Trek Releases new bike that can keep up with the V20
- Thread starter ratz
- Start date
hamishbarker
Well-Known Member
I think a well fitted time trial position would be close to but not better than the CdA of a vendetta, but only when in the optimum position, which takes effort and it isn't safe to have hands on the tt aero bars and head down all the time, whereas on a v one can be optimally positioned and aero all the time and have perfect forward .
to compare fairly though, a v20 with rear disc, tight suit and full aero helmet (not just giro air attack) should be unmatched my any tt df /rider combination.
to compare fairly though, a v20 with rear disc, tight suit and full aero helmet (not just giro air attack) should be unmatched my any tt df /rider combination.
JOSEPHWEISSERT
Zen MBB Master
Just curious, which helmet would you recommend? It seems that the traditional time trial helmets are meant to be used with the head somewhat looking down, instead of looking somewhat up, as when on the Vendetta. Maybe I'm way off base here, but please correct me if I'm wrong.
battleaxe0
Guru
bladderhead
Zen MBB Master
People are always talking about bike racers being drugged up to the eyeballs. It is the only way they can catch Maria Parker, Oslund, Weissert et al
MrSteve
Zen MBB Master
Any modern time-trial helmet design, one that resembles a jelly bean, will work better with a recumbent.
They look right to my eye, and more importantly, both wind-tunnel numbers and track numbers confirm that
they're good helmets for speed.
They are expensive, so, any time trial helmet would probably be better than none.
If you can keep off of the tarmac, I'm pretty sure that a completely shaved head would be pretty fast,
especially if you were born with a long skull and wore some aerodynamically slick sunglasses.
Another idea is to keep your hair tucked under a rubber swimmer's cap along with the aero sunglasses.
Seriously, the new, rounded aero time-trial helmets with integrated visors look good.
They look right to my eye, and more importantly, both wind-tunnel numbers and track numbers confirm that
they're good helmets for speed.
They are expensive, so, any time trial helmet would probably be better than none.
If you can keep off of the tarmac, I'm pretty sure that a completely shaved head would be pretty fast,
especially if you were born with a long skull and wore some aerodynamically slick sunglasses.
Another idea is to keep your hair tucked under a rubber swimmer's cap along with the aero sunglasses.
Seriously, the new, rounded aero time-trial helmets with integrated visors look good.
battleaxe0
Guru
Only sport I can think of offhand that uses aero helmets, is concerned with weight, and looks up from a recumbent position - luge.
hamishbarker
Well-Known Member
Yes bike tt helms are optimised for downward view, but the smoothed in ear flaps which then keep a smooth profile to the rear, and a flush visor should all be better than usual helmets and the non aero contours of nose, eye sockets, ears and helmet straps.
Giro selector looks good and has an exchangeable lower tail which could then be optimised.
Of course, since we have a headrest behind our necks and lower skull, adding a small head size fairing there shiuld be simple. Just enough to make the head and fairing about three times longer than wide should provide some drag reduction. Hence the cruzbike carbon bottle caddy and the caddies used by maria in raam and larry o. But they are fairings on the bike (no longer "unfaired" class), whereas fairing shaped helmets are "fair game" if you'll pardon the pun.
Giro selector looks good and has an exchangeable lower tail which could then be optimised.
Of course, since we have a headrest behind our necks and lower skull, adding a small head size fairing there shiuld be simple. Just enough to make the head and fairing about three times longer than wide should provide some drag reduction. Hence the cruzbike carbon bottle caddy and the caddies used by maria in raam and larry o. But they are fairings on the bike (no longer "unfaired" class), whereas fairing shaped helmets are "fair game" if you'll pardon the pun.
JOSEPHWEISSERT
Zen MBB Master
So, I've posted this before, but is this acceptable? http://www.icaro2000.com/Products/Helmets/4fight/Grid-Cut/Grid-Cut.htm
LarryOz
Cruzeum Curator & Sigma Wrangler
Yes, I agree - I'll have to start looking around for one
LarryOz
Cruzeum Curator & Sigma Wrangler
Joe, I have been looking at these. Too bad you can't find one at your local bike shop to see if it fits well. I think they are about $300 bucks or so.
If I can't find a luge helmet, I may have to start saving my lunch money for one of these to try?
JOSEPHWEISSERT
Zen MBB Master
I think I like the matte black better than the silver.Joe, I have been looking at these. Too bad you can't find one at your local bike shop to see if it fits well. I think they are about $300 bucks or so.
If I can't find a luge helmet, I may have to start saving my lunch money for one of these to try?
JOSEPHWEISSERT
Zen MBB Master
$290 at the current exchange rate.
hamishbarker
Well-Known Member
The icaro helmets are rather heavy (close to 1kg if i recall correctly) because the en966 helmet test standard requires resistance to a much harder impact with a 60 degree, 1mm tip radius cone, which essentially dictates a very tough shell. I know this because i had to research the issue to get the list of acceptable helmets for Paragliding competition (i was on the board and paragliding subcommittee of the hang gliding and Paragliding commission of the FAI) widened to include astm and Snell snow sports test standards also.
apart from the weight, i think you'll find the icaro flying helmets insufficiently ventilated for cycling use in anything but very cold weather, and the visor will fog up. For luge/bobsled, such helmets might be ok because at their much higher speeds there is ok ventilation.
apart from the weight, i think you'll find the icaro flying helmets insufficiently ventilated for cycling use in anything but very cold weather, and the visor will fog up. For luge/bobsled, such helmets might be ok because at their much higher speeds there is ok ventilation.
battleaxe0
Guru
The street luge guys have a very real possibility of whacking the back of their head on pavement, so their helmets usually weigh in the 3 pound range. Of course, when you're bombing down a hill at say...54 mph on a vendetta, maybe a stronger helmet might not be such a bad idea.
ratz
Wielder of the Rubber Mallet
JOSEPHWEISSERT
Zen MBB Master
Larry, here's what you need. The Predator Berserker. $890. Custom paint job. 4.8 pounds. Probably not enough ventilation. Not as aerodynamic.
But one look at you, and your competition will drive off the road.
But one look at you, and your competition will drive off the road.
LarryOz
Cruzeum Curator & Sigma Wrangler
Great find Joe - haha - WOW 4.8 pounds! I'll have to really start doing some more strenuous neck exercises so I can hold it up when needed!
jond
Zen MBB Master
i dont know about cda all i know is time taken. i can say that a few of my cycling buddies over here downunda have very expensive top of the line TT bikes and are two race grades above me locally. even riding in a t-shirt /baggy shorts and training wheels pushing a metered 220 watts at local flat oval track i am 3klm per hour faster than the best time posted by any DF over 50klm. on the tuesday morning meet the strongest A grade rider with TT bike sits for about 35klm before falling off the back of the V. it is so unfair
i will be early next week taking the v out with aero wheelset and lycra in front of the track set of course. the v is causing quite a stir amongst the die hards and they are lining up to ride behind "mission". have to get one of those giro air attack helmets one day. so the bike is just fast fast fast and any aero add-ons are just thin extra icing on a very very tasty go fast cake. going for a bite this arvo.
hamishbarker
Well-Known Member
Hi Jond (and Larry if you're reading), if you have a bunch of power metered laps data, could you post the data file and if known, the temperature and elevation and perhaps location/ date (so i can look up the pressure), then i can run the numbers though r Chung cda calculation method to come up with likely cda and crr data.
