Rings sprockets and clamp on mechs

[Andy Welch]

Here's one for a Friday afternoon.

When I were a lad a racing bike had two rings up front and five sprockets at the back. Now, many
years later, the number of sprockets has risen to 9 or 10 but still only two rings up front. So why
has there been rampant inflation in sprockets but none in chainrings? Comparing a 3x7 (say 30,40,50
with 12-18) setup with a 2x10 (say 39,53 with 12-23) the former would give one more gear but
wouldn't require a narrow (fragile) chain and would need less dish (so more strength) on the rear
wheel. Surely one chainring (pluss a few mm on the BB axle) can't weigh much more than 3 sprockets
and the total difference in teeth is pretty much the same (i.e. no need for a longer rear mech). So
what am I missing here?

While I'm in pondering mood, what do you do if you have a frame with no braze on for a front mech a
seat tube diameter of 35mm and you want to use a Campagnolo triple? As far as I can tell they don't
make a triple band on mech that big.

Cheers,

Andy

 

[W K]

<[email protected]> wrote in message news:[email protected]...
> Here's one for a Friday afternoon.
>
> When I were a lad a racing bike had two rings up front and five sprockets
at
> the back. Now, many years later, the number of sprockets has risen to 9 or 10 but still only two
> rings up front. So why has there been rampant inflation in sprockets but none in chainrings?

A very interesting question when put like that. Partly because real men don't have triple chainsets.

Will sprocket inflation ever stop? Am I a luddite for thinking 7 was OK?

 

[Marten Gerritse]

[email protected] wrote:

>
> While I'm in pondering mood, what do you do if you have a frame with no braze on for a front mech
> a seat tube diameter of 35mm and you want to use a Campagnolo triple? As far as I can tell they
> don't make a triple band on mech that big.
>

get a 35 mm clamp (sachs or shimano) to fit a braze-on mech. Or a different mech, Campagnolo
shifters are not fussy, in contrast to the opposition /Marten

 

[Pete Biggs]

[email protected] wrote:
> When I were a lad a racing bike had two rings up front and five sprockets at the back. Now, many
> years later, the number of sprockets has risen to 9 or 10 but still only two rings up front.

Triples are starting to get popular for road bikes as well - but with 9 & 10 sprockets!

> So why has there been rampant inflation in sprockets but none in chainrings? Comparing a 3x7 (say
> 30,40,50 with 12-18) setup with a 2x10 (say 39,53 with 12-23) the former would give one more gear
> but wouldn't require a narrow (fragile) chain

A 3x7 does not actually provide 21 gears, and a 2x10 not 20. Chainline (chain angle) problems means
you can't (or shouldn't) use all the gears. It's debatable and depends on particular bike exactly
how many each provides.

9 & 10sp chains are strong enough for the most powerful road sprinters in the world, and they only
wear out fractionally faster than 7-speeds.

> and would need less dish (so more strength) on the rear wheel.

Less dish would certainly help, but 130 & 135 wheels are still reasonably strong for general use
(and racing) when built well; and modern cassette hubs are strong - axle failures are rare.

> Surely one chainring (pluss a few mm on the BB axle) can't weigh much more than 3 sprockets and
> the total difference in teeth is pretty much the same (i.e. no need for a longer rear mech). So
> what am I missing here?

Triples setups are more expensive, more hassle to change gear (arguably), higher Q factor (feet
further apart), and they do tend to weigh a few more grams - so many people still don't like them.
(I do though!).

Having a load of sprockets at the back can provide plenty of closely spaced ratios - which one can
very rapidly shift up and down along. This is the key. Overlap, redundent and duplicated ratios,
etc, etc - is all virtually irrelevant when you have the luxury of a 9 or 10-speed block.

> While I'm in pondering mood, what do you do if you have a frame with no braze on for a front mech
> a seat tube diameter of 35mm and you want to use a Campagnolo triple? As far as I can tell they
> don't make a triple band on mech that big.

They do. See Campag catalogues and website.

~PB

 

[Pete Biggs]

W K wrote:
> Will sprocket inflation ever stop?

Looked like it wouldn't even pause for breath when the rumours of $himaNO going one louder were
coming out, but fortunately they've seen sense and will only match Campagnolo's 10 speeds. I do like
me gears, but 11 seems OTT even to me.

> Am I a luddite for thinking 7 was OK?

Yyyyyno. I can perfectly understand that 7 is enough (or more than enough) for cyclists who don't
want to keep changing gear all the time. I, on the other hand, am starting to dream up ways of
filling the gap between 17 and 19 in my 13-14-15-16-17-19-21-24-27 cassette (and that's with a
triple!). Is there no cure for me?

~PB

 

[Clive George]

"Pete Biggs" <pLime{remove_fruit}@biggs.tc> wrote in message
news:[email protected]...
> > Am I a luddite for thinking 7 was OK?
>
> Yyyyyno. I can perfectly understand that 7 is enough (or more than enough) for cyclists who don't
> want to keep changing gear all the time. I, on the other hand, am starting to dream up ways of
> filling the gap between 17 and 19 in my 13-14-15-16-17-19-21-24-27 cassette (and that's with a
> triple!). Is there no cure for me?

