oversize chainring plus 12-25 cassette on 700c is just asking to be laughed at in the racks. that is the down side to doing it for the looks. plus the risk of being over-geared. as for the difference, go to sheldon brown gear inch calculator. Also note that big rings usually (have to?) go with 42T inner CR and there you will really notice the difference!

Wow, didn't realize I would be a laughing stock! ;)

Only amongst the linguini-legged, lilliputian lightweights.

I just went 2:15 in a flat half Ironman bike with my biggest gear at 48x12 and most of the time I was only in a 48x13 or 48x14. Even on a hilly course , the 48x12 at 110 RPM gets you up to around 60 kph on a downhill. Anything faster and it is better to coast and save your legs for the run. You don't need 54 or 55 and you likely only need a 50. Last time I checked, my engine is not even 10% lower than Lance (likely more likely 33% lamer based on my Alpe d'huez climb speed), so realistically if I am 10% undergeared compared to him this will suffice. You certainly don't need bigger gears than Lance.

Dev

"fastest man on a 48 tooth chainring"

Depends on the cadence you ride. And the type of racing. I think the added slightly increased gearing of a 55/42 over 53/39 when paired with a 12-XX (either 23-27 depending on the course) is a better choice if you can push it. If there is a ripping tailwind on a flat course, you may not want to be spinning 110 rpm's. You may prefer to be riding at your comfortable cadence and keeping watts consistent.

55-12 is about 1/2-way in between 53-12 & 53-11. People who say you only need a 55 if you spin out a 53-11 are just silly. It is about what gives you the best gearing in the meat of your cassette. If you like to ride 80-90 rpms and have decent watts, then a 55 might be a good fit for you.

Remember, Lance & the other UCI riders have HUGE climbs, the likes of which you will never see in a triathlon. And when they are riding really fast it is in the Peloton, which is a whole different beast. You will see many of them riding bigger rings on their TT bikes.

Rings are not that pricey. You can always buy a pair and see if they work for you. eBay them if not... FYI, do NOT use FSA rings with Shimano drivetrains. Use Shimano rings. Use FSA only with Campy drivetrains...

I am planning on switching to a 55/42. If I don't like it, so what. I think it'll give me more of what I want in the middle of my gearing and a slightly preferable range. I plan on pairing it with a 12-27 for hilly courses and a 12-23 on flats. From looking at gear calculators, both of those seem much more usable than a 53/39 paired with a 11-21 or 11-23.

It does help to be able to back up your ring selection with some watts, though...

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

"I think they look pretty cool"

Not cool but actually a bit silly if you undertand the science behind it. Many of these guys would actually do better on 50/34 compacts. Ulrich types are a minority among AG'ers

The exceptions are genuinely powerful riders who turn naturally at a low cadence and tend to not live in hilly areas.

Why not use FSA rings with Shimano? I used the 54t FSA with Shimano 9 speed and had no shifting problems at all.

The 54t with an 11t raised my spin out speed from 35 to 40 mph. It definitely made a difference on any long, gradual descents or tailwinds on the flats.

Since I moved, I am now using a 53/11 as the riding here has steeper descents and 40mph comes real quick and there are very few flat tailwind sections.

"You know you are getting old when you see your father in the mirror." anon.

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Dean Wilson
http://www.anaerobiczone.com
Bicycle Protection Indoors & Out

There are no shift-ramps on the FSA rings. Shimano, at least D/A-10, does not shift well without the shift-ramps cut into the back. Tom Demerly posted about this. Similar problems with the FSA compact on a Shimano drivetrain vs. Campy. Campy does NOT use shiftramps on the rings. It may work, but not as smoothly as it will with Shimano rings.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Hello,

My theory is that gearing should be chosen by the low gear. You definately don't want to run out of gears. But for your ride at the flat half you would have been better off with a 55 X what ever and rode with a straight chainline on bigger cogs rather that small cogs. Not a big difference but every free watt counts, especially when you are already doing 2:15.



Styrrell

I race a 55 - 11 at states TT, nothing to laugh at when going 30 mph (of course, with a tailwind)

"People who say you only need a 55 if you spin out a 53-11 are just silly. It is about what gives you the best gearing in the meat of your cassette."

The meat of the cassette is 3-4 cogs wide. In a 11 or 12 configuration, the meat will include maybe 13, definately 14, 15, and my fav 16. So if you really feel undergeared running 53x14 or 13 on an 11-23 then yes maybe a bigger CR is warranted. But 53x13 is a freaking big gear to push for 3 or 4 hours... so how many upgrades in the rack do you reckon are ego/cool driven, and how many are giving the rider optimal gearing???

"if you can push it."
There's the rub. I don't reckon hardly any AGer can push it effectively. Unfortunately a lot can fake it and then fry themselves on the run.

Of course the other big problem with jumping to big rings for hilly TTs (i.e, all IMs bar FLA) is the jump from 39 to 42. That 8% will really make itself felt on the run.

