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King Ankylosaurus Posted - 04/24/2011 : 12:28:10
Hello All,

This is my first post -- I am not sure if it is appropriate to post this here, but I am not sure where else to turn for help.

I am in the process of building a pedal car in the style of a 1930s Grand Prix car -- it will be 1:2 scale. I have minimal knowledge when it comes to bicycles and trikes. The car is basically a recumbent trike with four wheels. Currently, I am stuck at the drivetrain portion (where I have the least knowledge) and I am not sure where to turn for help. I have a few questions that I hope some of you can help me with.

First, here is a concept drawing of what the car will look like:

As you can see, the driver will be far up front to make the car appear to be mid-engined. When it comes to this project, aesthetics are extremely important; but the car also has to function -- functional art, I suppose.

A run down of things (that I can think of) that should be taken into consideration:

-The car in total (front of body to end of body) will be about 105", give or take a few inches
-The wheelbase is 60"
-Roughly 7 feet from the rear axle to the crank
-145mm crank
-24" wheels, 3" wide rear balloon tires, 2" front
-Two-wheel drive
-7-9 speeds
-The car will hopefully weigh around 80 pounds with the aluminium body and all, but I suspect it might hit close to 90-100

My main concern is whether or not I should be using a mid-drive with the chain being so long. I would like to keep the drivetrain as simple as possible. I came across an older thread on here where someone was concerned about having six feet between the gears and crank; in which there were responses along the lines of "chain length is not an issue as long as you have idlers and chain tubing." I'm wondering if this applies to my car as well.

My other concerns are the actual gearing, how to select them; and how to make the car two-wheel drive. I have seen people on a pedal car forum mention "dual freehubs" from Longstaff, but I can't seem to find anything like that on their site.

I realise these questions are a lot to ask, but any help at all would be very much appreciated; even if someone could just direct me to another person/forum to ask these questions.

Thanks so much.

25   L A T E S T    R E P L I E S    (Newest First)
Steven Challenge Posted - 06/29/2012 : 12:11:53
I've seen that before. It looks awesome! And, with the right material and a few airodynamic ajustments, it could be a decent recumbent trike. Frankly, I like the "vintage" look better than the futuristic look of a modern full faired recumbent.
jimincolorado Posted - 06/29/2012 : 11:49:33
Another idea, this time a trike!

Steven Challenge Posted - 06/28/2012 : 05:10:45

This one looks like what I'm going for. Problem is that the front is a little bit to narrow to house 2 sets of legs and pedals. I'm going to fix that with a bit wider front.
As for material, I can't weld aluminium myself, so I would have to let someone else do that, or choose an alternative material. I've worked with wood before (made 2 plywood bicycles) so for now, the option is wood. Lightweight, strong and easy to work with.
It also gives the quadcycle a vintage look.
I want the quad to be as versatile as possible. I want to ride alone with minimum bagage, but also I want to be able to transport kids or grocceries. The old Fords used to have a coupe, sedan and pickup version. I want those three options as a modulair system. With an easy connection being able to attach a kid seat or a pickup trunk. I've seen cars that have a seat hidden inside the trunk. I don't know how you call them.
As for gears, I'm thinking about each rider get their own set of derailleur gears. Both rear axles are connected and drive a third sprocket. A single chain goes from there to the back. A diferential should devide the power equaly to the rear wheels.
The structure that holds the wheels would have to be aluminium, not wood.
jimincolorado Posted - 06/27/2012 : 13:12:46
This T looks pretty aero:

Blue Ridge Biker Posted - 06/27/2012 : 09:10:59
Originally posted by Steven Challenge

I didn't realise that, I've found the thread by the way.
Back to the recumbent quadcycle. The model T would be a bad choice, what about the model A?

I wouldn't rule out T's so quickly...

I've thought about doing a "track style" T in electric, but I'm finding out batteries have their own problems.
PUGZCAT Posted - 06/26/2012 : 14:07:05

Every day is Critical Mass with this thing.

