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Brian Rourke tt f/set
- Thread starter Mike Muz
- Start date
Re:
Let me explain.
Unless you have all the time in the world, and ride around at 10mph, you will have tried to go fast. Getting your torso flatter in order to do so.
A lo pro bike is just a natural extension of that, to get your riding position more aerodynamic.
I imagine when this was built, there were no tri bars, so frames like these, along with handlebars with long extensions would have been used, to give your frontal area as LOW PROFILE a position as possible.
Since 1989, and Greg Lemond's tt victory in the TdF , tri-bars have been widely accepted as the way to go.
So it became a matter of saddle to armrest proportions in order to get thst aerodynamic tuck. It still is to this day, irrespective of tri bar angle.
You simply wouldn't get this by riding a small frame instead, as the top tube would be too short and you would be hunched up.
There have been some beautiful examples of lo-pro bikes IMO.
Please feel free to add anything I may have left out, Nob.
Mike
Let me explain.
Unless you have all the time in the world, and ride around at 10mph, you will have tried to go fast. Getting your torso flatter in order to do so.
A lo pro bike is just a natural extension of that, to get your riding position more aerodynamic.
I imagine when this was built, there were no tri bars, so frames like these, along with handlebars with long extensions would have been used, to give your frontal area as LOW PROFILE a position as possible.
Since 1989, and Greg Lemond's tt victory in the TdF , tri-bars have been widely accepted as the way to go.
So it became a matter of saddle to armrest proportions in order to get thst aerodynamic tuck. It still is to this day, irrespective of tri bar angle.
You simply wouldn't get this by riding a small frame instead, as the top tube would be too short and you would be hunched up.
There have been some beautiful examples of lo-pro bikes IMO.
Please feel free to add anything I may have left out, Nob.
Mike
Thanks Mike! I used to TT back in the day ('85 to about '00) and I used to win races, latterly on my own design of compact frame, built at Sonic Cycles of London, so I'm fully aware of the principles of basic aerodynamics on a bike (plus I'm also an aircraft engineer)
My point about low-pro frames was why would you have a low front end (which is aerodynamically more efficient) and then spoil it with a huge rear end? Why not just make the top tube horizontal and have a very large aero section seatpost instead? That way you would have a smaller, stiffer, lighter, more aerodynamic frame. Look at it this way - picture a low-pro bike head on, alongside an equivalent sized conventional bike; the overall aerodynamic profile of both bikes is exactly the same. I think a lot of low-pro bikes were sold as a gimmick - I saw lots of them where the rider had put on a conventional stem, or in some cases a riser stem(!), fitted tri bars with risers and so their overall height was no lower than they would have been on a conventional frame.
I get the idea that if you're tall, having a small front wheel means that you can get lower down, but there's a limit to how low you can go before you compress your diaphragm and your breathing suffers. Miguel Indurain was by far the best tester around at his peak, and even with tri bars he used to ride bolt upright; he had such large lungs that they extended past his lower rib cage, and he couldn't go too low without suffering.
A small frame doesn't have to have a short top tube either, of course - mine was built so that it was the same length as a conventional bike in my size, just that it was a whole lot lower, having a 4" head tube and a horizontal top tube. It had a Cinelli track stem, modified Mavic profile bars (so that the forward sections were horizontal) and a simple pair of Profile tri bars. Coupled with home made aero section aluminium forks (cut from a solid billet of aluminium, it took bloody weeks of filing) home-made aero front brake (which almost worked on a good day) and home made aero seatpost it worked pretty well. I deliberately went for a 700c front wheel because they have better rolling resistance than a 24" or 26" wheel. Despite this, using the Cinelli stem and modded bars I had a drop of about 13" from the top of the saddle to the handlebar clamp, and that was plenty low enough for me, and my back was pretty much horizontal. Of course it was a bit uncomfortable, but I always said that if I wanted to be comfortable I'd sit at home in an armchair with a beer and watch the footy instead of trying to win races.
