50 vs 53?

Triathlon Forum
1

I just found out that my TT bike and road bike were even more different then I thought.

I love my TT bike and I have never quite adapted to my road bike.

I have 172.5’s on both. (I messed with some shorter cranks earlier this year, but after the weather changed and warmed up, my flexibility came back)

bigring (TT=53 tooth , Road=50) I didn’t realize this when I bought my road bike.

Could this have something to do with me not feeling comfortable? It’s a sensation that I can never put my finger on. After a group ride this week that was hitting 30+ for quite some time, I realized I was on my big+12 and I needed another a gear or 2. I asked some guys and they said I will need to change my cogs up a bit. Then another guy realized that my front was a 50 and he said that would need to be changed first? What the hell…do I have to buy an entire new crankset because its an Ultegra compact?

Any recomendations?

2

a lot of cyclists think that a compact crank has a dramatic effect on your top speed.

however, having the 12 tooth as your fastest rear cog rather than an 11 actually has MORE impact on your top speed than having a 50 tooth front vs 53.

in other words, just get a cassette like an 11x25 and you will have plenty of top speed.

to summarize: 50x11 (which no roadie would be caught dead with because it is too slow) is FASTER than 53x12 (which many roadies will ride with to get closer gear spacing)

so, no need to change the crank or front chainring unless you prefer very low cadences.

3

Chances are position is the bigger difference in how you 'feel". But if you are in the 50/12 and want a bigger gear, you can get a cassette with a 11 tooth like Jack said or just by a bigger large chain ring for the crank you have. Any size can be had but 52 tooth CR for compact are readily available. 52 gives about 4% more speed at the same cadence 11 vs 12 gives about 10%,

Where I live with lots of ups and downs I think 52/36 with a 11/25 covers most everything for general riding. If I was doing a ride with the steepest climbs around I’d go with a bigger cassette.

4

Chances are position is the bigger difference in how you 'feel". But if you are in the 50/12 and want a bigger gear, you can get a cassette with a 11 tooth like Jack said or just by a bigger large chain ring for the crank you have. Any size can be had but 52 tooth CR for compact are readily available. 52 gives about 4% more speed at the same cadence 11 vs 12 gives about 10%,

Where I live with lots of ups and downs I think 52/36 with a 11/25 covers most everything for general riding. If I was doing a ride with the steepest climbs around I’d go with a bigger cassette.

Thanks to both of you…ok, this now sounds like cheaper fix. where I live is dead-pancake-flat. we do have consistent wind so when we get infront of a tail wind, the speeds were higher then I was ready for (95% of my riding is solo). I am new to the nervous-bunch-pack-cycling though I have been racing triathlon for 15 years. my 2 biggest problems was catching the last wheel after my rotation and suddenly have to accelerate when people were attacking or coming out of corners. I would go for a “click” and I was maxed out and missing the wheel all while spinning over 130-135 rpm’s. I felt like I was dropped because I am not used to the accelerations and my bike is NOT set up for me. I have since been fitted, but I didn’t spend time with my purchase like I did on my TT bike.

Soooo, you guys think I should just swap out some cogs? These new ultegra compact cranks…can I swap out the big chain ring?

5

You can swap out the cassette for one with an 11

and/or you can swap out the chainrings to any size you want. Cost will be similar, difficulty of install is similar (easy in both cases)

I would recommend the cassette, it makes the bigger difference, and less likely to require that you get a new chain. If you later find that still isn’t enough, you can get 52/38 chainrings and be good to go.

6

I second (or third?) the notion of switching to an 11-xx cassette before swapping out chainrings. The math is there. It seems there is a preconceived notion that running a compact limits your potential. I am not a fan of this. Unless you’re pushing 32+mph and spin out at 90 rpm there is no need for a standard ring. As a spinner myself, I’d rather run a compact on flats and a standard on hills. I’d be hard pressed to max out a compact without the nicest of tailwinds here in Houston. However, I’d be limiting myself on the downhills of Austin without a standard.

My ideal setups would be a compact with an 11-23 cassette for flats and a standard with an 11-28 for hills. Tighter gearing with the compact/11-23 will help you dial in your proper cadence on flats whereas you won’t miss that slight inefficiency on hills with the standard/11-28 due to the higher variance in speed.

As for it not feeling “right” that could come down to fit, as mentioned.

I would go for a “click” and I was maxed out and missing the wheel all while spinning over 130-135 rpm’s. I felt like I was dropped because I am not used to the accelerations and my bike is NOT set up for me.
135 rpm with a 50-12 puts you at about 44mph. What winds are you riding with? I want some of that action. Well, not on the way back.