Or for a slightly different twist check out Bicycle Forest "pimp your rhodes car".
Steven Challenge Posted - 06/22/2012 : 13:32:48
I didn't realise that, I've found the thread by the way.
Back to the recumbent quadcycle. The model T would be a bad choice, what about the model A?
I've copy/pasted with Google Sketchup a quick draft.

How's that for starters? I'm going to change the tires for BMX tires, remove the fenders and try to fiddle some structure inside the quadcycle. I made a twin seater because otherwise I couldn't keep the shape of the model A without making it more narrow. And it would be twice the fun.
This design would be purely hypothetical... for now.
(for the moderators: should I carry on in this thread, or make a new one?)
PUGZCAT Posted - 06/20/2012 : 13:18:01

It had it's own thread 6 months ago.

Steven Challenge Posted - 06/19/2012 : 00:38:44
Talking about gears and alternative drive, has anyone ever seen something like this:
It might be interesting to replace a long chain with this. I've seen on youtube the working model of this, with some explaination of how it works.
Grant-53 Posted - 06/14/2012 : 20:58:59
As for driveline position the ease of access is a key consideration. Ratios from 25 to 75 gear inches would work for cruising. Most cassettes have 28T as the largest gear and 11T as the smallest. Smaller gears have less weight but may wear faster. A mid line gear transfer need only be a pillow block bearing, a short tube, and two sprockets attached with set screws.
Grant-53 Posted - 06/14/2012 : 20:21:48
At some point a shaft drive may be desireable. A Model T would have a higher drag coefficient than a Formula car because of the flat front radiator. Chat with some garden tractor or ATV folks about what they use for differentials.
Steven Challenge Posted - 06/04/2012 : 07:29:01
If I had the time, space and $$$ I would like to make a dual seated quadcycle with Ford model-T hotrod appearance. Problem with a 2 seater is that you need 2 people to make it work properly. Unless you make it E-power assisted.
For an easy way to create a 4 wheeler, exchange the rear wheel from a regular recumbent trike with a trike back. Like the Utah Trikes Quad as mentioned before. I don't know if making a full fairing in a car shape would be practical. I would go for a self supporting chassis in a car shape with quadcycle components added. More like trying to turn a car into a quadcycle than trying to turn a quadcycle into a car.
Since the quad wouldn't be made for high speed, but more for cruising, I would use 20" 3" tires. With only front suspension, just to keep all wheels on the ground when going of and on sidewalks. Low gears for more power.
It would be a recumbent but it wouldn't be what a recumbent stands for: speed, low weight, airodynamic. It would be more of a cruiser bike that happens to be 4 wheeled and recumbent seats.
harv Posted - 06/01/2012 : 05:23:38
Looks like Greenspeed has added a quad version of the Anura to their product mix. http://tinyurl.com/c8bax5x
Steven Challenge Posted - 05/31/2012 : 07:50:38
It's been a year ago, but Maxbeer has revived it. I wonder if King has finished the quad. If not (and for others who want to make a quad) http://www.atomiczombie.com/ has got quite a few recumbent 2, 3 and 4 wheelers, complete with plans.
MaxBeer Posted - 05/31/2012 : 04:50:44

Itěs possible to have more photo of King's pedal car?
teubner Posted - 04/29/2011 : 20:26:25
Use this front drive in the back?
King Ankylosaurus Posted - 04/29/2011 : 16:59:31
Larry, I have not. Something I meant to mention along with the weight and size, is that I will be sitting very far towards the front -- other pedal car builders have told me that 2WD is probably the best way to go. While I do not doubt what you said is true, I am not exactly sure how far I will be pushing this car -- I would like the car to be able to adapt to most situations.

