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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

  • Can you give us the gearing on your Campag bike so we can give better recommendations? Count the teeth by hand if need be. [In a nutshell, if you find the lowest gear too tough, figure out gearing that's 10-20 % lower.] – oals Apr 21 '16 at 17:25
  • i use to have a 50/34 with 11/28. swapped for a new bike 52/34 with 11/28 and it was way to hard on the climb. ended up swapping for 11/32 cassette and even so i found that to be significantly harder than the 50/34 with 11/28. the gear calculator say that 34 compact with the 28 gear cassette is an harder gear to push than the semi compact 36 with the 32 cassette gear , all though i dont think is true . even so mathematically it says harder , in the reality the 36-32 its harder than 34-28 . – baptiste Jan 9 '18 at 6:19
  • 36 tooth chainring to a 32 tooth cog is 1.125 ratio, (ie the rear wheel turns 1 1/8 revs for each rev of the cranks) 34 tooth chainring to 28 tooth cog is 1.214 ratio or just over 1 1/5 revs. In degrees, the latter gearing does 32 degrees additional rotation, so its mechanically harder work. The differences you perceive are probably in the bike and bike fit more than the gearing. – Criggie Jan 9 '18 at 7:25
  • Also, welcome to SE. Please do have a browse through the tour to learn how things work around here. – Criggie Jan 9 '18 at 7:25
  • The math does not lie. – Argenti Apparatus Jan 9 '18 at 13:00
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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.

  • Good explanation, so even with a longer cage, you think 50/34 with 11/32 might be a problem with cadence? They already asked me to get a longer cage, that's ok. So, 52/11 is more powerful than 50/11 but on the other side, can we calculate in terms of speed or some other unit, what is the loss or gain b/w these two cranksets. With Shimano 105 FC 5800, they are already producing 2 speed (double) cranksets so maybe that's the reason to go with 50/34 with 11-32 as to kinda mimic the third one? – Sukhdeep Singh Apr 19 '16 at 9:20
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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

  • Thanks for your answer, sheldonbrown calculator is bit tough for me to use because I do not understand everything there. The guys at ROSE, recommended me to get a wider cage for 50/34 and 11-32 casette, that's all fine, I was just confused that which crankset to choose from, 50/34 or 52/36 as I like bit more power. – Sukhdeep Singh Apr 19 '16 at 9:12
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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...

  • 4% actually. (52 - 50 / 50 = .04, all other things being equal). – njzk2 Jun 8 '16 at 17:39
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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.

  • 3
    Welcome to SE BIcycles. Please browse through our Tour in the Help menu to learn how SE is different to conventional chat sites. – Criggie Jan 22 '17 at 3:58

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