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Posted: Fri Feb 09, 2007 1:49 am
by AUbicycles
Nothing against recumbent riders, but I prefer the idea of riding upright as it feels safer.

- Traffic can notice me better than on a recumbent (especially in traffic)
- I can react more efficiently, eg jump up a curb or dodge an obstacle (tighter turning curve).

Posted: Fri Feb 09, 2007 11:31 am
by Hotdog
The safety question is a difficult one. A really low recumbent that puts you below the height of car (or at least SUV) windowsills would certainly be scary from my point of view, but on the other hand some people say that because recumbents are rare they are more likely to catch the attention of motorists. It's a fair point that jumping the curb to escape a dangerous situation isn't going to work on a recumbent, but sharp swerves are still possible on most (depends on the wheelbase), and what's more due to the lower centre of gravity you can brake a lot harder without going over the front wheel. Looking behind you on a recumbent can be very difficult, but you can make up for that to some extent with handlebar and/or helmet mirrors. Overall I think it's about evens.

I'm worried about sounding like a recumbent fanboy here, which would be particularly silly as I don't even own one and I do like my upright. They're certainly not for everyone (no good off-road as you can't shift the weight distribution around) but I reckon there are some people who'd benefit (some tourers, speed fiends who aren't into UCI santioned racing, people with back or arm problems).

Posted: Fri Feb 09, 2007 11:52 am
by europa
Any bike in traffic is silly. Trouble is, we can't avoid it sometimes. I'm lucky, I can avoid most traffic here in Adelaide. I think it's like everything, you recognise the dangers, understand your machine and do the best you can. The car that tags you is more likely to be driven by someone who's made a monumental blunder than a lesser mistake.


Bentech Recumbent - pictures

Posted: Fri Feb 09, 2007 3:12 pm
by rdp_au

Happy to share a few pictures of the construction of my bike.

Basic frame components

Trial assembly

Completed bike

The bike was built at minimum cost as this was an experimental foray into recumbents. The frame is made of mild steel automotive exhaust pipe tubing. This was cheap, easily bent at the muffler shop, and required no special skills to weld. ChroMo would be lighter and stiffer, but would have cost much more and required access to TIG for welding . The rear seat support stays are aluminium. The whole thing is spray painted in automotive acrylic. I haven't weighed the completed bike, but lifting it around the garage I'd guess somewhere around 15 kg. Drive train is 7 speed Shimano SIS with a Biopace crankset. Rear wheel is a Shimano hub and Araya rim. These were sourced from my old mountain bike. Chain rollers are cut down rollerblade wheels. Front wheel is a new Velocity hub and Aeroheat rim. This was the single most expensive item - decent 20 inch wheels are hard to find, so I had to buy a new one. Also fitted new V-brakes front and rear. Tyres are Primo Comet slicks.



Posted: Fri Feb 09, 2007 3:30 pm
by Hotdog
Nice pics David, that's a very smart looking bike you've put together.

Posted: Fri Feb 09, 2007 6:06 pm
by europa
So exhaust pipe tubing does work eh?

Any thoughts on under seat steering? Especially using exhaust tubing?


Posted: Sat Feb 10, 2007 12:38 am
by europa
She looks very nice David. Now that I've got the time to look a bit more closely and really appreciate it.

Exhaust pipes eh? Anything to watch out for if going that route?


Posted: Sat Feb 10, 2007 12:12 pm
by tuco
Riding one looks tricky. If you ride it in traffic do you feel vulnerable being lower down?

I can picture that long chain coming off and taking a leg off.

Posted: Sat Feb 10, 2007 6:06 pm
by Bnej
The longer chain will actually last longer, because there is less wear per link, and as you're not standing on the pedals, a catastrophic chain whip is pretty unlikely.

Also means less torque applied to the drive train, and a straighter chain path between the chainrings and the freewheel, so in theory your running gear ought to last longer.

Exhaust pipe tricks

Posted: Sun Feb 11, 2007 3:42 pm
by rdp_au
Richard asked if there are any issues with building the bike from exhaust pipe. Well, not really, provided you make sure the ignition is ofF before you ride....... Actually, no issues at all. It's just simple mild steel tube. Muffler shops have all sorts of bending mandrels, so they can do the bending as well.

I've noticed no difference riding in traffic. My head is about as high as the average car driver, so I can see pretty much what they can. My approach when riding a bike is that I am invisible regardless of the type of bike I'm on (recumbent, diamond, or motorbike).

The long chain is also a non issue. It is actually constrained in the middle at the rollers, so in reality, the unsupported chain run is not much longer than on a diamond frame. I did have a chain break on my very first ride when a link plate pulled off a chain pin (that will teach me to reuse an old chain pin). The chain jammed as it passed through the rollers. Stopped me pedalling pretty quickly, but otherwise harmless.



Posted: Mon Feb 12, 2007 9:04 am
by Hotdog
I'm curious who said in the poll that they own more than one recumbent but didn't post about it. Don't be shy, testify! :wink:

Posted: Mon Feb 12, 2007 8:41 pm
by reparto corse
how much do these recumbet's sell for? I would never have thought that they were that expensive. Then again never had that much interest in them so never bothered to find out. This info on these things being that fast has realy surprised me. I would never have thought. I'll have to pay them more respect now. Still won't own one though. doesn't seem natural. Even when you go to the gym and they have the exercise bikes that resemble recumbents they just don't feel the same as normal exercise bikes. Each to their own i say. Anyways if anyone knows what recumbents sell for , i'd like to know just out of ciuriosity's sake :)

ps: pardon any spelling mistakes.
Pss: great work on building your own David.awesome stuff.

Posted: Mon Feb 12, 2007 8:47 pm
by Bnej
reparto corse wrote:how much do these recumbet's sell for?

Many, many dollars.

The cheap end starts at about $2,000 it seems. I've never seen a cheap recumbent, and you can't buy them in most shops. If I could go down the road and try one, I would. And if I could buy a cheap one, I would.

But I'm unlikely to go interstate and lay down a few grand for something I might not ride long term.

But some of them do look really nice. ;)

Posted: Tue Feb 13, 2007 9:03 am
by Hotdog
Seems about the only place you can buy recumbents bicycles in Australia (trikes are a bit easier to find as there are a couple of domestic manufacturers) is Flying Furniture in ACT. Cheapest bikes they have are around $1500, but you're looking at a budget of more like $2500 before you've got a decent number of options to choose between. There aren't any truly mass produced recumbents so no cheap entry level models unfortunately. So yes, a big investment of time (if you're not near Canberra) and money required to give these things a go.

As for them being fast, well that's half the point of the recumbent seating position. The intended benefits are 1) comfort and 2) aerodynamics, with some bikes concentrating on one more than the other.

Buying Recumbents

Posted: Tue Feb 13, 2007 11:17 am
by rdp_au
Hotdog is right that Flying Furniture sell a locally manufactuered recumbent for around $1,500. I think it's pretty good value, as the specs are quite good. There are also some cheaper ones coming onto the market from Taiwan and China. In Melbourne, Trisled sell a brand from Taiwan called TW-Bents. But, they are still a lot of money if you're not sure if they will work for you.

In Canberra there is a fairly active recumbent population. One thing they do is arrange regular "recumbent demo days". Recumbent owners bring their own bikes for interested people to try out. Sounds like a good idea. Perhaps people in other states could try something similar.




Posted: Mon Jan 21, 2008 7:22 pm
by Recycler
G'Day rdp-au, Good job Great idears!!! Looks nice, how does it ride? One problem, this will not be the last build. Good Luck.