Compact setup
 

Going to change to a compact setup but should I go for 34 or 36? I plan to pair it with a 11-26, 27 or 28. Prob dont need a 28 though. thanks

Depends a lot on the terrain you plan to ride and how strong you are. Even recreational riders sometimes complain that a 34 is too low if all your riding is on the flat.

If you get a 36T it's often recommended to go with a specific 10-speed ring like SRAM make rather than the generic 9/10 speed rings from FSA and others that may not shift as well.

Who rides the small ring on flats?

Get the 34 or stick with the double. With a 36, you only gain one lower gear compared to the 39, and the rest of the ratios are practically the same. With a 34, you gain 1.5 lower gears (2 lower gears but the ratios are skewed). If you're going to spend the money and time to change to a compact, make it worth your while.

Me, in a 15-20 mph headwind.

I ride whatever gear I need to to keep pedaling properly. I have lost my pride for showing off my Big Ring capabilities early this year when we started riding Lots of hilly routes. 34 will help you more than a 36 on the steep ones.

yea I thought about going 34/50, I can always play with the cassette if its too low of a gear. As in I will pair the 50/34 with 11/26 if its too easy then a 11/25. However, I think I should be able to climb many of the mountains around my area with a 34/26.

Now a days, gear RANGE is good. Outside of some fairly minor weight savings, I see no reason to put an 11-25 on anything when 11-28 is available. Neither is faster, but 1 is more useful. I am just saying.

but then again, I live in an area where 5k of climbing on 20 miles rides is pretty much automatic.

Okay, I think I knowh what setup I am going to go. With money and how easy I can get parts.

I will have a spare 12-27 cassette so I will pair it with my 53/39. In addition, I plan to change my inner 39 to a 38 so that I can climb better. In the end, I will have a 53/38 with a 12-27. 38x27 should provide a good amount of gearing to climb, I think. I struggle on on my 39/25 right now. How does that sound? This will the best way to save money compared to swapping for a new crankset (compact)

Thanks

seems like a little bit of work to just drop a tooth up front.

Yea.. true, I did some reading on the forums and came to an conclusion that a 38 isn't worth it. Any other suggestions?

It depends on the rider, terrain, riding style, and goals.

Come to think of it, that's the correct answer to about 90% of the questions posted in here. Sigh.

Hows the difference from a 12-25 switch to 12-27 on a 53/39 crank? Not much?

Guess I'm a bit at odds with consensus here...I ride a 36T front ring and LOVE it! Usually paired with 12-23, it gives me one more gear than my 39/23 setup...which covers the vast majority of hills in my area...but it's easy enough to change cassettes and/or chainrings, for a ton of versatility for early/late season riding or those more intensive hill workouts. But I echo what others have said...too each his/her own. By the way a 36/27 combo is the same as 39/30...

If you're in good shape and do alot of long climbs that aren't super steep, I would go with a 50/34 and a 11-25. If you climb steep stuff, 50/34 and 11-28 will do well. I don't see the utility in a 36t chainring really. For the riding I do, I'm usually in the big ring, or using the lowest gears, in which case I want the 34. YMMV though.

I started riding with a friend of a friend who rode recreationally. I let her set the pace for the first couple of rides for me to get an idea. The average speed at the end of the rides were between 9 and 10 mph. With less than 100' of elevation gain, there was no need for a big ring.

I like my 50/34 + 11/25. My dad however rides a 50/34 + 12/27. Depends on where on the cassette you think you would ride...

True say, I will have a 50/34 12-25 setup soon so I will be able to tell if I need to go higher or 11-25.

Are you able to run the 50/34 and 12/28 with a standard short cage rear derailleur?

Should be pretty easy...at least it is on my SRAM Force set-up.

If 34/26 is a low enough gear for you, then you should consider just staying with a 53/39 crankset. The difference between a 39/28 and a 34/26 is pretty small (37 gear inch versus 35)

i use a 50 34 compact with an 11-26 cassette and it works great for the mountains where i live. i made do with an 11-25 for a while but really like SRAMs 11-26. for where i ride its perfect.

Not with Shimano. Unless you like having an inch of slack in the chain in the smallest rings, or you deliberately shorten the chain so it's not long enough in the big-big combination (not recommended).

I've got a compact crankset with a DA 7800 RD, and have no problems with a 12-27 cassette. Does one tooth make that much difference?

+1 for the Sram Force set-up. I've got that exact set-up, Force 34/50 crank, FD/RD, PG-1070 12-28 cassette, 1091r chain.

Shifts like a dream, gets rid of the useless 11t & trades it for a 16t, and gives me a hill-friendly 34-28 climbing gear.

Peter

Are you sure you have a short cage derailleur? The short cage isn't supposed to be able to handle either a compact or the combination of compact and 12-27. Although both are only a couple of teeth over the maximum allowable, and might just work, I doubt it would come that way from the factory.

To be fair, I misread the original question which was about a 12-27 and was thinking about 11-27, which definitely is too much for the short cage RD to handle properly with a compact, as I found from experience.

My Allez came with a 50/34 and 12-27 stock, which is a chainwrap of 31 even thought the 2010 Shimano 105 spec limits it to 29. I don't know if that would cause a debate on the responsible party (Shimano or Specialized) should the rear derailleur need to be replaced under warranty, but it shows even the factories are willing to push the boundries a tad.

I should have been more clear -- I have a Shimano 6600 drivetrain. I have a hilly century ride this summer and need some lower gears for that ride (otherwise my standard crank is fine for the terrain I normally ride). Was looking at a new MTB rear derailleur/cassette with my standard crank, but then realized a compact crank might be cheaper and get me similar gearing. I just don't want to switch my rear derailleur.

It's a one ride sorta deal, and I can just avoid using the 50 & 12 combo (since, I will be panting some much on the descents there will only be coasting going on, haha).

Will that work?

I run a 34/50 - 11x28 and I don't experience problems in regards to shifting. Pretty sure it is short cage 105 5700 RD

The 50/12 combination is in the middle as far as chain wrap is concerned so the 50/12 is not your concern.

It's the extremes that are the issue the 50/ 27 (or 28) , and the 34/11 (or 12).

You need to size the chain so it comfortably goes into the big/big. You can't say I just won't use that, because it's inevitable you'll forget sometime, and it can trash your drivetrain.

So the issue becomes whether the chain is too slack for the little/little, when you size it for the big/big. If you're pushing the wrap capacity of the derailleur, the chain may be a bit slack in the 34/11. However, you can just choose to stay out of the small cogs, when you're on the little ring because you're not likely to have a catastrophic failure if you use them inadvertantly.

Thanks -- yes, I had the issue wrong in my head -- it's the cross-chaining that is the problem.

So, would it be ok, or at least, less of an issue if I just stayed with my 12-25 cassette (with a compact crank 50/34)?