bdc1234

I own a 2005 LiteSpeed Saber with Dura-Ace and a FSA SLK Carbon crank (10 speed).
I have chain drag on my big crank ring when IM in my small crank ring and I use the small cog/cassette gear.
Iv been told by the LBS to avoid doing this because your stretcing your chain.
I say thats crazy all of my other bikes don't/didnt do this plus I want that gear selection without jumping to the big ring.
Example: when riding down a short hill with an up hill coming I want to take full advantage of the down without moving to my big ring up front so Ill stay small front and drop to the smallest in the rear, if I move to the big ring then its just a lot of extra shifting for no reason other than trying to avoid stretching my chain (who Cares if the chain stretches, Ill replace it!) plus I say the chain shouldn't rub against the big crank ring anyway. Does this make any sense? Ant thoughts on this?

Thanks for your time

Triguy

I've heard that its bad for chain/cog wear. I usually do shift in the front, but I have dropped my chain maybe once this year shifting up front.

I do believe the chain rubbing is inevitable. Two points connected by a strait line, the big chain ring intersects that line slightly, no two ways about it.

merlinextraligh

your other bikes may have the chain line adjusted just a little different, or you may have different sized chain rings on your other bikes. Regardless, the little/little combo is not preferred. You are getting more friction on the chain because of the angle, increasing wear, and because of the slack in the chain, a little more likely to have the chain fall off.

rknj

It puts a lot of stress on the drivetrain, and wastes a bit of energy to boot. It almost sounds like you should be looking further ahead and when you hit the midpoint in your cassette, change chainrings and shift your cassette to a gearing similar to what you'd be looking for if you just went linearly. I'll usually shift from small->big and drop down one or two depending on whether I'm going downhill or on a flat.

bdc1234

I just took a look at a friend bike with Dura-Ace cranks and all (10 speed) and he has zero drag from small ring to small cog. If the B.B. Spindle is just a bit longer making the cranks a bit wider than the drag would not exist as with his Dura-Ace cranks. I think the B.B. for the FSA SLK cranks is just a bit to narrow for the 10 speed cassette.

bdc1234

I hear what your saying but does your chain rub against your big crank ring when in your smallest cassette gear?

Gonzo Bob

Tri-bikes usually have shorter chain stays than road bikes and this means the chain deflection angle is slightly greater in the small-small combo leading to greater chance of chain rub. Also, the bigger the difference in your chain rings, the more likely you are to get some chain rub in small-small - e.g. a 53x42 combo might not rub but 53x39 might.

Some of my bikes get chain rub, others don't. In general, I stay out of small-small and big-big but like you, I may use them for short periods.

Jstyle

That is the only part that matters to me when it comes to cross training.