Future tech, could 12 spd solve the touring cassette problem

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reohn2
Posts: 45158
Joined: 26 Jun 2009, 8:21pm

Re: Future tech, could 12 spd solve the touring cassette pro

Post by reohn2 »

Tonyf33 wrote:
reohn2 wrote:Tony

But if electronic shifting were ultra reliable,cost effective(say run off long lasting AA batteries lasting six months or more) with shift buttons that could be placed anywhere on the handlebars,say in three positions per side,then I could be swayed.
We can all dream :wink:

Oh yes, flat bar/drop bar electronic triple shifting that is accessible from almost any hand position would be fantastic. Di2 packs (500maH) seem to get about 40-60 hours of use (And often much more) from those reporting it but a AA powered unit could be useful. With 500 charge/discharge cycles for Li-ion fairly common place that's about 20,000 cycling hours before your battery needs consideration for replacement.


The only obstacle being cost,one arm and one leg perhaps? :?
Quality stainless steel gear cables are £2.50,I don't think I'll be changing any time soon :wink:
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merseymouth
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Joined: 23 Jan 2011, 11:16am

Re: Future tech, could 12 spd solve the touring cassette pro

Post by merseymouth »

Hi there, Can we get this back to the realms of actuality, not drift off into cloud cuckoo land?
Speaking as a "Tricyclist" I am always having to create work arounds, as C & S only think Bicycle when creating components! Gearing is always an issue, with even a 13t smallest sprocket causing problems. In the past with Maillard blocks I could create a trike specific cluster, with a 15t or 16t top I could use standard chainsets. This would set the top jockey wheel in a nice position with the sprocket. This was necessary because the rear mech was not attached to a close rear drop-out, but bolted to an "L" shaped bracket which bolted onto a lamp boss brazed onto the axle case, which set it a fair bit lower thann as needed!
Sure my blocks were heavy, but I got a good change and the right ratio for trike needs.
With such blocks no longer available we have to create new work arounds using cassettes, which is getting much harder by the day.
Now I'm certain that some folk will offer the usual advice, (1) Learn To Ride A Bike (2) Learn To Ride A Bike! Second only of the list of all time greats after "Can You Ride Tandem"?
My response is "If it wasn't for tricyclist's you'd still be riding "High Wheelers"!
Why shouldn't I try to keep my brace of 1953 Higgins Trikes going? Using small sprockets means having to lower the gearing at the chain-set, which raises yet more issues with the front mech & the chain-stays! Catch 22.
You don't know the half of it! TTFN MM
reohn2
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Joined: 26 Jun 2009, 8:21pm

Re: Future tech, could 12 spd solve the touring cassette pro

Post by reohn2 »

MM
Has someone upset you?
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"All we are not stares back at what we are"
W H Auden
beardy
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Joined: 23 Feb 2010, 4:10pm

Re: Future tech, could 12 spd solve the touring cassette pro

Post by beardy »

I could use standard chainsets.


If by that you mean something like a 36-50 double then Shimano offered you an alternative with triples going down to 22 teeth on the inner ring and Campagnoloo offered triples that can get down to 24 teeth inner rings. Is this not enough?
Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Future tech, could 12 spd solve the touring cassette pro

Post by Brucey »

merseymouth wrote:Hi there, Can we get this back to the realms of actuality... In the past with Maillard blocks I could create a trike specific cluster, with a 15t or 16t top I could use standard chainsets. This would set the top jockey wheel in a nice position with the sprocket. This was necessary because the rear mech was not attached to a close rear drop-out, but bolted to an "L" shaped bracket which bolted onto a lamp boss brazed onto the axle case, which set it a fair bit lower thann as needed!


well there are always going to be older machines and machines that are not commonplace and keeping these going is often a challenge. But it is just engineering, when all is said and done.

First the bracket; I'd make a new one so that the mech was in a different place. Anyone competent with a welding set and a few bits and pieces (eg gear hanger off an old cheap mech) would be done in about an hour. That would let you use different sprockets/mech etc but it won't solve the gearing issue per se.

