Road Cycling - Cross chaining

I have seen in several places that with a triple, I should probably not use the two far opposite sprockets with the outer and inner chain rings, and not use one at either end for the middle one.

That seemed reasonable enough on the face of it. [Though pondering the geometry makes me think
that perhaps you should forego more with the outer chain ring because of the extra angle produced due to the sheer size of it, the tautness in the chain, etc. Seems like 50x28 might create more stresses than 30x13.]

Just for grins today, I asked Campagnolo. Their response - while carefully saying that it was only a recommendation to save excess wear and tear, as if using them all might be OK - they said not to use the three opposite sprockets with the
inner and outer chain rings, but to use them all with the middle one.

I was not expecting that. Any practical experience here that says something else?

We are talking about a 30x40x50 with 13-28.

Thanks...Gary

Here's the deal, you want to keeep the chain riding as close to a right angle as possible to the cogs/chainrings, so the pressure is distributed evenly on the pins and bushings in the chain so they will wear evenly.
When the chain is placed at a severe angle, little to big/big to little combos, the sides of the link plates tend to rub on the sides of the cogs and chainrings.
When all we had were 5 speed freewheels, the advice was don't use the innner to outer combinations on the outer most cogs. When we started getting 7 and 8 speed cog sets it became the two outermost cogs because everything was getting wider and increasing the places where damage could occur. Now that we have 9 and 10 cog combos, the advice, is don't use the outer 3 on cross-overs. There is so much overlap/redundentcy in the gear selection from chainring to chainring, you really don't need to use the cross-over gears very much at all.

Ride Straight
Pat

Hi gmason,

I use a nine speed chain on a seven speed cassette. Works great and never get the chain rub noise.

Ride Safe....Dudley

AAAHHH great to be back *S*

I guess it was not the "don't use three" as much as the "use all of them" for the middle ring that surprised me. I will have to look at the actual geometry of the gears, but it seemed to me that you might not want to use the outer or inner sprocket with the middle ring either.

From what you have sauid, I should be able to hear/feel the interference with the side plates if there is any.

Thanks...Gary

There might not be obvious noise from the outer cogs when in the middle ring, but the chain will still be quite a bit crossed over. I can actually feel the extra friction from middle ring + largest cog. Manufacturers' recommendations seem to be dumb altogether - so I would ignore their advice on what gears to use!

Here's the gears I generally stick to with my 27sp system:

inner ring + rear cogs 1 to 4
middle + 2 to 8
big + 5 to 9

["1" = largest]


Ideal gears will depend on your own bike's chainline - bottom brackets (and other things) vary from bike to bike.