It's not legal..

Pantani used to race like that (in the pro cycling ranks), as did Joe Bonness...

Not legal for UCI? or for Ironman? or USAT? or all of them

Where is that rule?

I looked up the GTG rules. I don't see any mention of this.

http://www.globaltrigroup.com/assets/pdf/competitiverules.pdf

Actually, I was just double checking this....and it's interesting. The rule is a UCI rule. But according to the rules adopted by USAT, you are allowed to run a front wheel with a different diameter than the rear wheel.

So unless what I just read has been amended, I guess your question is a good one...

Use to be very poplular but.....not really visually appealing [unless your talking the HOOKER aero bike]...

lower front end...yes but most would not be flexible enough to make it worth while or want to be that far over [hard on the back and hips]

reduce weight....yes but not enough to make a big difference

more aero wheel...not really, same wheels only 50c smaller...more aero body position though

I think the other reason it's not popular is it required teams to carry 2 seperate size tube's...2 seperate size wheels and most "funny bikes" used thinner front fork width so it required custom front hubs.....

I have seen a few Elites like this and thought Joe Bonness' Elite was at one time 650/700.

1. Beauty is in the eye of the beholder. Who cares if it faster

2. Maybe not as comfortable, but being aero isn't as comfortable as riding a slack road position, kind of moot if one wants to be more aero

3. Weight: still lighter, plus the fork would be smaller and lighter

4. Wheel + different fork for smaller wheel would be more aero. Plus body position probably more aero

5. Different wheel sizes, whats the big deal, clincher inner tbes aren't that heavy or big to carry with you.

6. I don't understand the hub comment, seems like one could buy off the shelf 650 fork and wheel.

The question isn't 'why aren't people doing this?' Now that we've established its legality (only in non-drafting USAT races, mind you) and it's been done (most recently by Joe Bonness and Elite)--the question is, why aren't YOU doing it, therascal?

For what it's worth, i've seen Marco Pantani's old Wilier TT bike with the 650 front and 700 rear, and it does look cool. So go for it!

#1. i'm not the masses...i like it...

#2. take another 1" off your current set up and see how long you can ride for

#3. yes but not much

#4. true

#5. instead of carrying one size your now carrying 2 or 4 if you want doubles

#6. you could buy off the shelf but your frame is not designed for 650/700 so the geometry is all wrong...most frames that were design for 650/700 had custom forks to allow for a narrower front end...hence the custom hubs...

it mainly has to do with hip angle, and getting low while keeping the hip angle as open as possible, to increase power, as you can sit 1" higher with a 650 front wheel while keeping the same height as on a dual 700c set up

for UCI and USCF (?) races it is illegal, I think it is USAT legal still

Could be more aero, but...... only if it enables you to get lower on the front end, you would need to be pretty short for it to work, if all you had was a taller head tube the drag would probably be higher.

When I was track racing back in the late 80's early 90's many people used it for the team pursuit and for team TT's because you could get a little closer to the rider in front and get a slightly better draft. Also in those days the old style quill stems and headsets wouldnt allow you to get as low as the newer style threadless do so it was an advantage to run the smaller front wheel.

I remember in a tri in Australia in '89 (I think) there was a bloke using a custom built funny bike with a 24 inch front wheel. The problem was he couldnt get anwhere near low on the front end so he had the headset extended with a stack of spacers 2 inches high. It looked pretty stupid.

Good question. You see a lot of those "funny bikes" from the 80's with the 700/650 on ebay at a very good price. It would be easy and cheap to update one for tri.

Surprised nobody seems to have done it.

It would only be more aero if it allows you to get lower in front. And then you still have to be able to power the bike through the air.

But as for whether the wheel itself is more aero... No. Anything you gain with the wheel you lose in longer frame tubes.

And then you have to carry 2 spare sizes.

Now I remember the REAL funny bikes... 700 rear and a 24" front. The Shogun Kaze... Fuji Team... (there's a shop near me that has a Fuji Team in mint condition with Shimano Sante... I'm tempted)

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Some are born to move the world to live their fantasies...

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The small front wheels were originally done for team TT and team pursuit racing. It let's the drafting rider get closer and it let's the drafting rider see the wheel better. Back in the 80's it was a little more aero because there were not any deep section front wheels but when they came out, then having the more surface area of a 700c was faster. The rolling resistance want add up to offset the added wheel rpm, carrying 2 different size spares for a Tri is a hassle.

SOunds interesting but I'm guessing if you tried it on a regular bike and just slapped on a shorter fork you'd really screw up the handling as the fork would suddenly be x degrees steeper and I imagine that'd make the bike really twitchy

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"Are you sure we're going fast enough?" - Emil Zatopek

"I imagine that'd make the bike really twitchy "

A guy in our roadie group several years back tried to convert his old funny bike into a road bike with drops, STI, etc.

He was a fairly good roadie rider but was wobbling all over the road so badly that nobody wanted to be near him.

I ride one, a steel frame DaVinchi from Italy (not the company that make the tandems), all campy. Strictly a TT type bike. 52/42 chainring. Very comfortable for short, fast rides. Not so nice for longer stuff. I just bought a road bike to do the long rides and I'm trying to decide if I will keep the funny bike to race with. I may sell it. When you walk into a bikeshop with it, people look at you like your from outerspace.

J

Another factor is that with modern integrated head sets and low profile aerobar pads that it is much easier to get super low on a 700c frame.

Also despite the fact that they are still legal in triathlons, the fact that it is now UCI illegal means that fewer companies will even make them.

As far as Joe Bonness goes, his old Nishiki funny bikes had a 24 inch front wheel and threaded head sets. I am pretty sure that when he went to Elite that his funny bike was custom and it had a bigger front wheel than the Nishiki having a 650. I am not 100% positive if he is as low as the previous 2 bikes but he is very low on the duall 700 Trek, it uses a downsloping stem. He told me a couple of months ago his drop is 7 inches which is ~17.8 cm drop.