Edit: I do have a cheaper 1WD pedal car which is much smaller than the car I am building (based off of a Rhoades car, I believe), and the 1WD is most certainly an issue with cornering and loss of traction. Based on my experiences with that car, I think it would be best to make this car 2WD.
Larry Lem Posted - 04/29/2011 : 14:11:35
Big and heavy do not dictate whether single-wheel drive would be unacceptable. It depends on whether you think you'll be cornering hard enough to lift an inside, driven-wheel. Have you ridden an adult, upright, tricycle with single-wheel drive, like a Workman Cycle?

Larry Lem
King Ankylosaurus Posted - 04/29/2011 : 10:44:23
Thanks for the links. I am definitely sticking with a 2WD setup, though. Because of how heavy and big the car will be, I think I will need all of the traction that I can get.

I am wondering if the tooth choice for the rear freewheels and sprockets matter much, and if so; can anyone recommend what I should try?
Speedy Posted - 04/29/2011 : 06:06:27
it's common practice to drive one wheel and the opposite to coast on bearings
off the self parts are low cost from the following company ~ products
hubs, axles, bearings, sprockets, adapters etc.



the Sun bicycle parts are at : http://www.jbimporters.com/web/
King Ankylosaurus Posted - 04/27/2011 : 13:44:17
It looks like shipping from Taiwan for the Samagaga differentials will cost about $125-$200, depending on how quickly you want it. That seems insane to me. I am going to use the setup that 25hz mentioned earlier.

As for the BMX freewheels, does it matter how many teeth are on them considering the hub sprockets will have the same amount?
Speedy Posted - 04/26/2011 : 12:03:19
the mountain quad frame was made in my shop as a sub-contract
just recently cleaned out the last of the tooling and spare parts
King Ankylosaurus Posted - 04/26/2011 : 10:56:26
25hz, that's a lot of great information. I've actually been to your site, which has been one of my main sources for information.

Do you think it would be lighter to just use the Samagaga differential (which will accept a multi-speed freewheel), with one chain in total? It will definitely be cheaper, but will there be a downside to the performance by doing it this way?

Also, Speedy -- that is a really awesome quad! A very clean design. Who makes those?

Edit: I found the site. It is now out of production.
Speedy Posted - 04/26/2011 : 08:20:29
examples of a BMX freewheel type differential can be seen here :

25hz Posted - 04/26/2011 : 07:49:17
Looks like you're well into the fabrication and decision-making process already.

Your car is going to be big and heavy. Any place you can save weight and cost and drag, is going to be a good thing - whether you are racing it or not. I have some experience with mid drives and mid-idlers, etc etc, and if you can avoid them, avoid them. They are more weight, more cost, more complexity and most importantly, will add more drag, whether you "do them right" or not. Try some small idlers and chain tubes to help with chain management. You can always add the idlers later if you absolutely need to. A 7' long chain is long, but it's not exceedingly so in the world of recumbents.

You can make a simple, and effective differential yourself, no fancy custom machining, using nothign more than standard bike parts.
- use two half shafts like you're doing now, and put a single sprocket BMX freewheel on the end of each half shaft.
- take any multi-speed hub (a disc brake hub is easiest) and attach a sprocket to the disc brake mounting side, and have the inside sprocket on the cassette with the same tooth count. The rest of the cassette sprockets can be whatever setup you want.
- mount the rear wheel hub in front of the jack shafts, far enough ahead of them to maintain clearance between the cassette gears and the jackshafts
- how it works, is when you pedal, the chain drives the rear hub, just like normal. The the sprocket on the disc side is connected to the left jackshaft with a short section of chain. The cassette sprocket that is the same tooth count as the disc brake side sprocket, is connected to the right jackshaft with another short section of chain. The rear hub is mounted on slots so it can be adjusted fore and aft to apply chain tension to the short jackshaft chains.

In the end, you have a posi-track drive line that also has a built in slip differential. Nothing fancy, nothing expensive. As you corner the slowest wheel automatically gets the drive while the fastest wheel freewheels. Also a very effective traction aide. Another option is you can hook the sprockets directly to the spoke flanges using small AL adapters instead of using one of the cassettes and the disc bolts.

These boys do quads all the time.

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