urbanknight

Agree with Shelby, you might as well go with the higher gearing. If you need a lower gear in a race (assuming no super steep climbs), you're probably off he back and might as well soft pedal home. If you need a bigger gear to keep up, that's important. That being said, I have also never needed a 52/11 in any of the amateur races I did, so it probably won't hurt you to just get the 50/34 for now and worry about changing the chainrings if and when you need to.

genejockey 

See above, from earlier this morning.

KerryIrons

151W is a fair distance from the kind of power you need to race. What can you put out for a half hour on flat roads at maximum effort? That would give a lot more insight into the kind of gearing you would need for flat road racing.

tomato coupe

One of those setups causes you to shift more? Why?

genejockey 

TiHabanero

The old standard of 53/39 is tough to beat in my experience. Of course I have not crit or road raced or mountain raced in 30+ years, however I was not a high watt rider, but ran a 12-24 out back, and on hilly courses a 13-28. My job on the team was to be a body, hahaha. Blocking and sprint lead out man. My son, who is built just like me, serves the same rolls on his team.
With today's 11-12 speed drive trains, the cassette offerings are very useful with 53/39 rings.

Maelochs

Here is the deal ... as I see it.

The guy is not yet spinning out his existing gearing, and while he Wants to race, it is unclear if he ever has. What he would need should Not be based won what others used "When I raced" because he is not at that power or performance level, not at that fitness level.

I would suggest a 52-36 but whether or not that is available readily and affordably for his bike ... I would suggest he train more scientifically.

I suggest more intervals, more half-hour/max-power rides, mixed with long days.

Actually, I suggest he go to the pages on this site about nutrition and training and plan a dedicated program which will take him to the level where he will absolutely need bigger gears.

This is a "cart before the horse" issue. Build the motor, then build the transmission to handle the greater power.

HTupolev

Install a 52-50-36-34 crankset. Cover all the bases.

Eric F 

Alternately...

Go race. Suffer. Get your @$$ handed to you with extreme prejudice. Do it again. Figure out what it's going to take to survive. Go race a bunch more. Eventually, you'll figure out how to compete.

bruce19

This

bruce19

I have 2 road bikes with 50/34 and 2 with 52/36. I notice the difference for sure. I'm 77 yrs old but I prefer the 52/36.

LarrySellerz

Kind of shocked to see the amount of people who say 52 is significantly bigger than 50

tomato coupe

Just curious ...

genejockey 

I understand that can be fatal to felines.

tomato coupe

It's just a simple question. I honestly don't see why the shifting would be different with those two setups.

rm -rf

This is 11-speed, I think?
Usually, Sram and Shimano have the same cogs for the same size cassettes. But not in 11-28. Sram is biased toward closer shifts at faster speeds. Shimano has more gears at the slower end of the cassette.

11 12 13 14 15 16 17 19 22 25 28 Sram
11 12 13 14 15 17 19 21 23 25 28 Shimano

~~~
I like Mike Sherman's Gear Calculator to visualize speeds for different gearing. And I look at the overlap ranges between the large and small chainring.
All the charts update on the fly if I change cadence ranges or try different cassettes.
This tab is the Speed Range, the most useful chart for me.

Click in the Save tab to create a URL that can be bookmarked for later, like this:
Calculator link to this setup: Sram 11-28 and 34, 50, 52

Here are charts at common fast group or racing cadences. I picked 88-100 rpm here.
52 chainring in blue, 50 chainring in black, 34 chainring in red.
The 52 is just about a half shift faster in general, which makes sense, it's 4% larger and shifts range from 5-6% to 12-15%, depending on the cogs arrangements.

Sram 11-28 in metric





The same Sram 11-28 in mph, including the calculator titles.



~~~
Compare to Shimano 11-28:

genejockey 

I'm not sure why it is, but it is. It's the front, like I said. I end up shifting between rings a lot more with my 50/34 than with my 52/36, or with 53/39.

tomato coupe

Okay, thanks for the answer.

genejockey 

(All I did was repeat what I said above, but...you're welcome.)

3alarmer 

...I started noticing the difference between 53 and 52 in the front, at about age 70. It's become more noticeable in the ensuing years.

Broctoon

It is 4% bigger.

rosefarts

Something I noticed my first year as a Cat 5. Take all the best local riders, and that’s where they start. So your average slow Cat 5 is actually a pretty decent rider able to keep up a fast pace. We all started on 53/39 x 11-23 moved up to 12-25 for the hills or 12-27 if you were a “spinner”. For Cat 5,4,3 (never went beyond that) we weren’t mashing. A 50/34 would have been pretty worrisome.

Things have changed a little since the introduction of gravel and enduro MTB and stuff like that, but for straight road racing, you’ve got to keep up. That’s what big gears are for. If your legs can’t do it, you can join me on my slow rides and talk about how fast you used to be with me.

53/39 x 11-32 is a friggin dream compared to what was available even in the mid 2000’s. I wouldn’t consider going any lower if you’ve actually got the legs to race.

Eric F 

When you’re pushing the limits of your body and machine, 4% can be very significant.

Eric F 

My early-2000s crit bike was 53/39 x 11-21. Road races were usually 11-23.

20 years past my racing days, I’m using all of an 11-29, but still turning a 53/39 up front.

TiHabanero

Genejockey, there is no question about it, my experience mimics yours. With 50/36 I am in and out of the big ring more often than with the 53/39. I'm over 60 and up until 4 years ago I used a 53/39 with a 13-28 out back, and of course not racing. I can't see using a 50/36 for crit or road racing, however I'm sure some people do it. My son started out with a 50/34 and moved to 53/39 in short order. Simply needed a different selection of grear ratios better suited for putting out high efforts.

As for gear charts, they are nice to look at, however they do not tell the entire story. On the bike "feel" (quote marks as I don't know how else to explain "feel") plays a role, and an individuals legs have a roll in it. The human body is not a machine, no two are alike, and I believe that makes a difference.