Second the gearing; here is a 16T top freewheel you can buy

http://www.sjscycles.co.uk/regina-synchro-90-6-speed-index-compatible-screw-on-freewheel-prod7095/

and of course there are loads of 14T up 5 and 6s freewheels available too. I can't believe that a 14T-up freewheel won't work for you; if you try a modern freewheel (even a cheap one like a sun-race) and chain I think you will be stunned at how good the shift quality is vs old-school maillard etc., even if they are not terribly durable.

In the long run perhaps a system that accepts cassette sprockets might be a better idea? At worst it might mean (say) a new/modified half-shaft to accept a suitable freehub body. With this system you will be able to make almost any cassette ratios you want. in addition to derallieur cassettes, you can fit modified 3-lug IGH sprockets to a cassette body and furthermore there are IGHs that use the cassette spline interface too, so one way or another I don't think you are going to be stuck for sprockets anytime soon.

As for 'reality', much as I like IGHs, etc the reality is that 90-something percent of club cyclists will be using a cassette hub of some kind with derailleur gears for the foreseeable future.

Whilst the prospect of a 12 sprocket cassette is here I think it is a stalking horse and that the real question at hand in this thread is 'for touring, how many sprockets do you need?'

cheers
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merseymouth
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Re: Future tech, could 12 spd solve the touring cassette pro

Post by merseymouth »

Hi Brucey :) , I enjoy your input. Trikes, yes we are very much a minority taste! Your suggestions are well known to me, the re-sited gear hanger was designed nearly 40 years ago, but it still puts the rear mech in the less than ideal position. Trykit make the best version yet. But even that reduces the wrap round of the chain, whereby 11t, 12t, 13t ain't up to the job! The suggested 16t - 21t 6speed block would be fine for time-trialing, but I'd have to walk up a lot of hills.
The suggested "Cassette Adapter" is also extant, again thanks to Trykit Conversions. But then we hit the silly sprocket issue ? The adapter uses a Shimano Freehub, which sits on a tapered carrier, I already have one trike running on that!
A side issue with many Higgins/Rogers trike frames is the small capacity of the axle cage. Many can only accept a 26t largest sprocket, my 53 Diff Higgins can only just cope with a 24t ! That is limiting! Fortunately that has a very narrow chain-stay arrangement so I can use a small ring chain-set without having too serious an issue with the front mech.
I did a lengthy piece about that issue on the on3wheels forum.
There is no real problem with my new trikes, the most recent runs Shimano 10s with a 15t - 25t cassette, coupled with a Raceface Triple Chain-set 42t - 32t- 24t, nice set of ratios to suit my needs. Two Wheel Drive with an ingenious Trykit drive System, and no, I'm not their paid spokesperson, merely a very satisfied customer! With the rear mech sited at the correct operating position, as on a bicycle drop-out, the change is slick & precise.
But the real problem is the take it or leave it attitude presented to the customer at Bicycle Obsessed dealers, it is a real learning curve for the specialists in the workshop. Getting wheels built can involve a two hour explanation? No bearings in the hubs stumps them :lol: . Well TTFN MM
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RickH
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Re: Future tech, could 12 spd solve the touring cassette pro

Post by RickH »

For those discussing the wisdom, or otherwise, of increasing numbers of gears I got a link to an article on BikeRadar in an email last week

Shimano XTR 12-speed Di2 and mechanical: What we want
"Features we'd like to see with Shimano XTR M9100 and Di2 M9150". :)

Rick.
Former member of the Cult of the Polystyrene Head Carbuncle.
bryce
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Re: Future tech, could 12 spd solve the touring cassette pro

Post by bryce »

It should be possible today to get very close using the Ultegra 11-32 tooth cassette and triple like 531Colin's. Reducing the inner chainring down to 20 teeth, would provide a slightly lower gear than Colin's. No gaps worse than the 14% going from 14 to 16 teeth with a range from 17 to 107 gear inches.

I don't know if the Athena triple rear derailleur will support a 32 tooth cassette but it manages very comfortably with a 12-30 tooth one, so it's very possible. With 20-32-44 chainrings, there's 45 tooth capacity which is only 2 teeth more than I'm currently running, small-small may be noisy.

