Turning a TT bike into a Race bike?

Paul-Posh
Paul-Posh Posts: 31
edited August 2013 in Road general
Has anyone done it?

Would the set up be a complete mess?

Is there any reason it would work?

My thinking is rather than spend money on another new bike I could just put drop bars and new brakes/shifters on my TT bike so I could use it for racing.

Having looked at a few random bikes I've noticed that tube angles are different between a 'normal' bike and a TT bike. Not really sure what this means/would affect.

Comments

  • Grill
    Grill Posts: 5,610
    Don't do it. Absolutely not. Put the tools down.

    Geometry is completely wrong. You may as well race a big wheel.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • imposter2.0
    imposter2.0 Posts: 12,028
    Paul-Posh wrote:
    Has anyone done it?

    Would the set up be a complete mess?

    Is there any reason it would work?

    My thinking is rather than spend money on another new bike I could just put drop bars and new brakes/shifters on my TT bike so I could use it for racing.

    Having looked at a few random bikes I've noticed that tube angles are different between a 'normal' bike and a TT bike. Not really sure what this means/would affect.

    Unlikely to work, as Grill says. A lot will depend on what frame your TT bike is based on. That would obviously be useful info...
  • iPete
    iPete Posts: 6,076
    As others have said, don't do it. Buy a second hand stiff alu frame, a CAAD 8 or something and take that racing..
  • ^ What they said!
    Storck Scenario C1.1 | Ridley Damocles ISP

    "The race is long, but in the end it's only with yourself"

    http://www.twitter.com/TwitRides
  • Bike is a planet X stealth. In size XL - bought for long distance rather than 10milers so went for a slightly longer top tube

    Building a bike over a few months was my other thought. Trying to save money for other things so don't want to spend loads in one hit.

    Can someone explain how/why the geometry would be wrong?
  • alihisgreat
    alihisgreat Posts: 3,872
    Paul-Posh wrote:
    Bike is a planet X stealth. In size XL - bought for long distance rather than 10milers so went for a slightly longer top tube

    Building a bike over a few months was my other thought. Trying to save money for other things so don't want to spend loads in one hit.

    Can someone explain how/why the geometry would be wrong?

    Two main differences:

    1) Steeper seat-tube angle - means riders can get forward in a much lower TT position opening he hips out more
    2) Different front end geometry - the steeper seat angle puts your weight over the front end of the bike meaning the handling would be twitchy whilst riding on the aerobars - so they use a shallower head-angle and less trail to improve the handling from the aero-bar TT position.

    So it would be harder to get a good comfortable non-TT position on the bike, and if you do manage that it will still handle a lot worse than a road bike.
  • I have...although I don't race it. Mine's a transition pro 2007 (Alu).
    I compared the geometry of mine to a Scott Foil 20 and here's some measurements...not as crazy as you might first think.

    Spec Tran Scott Foil
    Head Tube Angle 72deg 72deg
    Head Tube Length 115mm 120mm
    TT length (horizontal) 534mm 535mm
    seat tube angle 76deg 74deg
    chainstay length 400mm 405mm
    wheelbase 992mm 980mm

    Shows that the only real differences are 2 degrees in the seat tube angle and the odd millimetre here and there.
    Only did it to show an interesting comparison...obviously all frames are different!

    Andy
  • meesterbond
    meesterbond Posts: 1,240
    Someone on Weight Weenies tried it with a Speed Concept and another with Plasma.

    I think the consensus was that it worked for short blasts but the steering was compromised and it put far too much weight on your hands to be comfortable over any real distance.

    You probably won't die though, so why not give it a go!

    Pics Here
  • Grill
    Grill Posts: 5,610
    You ride a small size. In an L the Foil has a 73deg HT angle and 73.3 ST angle as well as a much shorter head tube. It is a silly idea and you shouldn't go filling the OP's head with it.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • meesterbond
    meesterbond Posts: 1,240
    Grill wrote:
    You ride a small size. In an L the Foil has a 73deg HT angle and 73.3 ST angle as well as a much shorter head tube. It is a silly idea and you shouldn't go filling the OP's head with it.


    That's exactly why you should encourage such behaviour. :twisted:
  • No I don't ride a small size, I ride a 54cm frame. It is however a compact frame. I compared my frame size to the equivalent frame in the Foil with roughly the same horizontal TT length.
  • Grill
    Grill Posts: 5,610
    No I don't ride a small size, I ride a 54cm frame. It is however a compact frame. I compared my frame size to the equivalent frame in the Foil with roughly the same horizontal TT length.

