1. https://www.bikecalc.com/speed_at_cadence
2. Export a few race rides from Strava. Save as .XLS from the text doc and open it, accept prompts.
3. Add a cell to reference for your tire size
4. Add a column with a calculation for estimated gear using the speed and cadences.
5. Plot it.

See where it puts you most of the time. Assuming you stay in the big ring most TT/tri rides, which I'd assume.

Could be less technical and just plot your speeds if you don't have a power meter and guess at a cadence, or just use speed.

If it seems skewed, maybe so.

Folks with a factory 11spd 11-28 cassette and 50 ring are missing out on some single tooth jumps in prime riding range.

Consider a 52/53/54 and going to 12-25. If staying 2x, you've always got the inner ring. 12-25 11spd gets you one tooth jumps over a broad part of 90% of your riding time.

The 16t ain't everything, but it's an area tri/TT folks spend a lot of time. It's not as fun constantly going 15/17 and messing with cadence.

Just IMHO. YMMV.

Depends on your ability, how you spin, the courses you ride etc. 50/34 is really easy to spin out in so you will likely be swapping it.

with a 50-34 11-23 you'll get a wider range and smaller jumps than a 12-25 on a 53-39.

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Keep it. 100%.

I'm a strong cyclist. I have 50-34 on my road bike and it transformed my riding significantly. If you are spinning out in a trip you are doing 60kph+ and do could be recovering.

Ride the bike. If some issue with the gearing arrangement becomes evident in your riding, then worry about fixing it.

What makes you think you need bigger gearing than 50/34?

You likely will not be able to go bigger than 52/36 without swapping the whole crank. 50/34 means its 110 BCD and you'll need 130 BCD to run 53+

That depends on the crank, TP. The 4 arm 11sp Shimano support all combinations. I believe 4 arm FSA and Campy do that also.

55-42, 11-21 and htfu.

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Thank you guys for all the answers.



New tri guy but what I see out there it is that usually all the tri bikes come with 52/36, I guess there are some benefits behind that.

I have the specialized pro crank arms, and Praxis chainrings, so in case I decide to go with the 52/36 Will I need to change completely the crankset?
Praxis offers 52/36 chainrings so I guess I just need to change that. The price is 150 dollars...Is it worth it or better to change the crankset completely and go with a different brand?

This although as it's a second hand bike then there is a fair chance that the crankset is the old style where it did vary. You'll also need new chains, possibly rear mech, likely new front shift cable, etc, etc.

I had 52/36 on my last road bike (and currently have it on my tri bike). I’m planning on going with 50/34 with the next one. I used to spin out in the 50-12, but with an 11 tooth cassette I almost never do. And if I am to that point I’m going fast enough where I’m happy to just coast and take a break

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Matt

What is your FTP/KG and what type of courses do you ride. Unless >3.5watt/kg or only riding flat or short courses, I’d stick with the compact and an 11x28 or 11x25. 11x50 is enough gear for all but the strongest riders in a TT

Just ride what you have now. The bike is already used, so it's not like you retain more value by replacing the crank or chain rings now as a "brand new take off."

There are reasons to switch from 50/34 to 52/36, but "usually all the tri bikes come with 52/36" is not one of them. If after riding many miles on the bike that you determine you indeed need more gearing, you can make the switch then. But it's pretty much impossible for you to know now if you've not spent a lot of time riding the bike on the terrain you intend to use it on. Furthermore, it's more likely that you'll find that you want to replace the entire crank completely not because of chain ring size, but because of crank arm length to optimize your fit. Again, that will likely take time to figure out, but no point in jumping to swap chain rings first if you end up buying them for a crank you will eventually replace and can't reuse the rings.

I had 50/34 -- 11/28 on my Trek SC when I bought it. As a low power flatlander my best option was to go to a 12/25 on the back and swap the 34 for a 36 on the small chainring. I'm super happy with that combo. I also drank the ST KoolAid and went to a 165mm crank length. I'm very happy with that choice too.

Between the 36x25 and the 50x12 I'v got it covered with sequential steps between nearly all the gears. I would buy a 13/23 11sp cassette if they made one.

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"They know f_ck-all over at Slowtwitch"
- Lionel Sanders

Since it’s a TT bike, I’d likely recommend a bigger chainring depending on your ability. Most people spin too much for TT. It’s very different from cycling and the energy expenditure is different. My coach has brought my cadence down to about 75. My power is up and my heart rate is down.

Read this: http://blog.trisutto.com/...bike-cadence-debate/

The results don’t lie.

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i'm currently at 3.5w/kg on a 11x28 with a 50t 1x setup - plenty gearing for me and accommodating for any rolling hills. chain line is pretty straight, but for hillier IM's i put on the front derailleur.

Jumps are smaller with a 50, giving you more fine tuning. Stick to 11-25 if possible (11sp), I made the mistake of going 11-28 on my 50/34 and really missed the 16t, as the jump from 17t to 15t at 90-95 RPM is almost a whopping 3 mph, I also miss it on tempo-ish climbs where it's a 2 mph jump in the 34.

In tri, if you think you're going to spin out a 50/11, say > 110 RPM, you could probably just be coasting as you'll be at 40 mph. For road racing, if you're a sprinter, you'd probably want the 52 or 53.

I do a ton of climbing where I live, so I really like the 34. The 50 isn't big enough though for the flats / descents. I was able to change the big ring on both my road & TT bikes to a 52. I'm running 52/34 on both bikes and have never had issues. Have had this set up for the past two years or so.

I live in a largely flat area with some 1-2 minute steep climbs. I run 50/34 and 11-25 which gives me plenty of range, narrow steps between gears and allows me to spin nicely. I have used a 53/39, all that does is move me 1-2 cogs higher on the block. A 50 puts me square in the middle of the block at 23-24 mph which is perfect for my group rides.

Also, I've sprinted a 50-11 at 37-38 MPH and not gotten close to spinning out. That gear gives you 40 mph at 110 rpm, that's plenty fast for me. If you're routinely descending at 40+ mph, your needs may differ from mine.

If you want a 11-28 with a 16t, look at SRAM 11 speed cassettes. They are 11,12,13,14,15,16,17,19,22,25,28. This is the main reason I don't use Shimano cassettes.

That sounds great. Thanks for the heads up. When I ran 53/39 10sp, I went to SRAM cassette for 12-27 as they were the only ones that offered it at the time. Those jumps on the 11-28 make way more sense to me than that mid-cassette miss on Shimano.

No free lunch, though. The compromise they make to plug the hole at 16T results in two even bigger gaps in the climbing range. And the 21-24-28(-33) progression they're moving to with AXS is even wider. SRAM cassettes usually feel great when riding lightly-undulating terrain and flats, but I dislike them in the hills.

If Shimano offered a 12-28 cassette below Dura-Ace, I'd probably use it on my 2x11 road bike. The only thing that makes me hesitant is that we sometimes get a Bacchetta or two at one of the group rides I go to, and those things can drive absurd paces down shallow descents, where you still need to pedal in the draft at 50mph.

I used to have 50/34 and 11/28 on my TT bike.. Worked well for me on both hilly and flat courses as a more novice tri-cyclist (2u30 HIM ride). Above 60kph, you are indeed coasting and recovering :-) . But any steeper climb, you can keep a good, high cadence which makes it worthwhile imho. If it comes with the bike I wouldnt swap it immediatly..