I have that chainring (54) and its little cousin (42) on my TT bike...

But i took a picture of the wrong side, so yuo cant see it...

My guess it, It probably will gain you about 5 seconds over 40k...

But it is SOOOoooooo Cool looking, its worth it... And it is so FRICKIN LIGHT!!! It looks like it would be heavy, but when i took mine out of the box, BAM!!! it was like a feather... Incredible... Also the DA crankset is about 180-190$ and if you substitute the chainrings it is only 220-230... So the price difference is small... Also i like 54 teeth... With my 54 , i can cruise in my 16/17 at a good cadance... about 80-85... With my 53 my cadance goes up to 82-87... And i like the lower cadance... because i ride 177.5 mm cranks... Also you can get that same chainring in a 55 and a 56... Its sweet... Get it... Your bike will look AWESOME!!!

My understanding was that the chainring is marketed as providing increased stiffness as opposed to offering some sort of an aero benefit. Perhaps now they claim both? Personally, I think it's just another place to splash their name on your bike.

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the reason I am asking is because I am using Rotor Cranks now and I want to see if it is beneficial to have Rotor create an aero ring. I was using Dura Ace and the TT aero ring and noticed no differences. I alsop used the FSA ring which weighed 275 gms!! What an anchor. The DA TT ring is 75 gms heavier than the non-TT version.

Where are the freakin' SBW TT results???????????????????????

Someone asked this question some time ago on the Bicycle Sports board.

If I remember correctly, John Cobb said something along the lines of, "It will do you as much good as shaving your eyebrows."

Aero chainrings are (without a doubt) much higher on the cool factor than your standard chainring.

IMHO, if you have the cash, go for it, I wouldn't expect any time improvements.

-gc

HAHAHaha....

The SBW TT results are probably going to be posted the day after the next TT ! ! !

hahahaha....

The way i look at it is... If you want to volunteer, thats great... But if you dont acctually have the time to do what you say you will do... Maybe you should let someone else do it... Someone like me... Next TT i will ask for the results and all that... Then i will update the TT results .pdf file within 24 hours of recieving the data sheet...



DAMN!!!

I don't remember these chainrings ever being touted as "aero". They are advertised as being slightly stiffer than the 53, but I'd guess the difference is negligible in real world terms. Mostly, they just look cool. I used the 54 on my 650 bike to improve my gearing spread.

I think they're crap. The only aero chainring I have ever seen is a Bartol system. It gets rid of the aerodynamically unclean front mech. You also save the weight of a shifter and a cable, besides the front mech. The "aero" chainring is pretty silly and does not do much, except possibly stiffen the chainring marginally. Save your money and some weight- get a Bartol System.

well, I just installed the Dura Ace 54 TT chainring last week and instantly my shifting improved. Shifting on to the big ring during a ride also gives me a kick like "ok, let´s hammer it!" and that definitely makes me faster. I don´t know if they are aero, but they make a clearer area up front by hiding the little ring. And in crosswinds they might work like discwheels and transform wind in to energy. Or not :-)



Regards



Martin

If you like it, use it. I even like the way they look, but it is my blunt opinion that aerodynamics can be cleaned considering by using a viable system to get rid of the front mech that allows use of the big and small chainrings.

not compatable with Rotor

so far the bartol system (actually this is the system name but the brand is TISO) is only available as a 53 chain ring with 39 or 42.
If you want bigger, you have to use the TT chain rings made by TISO (that are very cool as coming in
black, red, green, gold etc....) up to 56 I believe.
They are lighter than the Dura ace too.
But these are "aero" but need a front derailleur.
That said, I heard TISO was planning at some stage to get these aero chainring available with the bartol system, which would be very very neat...

www.cyclinginnovations.com
www.tisobike.com

Martin, what are you using as the small chainring?

I've been thinking of using the 54 with a stock 39.

Simon

it´s supposed to be used with a 42 tooth ring (this is printed on the big ring!) for perfect shifting and hiding. That´s what I use with 12-21 or 13-25 depending on the course.



Regards



Martin

Hi, this is Dave at FSA.

To answer your question:

The FSA disk chainrings are designed with only one goal in mind: for speed on the road, for aerodynamics and stiffness. The intended user is the top pro athlete.

Most certainly, the drag of the spinning crankset and chainwheels is significant. Keep in mind that although they are a relatively small component, they are spinning 3x or 4x faster than your wheels! As we all know, drag increases at a much higher rate than speed. So, there is a lot of drag there. Also, the airflow is quite turbulent, as you would expect.

(Aside: The FSA chainrings are not just filled-in, like flat aero chainrings, they are bulged wider than a flat chainring. Not only does this increase the stiffness, but it helps fair the airflow as it comes off the chain and also fair in the turbulent region between the spinning crank-arm/spider/pedal/foot. (This is similar to a lenticular disk wheel or bulged aero-rim, which helps control the airflow as it comes off the tire.))

As for the weight, comparing a disk chainring to a standard chainring is like comparing a disk wheel to a lightweight spoked wheel. Different designs for different purposes. The main criteria for a traditional chainring is that it should be as light as possible while being strong enough and acceptably stiff, with minimal regard to aerodynamics (similar to a lightweight road wheel). The criteria for a disk chainring or a disk wheel is: speed!

Furthermore, part of the weight difference is that larger chainrings are inherently heavier (they're bigger!). For examples a 54 or 55 or 56T chainring will be heavier than a 53T Unless the 56T is reinforced to increase the stiffness to the same level as a 53T, the 56T will be more flexible. So, a 56T traditional chainring with the same stiffness as a 53T chainrng will be noticeably heavier.

(Aside: As for the looks...hey, the FSA chainring looks great, if I do say so myself...they mean business (and they just plain mean-looking!) It looks even better up close, where the true quality and detail is apparent. Unlike most chainrings which are stamped and/or cut from 4mm plate, the FSA disk chainring is 100% CNC'd from a solid slab of 10mm AL7075 plate. That equals a lot of machine time and material cost! The logo is fully by laser-marking (=time-consuming=$$) which will not wear off. )

Dave

 
The Bartol system looks good (had a look at tisobike.com) but how does it actually work?

there is some machining and a few extra metal parts on the inside of the big chain ring that, depending on the chain line will switch from small chain ring to big one or vice versa.
in short, it chooses the most efficient chain line from a mechanic point of view.

I would not race a road race with it, but it shifts decently for a TT/tri situation. Do use the included "protection" (a small puiece of aluminium that mounts to the BB), as the chain CAN (and sometimes does) get thrown, but easily remounts itself without getting off of the bike.

Some of the kinks are getting out of it. I had to file a tooth down to make it not skip on that tooth. I believe a lot of the little silly problems are worked out. I highly recommend it for any TT bike, just not a road bike.