7

I’ll be the lone dissenting voice here. I road raced for several years, before compacts hit any kind of popularity. I’d race and train on a 54/42 with an 11-23 (or 11-21 depending on the course for the day), and sometimes would be topped out. Not “topped out” meaning spinning the 54-11 at 140 rpm, but staying in a comfortable cadence in the 54-11 while dragging along in the pack (and wondering who the hell was driving that train).

So I’d say swap the cranks. Put the 50 on the TT bike, and the 53 on the roadie, AND swap the cassettes. If you’re gonna be doing spirited group rides like that often, gear up.

8

Of course the trick is, depending on the local terrain, it can be far better to occasionally hit an uncomfortable cadence, than to run out of gear up a 19% hill!

I’ll be the lone dissenting voice here. I road raced for several years, before compacts hit any kind of popularity. I’d race and train on a 54/42 with an 11-23 (or 11-21 depending on the course for the day), and sometimes would be topped out. Not “topped out” meaning spinning the 54-11 at 140 rpm, but staying in a comfortable cadence in the 54-11 while dragging along in the pack (and wondering who the hell was driving that train).

So I’d say swap the cranks. Put the 50 on the TT bike, and the 53 on the roadie, AND swap the cassettes. If you’re gonna be doing spirited group rides like that often, gear up.

9

Of course the trick is, depending on the local terrain, it can be far better to occasionally hit an uncomfortable cadence, than to run out of gear up a 19% hill!

I was pretty much a mountain goat, by Washington standards. I did just fine with a 42/21 on most climbs, and on REALLY long/steep ascents, the 23. Not saying I recommend that kind of bottom gear for any one else, but the top end is relevant here.

And I can’t ride that kind of gearing now… Ah, to be young and stupid again…

10

[quote Tri or DieThanks to both of you…ok, this now sounds like cheaper fix. where I live is dead-pancake-flat. we do have consistent wind so when we get infront of a tail wind, the speeds were higher then I was ready for (95% of my riding is solo). I am new to the nervous-bunch-pack-cycling though I have been racing triathlon for 15 years. my 2 biggest problems was catching the last wheel after my rotation and suddenly have to accelerate when people were attacking or coming out of corners. I would go for a “click” and I was maxed out and missing the wheel all while spinning over 130-135 rpm’s. I felt like I was dropped because I am not used to the accelerations and my bike is NOT set up for me. I have since been fitted, but I didn’t spend time with my purchase like I did on my TT bike.

Soooo, you guys think I should just swap out some cogs? These new ultegra compact cranks…can I swap out the big chain ring?

Are you sure about that? 50x12 at 130 rpm is 43mph…

“Back in the day”, I used to do NRC races and never used anything smaller than a 39x23. If at all possible I’d use an 12x19 or 12x21 to keep the spacing close with 7 or 8 speed cassette’s. Now I’m older and of course, not quite as strong. But not by much. I can still make the front group over the climb of a local race with D3 pro’s in it, it just involves a LOT more groveling than it used to. Now I ride a compact, 50x36 and if it’s hilly a 12x27 cassette. The fact that I CAN make it up a climb in a certain gear does NOT mean that I SHOULD. Frankly, I think that if I had access to a compact “back in the day”, that I would have done better in some races than I did back then. Mashing a big gear was never my strong point and on steep hills I had a harder time that I would have with a smaller gear. Assuming that my young ego would have let me try it…

As for the flats, a 50x12 is a slightly bigger gear than Eddy Merckx used. 53x13 was the norm back then. I rode a 40km TT in 50:11 and never used anything bigger than 50x12. In fact, the only situation where that gear has been an issue is on one course that has a section with a perfect combination of a strong tail wind and downhill, but not steep enough to tuck. We hit speeds of around 45-50 mph and it was hard. Spin like mad, tuck in, repeat.

What I’m getting at is that a short burst of 120-125 rpm should be no big deal. If it is, then the problem is not the mechanical gears, but the legs pushing those gears. Granted, being able to spin at 120 rpm isn’t generally relevant to performing well in a triathlon, but it is to road racing and criteriums or groups rides. Gearing up might help some, but I suspect that the problem has more to do with a lack of acceleration than pure speed. If they are opening a big gap out of the corner you will have to hit a higher top speed than the pack to close the gap. With better acceleration you can follow the group and end up with a slightly lower top speed. The further back you are, the worse it gets. BTW, you can generally accelerate better in a smaller gear. Think about how fast your car is off the line in 5th gear…

In a 50x12:
90 rpm is 29.7 mph
100 rpm is 33 mph
110 rpm is 36 mph
120 rpm is 39.6 mph

Okay, show of hands. Who finds themselves at the front going 30mph for extended periods of time and wishes that they could go even faster?