Easy - 12-18 or 13-19 in 7 with a triple (46-36-26 in my case) has no gaps and a sensible gear
progression (no interleaving). I regularly do a hill with an arrow on it, both up and down, which
shows a sensibly wide range.

cheers, clive

 

[Marc]

W K <[email protected]> wrote:

> Partly because real men don't have triple chainsets.

Oh! :-(

 

[Andy Welch]

On 21-Feb-2003, marten gerritsen <[email protected]> wrote:

> get a 35 mm clamp (sachs or shimano) to fit a braze-on mech. Or a different mech, Campagnolo
> shifters are not fussy, in contrast to the opposition

Doh. Should have thought of that one. The right lever isn't indexed is it, so of course you can use
any front mech.

Cheers,

Andy

 

[David E. Belche]

[email protected] wrote in message news:<[email protected]>...
> On 21-Feb-2003, marten gerritsen <[email protected]> wrote:
>
> > get a 35 mm clamp (sachs or shimano) to fit a braze-on mech. Or a different mech, Campagnolo
> > shifters are not fussy, in contrast to the opposition
>
> Doh. Should have thought of that one. The right lever isn't indexed is it, so of course you can
> use any front mech.
>

Right? Surely left lever - that's the one that takes care of the front mech. It's sort of indexed,
but on a very fine ratchet ("Micro-Index", as Sachs-Huret used to define it), which takes care of
pretty much any brand of mech and/or chainset, whether double or triple.

David E. Belcher

Dept. of Chemistry, University of York

 

[David E. Belche]

"Pete Biggs" <pLime{remove_fruit}@biggs.tc> wrote in message
news:<[email protected]>...
> W K wrote:
>
> > Am I a luddite for thinking 7 was OK?

Nope, it's just a pity that "market forces" seem to be restricting the options for people happy with
8 or less sprockets.

> Yyyyyno. I can perfectly understand that 7 is enough (or more than enough) for cyclists who don't
> want to keep changing gear all the time.

Or for 'cross riders who don't like their narrow-spaced 8/9 sp. blocks clogging up with mud :-( Oh
for a high quality 5 or 6-speed set-up with decent shifters
[1].....

David E. Belcher

Dept. of Chemistry, University of York

[2] Bit of a limited market, though, I guess - just like that other potentially handy bit of kit for
'cross, a top-pull double front mech.

 

[Pete Biggs]

[email protected] wrote:

>> get a 35 mm clamp (sachs or shimano) to fit a braze-on mech. Or a different mech, Campagnolo
>> shifters are not fussy, in contrast to the opposition
>
> Doh. Should have thought of that one. The right lever isn't indexed is it

(left) No.

>, so of course you can use any front mech.

That's right. Ergos will work with any front mech - but Campag do make band-on jobs for 35mm if you
fancy one.

~PB

 

[Andy Welch]

On 25-Feb-2003, [email protected] (David E. Belcher) wrote:

> Right? Surely left lever -

Blimey I'm on a roll at the moment. Can't even tell my left from my right now. Pity the poor
students who will have to endure me lecturing in a few hours time. That's if I can remember which
room I'm in?

Cheers,

Andy

 

[Jim King]

David E. Belcher wrote: <snip>>
> [1] Bit of a limited market, though, I guess - just like that other potentially handy bit of kit
> for 'cross, a top-pull double front mech.

How much difference is there between a double and triple mech? I can't see anything fundamental, so
why not just use a top-pull MTB triple? I guess you probably do already.
--
Jim King [email protected] Infineon Technologies UK Ltd. Swindon, U.K.

 

[David E. Belche]

Jim King <[email protected]> wrote in message news:<[email protected]>...
> David E. Belcher wrote: <snip>>
> > [1] Bit of a limited market, though, I guess - just like that other potentially handy bit of kit
> > for 'cross, a top-pull double front mech.
>
> How much difference is there between a double and triple mech? I can't see anything fundamental,
> so why not just use a top-pull MTB triple? I guess you probably do already.

I suppose so, provided the limit screws on a MTB triple are set carefully. As it happens, I actually
use an ordinary bottom-pull Campag Record mech - it's one of those 'cross frames where the top
tube-routed front gear cable goes round a little plastic pulley before ending up at the rear mech.
Trouble is, spare pulleys for my frame (built way back in '86 when I wasn't even in my teens yet; I
got it S/H 2 years ago) are probably like hens' teeth; the one fitted to it was made by now-defunct
Sturmey Archer [1]. Woe betide if the plastic eventually cracks :-(

David E. Belcher

Dept. of Chemistry, University of York

[1] I doubt if Sunrace have continued the production of such obscure odds 'n' sods as well as the
hub brakes and hub gears.