Building an adult trike

My mother in law is interested in an adult trike, but so far, I haven't found a used (or new) one
within budget. I'd like to try building one. I can braze,and I think I can handle the frame
construction, However, I'm not so sure about the drivetrain. Before I go through a bunch of
experimentation, I'd like to learn from the experience of anyone else who's tried this

Will single wheel drive work?

How about a solid axle, with no freewheel or differential?

Separate freewheels for each drive wheel? I think I could manage this with BMX freewheels.

Something else entirely?

Dave Johnson wrote:
> My mother in law is interested in an adult trike, but so far, I haven't found a used (or new) one
> within budget. I'd like to try building one. I can braze,and I think I can handle the frame
> construction, However, I'm not so sure about the drivetrain. Before I go through a bunch of
> experimentation, I'd like to learn from the experience of anyone else who's tried this
>
> Will single wheel drive work?

Yes, for light duty, low speeds.

> How about a solid axle, with no freewheel or differential?

Nope.

> Separate freewheels for each drive wheel?

Possible, but this would greatly add to the complexity of the design.

Left wheel drive is the usual way to go in the abscence of a differential, and affordable
differentials are no longer to be had.

You might be able to find to find a conversion kit that would work.

Note that with a trike, you can put the bottom bracket considerably lower than with a bike, since it
doesn't need cornering clearance.

Trikes are generally a major hemorrhoid, not recommended if theres'a any possibility of her riding a
bike. They're amazingly cumbersome and awkward, also generally more dangerous than bikes.

Sheldon "Not Talking About Recumbent Tadpoles" Brown
+----------------------------------------------------+
| A little inaccuracy sometimes saves tons of |
| explanation. --H.H.Munro ("Saki")(1870-1916) |
+----------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

In college I worked on a project building an adult trike, delta style. It didn't have a differential
per se, but the rear wheel hubs had needle bearings that would engage (and be driven by) the axle,
but which could also allow the wheel to "freewheel" faster than the axle, allowing the outer wheel
to properly track through a turn. We found this preferable to strict one-wheel drive. With one wheel
drive, your legs can really tell that it's only the one wheel doing the driving, and right turns
feel a lot different from left turns.

The rear hubs were a simple design, with standard needle bearings pressed-in. We used a solid
rear axle, but made a special piece to attach a freewheel to it (the axle ran right through the
freewheel). I don't remember what that thing looked like. Sure helps to have access to a
machine shop.

I've also seen true differential units on tricycles at Sears. They might be able to order you just
the differential or axle unit. Two-wheel drive will definitely take more effort to build, but I
think it's worth it. We have the technology.

Check with the HPV/recumbent crowd; lots of trike enthusiasts there, and lot's of people who build
their own HPVs.

http://www.ihpva.org/ is a great place to start. Has lot's of trike designs in the Builder's Corner.

Good luck with your project,

-Bruce-

"Dave Johnson" <djohnson+rbt@spamblocked.com> wrote in message
news:dqi67vg1qbqer1av3q9rkgcbk7mok035cp@4ax.com...
> My mother in law is interested in an adult trike, but so far, I haven't found a used (or new) one
> within budget. I'd like to try building one. I can braze,and I think I can handle the frame
> construction, However, I'm not so sure about the drivetrain. Before I go through a bunch of
> experimentation, I'd like to learn from the experience of anyone else who's tried this
>
> Will single wheel drive work?
>
> How about a solid axle, with no freewheel or differential?
>
> Separate freewheels for each drive wheel? I think I could manage this with BMX freewheels.
>
> Something else entirely?

Dave Johnson wrote:
>
> My mother in law is interested in an adult trike, but so far, I haven't found a used (or new) one
> within budget. I'd like to try building one. I can braze,and I think I can handle the frame
> construction, However, I'm not so sure about the drivetrain. Before I go through a bunch of
> experimentation, I'd like to learn from the experience of anyone else who's tried this
>
> Will single wheel drive work?
>
> How about a solid axle, with no freewheel or differential?
>
> Separate freewheels for each drive wheel? I think I could manage this with BMX freewheels.
>
> Something else entirely?

something along the lines of : http://www.freewiel.nl/uk/uk/producten/trike.html

makes more sense to me
--
Marten

"Dave Johnson" <djohnson+rbt@spamblocked.com> wrote in message
news:dqi67vg1qbqer1av3q9rkgcbk7mok035cp@4ax.com...
> My mother in law is interested in an adult trike, but so far, I haven't found a used (or new) one
> within budget. I'd like to try building one. I can braze,and I think I can handle the frame
> construction, However, I'm not so sure about the drivetrain. Before I go through a bunch of
> experimentation, I'd like to learn from the experience of anyone else who's tried this
>
> Will single wheel drive work?
>
> How about a solid axle, with no freewheel or differential?
>
> Separate freewheels for each drive wheel? I think I could manage this with BMX freewheels.
>
> Something else entirely?

