Johno59

Amazing bicycle but how would you get a horizontal back?
The front forks are wrong. It needs a 24 inch front wheel.
Ah hah!. Upon closer examination I see the front forks aren't original.
How do I know? Coz I have a proper one with a junior 24 inch , 100 mm spaced front fork.

malcala622

VintageTTfan



This one arrived last week from Colorado.

Johno59

All wheelchairs wheels are 24 inch Junior. You can get clincher or tubular, high or low spec. No problem. 100mm axle hubs more difficult but Brampton folding bicycles are all 100 mm hubs. They range from cheapo to titanium IED-proof but eye-wateringly expensive.

Trakhak

Yes.

Very few of the people who currently own a plongeant bicicleta understand how to set it up as originally intended, judging from the photos.

Correctly done, the rider's position should be nearly identical to that on a conventional racing bike, with the bullhorns positioning the hands where they would be in the hooks of the conventional bike's drop bars or slightly below that level.

Also, depending on the steepness of the top tube slope, no more than 3 inches of the seat post, if that much, should be visible if the bike is the correct fit.

Finally, look at photos of the funny bikes ridden by the pros in the '80s. You'll never see one where the saddle isn't level.

This thread is absolutely one of the best ever started on BikeForums, and we should be grateful to VintageTTFan. It's just a shame that so many of the setups in the photos are just wrong.

I think many of us here would agree that a 1980's-era pro-level racing bike, conventional or plongeant, set up correctly, is aesthetic perfection, never to be surpassed. But funny bikes with wacky setups grate on the senses of those who know how they were meant to be set up.

For me, the effect is the same as that triggered by the sight of a racing bike with the bars rotated up and back, DUI rider style.

Johno59

This angle of the lotus bike shows the single bladed steerer and the one side only seatstay and chainstay..

T-Mar

You should never ride with straight arms. It decreases the amount of control and shock absorption. It's true that it consumes energy to maintain an optimal aero position with bullhorns but it's more than offset by the increased aerodynamics, resulting in a net gain in speed. A trained athlete can ride bullhorns in this position for over an hour, which easily covers most TTs.

Aero bars have a similar issue. They reduce power output due to compression of the chest cavity which reduces oxygen intake. However, they're still faster because of aerodymanics. The energy savings from the supported forearms is a secondary benefit.

Aero bars are just about unrideable on rough roads due to shock transmission, especially when paired with stiffer aero wheels and forks. This, in conjunction with the decreased steering control increases the crash probability.

While the aero bars were a factor in Fignon's loss,he could still have one without them, were it not for his saddle sore or the the decision not to use his aero helmet. The relevant point is that UCI permitted a non-level playing field by allowing Lemond to compete with the clip-on aero bars. Technically, they were illegal under the rules that were in effect at the time.

P!N20

Stelbel did some pretty mad frames:

T-Mar

Here's my candidate for the 1st of the modern TT/Pursuit bicycles. It's a 1976 Assos. Notable features include what is considered the 1st bullhorn handlebar (though one could argue that they date back to the 19th century, just like disc wheels). The fork is straight bladed. The wheels are 24 spoke, radially laced. The frame has aerodynamically shaped tubes including a faired head tube, all in carbon fibre. Daniel Gisiger rode it at the 1978 World Championships in what is claimed to be the 1st cycling skinsuit.

markwesti

Happy Thanks Giving !

markwesti

Right , OK , a little bit more C&V but I do miss the skin suite ..

markwesti

Sorry VintageTTfan , the Thai chick is looking a little butch , seriously she could prolly kick my ass . And that CF bike , it hurts my eyes not to mention the shot was taken at a drome . And I know for sure the Velominati would not approve of where she parked her safety glasses . https://www.velominati.com/ .