BTW, one piece of advice if you have two different setups. Go with the 54 on the TT bike as the gear ratios on a 54 line up fairly well with the 50 for the small half of the cassette… i.e. 54x14 is pretty close to 50x13, so you’ll find yourself with fairly similar gears on the two bikes, just slightly more top or bottom end depending on which bike.

11

I like this web page to help you calculate which cassette will work for you.
http://home.earthlink.net/~mike.sherman/shift.html

I like the plot where you can put in your optimal cadence range, and see where the gears fall.

the difference between a 53/39 and a 50/34- is less that the compact is smaller, and more that it has a broader range. 16 teeth vs 14 teeth.

12

Why don’t you try switching the cranksets? Assuming they take the same bottom bracket, it’s like a 5minute process.

I’d be shocked if this were the source of your unaccountability on the roadie but just a quick swap may tell you.

13

You are not by yourself :wink:

I run 53/39 - 12/27 on both bikes. Last week during a group ride, on a flat road in a group of 12 bikes, with a slight tail wind I nearly spun out the 53-12 - and I’m no “big engine” at this time of year. That was in the drops on a 2009 Allez running 105, BTW.

I don’t like compact gearing because it doesn’t feel right to me for some reason. The front end shift is “awkward” for lack of a better term and in hills I seem to be constantly shifting the front end.

But, to each his own.

14

The reason your front shift on the 2009 Allez (which i also own) is awkward is that that bike packs a 34x50 crank which is the max a normal FD can handle in one shift. 53/39 generally shifts smoother because of the smaller jump between.

I have 50/34 on my rain bike and 53/39 on my race bike. Train on both, really can’t tell much of a difference. If anything, I prefer the 50 for racing because it gives you the option to power over some climbs in the big ring where others may have to downshift. As well adjusted as your drivetrain may be, anytime you can avoid a front ring shift in a road race, its a good thing.

15

I had the same problem with a fast group ride with tailwind. I was running 50X12 and spun out around 40mph. Changed to a 50X11 and it did not happen again.

I have now changed to Super Record 11 with 50,34 rings and 11X23 cassette which give me a nice straight block for most of the cassette.

as was noted earlier 50X11 is a bigger gear inch than 53X12 so any roady that tell you he can go faster on his 53X12 is full of it.

I live in flat lousiana so downhill speeds don’t apply but we have plenty of wind.

16

why don’t you just swap the cranks between your bikes? Then, if you need more gears on the TT bike with a compact, just put an 11xsomething cassette on it.

as has been pointed out, a 50x11 is bigger than a 53x12.

17

You are not by yourself :wink:

I run 53/39 - 12/27 on both bikes. Last week during a group ride, on a flat road in a group of 12 bikes, with a slight tail wind I nearly spun out the 53-12 - and I’m no “big engine” at this time of year. That was in the drops on a 2009 Allez running 105, BTW.

Are you saying 105 rpm or Shimano 105?

105 rpm is not anywhere near spun out by any roadie’s definition. In fact, that is about the cadence that most hour records are set at.

I’m not trying to be a dick here. It just seems that everybody goes straight for the bigger gear and never thinks about how they actually ride the bike and whether or not there are other things to consider. (like working on their leg speed…) Consider this, if somebody feels that they can’t run fast enough, what do they do? Look for better shoes? Or improve their run training program?

18

I like this web page to help you calculate which cassette will work for you.
http://home.earthlink.net/...e.sherman/shift.html

I like the plot where you can put in your optimal cadence range, and see where the gears fall.

the difference between a 53/39 and a 50/34- is less that the compact is smaller, and more that it has a broader range. 16 teeth vs 14 teeth.

This is a cool link, Thanks!

I went back and looked at my data from the last group ride (when I was dropped). Several things to consider from weekly run miles, morning swim set and etc. But, something has always felt off about my road bike.

My TT has Sram w/an FSA 53t/12. Road has Ultegra compact 50t/12. I love my TT bike. Love it. Should I just purchase the same crankset and put it on my roadie?

Anyways, I am getting the suggestion to switch cranksets first? And then cogs?

From my data, my highest cadence recorded was 143rpm, but averaged at 107rpm. I can not tell exactly when I was dropped because I tried to linger off the back for quite a while, but I really ‘feel’ like it was a cadence issue (more so a different kind of fitness that I am not used to.) I don’t know if this will fix the problemo, but, I will go ahead and switch it out…and…I am in my house trying to figure out what tools I need to buy to get both cranksets off. (I suck at bike mechanics and this stupid android bike tech download is USELESS) F my life!

19

Go with 50/34 and 11-- The 53/39 is over rated, like many have said!

20

Go with 50/34 and 11-- The 53/39 is over rated, like many have said!

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