A few questions before i build my motor bike

Mr. Manta Ray · #21 (**permalink**) 11-07-2009, 12:23 PM

it just sounds like a good idea for a vertical friction drive no tire wear or blowouts and a lot easier over the precision involved when you put it on the rim which is only a half inch wide

Clotho · #22 (**permalink**) 11-07-2009, 01:22 PM

There are numerous problems with this idea. In fact there is more wrong with it than there is right. Unless I am not understanding you correctly. Please answer the following:

How will you mount the motor?

If the motor is a rack mounted vertical shaft how will you get the drive down to the area of the brake disc?

Brake disc's are flexible. How will you overcome this so that the friction roller can grab?

Brake disc's are smooth. How will you overcome this so that the friction roller can grab?

With the disc so small your gearing is now way out of whack and is to high. The bike will have little torque and won't climb any hills. It will be quite fast on the top end however. Once you pedal enough to get the drive to grab. Will this be ok for your use?

I honestly think that you will have the most rewarding experience if you build some sort of rack mount kit. You will likely find the installation challenging and the net result is that you will have a working bike. You will learn much from this endeavor. If you still feel the need to build a motorized bike with your vertical shaft then I would study the videos above and duplicate his plans as closely as possible.

Trying to second guess and re-engineer a design that is already proven to work isn't a good idea. Chances are that the builder in that video has already tried the things you are suggesting and found it didn't work well. I would get in contact with him and find out as much as I could.

If you absolutely positively must build a bike with as little cash input as possible then please consider one of Deacon's weedwhacker (horizontal shaft) friction designs. The motors can be found for next to nothing and often free. It is a much easier build than the vertical shaft design and there are many experienced builders here to offer assistance.

Mr. Manta Ray · #23 (**permalink**) 11-07-2009, 02:16 PM

Quote:

Originally Posted by Clotho

There are numerous problems with this idea. In fact there is more wrong with it than there is right. Unless I am not understanding you correctly. Please answer the following:

How will you mount the motor?

If the motor is a rack mounted vertical shaft how will you get the drive down to the area of the brake disc?

Brake disc's are flexible. How will you overcome this so that the friction roller can grab?

Brake disc's are smooth. How will you overcome this so that the friction roller can grab?

With the disc so small your gearing is now way out of whack and is to high. The bike will have little torque and won't climb any hills. It will be quite fast on the top end however. Once you pedal enough to get the drive to grab. Will this be ok for your use?

I honestly think that you will have the most rewarding experience if you build some sort of rack mount kit. You will likely find the installation challenging and the net result is that you will have a working bike. You will learn much from this endeavor. If you still feel the need to build a motorized bike with your vertical shaft then I would study the videos above and duplicate his plans as closely as possible.

Trying to second guess and re-engineer a design that is already proven to work isn't a good idea. Chances are that the builder in that video has already tried the things you are suggesting and found it didn't work well. I would get in contact with him and find out as much as I could.

If you absolutely positively must build a bike with as little cash input as possible then please consider one of Deacon's weedwhacker (horizontal shaft) friction designs. The motors can be found for next to nothing and often free. It is a much easier build than the vertical shaft design and there are many experienced builders here to offer assistance.

was just bringing up the idea because the motor will still be mounted above the back tire and the vertical shaft can just go straight down to the disk pad and the disk pad seemed pretty stiff but i was wrong so forget that idea one question though can you explain those videos i can't watch them on my computer oh and my bike won't be a pedal bike any more i took that out and just made foot rests

Clotho · #24 (**permalink**) 11-07-2009, 03:02 PM

You want me to type out in words what the videos describe? This is not possible. I could never do an adequate job.

I can only judge your ability based on the comments in this thread. Please forgive me if I am wrong but I really want you to have a good experience with your motorized bike and not a poor one.

The build you are proposing (vertical shaft motor) is a moderately challenging one. I honestly don't think you have the experience, ability and aptitude to build a safe and reliable bike from this motor. For that reason I strongly encourage you to look at the rack mount kits sold by Staton and Gebe. I think you are capable of building one of these and will have a good experience and much fun. If after building one of these you still decide to build a bike with your vertical shaft motor you will at least have some knowledge and experience to draw from.

Perhaps by then you will get the videos to work on your computer and you can see what it takes for yourself.

If my judgement is incorrect and you are so very confident in your skills that you decide to proceed then please do so and I hope you are successful. Please post pictures here so that I may applaud your achievement and apologize for my incorrect assessment.

Mr. Manta Ray · #25 (**permalink**) 11-07-2009, 09:26 PM

sorry about the video and stuff i got it to play and the video showed something that is basically exactly what i was going to do only i will have a clutch on the handlebars like a brake and i will have a throttle control so it is not all out all the time also i will try to design something to widen the rim so that i can put the friction drive on the rim more easily rather than on the tire then there is more griping area. ALSO if anyone knows where i can possibly find some parts for a schwinn manta ray 2005 that would be great because i can't find it anywhere on the internet and the people at the local bike shops can't really help i just need the parts for a schwinn coaster brake so all the guts in the back axle the pros at the bike store said it is generic so really any schwinn coaster brake will work for mine i just need to find some on the internet so please keep your eyes peeled thanks