Time Trial Bike
I started racing TTs earlier this year. I race in the standard (no aero) bike class , Cadd 8 frame with mostly Ultegra. I am hoping to build a full aero lugged steel TT bike. If the lugs don't exist, I am willing to try fillet brazing. Do TT lugs exist. Is there a drawing of a TT bike showing typical angles and other critical measurements.? Thanks, Jerry
Men of Steel Racing Club
Here is the geometry matrix for Waterford's TIG welded TT-33 time trial bike:
Note the steep seat tube angles and relatively "normal" head tube angles.
The lugged TT-22 has similar geometry, but with a level top tube:
They didn't put much effort into trying to make it look like a TT bike. Forget the lugs, TTs are supposed to have clean lines and look sleek and aero. Fillet-braze it, use an aero-shaped down tube and maybe some teardrop seatstays, slope the top tube down toward the front like the older steel TT frames. Give it a schweeeet fast paint job. Make it look fast and you'll feel faster on it. Thats just my opinion, I'm into TT bikes though. Those bikes above are nice bikes I'm sure but they just look like something you bought off the floor and added clip-ons. TRICKIT-IT OUT and send some photos.
Yeah, I had a similar response, though not interested in TT bikes, so I wasn't sure. Sorta seems like a time trial bike aught to slope down at the front , not have that bull moose look. Those look like those bikes you see with the forward controls that are set up higher than a comfort bike...
sloping top tubes may not be the best approach, at least that's what I've learned from looking at pro bikes. The trick is to get the body as far over towards the horizontal as possible, which usually requires a small head tube. As can be seen from all the efforts to push the rules in pro bike design, you really need a fairly large fairing to get any aerodynamic effect at all. An aero downtube may or may not have much effect.
I agree that the way you build it for the individual rider will affect the aerodynamics but after you get it designed you might as well make it look racey. Correct body positioning is the ticket to good time trialing but if you are gonna spend the time building a TT bike at least make it look like something fast. Who is the guy on this forum who always says, "When in doubt, trick it out!"? Thats what I'm talking about. I think those old steel TT bikes look cool, I am gonna build one. Those bikes up above would be good for bicycle jousting.
I don't know but after putting my ignorance out there, I googled tt bikes and many have a huge downward bias, mostly from the seat. The first waterford has a handlebar position like my touring bike. Not anything that couldn't be adjusted...
Obviously I picked this one, :
Not all the riders are that extreme and there seems to be some bias towards, if not comfort, at least a position that will allow the rider to breath and work sensibly.
I believe I am gonna have to modify my jig a bit to build that one, but I like it alot.
I don't really understand the Waterfords shown above. If you are going to have a time trial specific bike, it makes sense to get into a fairly extreme forward position. The only problem with that is getting your neck used to it, but the time trial position is not really a trade off between aero and physiological performance.
There was a pretty neat looking steel time trial bike at the NAHBS in Indianapolis, I have though of building something like that.