RedWhiteandRed

Hello -

I am returning to road cycling after a 20 year break - my last road bike was Dura Ace with a 5 speed cassette.

I am buying a Specialized Roubaix with the Ultegra parts. My LBS (there are actually about 30 bike stores within 10 miles of my house) is giving me a deal on the 2010 model and I am quite keen.

Which gears are useable with the "compact" crank? The bike will have the 50/34 on the front and I will stick a 12-25 cassette on the rear. Can you use the 34/12 - I know extreme cross gears are not recommended but what is the normal practice for riding?

Thanks for your advice and source of enthusiasm.

badhat

i dunno man i cannot imagine needing anything lower than a 50/34 with an 11/28 in the back.

DScott

Usually, cross-chaining is only an issue when in the two- or three-most extreme cogs. Even then it's doable, just annoying. With that crank/cassette combo, you have about 16 usable gear combos. These days, well-tuned derailleurs make front and rear shifting very efficient, so you have lots of choices on either chainring.

Pinyon

I would not go above 28 teeth on the largest cog in the back. That is standard issue on other Specialized bikes, like mine and other people that I know, so I also know for a fact that it works well.

If you are coming back after 20 years, you will be amazed at how fast you will get used to the increase in the number of gears you have. You will be shifting more often, and this often results in people not having to resort to the "bail out gear" as often.

You can also play with the gears to dial-in the gearing to the way you like it. I have a bad habit of staying on the big front cog a vast majority of the time. In fact, I only use the 34-tooth front cog when going up hills with 8% or greater slope. I have front and rear derailure tuned to shift and run smoothly on all gears when I'm on the big front cog. The trade-offs, are that the drivetrain is noisy on the hardest 3-4 gears when I'm on the small front cog, and that I have to switch-out my chain every 4000 miles or so.

Randochap

Cross-chaining isn't such an issue with doubles. Personally, I'd be asking if I had low enough useable gears.

You're in TO right? Not really BIG hills unless you go up into granite country where things can be pretty "rolling." 36" isn't a very low gear. Are you planning on ever carrying anything on the bike?

I use a triple w/ 30T inner ... 29T on cassette for lightly-loaded riding over extreme distances.

These thoughts on gearing for long-distance might be helpful.

Retro Grouch 

I doubt the 34/12 combination will work for you. The issue is that the chain tends to rub on the inside of the 50 chainring.

That's the gearing that I have on my Klein. Typically I use the 50 chainring almost all of the time and only shift into the 34 chainring for climbing hills.

Beaker

I wouldn't use your 34x12 except for brief downhill sections on a climb, normally max it at 34x13 or 34x14 for any reasonable period, but you should be in your 50T if you need that kind of gearing for any period.

As far as your 50T is concerned you should be able to tool around as much as you need in your 50x21, but I wouldn't use 50x23 very much and wouldn't touch the 50x25.

FWIW, I run a Shimano Ultegra SL 50/34 with an SRAM PG1070 11-26 on the back.

Eclectus

I rarely go to the 34 either. If you ride the 50 with your 25-27-28 rear cog, you may potentially have to replace your chain and cassette earlier. Or maybe not for the cassette, because if you downshift to your 34 ring in front, you're going to put more wear on your most-used smaller cogs in the back.

Having grown up when "10 speed" meant two rings in the front and five cogs in the back, I'd say, enjoy the new generation of equipment. Lots of lower gears for climbing not seen in the old 52-42, 13-21.

Barrettscv 

I would avoid the Big-Biggest and Small-Smallest combination. It will improve the life of the chain.

Michael

Dilberto

I ride 34/50 front and 11/21 back. My ideal combo is 50/15 on the flats.