Recumbent Handel Bars

Discussion in 'Recumbent bicycles' started by Athol, Nov 9, 2004.

  1. Athol

    Athol New Member

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    :confused: Which are the best in the view of those who actually ride?
    Handel bars under the seat or easy rider style?
    It seems to me that handle bars under the seat would offer much less air resistance than arms raised and high easy rider style bars. Which have the best control or is it not an issue? Also if you built under seat bars and did not like them then it would be an easy matter to add on to front wheel assembly and weld in ape hangers.
    Views please, to aid a new constuctor getting close to the welding stage.
    Thanks
    Athol in New Zealand:) :) :)
     
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  2. blazingpedals

    blazingpedals New Member

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    The OSS (ape hanger, praying hamster, superman, etc) type steering keeps the rider's arms more-or-less parallel to the airflow. This presents less frontal area. For very laid-back seating positions like the Reynolds bikes, USS can also be aerodynamic, but not for most US style bikes that have more upright seating positions.

    Not an issue. Whichever is more comfortable for you.

    You shouldn't have to do any welding to return the bike to standard steering. At most it would involve changing a fork and removing the bolt-on bits used by the USS setup. And of course bolting on a new stem and handlebar.
     
  3. tyler_derden

    tyler_derden New Member

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    For me the main idea of a recumbent is rider comfort. I have always liked under seat steering. How comfortable will you be after an hour or two of riding while holding your arms up on handle bars? With USS, your hands are down at your side, and in the natural position to which they fall. Controls are at your finger tips. What could be more comfortable?

    I have no idea if there is any aerodynamic advantage to one style over the other, but if you're a racer I suppose you need to consider that.

    I have never cared much for long wheelbase recumbents. They take too much space to turn around, and typically come with over seat, tiller-type steering. I haven't ridden any for more than a couple minutes but my first impression is that the long wheel base makes them sort of wobbly at low speeds. Maybe that wobbliness goes away with experience, but my SWB bike took no more than 10 seconds for me or anyone else who has ridden it to become very stable at even sub-walking speeds.

    TD
     
  4. blazingpedals

    blazingpedals New Member

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    My current bents have 'praying hamster' type steering. The bars are just far enough in front of my chest that my elbows are at my sides and my hands are just behind my knees at the nearest point of the pedal stroke. I find this very comfortable and natural. I don't dispute that USS is comfortable too, but for most people it's not a natural way to steer. Other disadvantages of USS are that they make the bike harder to walk and that handlebar not being in front of the rider also means no easy place to mount things like computers. All these problems have solutions, BTW. OTOH, USS has a more 'open' feeling, since the handlebar isn't in the rider's view. Linkage USS has no tiller effect. (Linkage OSS exists, too, but is very uncommon.) And there's the 'alien' factor: most DF riders can't figure it out and think you're steering by mind control.

    I'm a SWB kinda guy, but I'd say a TourEasy is much easier than a SWB for the average newbie to ride on the first attempt. Getting your feet up high enough to pedal a SWB can be a trick! In general, the things that make any bent easy for a newbie to ride are having a fairly upright seatback, minimal tiller, and low bottom bracket. A low seat height helps, too. One bike that really excels at test rides is the lowly BikeE. The pedals are up a bit higher than a TE but the seat is upright and there's no tiller effect at all. Tiller is not a major problem for EasyRacer bikes, or some of the new RANS LWBs, but some older RANS bikes had massive amounts of tiller.
     
  5. tyler_derden

    tyler_derden New Member

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    I saw someone riding in the praying hamster position and couldn't imagine how that would be comfortable for more than a few minutes. When I saw it I thought ths must be a new bike and the person hasn't had time to adjust the steering to a proper position yet. So people actually do that intentionally? It might be pretty aerodynamic, and that might matter if you're trying to win a race, but I don't race and don't care much about aerodynamics or weight.

    One other reason I don't like OSS is that when you go down, the OSS crap keeps you tangled up in the bike. I went down on my SWB with USS once when I was daydreaming and dropped the front wheel into a sewer grate. I was launched into the air and landed on my feet in front of the bike! Try that with OSS!

    TD
     
  6. blazingpedals

    blazingpedals New Member

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    Whew! I need a break from the idiocy of the 'who's faster' threads. Tyler, what kind of bike do you ride? Homebuilt? Details of your USS!
     
  7. tyler_derden

    tyler_derden New Member

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    I agree completely. I have added a few of those folks to my ignore list. It's a shame because they might have something useful to say but i don't feel like wading through all the childishness to find it.

    I have an old "hypercycle" which is sort of a toy recumbent. I bought the frame and built it up about 20 years ago and then made some modifications to the drive train make it quieter, smoother, and improve chain control.

