new build question

[no whereman]

hello forum.i am building a 3 wheel go cart type conveyance.the motor is a 208 cc powerhorse electric start. I am going with a single wheel drive setup.my question is ,will a single flange flange 2 pc split wheel be ok for the drive sprocket and the drum for a band brake?and will there be any harm in using the same wheel on the non drive side if I should choose double band set up?the parts sellers seem to know absolutely zero about anything except money.oh yes a little more info on design,this is for an amputee so the seat needs to be 20 inches at least from the ground so a widesh axle is in order.longish wheelbase 12 tooth clutch 72 tooth drive sprocket.i am aiming for a cruising speed of aprx.12 to 15 mph at about 2600 rpm.any thing ive overlooked?any advice is much appreciated thanks

 

[OzFab]

It sounds like you've done your homework, all that sounds fine but, I will make a few points just to help you along:

-long wheelbase will counteract the wide axle; if you're using a wide axle for stability, don't make the wheelbase too long

-your calculated speed is a bit off; using those figures, you'll get 15mph on 12" tyres (or is that what you're going for?)

 

[landuse]

Welcome

 

[no whereman]

fabroman,thank you for the resonse.and you are spot on about the width versus length variable.i had not considered that at all.this is my first foray into the motorized realm.while iam by no stretch of the imagination a master fabricator,i have built a recumbent bicycle 2 tall bikes and some other human powered conveyances.to me the hardest part of any build is not the fabrication but rather doing the mental arithmetic.what a shame it would be put all of ones energy into a build only to find out that important aspects had been overlooked.if I may ask one more question of the collective forum here,given the intended use{priority on low end tourqe top speed not important}I am considering utilizing a 26 inch mountainbike wheel for the front(3 wheeler)approximately 11 mm solid axle length 110 mm keeping in mind this will mostly be used on paved surfaces by an adult amputee of about 160 pounds.assuming the frame will be more than adequate the two points that must bear the load are the axle itself and the steering axes.to get to the gist it ,given the variables(fork angle and its effect on overallstability and how it changes braking stress is this feasible?i realize there are other options but this is my preference.by all means ,though ,be that as it may,i am open minded to any point that I may not have seen from my angle.and fabroman, sorry for that omission,yes I do plan on 12 inch tires.(trying to get a hillclimber of moderate speed without complication and expense of a torque converter.i realized im all over the place here so thank all for your paticence(long time lurker first ever post)thanks to all

 

[OzFab]

First off, just to help with the planning/layout/setup, can you tell us a little about the "amputee" user? You don't have to go into detail, it's more about what limbs are missing...

The most important thing to always keep in mind is balance; with a seat height of 20", weight will need to be distributed evenly, otherwise you will either lose traction or the steering will suffer. the upside is you can place the engine directly under the rider, putting all the weight in the middle...

If I understand correctly, what you're hoping to achieve is something like a three wheel bar stool racer, only not as high & a little more "safety" concious; it may help to research them...

Any help you need, all you need to do is ask

 

[no whereman]

fabroman ,first of all thank you for your response.you have bought up two
important aspects that I would have likey overlooked on my own.while I had considered the importance of weight distribution my solution would have been to lenghthen the wheelbase.again,thank you for saving me from a big potential setback.the amputee is my wife.her left leg is gone from the midthigh up.she is fully capable of transferring to a well designed device un assisted and is in every other way sound and whole.so may I ask you to elaborate a bit more on weight placement?what I have gathered is that it is best to shoot for a 50 50 balance,that makes perfect logic to me.after all why put that 50 or so pounds of metal out in the back when ther is aperfectly good spot directly beneath the riders center?an anchor if you will to stabilize the elevated seat.a seat belt in the absence of a roll cage is actually more of a danger to the rider I have come to understand.other safety considerations perhaps a n armrest/no fall off thingamagig on her left(read non mounting side)is in order.i am building this for my most. precious cargo after all.not a task I enter into lighty.any other safety aspects you see that I overlooked?one last question if I may sir.i intend to utilize a mountain bike front end for the front portion.the frame itself will be more than capable of supporting the loads.it is the wheel size(26 inch is the current plan.a quality mountain bike suspention fork is probably a lot sturdier than most would think(think lightweight motorcross fork.solid steel wheel axle,diameter 11 mm axle overalllenght 110 mm.leaning towards rim brake as opposed to mechanical disc.i have had a past flange failure before with disc brakes on a tall bike.rim brakes mutch better at dealing with brake stress.and in conclusion,pros and cons of different diameter wheels 26 24 20inch ect? im finally getting better at math but I must confess I lack the current ability to crunch all numbers to definitively answer all these questions.your assistance has been a big plus and I am very thankfull for your time and consideration.i perceive that you are a man of much knowledge in this field and I could pick your brain for a long time but that would not be expressing gratitube so ,once again many thanks for your time and experience.should you ever find yourself in arcadia florida ihave a gratis bullwhip with your name on it.(another hobby of mine)thanks again,later on.

