5 person bike...possible?

skeetsh00ter · Post by **skeetsh00ter** » Thu Jan 17, 2008 5:27 pm

So I really really want to make a 5 person bike to bring to the playa this year. Think Black Rock Taxi... Anyways, today is the first day i really thought about it. I don't want to do anything too complicated. I'd rather not have to deal w/ a ridiculously long chain and everything that goes along w/ a long chain so i was just going to keep each set of pedals w/ their own wheel. (Imagine the front wheel of each bike missing, except for the first bike, and the frame welded to the bike in front of it...if that makes sense to you; so for 5 people that would be 6 wheels)

Well, i've hit my first road block in the design. I figure that the pedals in typical tandems are synchronized to help w/ the balance, you can't have two people, let alone 5, all at different points in their pedal stroke. right?

Do you think it might work having 5 people all pedaling at different speeds (depending on which gear they are in...i would hopefully leave those on) and different rhythms?

Token · Post by **Token** » Thu Jan 17, 2008 5:50 pm

With one wheel to steer and 5 wheels inline, how would you turn?

phil · Post by **phil** » Thu Jan 17, 2008 5:50 pm

You're thinking linearly. :->

> you can't have two people, let alone 5, all at different
> points in their pedal stroke. right?

I think you not only can, you should. If people are at different points in their power stroke, then the power is applied all the time instead of one big oomph as all five hit the downstroke. All the cylinders in your car fire at different times, right?

skeetsh00ter · Post by **skeetsh00ter** » Thu Jan 17, 2008 5:57 pm

we would turn very carefully.

phil, i was thinking straight line, but that is a pretty cool looking bike though...probably a step beyond my limited capabilities.

what you say makes sense about having power at different times, but think about when you are riding a bike by yourself you tend to push the bike left to right as you pedal (if you're pedaling hard that is). Having 5 people leaning the bike in different directions at different times is what bothers me about the idea.

Dork · Post by **Dork** » Thu Jan 17, 2008 5:58 pm

I'm with Phil - different ends of the stroke is a good thing.

A few thoughts:
Gears are overrated. It's just more parts to get gummed up with playa dust.
The thing you have will be hard to steer. A 2x2 or 3x2 arrangement with a rod connecting the steering of the front bikes might work better.
Seperately run wheels *might* mean the more forceful riders would spin their wheels. You'd have to work together to get it moving. Not necessarily a bad thing.

phil · Post by **phil** » Thu Jan 17, 2008 6:10 pm

> Having 5 people leaning the bike in different directions at
> different times is what bothers me about the idea.

I would suggest that having people leaning in different directions at different times would average out the lean and would be better than having all five people leaning over to the right at the same time. Think of a canoe. :->

Captain Goddammit · Post by **Captain Goddammit** » Thu Jan 17, 2008 7:21 pm

I've already been involved in such a bike.
It can be done, without too much difficulty. Here's some design considerations:
The separate pedal/wheel for each rider turns out to be a good idea, because 5 people are too heavy for just two standard bike wheels.
Synchronizing the pedal stroke positions isn't a concern.
Making the frame rigid, so you have 4 wheels pointing straight and one up front trying to steer, is a lousy arrangement that doesn't work. It even sucks when going straight unless you PERFECTLY align all the wheels.

What does work pretty well is to make each bike a "trailer" to the one ahead of it. You can remove the front wheel of the "trailer" bike and weld the forks to the rear of the frame of the lead bike. That lets the bike turn. Then, you can add another trailer bike... and another...

This tandem/trailer setup only works on flat ground (like the playa!) because it doesn't allow for separate up/down movement of each wheel. In a dip the middle wheels would be airborne, over a bump one end or the other tries to fly.
If you wanna get fancier, you can fix that by attaching the forks of the trailer bike to the rear of the lead bike with a hinge type setup rather than welding it solid. The connection needs a lot of side-to-side rigidity.
I was thinking of cutting and widening the trailer bike's front fork, and putting it right on the ends of the lead bike's rear axle. The end of the fork would have to be welded closed so it looped all the way around the axle so it wouldn't simply lift off. You can't just tighten it on cuz then you'd eliminate the flex you're trying to get. If there isn't enough extra axle sticking out of the lead bike, maybe weld on some solid rod, or make some screw-on axle extenders...
I didn't end up doing the extra flexy thing because I only wanted to use it on the playa anyway.
Who am I to worry about real-world practicality?
I mean... what the hell else does one do with a land yacht...

theCryptofishist · Post by **theCryptofishist** » Thu Jan 17, 2008 7:58 pm

The Herrings had a multiple. I carried six in two tiers, but I don't know if they all pedaled. I think they did.

