Why use disc wheels for a time trial

Here's a list of supposed gains to be had with different aerodynamic setups. If you have the option to use the bike a few times to get a feel for it (and it feels fine) I see no reason to not use it.
http://www.timetrial.org/aerodynamics.htm

There are new rules now that state that in road races all wheels must pass certain tests unless they meet certain other criteria (something to do with the way they break on impact. Do they create dangerous edges etc that may injure other races in the event of a fall). Most carbon wheels dont meet these standards. The ruling is different for TT's though, so u often see people bring out there "fast" wheels. I might also make a point that many of these wheels are actually heavier, and more cumbersome in crosswinds than your normal road bike wheels so over a longer/hillier race there is no advantage in having the extra aerodynamics anyway. In a shorter TT race there is normally fewer hills and the crosswinds are of little worry over this distance. You are not going to be blown sideways into another rider in a TT are you?

On the topic of a different bike, i would say that with a couple of rides on it (preferably at race pace) then it shouldnt be a hassle and will infact help rather than hinder your performance.

As to why the guy who u beat on the first day, has beated u by 51 seconds on the second may have something to do with tactics and bunch riding skills as much as anything. U may be able to hold a wheel much better in a bunch and therefore get further for the same amount of effort. Or it may be on account of the course. U may be a better/worse climber/flatlander etc, and this is what contributed to your result in the race the day b4. There are many factors that can change the result of a race. Then again his disc wheel and carbon tri-spoke probably helped somewhat!!!

Simply put, some people are great TTers, and not so great at RR.

Over a 13 mile TT, I would not bother, especially if there any hills at all. The aero benefit comes from a longer TT, where a tiny advantage can begin to add up to something more meaningful.

Of course, the exception to that is the rider's position. For a 13 mile blast, you could handle a really aggressive body position (i.e., parallel to the ground) which is way more aero than what you would choose for a 112 mile Ironman bike leg (body at least somewhat more upright).

But, you have not been training in the aero position... you will definitely need to adapt to that, and its effect on your legs (most tend to use more quad power in that position). That's why tour riders train in the aero position once in awhile all year.

Altho i agree w/ the observation that some make great TTers and others RRers. But lets consider for a moment that both of u are of equal capabilities. In 1989 Greg Lemond won the TdF in the final stage which was a 26km. TT (a little more than your 13 mile TT). He won by 8 seconds over Laurent Fignon who had a 50 second advantage over him before the start of the race. In other words he gained 58 seconds over Fignon in just 26kms. The interesting part is by comparing their kits:

1) Both men used 26" wheels up front but Fignon used solid discs front and rear while Lemond used a laced-up wheel up front and solid discs at the back.

2) Lemond used a Giro Hammerhead Aero helmet (with its rear chopped off to be w/in the UCI helmet regulations) while Fignon chose to wear nothing over his ponytailed hair-do.

3) The biggest difference was the use of profile tri-bars by Greg.

The last actually pave the way for the use and later on, popularity of tri bars on TTs and nowadays they have become invaluable. Here is the tale of the tape how Aerodynamicists assessed Greg's win in terms of equipment and style used (as shown in Bicycling Magazine):

Lemond Fignon
Disc Front - +8 secs.
Skin Suit - -
Tri-Bars +20secs. -
Aero Helmet +10secs. -
Ponytail - -10secs.
Steady Posture +10 -
Erratic Posture - -10secs.
-----------------------------------------------------
Total +40secs. -12secs.

Above as shows Lemond gained 52 secs. over Fignon. Of course Greg being a superior TTist vs. Fignon gained more than that. The interesting part is where Fignon gained over Lemond and that is in the use of a front disc.

Also Lemond concentrated on his aerodynamic tuck perched steadily in his seat which gained him valuable seconds while Fignon stood and stomped on his pedals whenever he wanted to gain momentum only contributed to him losing more time.

On Solid Discs & Spoked Aero wheels:
Solid discs are susceptible to crosswinds. Using solid dics up front on windy days specially if its a cross wind will make your front end unstable versus spoked wheels. A rear disc and a spoked aero wheel up front is a good compromise.