 

[OzFab]

Hey, that's why we're here, you have questions, we have answers... Somehow, I don't see myself being anywhere near Florida any time soon (check my location)

This whole thread begs the question "why not just buy her a mobility scooter?" but, I think already know the answer...

I can envision exactly what you're shooting for & I like it; the only suggestions I can make, for now, are do some research into bar stool racers & drift trikes (my image is a tame bastard child of the two) &, when you're ready, start a build log in the projects section...

Oh, one more thing; in future, can you please make use of your ENTER key? Massive block of text can be rather daunting & difficult to follow

 

[no whereman]

reply

fabroman,thanks for the reply.I have been doing a bit of forum browsing and I understand you have been undergoing some difficulties of late.I don't want to get all sappy on you but I have this to say.When things get rough know that it is an indicator of good things coming your way.not to preach at you,i can only imagine a mile in your shoes.I bring myself back to center with this simple phrase,look up ,not down.

Ok,moving on, I will soon do some reseach on drift trikes and barstool racers.i see you believe in making me work for it .nothing wrong with that!!after I do some homework I will see where im at.

forgive my density but I really don't understand what you meant by using my enter key,could you please use an example?thanks again.

p.s. I knew you where an aussie,and my offer was indeed sincere.(austraillians are world reknowned as master whip makers)...well you never know.later on

 

[OzFab]

I understand you have been undergoing some difficulties of late.

I have?

i see you believe in making me work for it .nothing wrong with that!!

Give a man a fish, he eats for a day; teach a man to fish & he eats for a lifetime...

forgive my density but I really don't understand what you meant by using my enter key,could you please use an example?thanks again.

I've edited you last post to show you what I mean

 

[Poboy kartman]

I know this is your wife.....and maybe your attention may be focused in a different direction......but how can her leg be gone from the midthigh up???

This is 2014......not '69.....

 

[no whereman]

POBOY.touche I say,point taken.kinda like in order to poke your eye"out"with an arrow you would need to go up the nose,be that as it may,it is easy enough to poke it "in".Fabroman,greetings.I had you confused with Poboy I believe.anyhooo...may you both be well.As to the enter key,i am still scrathing my head to a point.I will do my best to stay aware of my tendacy to make my own grahmmer up as I go along.I am prone to ocassionaly lose sight of all the angles.thanks to all for the replys

 

[Poboy kartman]

Yeah. ....I think what you meant to say was it was amputated above mid thigh......

The way you said it had me stumped....... (oooooooooh..........I am so going to he77 for that one........)

Yeah people are always mixing me and fab up......you will have to be around awhile before you realize how funny that is.........

 

[Poboy kartman]

I have?



Give a man a fish, he eats for a day; teach a man to fish & he eats for a lfetime.

No.....it's give a man a fish, he eats for a day; teach a man to fish and he spends $40, 000 on a boat and tackle so he can drink beer all day. ......

 

[firemanjim]

 

[OzFab]

Fabroman,greetings.I had you confused with Poboy I believe.

Oh dear lord, please don't do that; that's like confusing the mayors assistant with the village idiot

 

[firemanjim]

but Tony, (no diss to you) aren't those the same thing?
Getting Fabroman and poorboy mixed up is like mixing up salt and pepper.....

 

[OzFab]

but Tony, (no diss to you) aren't those the same thing?

Um, NO! I enforce the rules & he breaks 'em...