"Bob Flumere" <
[email protected]> a écrit:
> It kind of boils down to this;
> Roadies want and need several close ratios in a narrow
> band to maintain a very rnarrow, specific cadence range
> at a nearly constant speed.
> (39-52/3 - 11/12-23 being a nice tight combo, and quite
> common).
> Gearing for road = Narrow range/lots of choices. (Narrow
> range of operating conditions - maintaining cadence
> important)
> Fine, I don't see any problem with that at all, but.........
> Mtn, (read typical trail type mtn riders) need only a few choices
> with an extremely broad range to deal with all types of terrain..
> Cadence, while entering into the picture is also spread over
> an extemely wide range when trail riding here in NE.
In your description of "roadies", you focus on one particular type of road
rider - the club rider or racer, or wannabe. The mtb equivalent would be the
lycra-wearing XC racer (or wannabe), who may well be riding fast, flat,
grassy courses for an hour or two at high speeds. There's a far greater
diversity of road riders, and of off-road riders than in the picture you
paint - the alpine cyclosportif with 48-34 and 12-27 or 13-29, for example,
or the transcontinental tourist, or the fixed wheel "fakenger".
I've ridden alpine (road) routes where two gears would have been sufficient:
40" up and 110" down.
I fully agree that cadence is far more variable for a typical off-road
rider, and shifting under load at low cadence is generally far more
important. I don't think that 1-tooth jumps are desirable off road, when it
makes far more sense to grab two 2-tooth gaps at a time than four 1-tooth
gaps, but I think that an 11-32 9-speed cassette is a very good combination
of wide range and moderate jumps. As for 10-speeds off road, I don't think
adding an extra gear in the current range makes much sense, but an 11-38
2x10 might not be out of the question. Losing the granny ring would reduce
the maximum chain tension if chain strength is an issue.
> For instance, on one of my own mtn bikes, I have had a 20t - 32t front
> with an 11-34 rear..
> (I've been told that it is impossible to stay upright with this low
> gear combination, but I guess I didn't listen <BG>)
> Have NO big ring at all, and have never gone fast enough (where I
> ride) to ever use or need the 32t 11t combo. I use a small
> bash ring on the outside position to get the added ground clearance
> which is worth many times the value of the non-existant, (unusable
> anyhow) "big" ring. <G>
>
> On another, I have 22t-32t-Bashring and 11-34.. same reasons as above,
> but the bike is a little lighter and I can "force it" up a steep
> banking or grade a little more easily..
In bumpy terrain, that's effectively what I'm riding, but the 42t comes
along for the flats, and riding to and from the trails. This isn't, by and
large, a hilly part of the world.
> Mountain Bike Action Mag recently did an article on converting
> back to 8 speed from 9. Shifting under dirty and adverse conditions
> was improved. Going back to seven would be even better from
> that standpoint.
I held out against 9-speed for a long time - until all my seven-speed
equipment was worn out, and 9-speed cassettes were available cheaply. I
don't think there's anything to choose between seven and eight in terms of
mud resistance. Nine may be a little fussier in the dirt, but there's not a
lot in it, in my opinion.
> Again a really big advantage off road. (Same range - fewer
> steps, and you'll never miss them - I defy anyone to even notice
> any difference in actual use except for the improved shifting in
> snow, ice, mud, etc.. )
That's what my Rohloff's for.
> Now let's look at the Single Speeders on my trails around
> here to tell us that the whole range of ANY riding conditions
> can be dealt with ONLY by cadence.. The extreme example
> of choiceless gearing.. Pick one, screw it on and go.
> I'm not one of them, however. <G>
I am.
Unless you gear very low, a typical singlespeeder spends more time pushing
or carrying than a typical geared rider. If you do gear very low, twiddling
along on flatter terrain quickly becomes tedious. I enjoy singlespeed a lot,
but there are climbs in the woods I ride in that I can't clean on any
singlespeed I'd care to ride out there.
> So you see, you really don't need any gearing choices at all unless
> dealing with a very specific situation, and the guy training on the SS
> will tell you that he is a better rider on his multi-speed bike
> because of it...
>
> Gearing is a very personal thing, and whether you have one speed or
> thirty, like to spin or have to grunt or need something other that
> what comes stock to ride the bike under conditions that it wasn't made
> for, like a mtn bike on pavement, or a road bike by a normal human
> being who would like think that he can push a 53 - 11 at 120 RPM but
> would be a lot happier with a 48 - 13 and a dose of reality.. <G>
>
> Bottom line.. gear it any way you like.. if you can't get it so you
> like it, you probably won't ride it as much as you should....
I have no argument with any of that.
James Thomson