Bob · Post by **Bob** » Thu Jan 17, 2008 8:43 pm

http://images.burningman.com/index.cgi?image=169

BAS · Post by **BAS** » Thu Jan 17, 2008 11:24 pm

Good grief, the piano has a rearview mirror on top! I never noticed that before!

(Kinda cool, actually.

)

Fire Wire · Post by **Fire Wire** » Fri Jan 18, 2008 12:50 am

The "four stooges" Hot Wire, Barb Wire, El Wire and Live Wire
and the always smiling Her Majesty Pinemom (picture below)

BAS · Post by **BAS** » Fri Jan 18, 2008 10:05 am

Hey Fire Wire! How on Earth do you steer that thing?

I'm really curious.

Fire Wire · Post by **Fire Wire** » Fri Jan 18, 2008 11:29 am

BAS wrote:Hey Fire Wire! How on Earth do you steer that thing? I'm really curious.

Hey BAS, that was the funny part. If you will turn left, the man on the right had to trottle more and the man on left stop trottle. If you will turn right the man on the left will trottle and the right side stop trottling. The man in the middle is only trottling. It works if you are leaning to the right you go left or leaning to the left you got right. Confused!!!! Hahaha, you ain't seen nothing yet!!

You better look out for the Puke-O-Bike for Burning man 2008, four unicycles attached to a centre moving in circles. Camp Herring is back on track!

skeetsh00ter · Post by **skeetsh00ter** » Fri Jan 18, 2008 1:02 pm

so many ideas! i'll report back once i've banged out a design.

Captn. Goddammit, i like the idea of just attaching the front fork of one bike to the rear wheel of the bike in front of it. That will work perfectly!

oneeyeddick · Post by **oneeyeddick** » Fri Jan 18, 2008 1:19 pm

I can't wait to ride the Puke-O-Bike...who wants to sit in front of me ?

Fire Wire · Post by **Fire Wire** » Fri Jan 18, 2008 4:46 pm

oneeyeddick wrote:I can't wait to ride the Puke-O-Bike...who wants to sit in front of me ?

Take a number and get on line! Did I said "on line"? You will be tossed away anyway or another...... Mohohahahaha BURP!!!!

oneeyeddick · Post by **oneeyeddick** » Fri Jan 18, 2008 5:50 pm

I will have to eat a big bowl of Green Pea(ness) soup before riding.
Just another way to spread the message of going green.

BAS · Post by **BAS** » Fri Jan 18, 2008 11:31 pm

Fire Wire wrote:
BAS wrote:Hey Fire Wire! How on Earth do you steer that thing? I'm really curious.
Hey BAS, that was the funny part. If you will turn left, the man on the right had to trottle more and the man on left stop trottle. If you will turn right the man on the left will trottle and the right side stop trottling. The man in the middle is only trottling. It works if you are leaning to the right you go left or leaning to the left you got right. Confused!!!! Hahaha, you ain't seen nothing yet!!

You better look out for the Puke-O-Bike for Burning man 2008, four unicycles attached to a centre moving in circles. Camp Herring is back on track!

Well, I was confused before I even sat down at the computer, so that's nothing new!

I really hope I will find some way to make it to BM2008! Right now it looks like it will be another case of either having the money OR the time....

I have a job, but Burning Man is almost certainly too close to the start of the school year for me to get the time off...

(Of course, I really doubt that the students need me to be there to move in..., still, my superiors probably won't see it that way!)

Oh, and I think I will pass up the opportunity to ride the Puke-O-Bike-- too likely for me to get dehydrated while spewing copious volumes of tuna fish, vodka, and whatever else I have poured down my gullet!

(I've been toying with a "bike" design to specifically make getting around easier, no matter what my state. Now, if only I actually knew what I was doing, the design process would be much easier.

)

skeetsh00ter · Post by **skeetsh00ter** » Sat Jan 19, 2008 9:45 am

so this is what it will hopefully look like. When it gets closer to summer i'll start trying to find some cheap mtn bikes for the project

http://people.tribe.net/6075467f-0ec3-4 ... fed5de03aa

BAS · Post by **BAS** » Sat Jan 19, 2008 10:54 am

I don't know what the situation is like down where you live, but up here, when all the students go home for summer break, there are suddenly a flood of second hand, abandoned bikes on the market. The university rounds them up and sells the best of the bunch for cheap, the rest go for scrap. Part of what's finally got me interested in making something is the prospect of cheap parts. You might check to see what the university scene is like where you are at.

I finally figured out what I was doing wrong with loading the full sized picture! (Reading the directions really does help-- imagine that!)

