PDA

View Full Version : Need Education on Compact Double verses Triple



Cyclesome
07-10-2007, 09:46 AM
I recently purchased a Specialized Ruby with a Compact double cassette 50/34. How does this compare to my triple cassette on my Cannondale hybrid which is 28/38/48? Will I be able to climb hills with my compact double? My Ruby is as light as a feather compared to my 30 lbs. Hybrid, but will I have the gears necessary for climbing? I took my Ruby out yesterday and road her for 25 miles, but didn't tackled any huge hills.

I need a basic 101 explanation of these gearing systems. Sorry if I appear unknoweageable, I am still in the learning process.

Thanks!

Kalidurga
07-10-2007, 10:03 AM
Whether you can climb hills or not with a compact depends on what your cog range is (which I've been learning the hard way this year :rolleyes: ). A 34 tooth chain ring is perfectly sufficient for climbing, I think, if you have a big enough cog in the rear.

Two things I love about my compact chainring: Easier cleaning, and no chain suck :D

rij73
07-10-2007, 10:25 AM
My current bike has a 52-42-30 triple and my new bike is getting a 50-34 double. What I did was make sure to get a 12-27 cassette in the back. The 34 chainring with the 27 in back is only a tiny bit harder to pedal than the 30-26 combo I have currently. The bike will be 6 pounds lighter, so that should make up for it! :D

Check out this nifty online tool:
http://www.sheldonbrown.com/gears/

If you know the size of your old cassette and new cassette, you can use the tool to see how your new gearing compares to the old!

HillSlugger
07-10-2007, 10:29 AM
Chainring teeth divided by cog teeth gives you a power factor. If your largest cogs are the same you'd be getting something like 18% less low gear power from the compact double.

My 35 lb hybrid had a 28/34=0.82 low gear ratio. On my 23 lb triple road bike my lowest is 30/27=1.11 I could climb almost anything on that hybrid, even with the weight penalty.

Cyclesome
07-10-2007, 01:09 PM
Added Information for climbing ability comparison

Cannondale Hybrid (Aluminum) 28/38/48 Rear Cogs = 11/32
Specialized Ruby Pro (Carbon) 50/34 Cassette Free Wheel= 12 - 27

Thanks, I begining to learn. Any added comments knowledge is appreciated.

rij73
07-10-2007, 01:17 PM
I punched that into the online calculator.

Old bike:
Hardest gear - 115 gear inches (a pretty high gear)
Easiest gear - 23 gear inches (a very low gear!)

New bike:
Hardest gear - 110 gear inches (really high enough unless you are racing!)
Easiest gear - 33 gear inches (harder than before, but still low for a road bike)

So your easiest gear now corresponds to about the 4th lowest gear on the old bike. So, yes, it will be harder to pedal up the hills. The difference in weight will make up for part of that, but you may just struggle a bit until you get used to it if you have big hills to climb! It'll be good for you! :D

Eden
07-10-2007, 01:35 PM
I punched that into the online calculator.

Old bike:
Hardest gear - 115 gear inches (a pretty high gear)
Easiest gear - 23 gear inches (a very low gear!)

New bike:
Hardest gear - 110 gear inches (really high enough unless you are racing!)
Easiest gear - 33 gear inches (harder than before, but still low for a road bike)

So your easiest gear now corresponds to about the 4th lowest gear on the old bike. So, yes, it will be harder to pedal up the hills. The difference in weight will make up for part of that, but you may just struggle a bit until you get used to it if you have big hills to climb! It'll be good for you! :D

I think the difference in the weights of the bikes will make a great deal of difference - I doubt you will struggle with the new bike.
I have a big old utility bike too - a 34 pounder and it has a lowest combination of 28 - 32, same as your Cannondale, and I use it.

my race bike (Also a Ruby Pro) is a standard double (53-39) with a 27 on the back and I've been able to climb every thing I've come across so far on it. I think with your compact you'll be more than fine.

rij73
07-10-2007, 01:40 PM
Nice to hear that the weight reduction makes such a big difference. Makes me excited about my bike that's coming in one week!

sarahkonamojo
07-10-2007, 02:12 PM
It really depends on the terrain you ride, your fitness level, and tolerance for pain. I have heard from cyclists with compact doubles who switched to touring gearing because they didn't want to climb standing up. But this is Colorado and we like our mountain passes. I'd suggest that your bike shop be familiar with the terrain you intend to ride and give you assistance in choosing gearing.

There are hills everywhere.

Enjoy your new bike.

sarah

ladyicon
07-10-2007, 03:32 PM
I also went from a triple to a compact double (my Ruby expert). I have found the Ruby to be very responsive to climbing, the power goes to the wheels. We have a lot of very long slow hills here, also steep climbers. I find the long slows to be similar to a triple on the ruby, but those really steep climbs are a bit harder.
Just learn how and when to shift and keep that cadence up ;)
Congrats on your new bike !!!

Triskeliongirl
07-10-2007, 05:35 PM
If you find the 27 isn't low enough, you can switch it out for an 11/34 which is what I have, but you may also need a longer cage rear derailleur. It really depends what you are trying to climb, and how strong you are.

