Compact Chainsets & Road Bikes

Dave Larrington

David E. Belcher wrote:
> Pete Biggs wrote:
>> Helen Deborah Vecht wrote:
>>
>>> Remember, compact chainsets will wear *much* faster than larger
>>> ones.
>>
>> Not tooooo much faster if using only slightly smaller rings, say
>> 50/36 v 52/39. Even those few teeth make a nice difference to the
>> gearing.
>>
>
> I've not had any excessive wear problems using a 46/36 combo for
> cyclo-cross (as against most people's 48/38 or 48/39), and said
> chainset has run the same rings for nearly 3 years. It also enables me
> to use a rear cassette with a 23T or 24T max sprocket, which are much
> easier to come by than wide-ratio stuff in the Campag 8sp format my
> rear wheel uses, without being too highly geared for off-roading.

I used 42/28 for /years/ without undue wear prombles.

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
World Domination?
Just find a world that's into that kind of thing, then chain to the
floor and walk up and down on it in high heels. (Mr. Sunshine)

Pete Biggs

jtaylor wrote:

>> But they wear the knees out slower..
>
> Now just exactly HOW do you get this?
>
> Your knees don't know or care what size of ring is between them and
> the road. The only factors that affect them are load, range of
> motion, & frequency (with an asterisk should you have lever-drive or
> non-circular rings).

Knees can suffer if you're over-geared and trying to climb quickly.
There's only so low you can go without a compact or triple chainset.

~PB

David Martin

On 14/12/04 3:16 pm, in article OuDvd.86301$vO1.502798@nnrp1.uunet.ca,
"jtaylor" <jtaylor@deletethis.hfx.andara.com> wrote:

>
> "David Martin" <d.m.a.martin@dundee.ac.uk> wrote in message
> news:BDE4ABF6.5AF9%d.m.a.martin@dundee.ac.uk...
>> On 14/12/04 2:16 pm, in article 313030303736393541BEF5D311@zetnet.co.uk,
>> "Helen Deborah Vecht" <helenvecht@zetnet.co.uk> wrote:
>>
>>> Remember, compact chainsets will wear *much* faster than larger ones.
>>>
>>> Fine if you want disposable equipment :-(
>>
>> But they wear the knees out slower..
>>
>
> Now just exactly HOW do you get this?
>
> Your knees don't know or care what size of ring is between them and the
> road. The only factors that affect them are load, range of motion, &
> frequency (with an asterisk should you have lever-drive or non-circular
> rings).

And load is determined by gearing, hilliness and weight. As I am definitely
over weight, and Dundee environs could be regarded as over hilly, being
overgeared is a bad thing. I frequently use my lowest gear on the road bike
(39x26) and really could do with something a bit easier for the steeper
hills. I never use the top gears (52x12,13) and rarely the 52x14, even when
doing a TT.

> Or are the type of person who believes marketing blather?

Me? Gullible? really?

...d

Richard Goodman

"Dave Larrington" <smert.spamionam@privacy.net> wrote in message
news:328icgF3cohl4U1@individual.net...
> I used 42/28 for /years/ without undue wear prombles.
>

Well mtb'ers will use something like 44/32/22 for years without prombles. A
standard road triple could be something like 52/42/30 and you won't
necessarily see the middle and inner rings rapidly wearing out just because
of their size (my middle will probably wear before the other two but that's
because I tend to stay in it nearly all the time!) I don't really think you
can say compact chainsets are necessarily going to wear _much_ quicker than
bigger rings. I think that once I start training for a certain seriously
hilly ride I shall quite happily wimp out into a 48/36/26! I think
excessive wear on the chainrings will be the least of my problems!

Rich

Arthur Clune

Helen Deborah Vecht <helenvecht@zetnet.co.uk> wrote:

: Remember, compact chainsets will wear *much* faster than larger ones.

Really? Why?

I run either 34/48 or 38/48 depending. Most of the time I stay in the
48. By your argument (smaller rings wear quicker) things will last
longer than if I used a 32/42/52 triple or similar.

Arthur


--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
It is better to light a candle than to curse the darkness

Helen Deborah Vecht

"jtaylor" <jtaylor@deletethis.hfx.andara.com>typed


> Or are the type of person who believes marketing blather?

Just the reverse.

Engineer friends tell me smaller curvature radii and more frequent chain
cycles wear components more rapidly.

--
Helen D. Vecht: helenvecht@zetnet.co.uk
Edgware.

Pete Biggs

Helen Deborah Vecht wrote:
> "jtaylor" <jtaylor@deletethis.hfx.andara.com>typed
>
>> Or are the type of person who believes marketing blather?
>
> Just the reverse.
>
> Engineer friends tell me smaller curvature radii and more frequent
> chain cycles wear components more rapidly.

That's right but it seems like you're comparing big "road" chainsets with
MTB compact chainsets with diddy rings. The new breed of "compact" road
chainsets aren't really all that compact. Any slight difference in wear
won't be enough to worry about.

~PB

jtaylor

"Helen Deborah Vecht" <helenvecht@zetnet.co.uk> wrote in message
news:313030303736393541C03A7227@zetnet.co.uk...
> "jtaylor" <jtaylor@deletethis.hfx.andara.com>typed
>
>
> > Or are the type of person who believes marketing blather?
>
> Just the reverse.
>
> Engineer friends tell me smaller curvature radii and more frequent chain
> cycles wear components more rapidly.

True, but
a) by far the greatest causes of chain and cog wear are poor cleaning and
lubrication
b) the modern fad of rear clusters greater than 5 cogs has meant a thinning
of the cogs, and so they and the chain wear faster
c) you should re-read the thread; the poster to whom I replied stated that
a "compact drive" would put less stress on his _knees_.

A bit of a non-starter, seeing as for donkey's years you have been able to
get 26-tooth front chainrings on a bike, cheaply, and with good quality
components. That and a 28 or 32 on the back will see most people up most
hills. This "compact drive" is indeed marketing speak.

David Martin

On 16/12/04 3:02 pm, in article euhwd.86410$vO1.503847@nnrp1.uunet.ca,
"jtaylor" <jtaylor@deletethis.hfx.andara.com> wrote:


> A bit of a non-starter, seeing as for donkey's years you have been able to
> get 26-tooth front chainrings on a bike, cheaply, and with good quality
> components. That and a 28 or 32 on the back will see most people up most
> hills. This "compact drive" is indeed marketing speak.

It is indeed a marketing term for a practical solution. If I wanted to
change my current road bike chainset it would be for a 'compact drive'. Why?
Because it gives me the gears I want to use in a simple package that doesn't
require a new front changer, levers etc.

The major factor is cost. I like short cranks so the cheapest I can find
good quality components will still set me back in excess of 100 GBP to do
the conversion. But it will give me gears that can go on my current set up
(Sante rear derraileur and 7sp uniglide) and won't break my knees as the
gradient hits single figures.

...d