Compact vs Triple

[TBird]

Hello Ladies—
I am a MTBer, in the market for my first road bike in 20 years. I’ve demo’d a handful of bikes, and recently became smitten with Trek Madone 5.1. (Yes, it’s way more bike than I “need,” but that part I can justify!) My only concern is that it has a compact crankset rather than a triple. I live in a very hilly area, and I did notice that when climbing, I was wishing for some smaller gears. I’m not sure if this is because I’m used to my MTB’s granny gears, just not used to road bikes, or if I really would be happier with a traditional triple crankset. I know Trek makes this bike in a triple, but I can’t find an 08 in my size.

Any thoughts from those who love or hate compacts? Also, is it a big deal to switch it out if I don’t like it? I read somewhere I could swap the cassette and end up with almost as many gears. Is that expensive? I’m thinking maybe I could ask the shop to do that as part of the sale. Right now, it has a 34/50 in front and 12-27 in rear.

I appreciate any input. You’ve all been a huge help already—I’ve been trolling this forum for a few weeks now and have learned so much!

[melissam]

Hi TBird,

I can't help you with the compact vs. triple question, as I've never ridden a compact double. I'm currently getting a custom crankset made, and the guy who makes it is trying to convince me to go with a compact double. He says the shifting is much more precise than with a triple.

At one point, I considered switching a bike with a standard double to a triple. It was a slippery slope of equipment changes: new crankset, new front derailleur, new shifter. I ended up buying a bike with a triple.

As far as changing your cassette goes, I'm heartily in favor of it! I switched the road cassette to an 11-34 cassette, with a mountain bike rear derailleur, and a new chain. I picked up a new SRAM 9-speed cassette & chain on eBay for ~$40, and an XT derailleur for under $50. If you went with your compact double and an 11-34, this would give you a low gear of 34-34, vs. a 30-27 if you went with a triple and kept your current cassette.

The disadvantages of a mountain cassette is that your gears are wider apart. Sometimes on the flats, you might find that you either have to spin faster than you would like or mash harder than you'd like. (I rarely notice this and find that having the low gears is well worth it!)

I also wonder if you could switch the chainrings on your compact double. Think limbo: how low could it go? If you could get a 24 on there, that'd be a 24-27 low gear. Hmmmm..... Of course, your big ring would probably be a 40, so your high gear would be a 40-12, which might be to low for descents or flatland cruising.

Anyway, plenty to think about. And you were probably hoping for a simple answer.

[TBird]

Wow, thanks Melissa. Great food for thought.
I realize I gave the wrong specs for the existing cassette. It's 11-25 on the compact, not 12-27. I can see how a MTB cassette could make a huge difference. Do you think even a 12-27 would make a difference? (Might be able to convince the LBS to make that change for free...)

[melissam]

TBird,

I honestly don't think that a 34-27 will make a huge difference on hills vs. a 34-25. According to Sheldon Brown's gear calculator, a 34-25 will give you 35.7 gear inches, and 34-27 will give you 33.1 gear inches, assuming 700c wheels. Helpful, but not a huge difference on the hills.

Please keep in mind that this comes from someone who not only has a mountain cassette, but also a triple! I have to say that having my 30-34 available gives me great peace of mind on many a ride. I might not use it, but it's very reassuring to know that it's there.

One more thing: I rode with someone who had a mountain cassette with a 32 in the back, and he was able to use his Ultegra rear derailleur. You would just want to be careful and avoid shifting into the 32 while you're in your big ring. It's not something I'd do on purpose, but I can't guarantee that I wouldn't have a very blonde moment at some point during a long & strenuous ride.

- Melissa

[Aggie_Ama]

Wow, thanks Melissa. Great food for thought.
I realize I gave the wrong specs for the existing cassette. It's 11-25 on the compact, not 12-27. I can see how a MTB cassette could make a huge difference. Do you think even a 12-27 would make a difference? (Might be able to convince the LBS to make that change for free...)

I live in Central Texas, somewhat hilly but not mountains. I wasn't ready to chunk my Ultegra Deraileur on my bike so I swapped 12-25 to 12-27. My LBS is one that does not like the SRAM 28 they said it works okay but they don't advocate it themselves. "Works okay" doesn't work for me. It is a noticeable change with the 12-27 but not enough if you aren't a mountain goat. I will eventually put a XT or XTR with a mountain cassette. It is overkill for my area but I like to go out to the extreme TX Hill Country and even on vacation to the mountains as often as I can. I can't climb and am a bit too unmotivated for hill repeats. I just like to ride for the joy of it not much on training. I also ride a triple. I like puppy gears, I don't ever in my wildest dreams see myself becoming a strong climber.

[alpinerabbit]

I ride the swiss alps on a compact / 11-27 Ultegra. I'm fine. I'll struggle with 15-20% slopes but 8-12% is peachy.

[madscot13]

I never thought I would become a strong climber. So I have a triple and a mountain cassette (I think I have an 11-34, but next time I would choose a set with closer gears). I used to do this one will on my granny gear and just spin my legs off. I am better now and I can stay in my middle gear and keep my cadence going. I still get passed but more importantly I still pass some.

it took a lot of training to get to the point that I am at now. I also haul groceries some times and the extended gear ratio is nice then.

[aicabsolut]

I ride the swiss alps on a compact / 11-27 Ultegra. I'm fine. I'll struggle with 15-20% slopes but 8-12% is peachy.

I ride a compact (50/36) with a 12-27 cassette. That is equivalent to a 50/34 with a 12-25. I struggle in the mountains only when the grades get upwards of 15% as well. Over 20% is really really tough. However, long sustained climbs from anywhere in the 6-12% range is doable. I'm thinking of taking my old frame and putting a 50/34 on it (using my same cassette) to get just one more gear for riding the mountains.

My compact is perfect for my usual terrain and racing. I run out of gears on the top end more often than on the low end. If I lived in the mountains, I might prefer a triple, but I think even then I'd be more inclined to just put more gears on the back--like maybe a 50/34 with a SRAM or DA7900 cassette with a 28 cog. It's not that much of a difference in gear inches, but my current gearing is *almost* enough for steep grades.

[ilima]

The shop should be able to switch out the cassette to a SRAM 12-28 for essentially free. Shimano road rear derailleurs are rated for 27, but they work okay with a 28-tooth cog.

As to the compact, I think it offers a very versatile setup. I run a compact crankset and a 12-25 and I'm a hill slug. For my commuter I used a triple, but for regular, unloaded road riding a compact is going to do the trick for most folks.

It would be quite costly to switch to a triple crankset. So costly that I think you'd be better off looking for a bike that already has a triple if you really want one.