Need Advice Concerning Gearing on Compact Double

[Cyclesome]

Love my Specialized Ruby Pro 2007. But need a few more "clicks" to get me up many of the hills I ride on in western PA. I seem to run out of gears climbing up hills. Thinking of changing out my compact double 50 - 34 with 12-27 for either an 11-28 or changing just the rear derailleur to a mountain bike one with a 32, 34, or 36 in the back. Please give me a bit of advice.

[maillotpois]

On one of my bikes, I have a 30 with my standard compact Campy record rear derailleur, and that's great for all but the longest and steepest hills. My new bike has ultegra, and I built it up with a 105 long cage rear derailleur and that goes to 34 at present. I could put 36 on if I wanted to, but I feel like a 1 to 1 is enough.

[Becky]

I'm not sure that 27 ---> 28 would make enough of a difference. I'd lean towards either the MTB rear derailleur and cassette, or a triple crankset (depending on the shifter model).

This all depends on how much you need to lower the gearing. Is there any possibility of borrowing a bike with either configuration to test out?

Also, any time I'm experimenting with gearing, I play with a gear calculator to help me "visualize" the change.

Good luck!

[indysteel]

Well, switching from a 12-27 to an 11-28 isn't going to be much of an improvement for hill climbing purposes. So, that more or less leaves you with mountain gearing. I, personally, would opt for the 32, but that's because I currently hate the wide jumps I have to deal with on the flats with my own compact road set up. If that's not an issue for you, then go with a 34 or 36.

I'm no expert on road/mountian compatibility. Is your current group Shimano? Just make sure that whatever mountain set up you get is compatible with your road shifters. I vaguely remember reading that 10-speed Shimano road shifters are (or at least once were) only compatible with a 9-speed mountain cassette. I think SRAM also offers an Apex 12-32 10-speed road cassette that would be compatible with a Shimano 10-speed drivetrain--if that's what you have.

[Crankin]

I have the mountain derailleur on the back of my bike with a compact (11-34). It's a Deore XT with an Ultegra front derailleur. It's a lot of low gears, although the range in the middle of the cogs feels widely spaced compared to my triple with an 11-28. However, i am now used to the feel and it's fine. The combo works perfectly and I ride up steep grades (10-18%) on a regular basis.

[Hi Ho Silver]

As others have said, changing to a 28 in the rear isn't going to provide you with much relief. My bike has a compact crank (50, 34) and a 12-32 cogset in the rear. The lowest gear is more than sufficient to allow me to get up any of the nasty hills here in the Texas "hill country". In my experience with mountain bikes and road bikes, a low gear ratio of about 1-to-1 (e.g., 34 chainring to 32 cog) is low enough to get me up any incline.

[tzvia]

It's basically what SRAM calls 'WiFli'; it's nothing new but they put all the pieces together for the road and are doing a good marketing job with it.

You basically need a longer chain to be able to wrap around the larger cogs. That would require a medium or long cage derailleur to take up the slack of that longer chain when you are in the smaller gears. Then you could add a wider range cassette that goes to 32 or 34 (that would require a long cage).

I can't tell the difference between 26 and 27 in back so I just use a 26 on the road bike (I am a fan of the SRAM Red Cassette). On the commuter, which is 12 lbs heavier than the road bike before I put my stuff in the pack, I set it up with a long cage X5 mtn rear derailleur with a 26~39 up front and a 11-28 cassette as the route only has a slight incline at each end. But with that rear derailleur, I can lengthen the chain and put a MTB cassette that goes to 34 if I needed it.

[Cyclesome]

Thanks for all the advice. I went to my LBS who suggested I not switch to an 11 -28 nor change to a mountain bike derailleur, but instead keep the same derailleur and switch to a 12 - 30 rear cassette. Lower grade however, Shimano does not make a 12 - 30 in Dura-Ace. Hopefully, I will have a few more gears when I need them for the hills Thanks again.