    Here is a recent photo of my neice riding it. You can't see a lot of the bike from the angle the photo was taken. hypercycle

    The seat position on this bike is rather forward, so the steering is an almost normal set of handle bars that go right into the steerer tube on the fork with only a little backwards sweep. The hand position puts the backs of your hands facing forward, just adjacent to either side of the seat. I can u-turn on this bike in the width of a sidewalk! I have some ancient sun-tour bar-end shifters and some two-finger bmx bike brake levers mounted on the handle bars.

    The drive train uses a single chain ring up front. There is an idler that I made from a rear wheel hub and freewheel (minus the pawls) that splits the chain into two sections- one for front and one for rear. The front chain drives a largish gear on the idler and the rear chain is on a smaller gear, so the front chain ring at 42 teeth looks more like 50 or so teeth (I have forgotten the actual gearing and the bike is at my father's house right now).

    I had the 27" rear wheel built using a Sachs two speed internal mechanism, drum brake, and 6 gear freewheel, so I have 12 speeds available and a more than adequate brake for the rear end. I think the tire is a 1.125" fat-boy. The front wheel is a 16" wheel I had built from a cheap aluminum rim and an expensive racing hub (the only hub I could find at the time with the same number of spoke holes as the 16 inch rim). The front brake is a crappy bmx thing that was all I could find to allow cable clearance back in those days. It is a terrible brake considering how much rider weigth is over the front wheel.

    The seat is a hard fiberglass shell that looks like a miniature version of a typical school desk seat. It has some dense foam padding glued on. The riding position is quite upright, and VERY comfortable.

    Before I installed the idler gear in the drive train, there were two pulleys made from derailleur jockeys to lift both the top and the bottom of the chain. I experimented with a split chain ring that I made by cutting a chain ring in half and then mounting the two halves on an aluminum plate that I cut to mount in the crank. It was sort of extreme- If I recall correctly it started as a 42 tooth ring and I turned it into a 60+ tooth ring. I oriented the long axis of the chain ring so that the maximum gear ratio would occur at the top of the pedal stroke when legs are bent and ready to push hard. At the bottom of the stroke the ring was at minimum gear ratio allowing my legs to snap through to the next power stroke. I used that ring on a 75 mile ride from Tecate to Ensenada, Mexico one year and never stopped on the whole length of the ride including some very long moderate grade ascents up mountains. It felt like climbing stairs. Once I installed the idler, I was no longer able to use the split chain ring so I retired it to a box in the garage.

    This bike has a lot of limitations- I don't care too much for the hard shell seat, especially for long distance riding. The short wheel base makes for some really fun high speed turnability, but the fork rake and weight distribution make the steering unstable for no-hands riding. If you very lightly put a couple fingers on the steering and let it do what it wants, at any speed over about 10 mph it starts to wobble. It only takes a light touch to stabilize it, but I'd prefer something that is inherently stable.

    I am in the early stages of gathering tools, materials, and reading on the process of building frames using carbon fiber. I will start with something simple- probably just a swb, rear drive bike with over seat steering. After I make some mistakes there, I'll try for the final format. I am hoping to ultimately make a front wheel drive, mid height, short or mid length bike, USS, and maybe with suspension on at least the rear end. Right now I am thinking about 20" wheels front and rear, but may go bigger on the rear depending on the drive-train configuration.

    For front wheel drive I want to try to put in a universal joint to allow the front wheel to steer independent of the drive. Check this site:FWD.

    I also like this drive mechanism a lot, but I do not have the necessary machine tools or the budget to have something like this made:lucabike. I especially like the way the pedals/cranks are driven in an eliptical path by the gear belt. Very elegant!

    That's it. I showed you mine, now show me your's!

    TD
     
  8. blazingpedals

    blazingpedals New Member

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    The old hypercycle is almost a collector's item. Turner Recumbents makes the closest thing to it these days. Not surprising, since Milt was one of the Hypercycle designers. They sure can take a lot of mods, can't they? My V-Rex was a 63 speed for a few years, until I decided I didn't need a 17-144 inch gear range.

    I have two main rides, a V-Rex and a Baron. The Baron is for going fast, the V-Rex is for going NOT fast. It's not quite that easy, of course, but you get the idea! I often use the V-Rex in the summer for when I park-and-ride to work. The V-Rex have been through several versions of Coroplast fairings and full bodies. Currently, it's unfaired, with a 24 inch drive wheel, a 30/44/56 triple in front and a 11-32 9-speed rear. V-Brake in front and disc brake rear - I had that added after a few scares on big wet downhills. My Baron is set up with dual discs, a 30/44/58 chainring set, and a 12-28 9-speed cassette and Thracian wheels. Having the return chain dropped as in the pic looks cool but doesn't really help with speed; so I may put it back to the stock configuration this winter, for better turning at slow speeds.