I've built a lot of custom vehicles ( mostly for disabled children) and find that just buying a
trike rear end assembly from Trailmate is very cost effective. I get the subframe with bearings and
shafts in primer and the buy their hubs.

http://www.yellowjersey.org/photosfr...t/trikjn95.jpg
http://www.yellowjersey.org/photosfr...t/trikturq.jpg

And yes, one wheel drive is standard for that sort of thing. Write me if you do not have a local
Trailmate dealer.

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

Sheldon Brown said:

> Trikes are generally a major hemorrhoid, not recommended if theres'a any possibility of her riding
> a bike. They're amazingly cumbersome and awkward, also generally more dangerous than bikes.

Here's what Aedan Mcghie, a very happy owner of a George Longstaff tricycle has to say on
the subject:

<http://ourworld.compuserve.com/homepages/triker/technique.html>

<quote> If you ride a trike for any length of time you are going to get very fed up with people
asking "Can't you ride a bike?". The best (but risky) way to stop this is to let them have a shot.
Generally within a few feet they will panic and jump off or stay on and turn turtle. Then you can
get a photo like the one above showing the underside of a trike.

They assume that because, left to itself, a trike will stand up that it is easy to ride. It is a
completly different experience from riding a bike. The UK Tricycle Association Gazette had an
article about learning to ride a trike last year. They said that it took time to learn and would
never be mastered, the trike always has a surprise waiting for you.

Riding in a straight line is the first challenge. A trike will try to run off down the camber of the
road. On a bike you steer the way you are falling to correct the problem. If you do that on a trike
it just makes things worse. You have to dissconect what you feel like you are doing and focus on
what really is happening. It's OK for a trike to sit at an angle. If there is any camber on the road
then there is nothing you can do anyway, it will sit at whatever angle the road is at. If the angle
starts to get steep then steer a little up the camber. Trust your trike to look after itself and
things will become fine. Fight it and you are heading for a fall.

Once you have mastered the straight line you are faced with a corner. On a bike you steer with you
weight and balance with the steering. A trike is just the opposite. You steer with the steering and
keep it upright with your weight. Using the handlebars to steer takes a bit of getting used to. At
first I was worried that the latteral loading on a wirespoke wheel would cause it to taco. You have
to apply much more force to the steering than you do with a bike. When you figure out how to steer
you then have to worry about falling over. If you sit on the saddle then sooner or later you are
going to meet a bend which causes your centre of gravity to move outside the triangle of the wheels.
When that happens you will roll. To avoid this you should move your weight to the inside of the
bend. The tighter or faster the curve the further out you should move. It works the same way as a
motorcycle side car team.

Inspite of the above my trike is my mount of choice. This is not only because if its safety
but mainly...

BECAUSE IT"S FUN!

</quote>

Here's what he says about one wheel drive vs two wheel drive:

<quote> Trikes can be one wheel drive or two wheel drive (OWD or TWD).

One Wheel Drive is simpler to do and is lighter. Generally the wheel nearest the kerb is the driven
wheel as this tends to push the machine up the camber of the road and makes life a bit easier. On
ice or snow a one wheel drive trike will move at a slight angle to the direction of travel. Lifting
a wheel off the ground is easy to do and if it is your driven wheel which is off the ground then
life can seem empty and meaningless.

Some trikes have been fitted with car style differentials but, as anyone who has ever driven on snow
is aware, car diffs send the power to the faster wheel. This can be the one on the outside of the
curve, the one with less grip on the road... or the one up in the air.

Longstaff two wheel drive uses a double freewheel block which sends the drive to the wheel with most
grip, generally this is the one on the ground. It can be difficult to understand how this works, the
easiest way is to think that the faster wheel is freewheeling.

The only problem I have found with this system is that when doing very tight turns, in it's own
length, the inside wheel can slip a little.

The rear axle runs on sealed bearings, one at each end of each half shaft. The rear wheels are held
on in the same way as a crank is attached to a bottom bracket except the axle is six sided rather
than four. </quote>

McGhie owns a George Longstaff tricycle with two wheel drive.
<http://ourworld.compuserve.com/homepages/triker/axle.JPG> is a picture of the differential.

I have a Longstaff frame (bicycle, not trike) and I can attest to the craftsmanship of this builder.
His trikes are said to be the best available, and if one is serious about an English Racing
Tricycle, his are the trikes to get.