The killer point for me is that the best tester in the world right now doesn't use a low-profile frame....mind you, he also uses oval chainrings
I still have the frame and all the parts - I use it as my Sunday best fixie now, albeit with a conventional shaped seat post and carbon forks and flat bars. It still gives me a buzz. Even my custom road bike is a compact frame - it has a slightly longer head tube than my TT frame, but the top tube slopes back down to the seat cluster like a mountainbike, and I have a very long seat post. The effective top tube length is the same length as a 22" frame (what would be classed as my normal size) but the seat tube is only about 18". I just think it looks far more elegant than a low pro frame too.
I'm afraid I'm a bit rubbish with 'pooters so I can't add a pic of my TT bike; if I can find a way I have a couple of pics of me in action on it.
Cheers, Ian
My point about low-pro frames was why would you have a low front end (which is aerodynamically more efficient) and then spoil it with a huge rear end? Why not just make the top tube horizontal and have a very large aero section seatpost instead? That way you would have a smaller, stiffer, lighter, more aerodynamic frame. Look at it this way - picture a low-pro bike head on, alongside an equivalent sized conventional bike; the overall aerodynamic profile of both bikes is exactly the same. I think a lot of low-pro bikes were sold as a gimmick - I saw lots of them where the rider had put on a conventional stem, or in some cases a riser stem(!), fitted tri bars with risers and so their overall height was no lower than they would have been on a conventional frame.
I get the idea that if you're tall, having a small front wheel means that you can get lower down, but there's a limit to how low you can go before you compress your diaphragm and your breathing suffers. Miguel Indurain was by far the best tester around at his peak, and even with tri bars he used to ride bolt upright; he had such large lungs that they extended past his lower rib cage, and he couldn't go too low without suffering.
A small frame doesn't have to have a short top tube either, of course - mine was built so that it was the same length as a conventional bike in my size, just that it was a whole lot lower, having a 4" head tube and a horizontal top tube. It had a Cinelli track stem, modified Mavic profile bars (so that the forward sections were horizontal) and a simple pair of Profile tri bars. Coupled with home made aero section aluminium forks (cut from a solid billet of aluminium, it took bloody weeks of filing) home-made aero front brake (which almost worked on a good day) and home made aero seatpost it worked pretty well. I deliberately went for a 700c front wheel because they have better rolling resistance than a 24" or 26" wheel. Despite this, using the Cinelli stem and modded bars I had a drop of about 13" from the top of the saddle to the handlebar clamp, and that was plenty low enough for me, and my back was pretty much horizontal. Of course it was a bit uncomfortable, but I always said that if I wanted to be comfortable I'd sit at home in an armchair with a beer and watch the footy instead of trying to win races.
The killer point for me is that the best tester in the world right now doesn't use a low-profile frame....mind you, he also uses oval chainrings
I still have the frame and all the parts - I use it as my Sunday best fixie now, albeit with a conventional shaped seat post and carbon forks and flat bars. It still gives me a buzz. Even my custom road bike is a compact frame - it has a slightly longer head tube than my TT frame, but the top tube slopes back down to the seat cluster like a mountainbike, and I have a very long seat post. The effective top tube length is the same length as a 22" frame (what would be classed as my normal size) but the seat tube is only about 18". I just think it looks far more elegant than a low pro frame too.
I'm afraid I'm a bit rubbish with 'pooters so I can't add a pic of my TT bike; if I can find a way I have a couple of pics of me in action on it.
Cheers, Ian
Re:
So your bike was a low profile one too?
Who is the best tester? Wiggins surely, having just broken the hour record.
It was simply how frame design was back then. Either like the Rourke or with cuved top and sometimes seat tubes. Very elegant IMO.
When did flat top tube variances start appearing?
Boardman era?
Indurain was so effective owing to his power output which more than compensated for his riding position. His lung capacity having a big impact on that as you say.
My limiting factor wad being able to hold my head up for 20/56 mins.
So your bike was a low profile one too?
Who is the best tester? Wiggins surely, having just broken the hour record.
It was simply how frame design was back then. Either like the Rourke or with cuved top and sometimes seat tubes. Very elegant IMO.
When did flat top tube variances start appearing?
Boardman era?
Indurain was so effective owing to his power output which more than compensated for his riding position. His lung capacity having a big impact on that as you say.
My limiting factor wad being able to hold my head up for 20/56 mins.
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