With that tube you have connection the back of one seat to the front of the bicycle behind it, you are going to need some sort of hinge on one or both ends of the tube, or the whole thing will attempt to continue on straight, no matter what the lead bicycle is trying to do. Since the playa is pretty flat, I don't think a ball hinge would be needed, but something to allow turning left and right is. (I'm thinking that a hinge on the trailing bike is probably more needed, but maybe for stability purposes I am wrong...?)

skeetsh00ter · Post by **skeetsh00ter** » Sat Jan 19, 2008 11:16 am

all you naysayers out there.

I really do think that the bike should work as a rigid frame. As long as all the wheels are completely straight it should be no different than a regular quint ( http://quintbike.com/ ). If however, that isn't the case, then a hinged trailer type system will be the backup plan.

Thats a good idea about the end of school year thing BAS. I know that they do regularly clean out the bike racks every summer, but i'm not sure what they do with those bikes. I'll make sure to check it out.

skeetsh00ter · Post by **skeetsh00ter** » Sat Jan 19, 2008 11:35 am

Actually, you all might be correct that the snake would work better. The difference between the two designs to change from one version to another wouldn't be hard at all though. All that i would have to do is move the top connecting piece (the one from the back of a seat to the following bikes handlebar area) down to the forks ( http://people.tribe.net/6075467f-0ec3-4 ... 06f1e0d04b ).

I hadn't really though of it before, but this would solve the rigid frame problem and i wouldn't have to make any sort of hinges or trailer hitch contraptions on the bikes.

BAS · Post by **BAS** » Sat Jan 19, 2008 10:46 pm

Yeah, that looks like it should work! Good idea.

Captain Goddammit · Post by **Captain Goddammit** » Sun Jan 20, 2008 10:09 am

A rigid frame 5-bike would work great, probably way better than the flexy-bike, as long as you DON'T have a separate wheel under each rider.
When I did the flexy-bike, it was mostly for the sport of it. If I just wanted it to work best, I would do a rigid. I assumed that the weight of all those riders would be too much for the wheels and tires... I didn't actually try it. The "quint" in that link appears to have standard bike wheels and apparently works. Wow... now I'm thinking about building THAT next!
Sorting out the chain situation on a long rigid isn't hard. The way I see it there are two obvious options.
1) A long single chain that goes around every pedal-crank sprocket, with idler gears to maintain positive contact at each sprocket. You already said you don't wanna deal with a crazy long chain and idlers... I don't like that plan either.

2) Individual chains for each bike segment. This is easy.
Most bike pedal cranks have at least two sprockets on them. Just run a chain from the larger front sprocket to the larger sprocket on the next set of cranks. Then run a chain from the smaller sprocket on the second crank to the smaller sprocket on the third crank... then chain the third crank larger sprocket to the fourth crank larger sprocket... then pair up the smaller one to the fifth crank...

It won't really matter if the sprocket sizes aren't perfectly matched. Just arrange your sprockets so that if the second set spins faster, the next one spins slower, and the next set faster, etc. so that the mismatch doesn't add up to a crazy difference between the first and last set.

skeetsh00ter · Post by **skeetsh00ter** » Sun Jan 20, 2008 10:39 am

Captain Goddammit wrote:A rigid frame 5-bike would work great, probably way better than the flexy-bike, as long as you DON'T have a separate wheel under each rider.

I just don't see my shoddy welding being able to hold 5 people without having a wheel under everyone. Thats the biggest hang up thats keeping me from doing the standard quint like the one in the link. (that bike is badass, you should build one Captain).

The long chain probably could be solved pretty easily, i came a cross one site that used salvaged rear derailers (spelling? firefox can't fix this one....) to keep tension on the chain by mounting them on strategic points along the frame.

BAS · Post by **BAS** » Sun Jan 20, 2008 10:11 pm

Captain! There is a third option-- just have the last person do all the work! Of course, that runs the risk of losing friends, but it is an option.

Captain Goddammit · Post by **Captain Goddammit** » Mon Jan 21, 2008 6:41 am

Yeah... great... and there I was, doing my best to refrain from suggesting putting a motor on the thing, even though I was thinking it all along... and you had to go say that...

BAS · Post by **BAS** » Mon Jan 21, 2008 9:03 am

Now I have an image of a jet powered version of the bike...

skeetsh00ter · Post by **skeetsh00ter** » Mon Jan 21, 2008 11:19 am

hmmmm.....jets....that would solve lots of the bikes problems. no need for chains or pedals at all. someone make it happen.

BitterDan · Post by **BitterDan** » Mon Jan 21, 2008 2:47 pm

Jets would just introduce new problems such as melting the skin off of innocent bystanders. On second thought, someone make it happen.