Bent Basic Questions...

"DF" stands for Diamond Frame. You're right, it's a reference to a ubiquetous Safety Bike (the UCI standard.) I think it's pretty well established that the fastest type of bent is a lowracer, followed closely by its cousin the highracer. Most lowracers use a 26"/650C/700C rear wheel and a 20" front wheel, and the rider will be sitting at a low angle, with the seat typically about 12" off the ground. This makes for an extremely small frontal area and lots of ground-effect advantages. Most highracers use the same reclined rider position, but put the rider above a pair of 26"/650C wheels. The bike is not shielded by the rider's body, and thus represents a small additional amount of frontal area, but is still very aero. Lowracers and highracers ARE faster than DFs. "NoCom" stands for "No Compromise." It was designed to take advantage of HPRA rules that allow the bike's frame to incorporate as much aerodynamic advantage as possible while competing as a 'stock', i.e. unfaired bike. It incorporates spoilers between and around both wheels, a disk rear wheel, and a low 6 inch seat height.

Some other bents can be competitive, even faster than DFs, but it requires the use of a fairing. Many bents are slower than racing bikes, and are more comparable to DF hybrids. Fairings can make a bent obscenely fast. One of my riding buddies took a fully faired lowracer to Black Bear (a 100 mile road race, which due to a detour turned out to be 104 miles) and finished with a 3:40 in spite of a 6 mph headwind for most of the route. I got a 4:31 that day, riding solo most of the way. By contrast, I never broke 6 hours for a century on my DF, even with copious amounts of drafting behind stronger riders. BTW, I consider my lowracer very comfortable. It's not very visible in heavy city traffic, but then riding it in heavy traffic wouldn't be a good use of its capabilities.

blazingpedals said:

"DF" stands for Diamond Frame. You're right, it's a reference to a ubiquetous Safety Bike (the UCI standard.) I think it's pretty well established that the fastest type of bent is a lowracer, followed closely by its cousin the highracer. Most lowracers use a 26"/650C/700C rear wheel and a 20" front wheel, and the rider will be sitting at a low angle, with the seat typically about 12" off the ground. This makes for an extremely small frontal area and lots of ground-effect advantages. Most highracers use the same reclined rider position, but put the rider above a pair of 26"/650C wheels. The bike is not shielded by the rider's body, and thus represents a small additional amount of frontal area, but is still very aero. Lowracers and highracers ARE faster than DFs. "NoCom" stands for "No Compromise." It was designed to take advantage of HPRA rules that allow the bike's frame to incorporate as much aerodynamic advantage as possible while competing as a 'stock', i.e. unfaired bike. It incorporates spoilers between and around both wheels, a disk rear wheel, and a low 6 inch seat height.

Some other bents can be competitive, even faster than DFs, but it requires the use of a fairing. Many bents are slower than racing bikes, and are more comparable to DF hybrids. Fairings can make a bent obscenely fast. One of my riding buddies took a fully faired lowracer to Black Bear (a 100 mile road race, which due to a detour turned out to be 104 miles) and finished with a 3:40 in spite of a 6 mph headwind for most of the route. I got a 4:31 that day, riding solo most of the way. By contrast, I never broke 6 hours for a century on my DF, even with copious amounts of drafting behind stronger riders. BTW, I consider my lowracer very comfortable. It's not very visible in heavy city traffic, but then riding it in heavy traffic wouldn't be a good use of its capabilities.

Ahhh now I can sleep at night knowing what DF means, thank you.

Just over 28mph avg in a Century? Do you know how much power this guy generates? The thing about bents being faster makes sense, but only if you are way leaned back, as with proper position on a DF your legs are comparitively the only additional surface area. I wonder if you gain a larger advantage on a low racer bent the taller you are??? i.e. for me being 6'4" I have a lot more leg showing to the wind even if my upper body is perfectly flat. It would be so cool if I could use my larger than average power output and only have an average frontal area to deal with🙂

Anybody ever done a study on the parasitic losses due to the longer chain? Does the chain last forever since it is so long (less stress per link), or need to be replaced at same frequency as DF?

Regarding fairings, it seems from the pics I have seen no one uses them. If they are so much faster, why not use them?

How many guys/gals ride the bents for speed and not for comfort? In the racing scene are there many people below 40? Any below 30?

Ok one last question... I understand they don't climb as well, but what about steep hils even short in duration with grades >15%? With the low racers can you wind up with your head lower than your feet?

OK I lied, one more... Are the low racers legal on public roads? What about NoComs?

Thanks very much for the education!

wilmar13 said:

Just over 28mph avg in a Century? Do you know how much power this guy generates? The thing about bents being faster makes sense, but only if you are way leaned back, as with proper position on a DF your legs are comparitively the only additional surface area. I wonder if you gain a larger advantage on a low racer bent the taller you are??? i.e. for me being 6'4" I have a lot more leg showing to the wind even if my upper body is perfectly flat. It would be so cool if I could use my larger than average power output and only have an average frontal area to deal with🙂

He's approaching the half-century mark, and he only took his streamliner out a few times prior to the race. Otherwise, he does one or two group rides with the local club per week, usually on his DF. So he's not Cat 1/2 material, by any means. I can't answer the height question.