    Like you, I want to build something. I'm in a large club, with lots of recumbents, and one member has some experience with building - both with steel and CF. We are planning on making some CF highracers this winter. The checkpoints on our wish list are dual 700C wheels, semi-splitter, and lightweight. Seems reasonable enough! Construction will probably be a combination of bladder and vaccuum bagging, but that depends on the expert, not me! This spring we built a quick-and-dirty steel dual-26 'proof of concept' bike for me, which I have ridden a bit through the summer. I named it 'J-Rex' which in the spirit of my V-Rex is short for 'Junk-Rex,' or 'King of Junk.' It's actually faster than my V-Rex, and if I can get the darned U-Bars figured out it should be pretty comfy too - or at least the CF version will be. I'm looking forward to having a racing-profile bike that doesn't put me inches off the HOT pavement in the summer.
     
  9. tyler_derden

    tyler_derden New Member

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    Can that Baron make a u-turn on a two lane road, or do you have to get off and help it? Can you turn enough for street riding or does the front wheel hitting the chain cause any problems? I'd like to do something with a low seat but so far all those I've checked need too much room to turn around. I don't know if that is because of the wheelbase or if it is because of the chain hitting the tire.

    I have heard just a little about using a female mold and air bladder to make a frame, but can't find any details anywhere. I assume the bladder remains inside the frame. How do you insure that the carbon lays flat and doesn't move around when you inflate the bladder? How does the excess epoxy escape the mold when the bladder is inflated? How do you make a bladder and insure that it inflates all the way into narrow spaces like rear forks?

    I had not thought about being close to the hot ground in summer. That is an important consideration, especially since my main design goal is long distance comfort- it may be better to be up a bit higher.

    I test rode a wizwheels trike at the Des Moines MS150 ride. I liked it a lot, and may eventually try to make a carbon trike- I haven't seen any of those yet. I would think they would be popular because of the extra weight that results from the three wheel configuration. CF construction might allow a couple pounds to be shed.

    Another thought I had toward construction would be to start with plain CF tubes, then cut and join them using over-wrapped cloth and epoxy. It would not be beautiful, but pretty fast and easy, I think. I have been thinking about how to make tubes (the commercially available ones are too expensive for me). My vacuum pump should arrive in a few days and I will try making a small tube for test purposes. I plan to wrap the cloth and epoxy over a PVC pipe or cardboard tube, then vacuum bag the whole thing. I am not sure how hard it will be to get the CF tube off the core pipe- if I use cardboard, I can peel the cardboard from the inside of the CF tube. With PVC it gets a little trickier. I am thinking about splitting the pipe at a slight angle to the pipe's axis, then hold the two sections together with end caps and/or a threaded rod runing down the center of the pipe. After the epoxy has cured, I think a sharp rap on the small half of the pipe at one end will separate the two halves and allow them to slide out of the CF tube.

    PVC pipe would seem to make a good mold for making pipes using an air bladder. The inside surface of the pipe is relatively smooth and should leave a semi presentable finish on the CF tube once it comes out of the mold. I might try this as well. Here the problem will be getting the cloth into the pipe, then getting the air bladder in there. It doesn't seem easy.

    I also want to test vacuum bagging a piece of foam wrapped in cloth/epoxy. I haven't found anyone who can tell me if the foam can withstand the pressure when the air is pulled from the bag. If it works, I think the major frame shape can be cut from sheets of blue house-insulation foam, maybe three 1" layers glued together, then over wrapped with CF cloth. The rear fork can be formed from the two outer layers of foam suitably spaced, and a back support column for the seat can be integrated by including it in the foam sections. After it is done the biggest trick will be to drill out a hole for the head tube. I am thinking about how to just incorporate it right into the layup to eliminate having to drill a hole for it. Maybe an oversized CF pipe can be wrapped and epoxied into the foam first, then the rest of the frame ccompleted. Finally an aluminum head tube epoxied inside the CF pipe with enough wiggle room to allow some correction of alignment problems...

    TD
     
  10. blazingpedals

    blazingpedals New Member

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    Even the way it is, I can do a U-turn on a 2-lane road if I pay just a little attention. With the other two idlers in place to route the return-side of the chain up over the front wheel, it can easily do acute angle 'corners' on a local bike path. I originally dropped the return chain like that because I thought it would be faster. But it's not.

    You have lots of questions on CF, and unfortunately, I don't have answers. Let me ask around and see if I can find somebody that might know the answers. I'll post a reference to you privately, but you can then feel free to post the answers here so I can learn, too!
     
  11. john_hopkins

    john_hopkins New Member

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    Google for RC/glider forums and/or mailing lists. These folks vac-bag CF/Kevlar wings over foam regularly, some have web sites with extremely detailed instructions and photos of the whole process. It's been a few years since I kept up, or I'd give you links. I can tell you that a bagged, composite-over-foam wing is ridiculously strong. One of the sailplane competitions involves flying a 2-meter wingspan aircraft into a near-vertical dive, terminal velocity exceeding 100 mph, then pulling up hard to pass *under* a horizontal "limbo pole" set a few meters off the ground. Another duration event culminates in "landing" as close as possible to a target. Usual approach is to dive the plane, sticking its long, pointed nose into the ground right at the target, like a javelin. Lots of g's there ...

    Hope this helps,

    John
     
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