cross-chaining - how much is too much?

[wle]

ok.

i have a plain vanilla road bike with 53-42 chain ring in
front and 7 speed, 26-13 cassette in the rear.

700c wheels.

i ran through mr sheldon brown;s gear calculator and
found out that there is overlap between 3 pairs of gears,
they are practically the same.

comes out like this..
[mph @ 100 rpm]
32.7 24.7
28.4 21.4
25.0 18.9
22.4 16.9
20.3 15.3
18.5 14.0
16.4 12.4

if the speed i want is between 20 and 25 mph, no choice is good,
they all seem to involve too much cross chaining.

or is it?

should i only worry about going all the way across all 6[24.7 or 16.4]?
is 5 gears ok?
surely 4 would be ok?

how much is too much cross chaining?

i regularly do a '5 gear cross', small front ring and number 6 on the back.

but usually i steer clear of large front + 1-4 in the back.

wle.

 

[Booker C. Bense]

-----BEGIN PGP SIGNED MESSAGE-----

In article <[email protected]>,
wle <[email protected]> wrote:
>ok.
>
>i have a plain vanilla road bike with 53-42 chain ring in
> front and 7 speed, 26-13 cassette in the rear.
>
[snip]
>
>if the speed i want is between 20 and 25 mph, no choice is good,
> they all seem to involve too much cross chaining.
>
>or is it?
>
>should i only worry about going all the way across all 6[24.7 or 16.4]?
>is 5 gears ok?
>surely 4 would be ok?
>
>how much is too much cross chaining?

_ Nobody can answer this. I think even the most rabid
anti-crosser would allow 4 gears. People make a much
bigger deal of this than it really is. In general if
you have choice between two very similar gears, one
badly crossed and one straight, then you might want
to worry about it ( I don't ), however if it's the only
gear you have that matches your speed and revs use it.

>
>i regularly do a '5 gear cross', small front ring and number 6 on the back.
>
>but usually i steer clear of large front + 1-4 in the back.
>

_ Ride the gears that make you the most comfortable and regularly
measure your chain wear, if your chain lasts as long as anybody
else's then you're using the "right gears". In general,
small/small is the one you want to avoid more than big/big. And
heck even if your chain wears a bit faster than normal, so what.
The important thing is to check the chain regularly and replace
it before a stretched chain can damage the rest of your
drivetrain. Park makes a nifty little relatively cheap guage
to do this without even removing the chain from the bike.

_ Booker C. Bense

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[Peter]

Booker C. Bense wrote:
> In article <[email protected]>,
> wle <[email protected]> wrote:

>>if the speed i want is between 20 and 25 mph, no choice is good,
>>they all seem to involve too much cross chaining.
....
>>how much is too much cross chaining?
>
>
> _ Nobody can answer this. I think even the most rabid
> anti-crosser would allow 4 gears. People make a much
> bigger deal of this than it really is. In general if
> you have choice between two very similar gears, one
> badly crossed and one straight, then you might want
> to worry about it ( I don't ), however if it's the only
> gear you have that matches your speed and revs use it.

I agree. I tend to mainly use the large chainring
and frequently ride hills in the 52/30 combination even
though 39/23 would give about the same ratio with
a better chain angle.

But my chains last for 6-8 thousand miles, cassettes
for over 20 thousand, and over 100 thousand for
chain rings. That doesn't seem like excessively
fast wear compared to what I've heard from others
so it's not clear to me what harm I'm doing to the
drivetrain with a larger chain angle. Perhaps a
slight loss of efficiency, but I doubt if it's
enough to notice since I'm not riding competitively.