What Constitutes Cross-Chaining?

Paul Myron Hobson said:

Hey y'all...

You always hear, "don't ride in the big-big combo (or small-small)."
That makes perfect sense in every way. But it seems to me, that on a
modern 8/9/10 spd drive train, the big-second-biggest probably isn't
that great either.

Generally on my 9spd drivetrain, I avoid:
small chainring & smallest three cogs
big chainring & biggest two cogs

On my friend's 8spd triple, I suggested:
small chainring & smallest three cogs
middle chainring & biggest or smallest cogs
big chainring & biggest two cogs

Am I being overly (or insufficiently) paranoid here?

Thanks in advance,

\\paul

I don't think it makes any sense that one should need to avoid any
combos involving the middle ring on bike with good chainline (defining
"good" as either the middle ring lining up with the middle of the
cassette, or biased just a bit in either direction).

You can't really look at the question you're talking about without
taking into account how horrible the chainline is on all sorts of
modern bikes.

If chainline is good, then avoiding crossgears with the 2 largest/
smallest cogs probably does make sense. I'd be amazed if anyone had
real info about how much difference it makes. Also, it's relevant that
the chains that go along with 8/9/10 systems are more laterally
flexible than what came before.

I seem to remember in the book "The Dancing Chain" there was some
information explaining that the loss of efficiency due to chain bending was
nowhere as much as is generally thought.
My Tourer uses a 44/32/22 and a 8 speed 11/32. With this combination and a
long cage rear mech from Shimano's "Comfort" range all gear combinations are
available to me without massive inefficiency being noted whilst pedaling.
Chain line is spot on being (almost) dead straight when on middle front and
gear 4&5 at the rear.
So I still stand by my belief that ALL gears should be available to the
rider on a well executed derailleur set up.

Quoted message said:

You always hear, "don't ride in the big-big combo (or small-small)."
That makes perfect sense in every way. But it seems to me, that on a
modern 8/9/10 spd drive train, the big-second-biggest probably isn't
that great either.

For me, cross-chaining is when my drivetrain starts making more noise
than it normally should. By necessity*, my MTB is setup to 'warn' me
of cross-chaining. Chain rub on my FD plates (inner or outer) tells
me that I've gone too far.

* (using larger-than-normal chainrings and 'making-do' with my old
front/rear derailleur setup)

What is the net effect of cross-chaining? I'm certain that it
increases wear on the drivetrain...but probably not to a significant
extent. As far as efficiency goes, I can't notice a difference
(except for the noise). The only other thing I might be concerned
about is the additional lateral forces on the chain...then again,
shifting under load probably puts quite a bit more force on the chain
than cross-chaining.

Of course, because I haven't measured any of these forces and have
little experience with chain failures, this is pretty subjective
(i.e. it's all in my head). I hate noise in my drivetrain, so that's
enough to keep me from the 'evils' of cross-chaining. I also hate
noise in other people's drivetrain when not riding solo...I usually
tell them that their chain is gonna break if they keep cross-chaining,
just to avoid that terrible noise!! 🙂

Quoted message said:

Am I being overly (or insufficiently) paranoid here?

Yup.

Paul Myron Hobson said:

Hey y'all...

You always hear, "don't ride in the big-big combo (or small-small)."
That makes perfect sense in every way. But it seems to me, that on a
modern 8/9/10 spd drive train, the big-second-biggest probably isn't
that great either.

Generally on my 9spd drivetrain, I avoid:
small chainring & smallest three cogs
big chainring & biggest two cogs

On my friend's 8spd triple, I suggested:
small chainring & smallest three cogs
middle chainring & biggest or smallest cogs
big chainring & biggest two cogs

Am I being overly (or insufficiently) paranoid here?

Thanks in advance,

\\paul

Well, if the gear is set up correctly, nothing is going to explode,
you will just wear things out more quickly. Nothing 'wrong' with
starting your manual transmission car from a light in 2nd gear
either..just gonna need a clutch early.

Yer stuff, right it like you want.

Paul Myron Hobson said:

Hey y'all...

You always hear, "don't ride in the big-big combo (or small-small)."
That makes perfect sense in every way. But it seems to me, that on a
modern 8/9/10 spd drive train, the big-second-biggest probably isn't
that great either.

Quoted message said:

Am I being overly (or insufficiently) paranoid here?

Overly. For one thing, the biggest evil of cross-chaining is that,
horrors, things will wear out a little sooner. I might worry about
climbing a steep hill in the big-big combination, for fear it might want
to drop off the chainring, but on a steep hill I'd want to be in a lower
gear, anyway.

You certainly can avoid the gears you are talking about, since you have
equivalent ratios on the other chainring. You might want to think about
why that is so --- it has everything to do with history and tradition,
and nothing to do with the evils of cross-chaining. When, in days of
yore, we had 6 sprockets on a cluster, then a tight cluster and a 53/39
crankset gave 9 or 10 separate gears without the big-big or small-small.
Sometimes you would drop a chain with the big-big, and the chain would
rub the inside of the big ring in the small-small.

So, now we have 9 or 10 sprockets in the rear, but the same cranks. No
reason for that, except that is what we have, and they work well enough.
But that means a lot of duplicate gears. people come up with
rationales for why that is "better", but it really is inertia in the
design of the cranks. The big deal with compact cranks is that they
finally recognize, and use more effectively, what has become standard
for cassettes.

The thinner modern chains deal better with the wider angles than an
old-style chain would, so you can effectively use almost all of the
cassette on any chainring.

--

David L. Johnson

If all economists were laid end to end, they would not reach a
conclusion.
-- George Bernard Shaw

yeah. just went thru this act.
lined up the $11 nashbar triple, my first, with the rear wheel over
from the low end asian import I ride, mounted on the new Redline
Monodog for spindle length groking.
and found my Volvo 544 sensibilties stretched out dude
NOTHING LINES UP. CARHUMBA!
WORSER, the chain will (unless I get the much awaited chain guard on)
continuously run in grinding compuond. UGH UGH UGH
which is why the dirt folk need all those gears, right?
to pull the chain crossways thru the gringing compound. SHEEET!
As reported, 3 grams silica reduced the low end asian import 3 gears.
NOW WHAT? know the cartoons of the desert rat crawling to the coke
machine?

Paul Myron Hobson said:

Hey y'all...

....

Quoted message said:

Am I being overly (or insufficiently) paranoid here?

Most people just try to avoid extreme angles. It makes sense that it
would put a little more wear on the cassette and chainring as the angle
gets more acute.

Mike

Paul Myron Hobson said:

Hey y'all...

You always hear, "don't ride in the big-big combo (or small-small)."
That makes perfect sense in every way. But it seems to me, that on a
modern 8/9/10 spd drive train, the big-second-biggest probably isn't
that great either.

Generally on my 9spd drivetrain, I avoid:
small chainring & smallest three cogs
big chainring & biggest two cogs

On my friend's 8spd triple, I suggested:
small chainring & smallest three cogs
middle chainring & biggest or smallest cogs
big chainring & biggest two cogs

Am I being overly (or insufficiently) paranoid here?

Here is a picture of Cadel Evans in Spain last weekend:

http://i24.tinypic.com/2dv0al4.jpg

In spite of the blurring you can see he's in big/second biggest.

No wonder he lost his third place to Samuel "Sammy" Sanchez that day.