    Then you would ride a Foil in a 54 due to the difference in geometry as head and seat angle as well as HT length need to be taken into account along with effective TT length. My Foils and my Plasma are 54 (and my WM is a medium withe different geometry), but the Plasma has a much shorter TT due to change in position and geometry.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • Wirral_paul
    Wirral_paul Posts: 2,476
    I havent raced for about 15 years myself now, but I would think if you went racing and an organiser felt that your bike was unsuitable (ie potentially dangerous to all of those entering) then they would refuse to let you enter.
  • I can't see how the bike would be dangerous. The whole point of the idea was to make it safe for racing.

    Had a look at geo- it appears that the stack and HT would be noticeably shorter than a normal race bike. and the seat angle a couple of degrees higher.

    The rest seems pretty normal. Top tube is only a cm shorter than my winter bike so that would be fine. I guess the stack height and the seat angle would make all the difference though. the Stealth has a TT of 570, stack - 530, HT - 130. HA72.5degrees, SA - 76degrees
  • Grill wrote:
    Then you would ride a Foil in a 54 due to the difference in geometry as head and seat angle as well as HT length need to be taken into account along with effective TT length. My Foils and my Plasma are 54 (and my WM is a medium withe different geometry), but the Plasma has a much shorter TT due to change in position and geometry.

    You're correct Grill, a 2 degree difference in seat tube angle would effectively add 10mm length to my (effective) top tube, thats assuming my seat tube measures approximately 500mm. Also, on top of this you'd have to add another 5mm (ish) for circa 200mm of seat tube/saddle height. HT length steps up with the size of frame pretty much accordingly..mines a 54 and as I said goes 115mm. Go up to a 56 = 135mm, 58 = 160mm and finally 61 = 185mm. Head tube angle between these two is very close.
    I wasn't being arsey...I was trying to state and compare that my older tri frame resembles the foil 20 quite closely in general. In practice, I position the saddle back on its rails...and the geometry is close. Not perfect...but nicely rideable.
  • Wirral_paul
    Wirral_paul Posts: 2,476
    Paul-Posh wrote:
    I can't see how the bike would be dangerous. The whole point of the idea was to make it safe for racing.

    Having ridden a time trial bike down a mountain, and recently left my mate on his TT bike for dead descending down the Horse Shoe Pass - i know how apalling the handling can be compared to a road bike. Not what i would call suitable for bunch racing really - at least those frames weren't. I certainly wouldnt want someone around me on an bike with nervous handling at 30mph+.

    Still - you seem determined to go for it so try it. If it doesnt work and the bike handles like a pig then you'll know (and 2deg is a lot when looking at geometry of a frame)
  • lawrences
    lawrences Posts: 1,011
    This thread is the exact opposite of one we had a few days ago. Just message the guy and swap.
  • Pross
    Pross Posts: 40,421
    If you want a road bike without spending money why not just sell the TT bike and use the money for a road bike or (as above) try to swap it? By time you've messed about and ended up with something that's neither fish nor fowl and handles like a pig you probably won't want he hassle of putting it back as a TT bike.
  • Cheers for all the feedback chaps.

    Not keen on swapping the bike as I plan on using it for TT's next year (pos later this year too). I'd just swap the bars depending on what I was doing. Was just keen to know if it had been done and if it worked. It would seem that it doesn't seem like the most sensible plan. Though I have definitely had less sensible plans that have worked.

    I think (though this may change) I've been given permission to get myself another bike. So all I need to do now is test a few and then somehow sneak it into the shed...
  • mattjevans
    mattjevans Posts: 253
    Someone on Weight Weenies tried it with a Speed Concept and another with Plasma.

    I think the consensus was that it worked for short blasts but the steering was compromised and it put far too much weight on your hands to be comfortable over any real distance.

    You probably won't die though, so why not give it a go!

    Pics Here

    It's my bike (Speed Concept 9) on weight weenies. those pics of the orange one aren't my bike, they are the bike that inspired me to do the conversion. I put a UCI seatpost on, so my seat angle is 74 degrees. The main difference in geometry between what I have and a Madone 7 54cm H1 is lower BB and the SC is a bit more "reachy" so I use a 90mm stem.

    It's only had a couple of rides so far, another one today. But I only get the time to ride for an hour or so at a time, so can't really comment on comfort over long distances