Cyclesome
07-10-2007, 05:47 PM
Thanks for the Info. I just weighed my Ruby and she is 18 lbs with water bottle cages & added mirror. My Canondale was 30 lbs. w/o cages & mirror.

emily_in_nc
07-10-2007, 06:07 PM
Thanks for the Info. I just weighed my Ruby and she is 18 lbs with water bottle cages & added mirror. My Canondale was 30 lbs. w/o cages & mirror.

That's a HUGE weight difference -- I suspect you'll be just fine with the compact without changing your cogset. You'll be flying up the hills! :D

Emily

rij73
07-10-2007, 06:13 PM
Yeah, with THAT much weight difference, you may be just fine. If not, you'll have to practice the hills. If you want it easier, the idea of changing the gearing in back works too. But, yes, you would probably require a different derailleur too. I don't think you'll need to do that, though.

Enjoy the new ride!

Starfish
07-10-2007, 06:27 PM
When I went from my 40 pound steel mountain bike to my 24 pound aluminum road bike I went from:

26-36-48 and 12-34 to
30-42-52 and 11-27

Even with the huge weight reduction, my legs were used to spinning, and there was an adjustment period. Also, at that time, I had not ridden very much at all, so the change coincided with my tackling hillier terrain than I had before. Those two things together made the transition a little difficult, despite the large weight reduction.

Still, I got used to it and enjoyed riding. Then, I moved a couple years ago to where it is much harder to find a flat-ish ride...the hills are harder to avoid, and the climbs are longer. My aspirations changed, and last year I switched to an 11-32 on the back, including a change to a long derailleur.

I love my granny gears. They have helped me tackle much longer, harder climbing rides, and as a result of the easier gears, I am actually getting stronger than I did without them. My expectation is that in another year or two I am going to get a fancier bike, and I will probably try the compact double. I expect a transition, again, but with the strength I am gaining, ironically, with my granny gears, I think I will be ready.

I had one person (or at least one person who said what they thought out loud! ;) ) consider me a weeny for getting the granny gears, saying I would get stronger without them. But, for me, the granny gears have helped me build my strength and climbing endurance.

Hope all that makes sense, and just offers another viewpoint or experience.

anakiwa
07-10-2007, 06:34 PM
I recently purchased a Specialized Ruby with a Compact double cassette 54/34.

Are you sure it's a 54/34? 50/34 is the more common compact size.

In general if you switch from a triple to a compact and keep the same gearing in the back, you lose the uppermost and lowermost gears. This may or may not be a problem (depending on terrain, fitness, riding goals etc). The problem can usually be solved by changing the cassette on the back (though if you want gears as easy as you had with the triple, you will probably need to change to a mountainbike derailler/cassette in the rear).

Good luck!

Cyclesome
07-10-2007, 07:20 PM
Thanks! In my first post, I did indeed mistakenly have 54/34 instead of 50/34.
I have edited this mistake. I appeciate all the input thus far. I am taking Ruby out tomorrow to tackle some hills.

bikerHen
07-10-2007, 09:21 PM
I am not a climber by any means. I too have a Ruby Expert with a compact double. It has been a real confidence building experience. Suprisingly I have been getting better at climbing with the double. I'm not talking about climbing mountains, just really, really big hills.

Today I came up the back road to our house. It's a climb I NEVER thought I could do. Not only did I make it up the entire hill, I didn't stop, even when I got to the top. :eek: :D I totally floored my husband as I pulled into our driveway as he was backing the car out to come and get me. I didn't set any land speed records. Coming up the hill my speed was hovering around 5.something mph. But I did it!

Although the down side to this, as DH pointed out, now that I did it once, he won't have to come get me at the bottom of the hill any more!:eek:

So embrace the compact double. It may turn out to be your best friend. bikerHen

onimity
07-11-2007, 09:28 AM
I have a compact double on my road bike (50/34, 12-25) and really easy gearing on my MTB (42/34/24, 11-32) and find that climbing is very different on both. My road bike is 18 lbs, fully loaded, whereas my MTB is much heavier since it is not only a heavier bike but also often loaded down with work stuff, etc. But I can take that bike up hills I'd never manage on my road bike.

For me, I prefer the road bike for non-steep, sustained hills (below, say, 8%) and for short, steep climbs. The former just melt away on the road bike and the latter are more painful than on the MTB but they are over really quickly. :)

The hills that I still really have a hard time with on the road bike are *really* steep hills (i.e., the 18% grade on one of my commute options) and steep, sustained climbs. I have to walk up the former and stop occasionally on the latter, whereas on the MTB I can shift down, spin along a little then shift back up when I am refreshed. On the road bike I have to grind on up the hill, and maintaining a workable cadence really pushes the limits of my fitness; I have to stop every few miles to get my heart rate down. I definitely feel that the compact double is great for climbing, but I am having to increase my fitness to get up some of the hills that seemed a lot easier on the MTB.

For what it's worth, I personally feel that the weight issue is a little overstated. I notice little difference in the ease of a climb, for example, when I have 10+lbs more or less on my back. Tire size, pressure, bike stiffness shocks/no shocks, riding position...these all make a difference and for me at least it is difficult to separate them.

I do a decent amount of climbing and have been really happy with a compact double, hopefully you'll have the same experience. And congrats on the new bike!!! :D

Anne