50/34 vs 52/36 crankset for 11-32 cassette (shimano 105 5800FC)

Question

Following up on this enlightening answer, I would like to know the differences between 50/34(compact), 52/36(mid-compact) and 53/39 (standard). The cassette I am choosing is 11-32 to give me a wider flavour of gears but normally I don't use the lower(bigger teeth sprocket) gears, I've just trained like this. I put more power on small slopes rather than shifting down the gears. Thus, I was also thinking to go for 11/28 but then fixed 11/32 as my cassette.

What would be the best crankset to go with it? By default, its 50/34 but I can choose.

I am buying a cross bike from ROSE (DX-2000) and would mostly use it as a road bike for long distance (>100KM). I need a configuration where I can have the smallest gear possibility, in other words, I can put in maximum power and effort (which I miss in my current racing bike with Campagnolo Xenon 9 Speed set, I don't know the exact cassette configuration but its missing the few sprockets :D)

Thanks

Answer 1

The difference is simply in the number of teeth on the chainring, and therefore the distance that the chain will travel when you turn the crank. With the standard crank you will be pushing the chain further, and therefore given the same cassette, the standard chainring will provide longer gearing than a compact, and require more power to turn. There are tables available which show the gear inches for different sizes of chainring and cassette. Interestingly a 50/11 will provide a longer gear than a 52/12, meaning that a 50 tooth chainring and 11 tooth rear sprocket will be 'faster' than a 52 tooth chainring with a 12 tooth rear sprocket.

Importantly, you should consider what cassette goes best with the chainset you have chosen. A 34/30 gear is a very high ratio and is similar to what you would get from a triple crankset. If you chose the compact chainset then it might be more appropriate to use a the 11/28 cassette. Choosing a big widely spaced cassette like an 11/30 means the gears will be quite spaced out and you even if you have an 11spd cassette you might find there are times you cant get a gear which you can comfortably spin, or the change in cadence required to go from one gear to another is awkward. It will also mean you will need a longer cage rear mech, as the chain will need to be longer.

Answer 2

50/34 with and 11/32 on the rear is going to be very spinny. For me - the range is too wide and the gaps between the gears too big. But - this depends on the kind of riding you will be doing. If you are riding the very steepest of mountains - than the 34/32 combination might be what you are looking for. Purely for fast road work - that's too wide a combination (for my personal taste). The other thing you will have to consider is the rear mech. For such a wide range you will need to go with a mid or long cage rear mech. I don't think it will work with a standard short cage. However, I have used 50/34 with 11/28 on a short cage - and that has been OK.

Try the Sheldon Brown gear calculator to work out the combination which will work for you.

http://www.sheldonbrown.com/gear-calc.html

Answer 3

Here's another gear-inch calculator that may be easier to use: http://cycleseven.org/bicycle-gear-inch-calculator

Basically, the 52/36 will allow 5% higher top-speed before spinning-out compared to the 50/34. (Many say that your aero-tuck and other factors are more important at those speeds anyway.) But on the hills, you'll find the 36 to be harder to turn than the 34. Same logic applies to the 53/39, but even more drastic of a change.

Unless you're road racing, you'll likely find the 50/34 the most versatile. Like you, I also used to power-up the bunny hills, but have since changed to a high-cadence approach. (It will keep your legs fresher for a longer period.)

Now that I'm taking KOMs on my 45lb cross commuter, I'm starting to consider more competitive uses and the swap from 50/34 to 52/36. But the 8-10% grade hills around my house have me second-guessing...

Answer 4

52/36 is perfect! You'll rarely find troubles with the 11-28. I took the leap from 50/34 on 11-32 to the above set up, huge jump in speed immediately with no real issues with hills, even steep grades. I just got a new bike that came equipped with a 53/39 on 11-28, now I'm really worried, considering swapping chain rings to 52/36.

Answer 5

I have a 52/39 crank set with an hg51 11/32 cassette. The rear derailleur is a Sora rd-3000 and a Sora sl4000 downtube shifter. It works perfectly. For steep hills and for speed. Had an hg51 8 speed 11/28 and changed it. Where I live there are steep hills.