I’ve just hacked up a proof of concept ghetto bento box type thingy for my p2sl.
I can make it adjust to the width of the DT/ST so it fills the gap nicely by using an elasticated material for the bottom and back surfaces, the box can form fit around the tubes, mating pretty much flush (perfectly flush if tape is used) and the elastic means it also works with the round tubes of my litespeed capella - I think it would work with most tube shapes. The elasticated material essentially wraps around the tubes, the tubes providing the hard bottom and back surfaces of the box (so maybe some padding may be required to stop the stored stuff hitting the tubes)
2 small spars are used to provide the horizontal rigidity, ie prevents the elasticated material from pulling the two sides together, and these are cut to the width of the particular tube you want it to mate with. The sides of the box are rigid (and as a bonus for me, the plastic I am using looks almost exactly the same as the anodized finish of my bike). It will attach to the ST bottle cage mounts. It is obviously very narrow on the cervelo (the width of the p2s DT/ST) and so not particularly capacious, but can still fit a couple of co2s, the pump, an innertube (I dont have any tubulars lying around to see if one will fit), levers and some gels. It is obviously more roomy when used on the wider tubes of the litespeed.
It completely fills the gap of the bb triangle, to 1cm above the top ST bottle mount, and is completely **invisible from the front. The top of the box thing, where the vertical plane intersects with the horizontal, would have squared edges as I cant think of how I could ghetto a radius. A notch has been removed from the top surface/lid to allow it to mate flush with the DT trailing edge.
So, geeks (and I consider myself one so the word is used as a term of respect and endearment!), I know this makes intuitive sense, but do you think this would actually be aerodynamically effective? I dont intend to try and sell it or anything, just me tinkering - I think it might be stepping on the cervelo patent anyway. Just want to see what people who know better think before I go off and make a half decent version.
(my camera is on holiday with my lady so no photos sorry)
but without the drink bottle. On closer inspection, mine melds with the bb area, whereas the wedgie seems to leave a gap, if that makes any difference. Mine would also be about $133.95 cheaper
One of the challenges of manufacturing any component that fits in the lower triangle of a bicycle frame is the radius of the joint between the down tube and the seat tube (above the bottom bracket). You will find that 1/2 the bicycle frames have a small radius (two tubes going straight into the bottom bracket shell) and the other 1/2 have a large radius (common with carbon fiber frames). We’ve done field testing and studied all the major bicycle manufactures frame designs.
It is one thing to build a prototype that melds to the bottom bracket, but it is a greater challenge to build a version that fits the majority of bicycles (there is a great range of angles and radius).
For example, the Wedgie™ fits carbon framed Cervelo’s without any gaps (Cervelo’s use a large radius). Fit a Wedgie on a steel tube road bicycle and you will see a gap above the bottom bracket.
One of the challenges of manufacturing any component that fits in the lower triangle of a bicycle frame is the radius of the joint between the down tube and the seat tube (above the bottom bracket). You will find that 1/2 the bicycle frames have a small radius (two tubes going straight into the bottom bracket shell) and the other 1/2 have a large radius (common with carbon fiber frames). We’ve done field testing and studied all the major bicycle manufactures frame designs.
It is one thing to build a prototype that melds to the bottom bracket, but it is a greater challenge to build a version that fits the majority of bicycles (there is a great range of angles and radius).
For example, the Wedgie™ fits carbon framed Cervelo’s without any gaps (Cervelo’s use a large radius). Fit a Wedgie on a steel tube road bicycle and you will see a gap above the bottom bracket.
One of the challenges of manufacturing any component that fits in the lower triangle of a bicycle frame is the radius of the joint between the down tube and the seat tube (above the bottom bracket). You will find that 1/2 the bicycle frames have a small radius (two tubes going straight into the bottom bracket shell) and the other 1/2 have a large radius (common with carbon fiber frames). We’ve done field testing and studied all the major bicycle manufactures frame designs.
It is one thing to build a prototype that melds to the bottom bracket, but it is a greater challenge to build a version that fits the majority of bicycles (there is a great range of angles and radius).
For example, the Wedgie™ fits carbon framed Cervelo’s without any gaps (Cervelo’s use a large radius). Fit a Wedgie on a steel tube road bicycle and you will see a gap above the bottom bracket.
You should have a printable template on your website so people could check how well it would fit on their bike.
Hi Remnfa,
Yes, a printable (pdf) template will soon be posted along with a video on how to fit/install a Wedgie. In addition, we are offering a “fit kit”. This is a paper model (1mm card stock paper) that can be sent out in advance. You then can check the fit and mark it (if you want the Wedgie trimmed). All soon to be posted on the website.
Haha, yeah, pretty much like that. But does it really work???
Yes - Field testing/prototyping was conducted in 2008 and in 2009
So how much of a reduction in drag did you find?
FWIW, I field-tested a cardboard version of something quite similar on a P3C, and found that it really didn’t make a difference one way or the other compared to 1) not carrying any water bottle, or 2) compared to carrying one positioned horizontally between my forearms. I can’t say, though, whether it was better (or worse) than a bottle on the frame or behind the seat, and/or at non-zero yaw angles.
Wind tunnel testing is scheduled for early November. I’ll post the results once we’ve completed the testing.
In addition to aerodynamics we were field testing for:
Convenience
removing/replacing the water bottle
fast access to the tools
tools not rattling in the tool box
Weight
through the use of carbon fiber and RTM (Resin Transfer Molding), we were able to keep the weight at 100 grams. Given that the average water bottle cage weighs 150 grams and a tool bag weighs 400 grams, you can save approximately 450 grams (~ 1 lb.)