Quoted post said:

Anybody ever done a study on the parasitic losses due to the longer chain? Does the chain last forever since it is so long (less stress per link), or need to be replaced at same frequency as DF?

I'm not aware of any studies. There's probably a watt or two difference, but nothing you'd ever feel on the road. Chains last 2-3 times longer because there's 2-3 times as many links.

Quoted post said:

Regarding fairings, it seems from the pics I have seen no one uses them. If they are so much faster, why not use them?

They're faster, but if you're sealed inside one, it's hard to hold conversations with your buddies, who would also have to be in one in order to keep up! They are also more hassle to start/stop, and to transport.

Quoted post said:

How many guys/gals ride the bents for speed and not for comfort? In the racing scene are there many people below 40? Any below 30?

You're implying that fast recumbents aren't comfortable. I have not found that to be true. Something like the former world-record-holding Cheetah would be uncomfortable for anything but what it was designed for, but that's the only example I can think of. Sometimes-poster here, CKAudio, is 36. A few recumbent riders are in their 20s, and most that young are at least nterested in speed.

Quoted post said:

I understand they don't climb as well, but what about steep hils even short in duration with grades >15%? With the low racers can you wind up with your head lower than your feet?

That would be a pretty steep hill! I have climbed up to 20% grades with my lowracer. Once the initial speed is sloughed off, it's one pedal stroke at time. If it gets to that point, the DF will usually win the king-of-the-hill contest. Of course the greater cruising speed leading into the hill can carry me up the hill further; which might be enough to crest a short one.

Quoted post said:

Are the low racers legal on public roads? What about NoComs?

That depends on the locale. Some states have funny laws defining wheel sizes and seat heights. But AFAIK they are treated as regular bicycles everywhere regardless of any obscure laws out there.

blazingpedals said:

I'm not aware of any studies. There's probably a watt or two difference, but nothing you'd ever feel on the road. Chains last 2-3 times longer because there's 2-3 times as many links.

Hmmm, well why is it claimed that the front wheel drive models are more efficient? Just gimmick, or is there truth in it?

blazingpedals said:

You're implying that fast recumbents aren't comfortable.

Nah, I didn't think that, just that 99% of the posts I have read and articles praise the comfort and it seems most bent converts are older guys who have problems with DF's comfortwise. I have no comfort problem with my racing DFs but I am interested with bents because of the uniqueness and speed.

blazingpedals said:

That would be a pretty steep hill! I have climbed up to 20% grades with my lowracer.

OK I wasn't sure, I looked at the NoCom by Velocraft and it looked like it wouldn't take much to have you laying down the wrong way when climbing if you know what I mean. How stable are they? Can you eat and drink with some concentration?

Oh and thanks for your input... Are you the only one here? Everytime I check in here there are 30-35 people viewing, but 29-34 are lurkers. 😕

wilmar13 said:

Oh and thanks for your input... Are you the only one here? Everytime I check in here there are 30-35 people viewing, but 29-34 are lurkers. 😕

We had a troll a few months back, and everybody has been staying away since then. The troll was stalking me, actually. He's stalked me elsewhere since then. I think most of the 'lurkers' are using Cycling Forums as a gateway to Usenet (where they also lurk instead of post. 😉 )

You're right, most people get into bents because of a comfort issue. In the normal progression, they start with something more tame, and the ones that are interested in speed gravitate toward the speedier designs as they gain experience. Lowracers have a steeper learning curve than many of the 'sport' models. Balance is very different when you're that reclined, and there's no using body english to help - it's all in the steering. Once I learned to ride the lowracer, it was no longer a problem; but I had a few exciting moments in the early days. Now, I can dig around in my pockets, sit up and look behind me... I've even got a little tail waggle maneuver I do with the bike when I pass my group and want to tease them. But no riding no-handed. The bike won't do that at all, it immediately falls over if I try; so I always need at least one hand on the bars.

One thing you'll hear about bents is that you have to develop different muscles, and until that point in time a new rider will be slower on a bent. It's true. I took about 3 months to get back to my former 17 mph averages. With that kind of delay, some riders who get bents expecting to immediately be faster are disappointed and give up too soon. You didn't get your DF legs in a month, so don't expect to get your bent legs that quickly, either.

wilmar13 said:

Hmmm, well why is it claimed that the front wheel drive models are more efficient? Just gimmick, or is there truth in it?

IMHO they're not more efficient, but they can save a pound of chain, and they do solve some chain routing problems related to getting the chain around the seat of a lowracer. In return, twist chain (fixed boom) systems limit steering angles somewhat, and moving bottom bracket systems induce pedal steer.

Ok good info all, thanks Blazing pedals. Regarding the Troll, why not just use ignore?

Are there other more active forums, especially with folks bent towards speed?

wilmar13 said:

Ok good info all, thanks Blazing pedals. Regarding the Troll, why not just use ignore?

Are there other more active forums, especially with folks bent towards speed?

Being ignored only makes this guy more abusive. When the postings rose to flood proportions, the moderator had to step in.

Speed seems to be a small niche, no matter where you go. The most active recumbent-oriented site I know of is the BentRiderOnline Forums.