The 11-32 11 speed cassette struck me as ideal for a general purpose touring cassette, it'll provide low gears, with a big enough range for all riding, and reasonably small gaps. With a triple, and a 32 tooth cassette there's more to gain by reducing the inner chain ring than getting a bigger cassette. For my riding the 10 speed 12-30 provides smaller gaps and is cheaper.

The 60% jump moving from 20 to 32 teeth chainrings might be a bit large, but the 50% jump I've got going from 26 to 39 is fine especially with Campagnolo shifters that allow multiple gear shifts in both directions. And they allow the use of Shimano mountain front derailleurs to support small chainrings.

To use more than 11 speeds well, the rear derailleur would need a larger capacity, so a longer cage.

For a dedicated tourer that is only used to tour the high end gears may be pointless, but it would let the bike function well for other uses without needing to change the cassette and the chain.
Brucey
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Re: Future tech, could 12 spd solve the touring cassette pro

Post by Brucey »

Interesting piece that Rick has linked to. IMHO the bloke that wrote it has suffered some major oversights and has written it from a particular perspective. For example;

1) it has clearly escaped his notice that a) it makes a difference which way round you calculate your gearshift percentages... and b) everyone else does it the other way round, i.e. they calculate the upshift percentage. So he's right there is a big gap between SRAM's 10T and 12T sprockets but what he calls (downshift) 20% most people would call (upshift)
16.7%, which doesn't sound quite so bad, does it?

2) having struggled to list more than three things that might go wrong with a boring old mechanical cable, he then claims that it must be a small movement (it doesn't have to be...) and that by contrast your electronic shift is going to be reliable because it is 'electrons in, electrons out'. Ho ho.... He either has no idea whatsoever about the true complexity of the gubbins that do the movement of the mech and monitors its position, or he is choosing to ignore these things.

3) The whole article is written from the perspective that the new things that SRAM and Shimano are producing do represent progress and are therefore inherently, unconditionally, improvements over previous equipment. Barring some discussion of gear ratios (which more or less dismisses the very notion of having more than one, leave alone more than two, chainrings) there is no real discussion regarding the real-world utility of the resultant system.

Implicit in all this somewhere is that 'the wishes of racers' must be the same thing as 'the needs of ordinary riders'. The same thing pervades most equipment development these days and is largely responsible for transforming the average bicycle from 'durable transport' to 'ephemeral plaything'.

The article is couched as if it is a plea from normal folk to help the big S make things that 'the people really want'. This is of course nonsense, a perverse inversion of his true mission; his whole industry of journalism is geared towards readjusting our wishes and expectations to match the stuff that the manufacturers churn out. In a weird symbiosis, they only make stuff that they think that they can sell and they need the journalists as 'pushers' to encourage the 'bike buying habit' in us, the 'users'.... If we stop wanting it and buying it, he and they are out of a job.

cheers
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BigG
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Re: Future tech, could 12 spd solve the touring cassette pro

Post by BigG »

The link referred to by Rick would be more practical if the 11 and 45 tooth sprockets were removed. A 10 speed from 13 to 40 would be interesting - and just within the range of a modern Deore XT or similar mech.. I run a 7 speed from 13 to 41 but need the option of half steps in the main range to avoid being caught "between gears" from time to time. Incidentally, I always thought that it was normal to measure the gap between a 10 and a 12 tooth sprocket as 20%. This is the increase in cadence required to maintain speed when changing down or the increase in speed caused by maintaining cadence when changing up. Am I in a minority of one here? My 7 speed cassette has 21% gaps on my calculation but only 17% as Brucey calculates it.
Brucey
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Re: Future tech, could 12 spd solve the touring cassette pro

Post by Brucey »

if you look at the specifications for gearing systems they are almost invariably given as 'upshift percentages' rather than 'downshift percentages'. So (for example) a Rohloff hub is said to have gears at 14% intervals, (rather than 12% intervals as it seems on downshifts) and the hub is said to have a range of 526%, i.e. 5.26 x the low gear ratio.

Actually thinking about it, I got my derailleur percentages the wrong way round there; in the link he was right after all in a way because between 10 and 12T it is an upshift %age of 20% and a downshift percentage of ~16%. It is because the sprocket reciprocal appears in the gear ratio formula. D'oh!

cheers
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