dachshund

I just bought a new road bike with a 105 groupset, the standard 11-32 and 50/34. I知 used to a triple, which my older bike has. When I知 in the middle ring of that bike I can use every one of the gears in back, with no friction or chain rubbing noises. The new bike is a 2016 Ruby sport.

With a compact double, if it痴 adjusted properly, where do I expect to lose gears? On the small ring, where does it usually top out? And ditto the large ring - what痴 the largest sprocket I can hope to use?

I知 a little concerned because my comfortable gear on the flats is in the friction noise / chain grinding sections of this bike. It needs adjusting already since the largest sprockets are causing friction noise with the small ring starting at the 4th from the largest.

I've done some searches and didn't happen to find this.
Thanks!
Amy

10 Wheels

Moved from road.

Guessing the Rear Derailleur needs adjusted.

RPK79

I use every gear on my 5700 equipped bike. I get a little noise in the two biggest gears when on the big ring. I ignore it.

corrado33

On my old compact double (105 2x10), I could get all but the last 2 gears without front derailleur rub (In each direction.) If yours is significantly different, the FD needs adjusted.

Remember, doubles have a "trim" feature that allows you do to a "half shift between the front chainrings." This will allow you to reach smaller cogs in the back when you're on each chainring respectively. Nicer double shifters will have 4 "gears." Two main gears and two trim locations. It's tricky to shift down from one of the trim locations without shifting chainrings, but you'll get used to it.

Really nice double shifters will have 2 main "gears" then infinite adjustability for the trim feature. (My old dura ace set has this.) My dura ace set also lets me reach all of the gears without rub.

joejack951

With a properly adjusted front derailleur and double crank, you should be able to use every cog in the cassette without the chain touching the front derailleur, assuming you trim appropriately. You may get chain rub on the big ring when using the small/small combo depending on the geometry of your bike, with shorter chainstays being worse for this.

chrisjur

There's a difference between a bit of chain rub and "grinding", as you describe it. So I'm wondering if your derailleurs just need a bit of tuning?

Also, I'm curious that your "comfortable" gear is in such an extreme location. You have a few gear combinations that overlap with that setup, so wondering if you just tried futzing around until you find a front/rear combo that has the same comfort effect for you?

Moving to this setup is different if you relied on 3 rings up front on the old bike, but I'm confident that after a bit of riding you'll find the gearing that works for you. If it's really a problem, perhaps a cassette swap is a cheap and simple option for you. But I wouldn't go that route until you're absolutely, 100% sure that you can't make this one work.

joejack951

That's the annoying thing about compact doubles. Depending on where you are comfortable, you could end up at a fairly extreme chain angle regardless of which chainring you pick. If someone likes a 50/21 combo, the comparable cog when using the 34T ring is a 14T. Neither yields a very straight chainline on a 12/25 cassette. On the other hand, with a 42T middle ring on a triple, you'd be dead center in the cassette (17T cog).

dachshund

Ah - I didn't realize Shimano had a trim feature. I had the LBS look at it last night and the mechanic believes everything's working fine. I'll take it out later today and check it out. On my triple, with a 42 middle ring + 17 in back puts me in a good gear for the flats. That combination hits this system several cogs from the end with either ring, if that makes sense.

Thanks for the suggestion, that was a big help!