Sheldon Brown On Sat, 15 Mar 2003 16:28:45 GMT wrote,

>Dave Johnson wrote:

>> Will single wheel drive work?
>
>Yes, for light duty, low speeds.
>
..which this would be.

>> Separate freewheels for each drive wheel?
>
>Possible, but this would greatly add to the complexity of the design.

Seems like this would be almost exactly twice as hard as single wheel drive. Shouldn't I be able to
reverse a BMX freewheel for the opposite side? Isn't that what the wrong-side-drive BMX bikes do?

>
>Note that with a trike, you can put the bottom bracket considerably lower than with a bike, since
>it doesn't need cornering clearance.
>
I was planning on that.

>Trikes are generally a major hemorrhoid, not recommended if theres'a any possibility of her riding
>a bike. They're amazingly cumbersome and awkward, also generally more dangerous than bikes.

I don't disagree, but there's no realistic chance of getting her on a bike.
--

Ignorance killed the cat. Curiosity was framed.

Trying to build your own will cost 3 times what you think it wil and owrk half as well, if at all.
The brazing is the eay part. Most adult trikes stink. Period. Too heavy, limited choises,
beyond-bad positioning, flex and wobble. The English take a quality mountain bike and add a trike
conversion kit. Bob Jackson makes a sweet one as do a few others. These are real high kits-sealed
bearings, support struts, freewheeld, derailleured etc....They use a single wheel drive as using a
dual wheel offers no real advantage for the people that ride these. It's been done, but it's a LOT
of work to derive a differential to allow for cornering. The kits usually sell in the $500-750
range, install in a bout 2 hrs, and nothing is permamanent. Take it off and revert the bike to orig
spec. I sold them in my shop for years-mostly to elderly people that wereafraid of falling or to
people with neurological/physical deficits that wanted to ride but coudn't ride a std bike or the
terrible adult trikes.

"A Muzi" <am@yellowjersey.org> wrote in message news:<v77ftu27003gd3@corp.supernews.com>...
>
> I've built a lot of custom vehicles ( mostly for disabled children) and find that just buying a
> trike rear end assembly from Trailmate is very cost effective. I get the subframe with bearings
> and shafts in primer and the buy their hubs.
>
> http://www.yellowjersey.org/photosfr...t/trikjn95.jpg
> http://www.yellowjersey.org/photosfr...t/trikturq.jpg
>
> And yes, one wheel drive is standard for that sort of thing. Write me if you do not have a local
> Trailmate dealer.

As Andy said, there are conversion kits for modifying standard diamond frames. These used to be
(long ago) available from Schwinn dealers.

You might want to ask the local Goodwill people where all their bikes go to- generally they're sent
to the bigger warehouses instead of the smaller Goodwill stores (at least that's how it works here
in Portland). A *real* find would be a Schwinn Town & Country three-wheeler- this had a three-speed
hub driving a true differential on the rear axle. I don't think they've been made for 20 years- but
they were damn sturdy.

If "Mom" wants something really exotic, she should contact Pat Franz at Terracycle. He built a
carbon-fiber trike for a balance-challanged Special Olympics rider:
http://www.terracycle.com/cftrike.htm

Jeff

Dave Johnson <djohnson+rbt@spamblocked.com> wrote:

> Sheldon Brown wrote,
>
> >> Separate freewheels for each drive wheel?
> >
> >Possible, but this would greatly add to the complexity of the design.
>
> Seems like this would be almost exactly twice as hard as single wheel drive. Shouldn't I be
> able to reverse a BMX freewheel for the opposite side? Isn't that what the wrong-side-drive BMX
> bikes do?

Left side drive BMX bikes use special left-side, left-hand-threaded freewheels and hubs. If you want
to "wrong-side" a freewheel I'd suggest using one of those.

At the speeds within which a conventional "delta" trike is competent, single-wheel drive does work
pretty well.

You could use a trike conversion kit like this http://www.megalowrider.com/Item/F9901.htm on a
bicycle frame. This one is intended for 20" wheels, but it does not appear that there is anything to
prevent its use with larger rims laced to appropriate hubs. And as Sheldon pointed out, a trike BB
need not be nearly as high as a bike's, so 20 inch rear wheels might work just fine. It's not like
you're apt to screw up the handling, after all-- not significantly worse than "normal" anyway.

Some Schwinn trikes came with sub-frames that used an ordinary pair of bike wheels, the "rear" being
used to drive the assembly. If you could find one of those, it would allow the use of freely
available parts for both wheels and main frame.

Folks who fear falling from bikes and favor trikes for that reason are apt to give up on trikes as
well before too long. Trikes really are treacherous, ill-tempered beasts by comparison, which will
soon confirm any weenie rider's suspicion that cycling is a terribly hazardous undertaking.

Chalo Colina