cerealkilla

Hiya - li'll question; I'm finding my fitness levels are increasing and I've lost a good amount of weight (20+lbs). The compact setup I'm using of 50/34 with 12-25 cassette is starting to become a bit redundant in certain ratios. The hills I climbed last season in 34/25, I did last week in 50/25 which cased me to cross the chain big to big, which as we know is not a good idea. Could've dropped the front to 34 and gone lower perhaps 21 but I wanted to see if I could do the hilly 40 miles training loop I do in the 'big cog' which was more of a stamina/personal/mental challenge..

Anyhow I'm toying with the idea of going to this:

53/39 chainset with 11,12,13,14,15,17,19,21,24,28 cassette

from this:

50/34 chainset with 12,13,14,15,16,17,19,21,23,25 cassette

If theres any ratio gurus out there, please let me know ya opinions!

I already have the DA7900 chainsets in both compact and standard flava, just need to order the 11-28 cassette to complete the experiment

Up North

I dumped my compact for 53-39 - 11-25 and have not looked back. Flat land here, very few hills.

Homebrew01

What is the lowest gear you realistically need ? Pick the crank you want to use, and get the cassette that gives you the low gear you need in combination with the crank.

cerealkilla

Looking at ratio calculators in the web, the 34/25 and 39/28 are quite similar - if I understand them correctly that is!?

I can do the big hills in 34, 21/23 no probs.

prathmann

The low gear is almost the same with either arrangement, but your high gear would be increased by almost 16% which is pretty substantial. Are you currently feeling that you're spinning out in the 50/12 combination enough to offset the bigger jump you'll have in the middle gears by losing the 16t cog?

Drew Eckhardt 

1. There's no 16 cog in an 11-28
2. You don't need 53x11 which is two gears bigger than 50x12 or the 52x13 Eddy Merckx used to dominate the spring classics
3. 39x28 is almost the same gear as 34x25 which was ample at your old weight
4. 39x23 is almost the same gear as 34x21 which would have been fine

I'd try 53-39 x 12-13-14-15-16-17-19-21-23-25 or 12-13-14-15-16-17-18-19-21-23 to get the 18 cog too.

Personally when I need a gear lower than 39x23 I opt for 13-14-15-16-17-18-19-21-23-26 and/or run a triple crank to keep one tooth jumps through the 19 cog.

cerealkilla

chers guys, liking you thoughts re lower gears. It's nice to have a bailout gear for when the legs have gone... 39/28 will allow that and the 39/24 will push me up the hill bit quicker then I'm getting ATM. All good in theory!

BoSoxYacht

I live in a mostly flat area, but love my compact 50-34 crankset. When paired with a 12-25 11speed cassette I have single tooth gaps from 12-19,21,23,and 25 , but when I drop into the 34t ring I have all the gears I'll ever need to climb.

I used to use 53/39 and a 12-27 cassette in a hilly area, but the compact 50/34 & 12-25 11speed works much better for the flatish area I normally ride in, and I still have the same low gear ratios for climbs when needed.

BoSoxYacht

No matter what crankset you choose, it's nice to have the 18t cog.

cerealkilla

Yes, simply. Id like to keep a bailout gear but would like more pace at the other end. I'm at an average of 17mph in hilly terrain (+/-1000m) over 40 mile. Which I do 3-4 times a week. And am looking to do 120 mile rides at weekends.

rpenmanparker 

This is the second thread in just a few days by a rider who wants to change cranks instead of just upshifting (or downshifting) what they have. I don't get the pervasive dislike of the small ring especially when it is a 34 tooth one. Why not just (as OP even mentions) just go to 34/23 or 21 instead of a 39 or 53 or even his 50. What gives? Even an 11-26 cassette with the current crank makes sense.

crazyravr

Why?

BoSoxYacht

Because its a very usable gear to have with either a 50 or 53 big ring(19.5 or 20.7mph) with a 90 cadence.

cerealkilla

Simples - because when shifting between 50/34 its clunky and requires rear mech changes too; with 53/39 the transitions between are much more holistic.

Bah Humbug

I like 50/36 and 12-27. You might do well with 50/36 (which shifts better than 50/34, by a lot) and 11-25, unless you really want the little extra top-end boost from the 53. The 11-25 cassette will have nicer spacing than the 11-28.

redlude97

A better solution now that you feel you are stronger is to swap the 34T for a 36T

redlude97

beat me to it

merlinextraligh

Play with this: it will show you visually the ratios, gaps, and cross over points of various gear combinations:

https://www.gear-calculator.com/#

FWIW, I race crits at a Cat 3 level with a compact crank and an 11-23 cassette.

That will give you tighter spacing, and all the top end gear you need, if your name isn't Greipel, Kittel, or Cavendish.

Also, you can always throw an 11-28 on if you want to go ride something super steep.

Bah Humbug

You and me, the 5036 mafia.

sijray21

don't forget about the 52/36t 'semi-compact' route. I rented a bike in Colorado when I was there for vacation and I really liked this set-up. it came with an 11-28 and was perfect. I'm coming from a 53/39t standard from my bikes and the 52/36t provided me more range in the middle of the cassette. I've also used a range of cassettes and so far my favorite combo is the 53/39t with a 12-27 cassette, but it's a bit of a struggle to keep the cadence up with the pitch of the road goes up past 10* for a considerable time in the 39-27 combo (for me anyway).

you can use the same crankset you have now (110bcd) and put 52/36t chainrings on, but if you go to a 53/39t I think you'll have to go to a 130bcd crank (i'm not sure if they make those chainrings for a 110bcd crank, but I haven't done any research).

this can help you calculate gearing between chain rings and cassettes if you wanted to compare

Mike Sherman's Bicycle Gear Calculator

The only thing I think you'll notice is the spacing of the gears. 11-28 and 12-25 is a considerable difference, so you may find that the gear you want to spin in may be in between what's available to you.

big chainring 

One thing to consider are you really going to use 53/11,12,13,14,15?

Theres 5 gears you may never use. Or very rarely.

MinnMan

ymmv

rpenmanparker 

But that is all beside the OP's point. He just refused to move up one or two cogs in the back to climb the hill faster. He never complained about not liking compacts per se. He complains about riding with extreme cross chain, but there was no need for that. Humbug.

fstshrk

+1 on this.

banerjek

I think you're doing this backwards. When you widen the rings, you need to widen the cassette. When you tighten them, you can run tighter cassettes.

The 50 and 34 rings are pretty far apart so if you use a tighter cassette like you're proposing, you may well find that the speed you like to ride is such that you're either too high in the small ring or too low in the big ring. Overlapping gear ratios are a good thing and your proposed configuration is a little weak in that department even if it's not horrible.

The top seven cogs on your 11-28 are already nicely spaced, and the additional width at the bottom will give you great low and high end. You'll also have a much more useful small ring with the 11T. If you're going to go compact with a 12T, at least get a 12/27 since the cogs are exactly the same as the 12/25 except the last two. Realistically, whenever you want the 25, you probably want a 27.