On Dec 19, 1:52 pm, "
[email protected]"
<
[email protected]> wrote:
> Hi All,
>
> How do 80's funny bikes compare to contemporary TT bikes? To a
> contemporary road bike?
I have no firm idea. That won't stop my informed guesses!
> How much time is the smaller 24" wheel worth? How much is lost with
> the bull-horn bars vs aero bars?
The single biggest contribution to TT aero is the rider's position.
The single biggest non-rider contributor is the front wheel, and I
think the head tube may also be an issue.
I think the current wisdom is that all other things being equal, a
funny bike with a small wheel doesn't confer a meaningful aero
advantage. That is, if you built the most aero UCI-legal bike
possible, and then started again with a 24" front wheel, the resulting
bike wouldn't be any more aerodynamic. The frontal area doesn't really
change, because the seat height can't change, which means your body
doesn't get any lower. It's really just a question of what bike parts
actually face the wind.
But everything is not equal: modern deep-section TT wheels will be
more aero than your 80s-vintage small wheel. And the bullhorns will
put your body in a less favorable TT position.
> An 80's vintage 24" wheel has come into my possession, and I am
> considering building a period TT bike around it. With a little coaxing
> I can get my old frame back and I have almost all the other stuff too.
>
> And then I'd use it! Find me some of those old Oakleys and I'd be in
> business! But would I have any chance in the local ITT's or would it
> just be silly?
Your biggest problem might be the local authorities: current UCI TT
bike rules mandate equal-sized wheels, so if the commissaires are
sticklers, you won't get to start.
As for what chance you have, it's mostly about the motor. My feeling
is that the best use of ITTs is to race against yourself, and measure
against what you did on that bike last time.
Hopefully Carl will run a few numbers through one of the bike
computers to tell you how many seconds a good bike versus a bad bike
is likely to cost you in a 10k TT. It's not a lot, but it may be
enough to be the margin of victory, if you're a competitive rider in
the event.
But a funny bike will not be so slow as to be hopeless. in a typical
Cat 4 race, the TT performances are likely to be so widely distributed
that if you're a mid-pack rider on your road bike with no TT bars,
adding a full TT package will make you into a slightly better mid-pack
rider. Do you have some results we could see from previous events?