Also, smaller CRs (compacts) plus smaller cogs are lighter, usually deliver better bailout gear, and are IMO more aesthetically pleasing (b/c it is a smart choice for me and most AGers rather than impulsive "what does Jan ride?" choice)

But whatever. If money is no option get 2 of everything.

I was wondering about that. Is that a fact? Do you know what the watt loss is for running say 53x11 versus "straight" 53x15 or 16? I would have thought it was negligible but what do I know.

"Also note that big rings usually (have to?) go with 42T inner CR and there you will really notice the difference!"

Says who? I'm running 56/39 with no problems. So I've got enough on the low end (39-25) to get up the hills, and then plenty (56-12) to smoke 'em on the way down. No, I can't push 56-12 on the flats, but I heard several people say "holy shit" as I roared past them on the downhill section of San Jose International this year.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

I guess a better question might be - "Up to what speed should I pedal in a 1/2 IM?" I personally start banking watts at 28mph and cease pedaling entirely at 31-32mph. Those numbers would go lower for a full IM. I'm on the bigger side and a decent rider with a preferred cadence in the mid-80s...and I'm thinking of going to a compact for my P3.

Maybe a sprint tri would be different but putting 300watts into 35mph gains you awfully little relative to spending those watts at a lower speed (%speed increase for 300watts at 35mph is really small when you factor in you could be doing 0watts at 32mph).

ot

true in a half often you want to tuck and coast to save your legs, but then there are those shorter races like sprints and olympics where you have to get your legs a bit toasty if you want to be close enough for that run;) granted I rarely spin out my 53/11 but sometimes it happens and with a tailwind on a slight downhill I'm sometimes wishing for a bigger gear. I'm very tempted to go with a 55 or 56 front ring. I am a tucker though, spin up to max speed hard and then tuck as small as possible, definetely NOT in the aerobars, on a big descents. Probably tucking at anything over 35 mph or so, but will often keep pedalling to 40mph before kissing my stem.

some days here in Hawaii with a good tailwind coming back on the worlds course you can hammer it at 30-35 mph most of the main straightaway (5 miles or so) back to T2. Yeah 30-35 but you put a pretty hefty down payment on that return rocket ship ride on the way out;)

one thing nobody has noted, if you are running 650 (I'm not) you very well may want a bigger front ring to compensate for the smaller wheel diameter.

[reply]There are no shift-ramps on the FSA rings. Shimano, at least D/A-10, does not shift well without the shift-ramps cut into the back. Tom Demerly posted about this. Similar problems with the FSA compact on a Shimano drivetrain vs. Campy. Campy does NOT use shiftramps on the rings. It may work, but not as smoothly as it will with Shimano rings.[/reply]

mine shifts fine....

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I shall never misuse Rex Kwon Do
I shall be a champion of freedom and justice

Your're absolutely right Tai. A 55 x 11 on a 650c bike is still geared slightly lower than a 53 x 11 on a 700c. On mostly flat courses, I'm always in the 55 x 11 and sometimes feel I can use an extra gear so I'm going to bump up to a 56.

I think in the end it boils down to what your legs can push and what you want to have left after your ride....most top level time trial riders run 53 to 57 with 11-22 in the rear and no small ring!!! but like i said they are spent after there ride....it's your choice, after all isn't what this is all about??? knowing your limits and pushing it to the max at each step...

I'm running 56/39 with no problems.

Wow. That is good to know. I assumed there would be shifting or der clearance problems. That would seem to give the best of both worlds, but of course there would be an annoying jump from one ring to the other.

I ride a 55 on my Triathlon/Time Trial Bike which has 650 wheels and stay in it the majority of time on the flats ( & could maybe ride a 56), but would never have a chainring that large on my road bike with 700 wheels.

I ride a shimano 55-39 with cassettes from 11-23 to 12-25 I did lake placid and on the 25 and a local flat half on the 11-23. I have a low cadence and on local rides in the flats rarely get out of the low half of cassette and never off the 55.

I had the 53 stock gear and knew that i could push much harder and more comfortably than the gear would allow. So for the $90 I bought the 55 and have loved it since.

Like it has been said try it if does not work for you ebay it.

I have some other gearing if you want to work a deal pm if interested.

K

"I assumed there would be shifting or der clearance problems."

As did I. Chain length is critical, and I'm thinking about switching to a long cage derailleur in order to use am 11-27 cassette. I'm a weak climber, but for some reason I can hammer past most folks on the flats and downhills, so that tall gearing is important to me.

For flatter courses I'll go 11-23 or 12-25. but if I need small gears to get me up a hill, it's a cinch I'm gonna wat some huge ones coming down.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

You may want to read the attached Slowman article regarding compact cranks. http://www.slowtwitch.com/...techctr/gearing.html

I am a recent convert and think that they are brilliant. You have a tighter range of gears in the middle of the cassette allowing you to dial in based on cadence. The only change I am considering for the flat lands is to increase the small ring from a 34 to either a 36 or 38.

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Jim

I used the FSA 54 and realized I was kidding myself. When I read D Paul's reports, I went to a 50 and have been very happy with it. I like to ride at a higher cadence and this has worked well for me.

Now if anybody's interested in an aero 54T...

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