Johno59

One of the surprising findings of the research that went into Broadman's hour record was the fact that there was no cardiovascular loss when he assumed the highly contorted body position on his hour record bike.
Having done probably 30,000 miles over the last 15 years flat out on TT bikes in the UCI allowed position, I would agree with these findings.
I've done about 10K on a bullhorn TT bike and the extra effort does extract a toll in the last 5 miles when you start to hallucinate and begin to bonk out.
You get used to steering in the aero position and I have brake levers for both the aero and the postman position but it's a TT bike and you learn to transition if you want to live.
Fignon described it best when he remonstrated that Lemond had an unfair advantage as Lemond had four points of support - elbows, feet, seat and hands and he had only three.
One thing not often mentioned is the aero position is much warmer in winter as you are tucked in and your warm exhaled breath flows back over your ears as well as down your chest.

P!N20

Don't know much about this, but it's probably made by Denti for the Gregorad bike shop:

Johno59

Same same

.......but very different.
What these two photos reveal is that Boardman was not a big guy nor was he muscular like the modern day speedsters - he was merely faster.

Johno59

T-Mar

The Superman position was pioneered by Obree. He used it to win the 1995 World Championships. Boardman adopted the position and used it set a new record in the 4000m Pursuit at the 1996 World Championships. Very soon afterward he set a new Hour Record. Both were accomplished while Obree was afflicted with a virus. The UCI wasted no time instituting a new rule that made the position illegal, before Obree could regain his health and make his own attempt.

Unlike a traditional aero bar position, neither Obree's original Preying Mantis or Superman positions constrict the breathing. The cantilevered, Superman arm position provides the least support for the upper body, even less than bullhorn bars, yet Boardman used it to set world records in two disciplines.

Since the Superman position was used on the track, shock transmission is not a concern. Even if it were used on the road, the shock is transverse to the arm and not not axial, like it is through the upper arm on a traditional aero bar.

T-Mar

Since the posts are now trending towards females in skinsuits and banned items. here's a picture of the Columbian women's team in their banned skinsuits.

Photo deleted per PM request of VintageTTfan.

T-Mar

Totally missed the girl. My eyes went immediately to the Simpson lever chain.

Reynolds 

Earlier in this thread I mentioned a pic of an experimental front wheel by Pino Morroni - finally I found it:



And a similar FIR posted by Bikeforums member Dawes-man:





Sorry if these have been posted before, this thread has so many pics that I'm not sure...

Shrevvy 

I love these old ads, but I'm not sure I get this one. What is going on here?

T-Mar

I've been interested interested in the Simpson lever chain ever since I first saw it in Toulouse-Lautrec's famous poster, back in the mid-1970s. I've posted about it several times. Most recent was https://www.bikeforums.net/classic-v...l#post20849812, where I included an 1896 review of the chain that explains its concepts.The chain had only a very short period of popularity before the company went bankrupt, making the photo relatively easy to date.

T-Mar

See the above post for a link that will direct you another of my posts with history on the Simpson lever chain.

Regarding the Centurion Turbo TT, it appears to have been a Centurion (Germany) project. All the samples that have surfaced are from European markets and were manufactured by Yamaguchi of Japan in 1988. Given the wide variety of builds, it may have been a frameset offering. In my opinion, it was marketed an an entry level TT-style bicycle for the average consumer and not as a competition model. The main evidence supporting this is the construction using seamed Tange Infinity tubing, which was typically found on upper entry models. The S-bend top tube is also a cost concession allowing it to built using standard lugs, rather than custom angle lugs or fillet brazing. Finally, how many pure TT bicycle do you see with rear dropout eyelets so that it could accommodate a fender or rack? Unfortunately, I'm not aware of any literature that has surfaced to provide a definitive answer. For a more detailed discussion of this model, please see https://www.bikeforums.net/classic-v...n-experts.html

Johno59

Goddammit! That is a sweet piece of kit, I mean...…...smoke!!!

Johno59

She's saying 'grow a pair of these and come up and see me sometime'

m_sasso

These wheels were on Facebook two days ago and I heard you were looking for some! No relation.

And a topical picture of some nice bikes.