Ive been considering setting up a TT frame for road riding and know the disadvantages of this... mainly the sharp angles will cause discomfort for longer rides and also create a bike that is not as easy to handle ie twitchy steering.

Ive talked to a number of people and ive heard this comment multiple times: "It would be good for crit racing."

Why? I know they are usually flat, fast races but wouldnt the sharp turns at high speeds also mean that you need a more stable bike than this cross-over would allow?

Thoughts?

I have three bikes for comparison purposes. Road, track and Cervelo P2C.
Track = fast, predictable steering
Road = stable, predictable steering
TT = twitchy, unpredictable steering even on the base bar. I would never consider riding it in a crit. Only bad thing could result.

Ive talked to a number of people and ive heard this comment multiple times: "It would be good for crit racing."

Presumably, the argument here is that crit bikes have more upright geometry, and a TT bike has more upright geometry, therefore a TT bike would be good for crits. Wrong answer. android has described the situation accurately.

Depending on the TT bike you are looking for and your dimensions you may not encounter the problems stigmatizing TT bikes and their handling. What a lot of people seem to forget is that there are a handful of TT bikes with semi-relaxed geometry and assuming you aren't really tall you could get away with it (ie. if you are someone who needs a 72 deg. seat tube you might have some problems).

In my opinion most of the instability stems from the positioning of a TT setup (ie. the use of aero bars) and when riding a bike with aero bars the bike definitely feels twitchy/scary. Additionally, with most people setting up their TT bikes for timetrialing you will encounter some difficulty but set the bike up for road and you should be fine.

Isn't TT bike geometry illegal for road/crit racing ?

Isn't TT bike geometry illegal for road/crit racing ?

I'm not advocating cheating, and I don't know what the OP's cat is, but I doubt the race officials run around measuring all the angles on people's bikes at amateur races. Now, if you showed up at a crit on a Cervelo P3 Carbon, that might be different. That's obviously a TT/Tri bike.

Presumably, the argument here is that crit bikes have more upright geometry, and a TT bike has more upright geometry, therefore a TT bike would be good for crits. Wrong answer. android has described the situation accurately.


Kerry,
Aren't you generalizing things a little (not trying to be sarcastic :-). I've been considering doing the same thing because with the plasticity of carbon fiber I have no idea why there aren't more aero road frames (ie. why not take advantage of everything carbon fiber has to offer rather than use a space age plastic material to create another round tube bike frame). As long as you look at the geometry charts, most frames are not that extreme...once again as long as your morphology allows for it. For instance the frames I am looking at have:
STangle= 74-75 deg. and most seatposts seem to leave plenty of fore/aft adjustment
HTangle= 71.5-72.5 deg.
Fork rakes= pretty similar to most road bikes since they seem to use off the shelf forks (ie. 41-43 mm)

Most of what I am looking at seems to fall within the realm of road bike geometry. In fact most road bikes from 20+ years ago for my size (53-54cm seat tube) used to have 74 deg. seat angles. I don't know why but a lot of bikes today seem to have adopted a relaxed geometry and you see many pictures on these forums of people with their saddles slammed forward.

Isn't TT bike geometry illegal for road/crit racing ?
What makes you say that?*


Answer: Nothing.

What makes you say that?*


Answer: Nothing.

If you put road bars on, the only other problem you have to worry about is that nose of saddle is supposed to be 5cm behind BB center according to USAC rules. Of course officials are only going to check for events that qualify you for Nationals or higher.

Most of what I am looking at seems to fall within the realm of road bike geometry. In fact most road bikes from 20+ years ago for my size (53-54cm seat tube) used to have 74 deg. seat angles. I don't know why but a lot of bikes today seem to have adopted a relaxed geometry and you see many pictures on these forums of people with their saddles slammed forward.

Well, that's true. I road a Panasonic for years that had a 74 degree seat tube and 73 deg head tube. The difference was that back then, all seatposts were what is now called a setback seatpost and straight up seatposts that seem to be the norm on current bikes didn't exist. I bet the actual difference in the effective saddle position from the BB hasn't changed much on road bikes. It is certainly steeper on TT bikes though.

Of course officials are only going to check for events that qualify you for Nationals or higher.
You make it sound like the officials don't apply the rules except at bigger races. That isn't so. The USCF rules extend UCI equipment regulations only to Nationals, international qualifiers, record attempts, and NCR races.

when dave built his "criterium" model he used 74 (rather than 73) head angle with shorter fork rake, also oversize size seat stays and adapted track fork crown with round/oval/round fork blades added stiffness for out of the saddle sprinting, and he raised the BB 1/4 inch over his road models.