anyone using a 50 x 39 ?

[masking_agent]

since we are in the world of high cadences, i'm thinking of changing my 52 x 42 to a 50 x 39T and maintaining my 12-23 on the back.

Your thoughts ?

 

[Black Dog]

When I raced as a junoir we were limited to a 50 tooth maximum on the front and we all ran 50-39 or 50-42. No point unless you are running a compact with a 34. There will be a lot of duplication between the 50 and the 39.

 

[ergmonkey]

A lot depends upon what you run in the back. I'm a high cadence rider, but I love using a 54/42 because of the tighter spacing (I feel like it's easier to be in exactly the gear I want). I'll typically go for a 12-25 in back, though. Also, I like being able to stay in the small ring just a touch longer over the crest of a hill--lets me get up to speed soon before that split-second power loss while I shift back into the big ring.

Ditto what was posted about too many duplicate gears, though.

 

[kiwirider]

When I raced as a junoir we were limited to a 50 tooth maximum on the front and we all ran 50-39 or 50-42. No point unless you are running a compact with a 34. There will be a lot of duplication between the 50 and the 39.

I wouldn't be so sure about the "a lot of duplication". I just did a quick calculation of the ratios (too lazy to convert to inches ...), which shows the following:
(Excuse the formatting - shows up fine when I type or edit, but goes to hell when I post it ... Just move the 50, the 39 and the top two ratios to the right one column and all is good)
50 39
23 1.696
21 1.857
19 2.632 2.053
18 2.778 2.167
17 2.941 2.294
16 3.125 2.438
15 3.333 2.600
14 3.571 2.786
13 3.846
12 4.167


(Blanks are 'cos I know that no-one uses those crossed up chain lines ... )

To the OP - I run a 46-39 on my cross bike, with a 12-25 on the back. I have also run it with a 12-23 on the back (and a 53 on the front, but that's another story ...) Out of cross season, the bike gets used as my commuter - which means anything from 15 to 35 km road rides each way. I find that it works fine. Sure, there are times when I curse the 46, but it still lets me get along at a good enough pace. And of course if you're in the mood for a LSD ride in the small ring, there's no difference from a standard roadie.

I'd have to say that I'd rather have that set up to a compact crankset. My bike originally came with a 46-36 "cross specific crankset" and I definitely prefer the 39 as the small ring - for racing and general riding.

 

[steelciocc]

Yep

I rode 50/39 for years (Campagnolo). I havent been able to get on top of a 52 or 53 for a long time.

I've gone with 50/36 on a recent build and like it even better. Even so, I'm on the little ring 60% of the time.

13-26 in the back. I know...what a wimp!

 

[Notso Swift]

Hey even pro's go compact 36 x 29 when the mountains are big enough!

I rarely miss my 52/53 and I am a sprinter, I can spin a 50 x 11 so it is good past 70kph, so not many issues with that (except my strength!)

 

[Bustedknuckle]

since we are in the world of high cadences, i'm thinking of changing my 52 x 42 to a 50 x 39T and maintaining my 12-23 on the back.

Your thoughts ?

Ride on flat terrain in the big ring. You 'should' be somewhere around the middle of the cogset. If you aren't, then you are under or over geared. I found that with a 53, then 52, I was on the upper end, bigger cogs side of the cogset( freewheel in my case-13-23/7s) all the time, so i went to a 50t and now I am in the 15/17/19 all the time.

So if you are in the 17/19/21/23!! most of the time on the flats with the 52..try a 50t.

I have a 39t inner which gets me up any hills I want to climb. If I were to get a compact, I would get a 50/36..I think the 34 is too small for me and around here. BUT YMMV, gearing is a personal choice.