Quoted post said:

Originally posted by dennis dee
Altho i agree w/ the observation that some make great TTers and others RRers. But lets consider for a moment that both of u are of equal capabilities. In 1989 Greg Lemond won the TdF in the final stage which was a 26km. TT (a little more than your 13 mile TT). He won by 8 seconds over Laurent Fignon who had a 50 second advantage over him before the start of the race. In other words he gained 58 seconds over Fignon in just 26kms. The interesting part is by comparing their kits:

1) Both men used 26" wheels up front but Fignon used solid discs front and rear while Lemond used a laced-up wheel up front and solid discs at the back.

2) Lemond used a Giro Hammerhead Aero helmet (with its rear chopped off to be w/in the UCI helmet regulations) while Fignon chose to wear nothing over his ponytailed hair-do.

3) The biggest difference was the use of profile tri-bars by Greg.

The last actually pave the way for the use and later on, popularity of tri bars on TTs and nowadays they have become invaluable. Here is the tale of the tape how Aerodynamicists assessed Greg's win in terms of equipment and style used (as shown in Bicycling Magazine):

Lemond Fignon
Disc Front - +8 secs.
Skin Suit - -
Tri-Bars +20secs. -
Aero Helmet +10secs. -
Ponytail - -10secs.
Steady Posture +10 -
Erratic Posture - -10secs.
-----------------------------------------------------
Total +40secs. -12secs.

Above as shows Lemond gained 52 secs. over Fignon. Of course Greg being a superior TTist vs. Fignon gained more than that. The interesting part is where Fignon gained over Lemond and that is in the use of a front disc.

Also Lemond concentrated on his aerodynamic tuck perched steadily in his seat which gained him valuable seconds while Fignon stood and stomped on his pedals whenever he wanted to gain momentum only contributed to him losing more time.

On Solid Discs & Spoked Aero wheels:
Solid discs are susceptible to crosswinds. Using solid dics up front on windy days specially if its a cross wind will make your front end unstable versus spoked wheels. A rear disc and a spoked aero wheel up front is a good compromise.

wow, do you ever read your own posts

Quoted post said:

Originally posted by fushman
wow, do you ever read your own posts

No, i just write them.

Quoted post said:

Originally posted by dennis dee
No, i just write them.

well maybe you should change that cause that post was just embarassing

Quoted post said:

Originally posted by fushman
well maybe you should change that cause that post was just embarassing

Well as long as I have fans like you reading it then that makes it worthwhile. Its not the first time and I get all sorts of posers like you green with envy. If you want to be a superstar be my guest. But do it at other poeple's expense. I bet its the only thing you know - crab mentality.

:o :p

Quoted post said:

Originally posted by dennis dee
Well as long as I have fans like you reading it then that makes it worthwhile. Its not the first time and I get all sorts of posers like you green with envy. If you want to be a superstar be my guest. But do it at other poeple's expense. I bet its the only thing you know - crab mentality.

:o :p

um, youre post is still embarassingly bad

Quoted post said:

Originally posted by fushman
um, youre post is still embarassingly bad

Thank you for liking it so much.

as sd5500 stated...some better are better at tts than others. and some who would be good at tts just don't want to do the pain. I'm a much better time trialist than road racer...2003 age group state champion. go for all the aero you can, no matter what the distance (except on uphill time trials, then aero might hurt rather than help.) believe me, some riders will have the full gear out and will be knocking seconds off their time because of it. if a disc is worth 30 seconds in a 40k tt, it ought to be worth about 15 in a 13 miler. if an louis garneau prolgue helmet is worth 30 second in a 40k, then...you get the picture. you'd hate to lose by 4 seconds to some guy riding a disc. especially if you can borrow the stuff because I know everyone can't afford tt gear for just a few races per year. and the front wheel is even more important...you need deep section rims...more than 38mm.

and one other thing...during a road race, you're racing at the leader's pace. you have to go when he goes (even if the leader changes during the race) even if you're red-lining. during a tt, you race at your steady pace with out the wild swings in heart rate. its a high hr, and you have to train to be able to hold it for 50+ minutes, but its yours.