bike with an infinite gear variation (between the top and bottom limits of course).
Would you want one?

I would.
Mick F. Cornwall

tatanab
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Re: cassette gear increments

Postby tatanab » 16 Mar 2019, 9:19am

^^^ There is one. A few years ago NuVinci came up with a hub that did this. Middleburn proposed mounting the device around the bottom bracket to keep weight central and reduce clutter at the rear wheel of an MTB. There were magazine tests at the time. https://road.cc/content/feature/5664-nu ... s-you-need

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Mick F
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Re: cassette gear increments

Postby Mick F » 16 Mar 2019, 9:29am

Yes, I'd forgotten about that one.
It's not a wide enough ratio though. Maybe it could be amplified by using two chainrings, but that's defeating the object.
Mick F. Cornwall

willem jongman
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Re: cassette gear increments

Postby willem jongman » 16 Mar 2019, 9:32am

Infinitely small steps gearing does exist: it is called the Nuvinci system. However, the downside is significantly larger internal friction.
In my experience the optimum depends a lot on the situation. Riding with luggage in a hilly environment you do not only want a wide enough range (and hence inevitably somewhat larger steps between gears) but you also want to be able to shift quickly to a very different gearing ratio. Quickly shifting through half a dozen gears is pretty awkward. For loaded touring in hilly terrain I like the 13% difference between gears on my Rohloff hub. 13% is not too big for that application, and with one turn of the shifter I can shift about three or four gears in one movement, which is usually enough.
Here in the flat Netherlands the steps could be smaller, particularly on a faster bike without luggage. For that use a super compact double like the Sunxcd cranks with e.g. 28-42 is ideal in my experience. You can have quite small steps on the cassette, and only shift from the large to the small front chainwheel when you encounter a hill. Conversely, once you have crested the hill you can change to the large chainwheel at the front for a big change in gearing.
Last edited by willem jongman on 16 Mar 2019, 10:45am, edited 2 times in total.