Building my own brakes and axles

[CatmanDobbins]

Hi again everybody. I finally got 4 free golf cart hubs! YAY! Next step, though, is to figure out how to mount them to a back axle or back axles.




1.
So, although the idea of having galvanized pipe as a live axle was quickly shot down, I decided that perhaps it would work if it was two (shorter) dead axles. I could possibly attach these to my kart and then put the hubs on those (because the threading does match up). Would they still bend and break as people told me before? Would it be too weak in every way?




2.
Next question is what exactly is a brake-drum band made out of.

This type: https://www.amazon.com/s/ref=nb_sb_...ke+drum+go+kart&rh=i:aps,k:brake+drum+go+kart

I have some thin alloy that I could cut and bend into the shape of this, but what is the material on the inside? How strong does it have to be? It looks like some foamy stuff that would provide friction. In my eyes, I could build a couple and replace them often. It would save me like 15 to 20 bucks.




3.
Also, I need help with deciding on what gear ratio to use. I am getting a 6.5 hp predator engine and have about 17 inch wheels. I'm thinking I need at least an 8:1 ratio for the wheel size, or should it be less? I don't really know much about that (I don't know much about any of this, which is why I'm asking haha).

Also, what number chain is bike chain? It seems like most of these go kart parts use #35 or #40, so would I be able to use a bike chain on the sprocket and centrifugal clutch?

Any advise is helpful! Thanks.

 

[mckutzy]

It's not worth it to cheap out in the brake department. Those are pretty good prices...

Your ratio could work.. Usually start with 6:1, then 7:1 and so on...

 

[CatmanDobbins]

Interesting, so this article (http://www.diygokarts.com/vb/showthread.php?t=26445) says that your ratio should be lower for bigger wheels. Does that mean I should actually have 5:1 or even 4:1? I'm confused because you're saying that 7:1 will work.

I agree that it's better not to cheap out on brakes, but if I can get the same materials then there shouldn't really be too big a difference right?

Thanks for the help!

 

[chancer]

YES lower gear for taller tires.
But a lower Gear is 7:1 or 8:1 not 4 or 5.
It is opposite of what you would think.
Higher the number the lower the gear.

 

[pRoFiT]

7:1 should be fine for 17"
I run a 6:1 ratio on my 15" tires. Gives me about 27MPH

7:1 with regular unmodified 6.5 engine should get you 26MPH. if you remove engine governor and increase RPM to around 5400RPM then you could go 39MPH.

So I would want good brakes when driving anywhere near 26-39 MPH. be safe.

 

[Hellion]

2.
Next question is what exactly is a brake-drum band made out of.

This type: https://www.amazon.com/s/ref=nb_sb_...ke+drum+go+kart&rh=i:aps,k:brake+drum+go+kart

I have some thin alloy that I could cut and bend into the shape of this, but what is the material on the inside? How strong does it have to be? It looks like some foamy stuff that would provide friction. In my eyes, I could build a couple and replace them often. It would save me like 15 to 20 bucks.

...Also, what number chain is bike chain? It seems like most of these go kart parts use #35 or #40, so would I be able to use a bike chain on the sprocket and centrifugal clutch?

The band itself is made of spring steel so that it snaps back after contraction.

The braking material is 'brake pad material' (semi-metallic, organic, or ceramic materials) that is bonded to the steel band. It's not 'foamy stuff' by any stretch of the imagination but a hard, semi flexible material.

Bike chain? Bicycle chain or motorcycle chain? Stay away from bicycle chain--too weak and made for....bicycles not engine powered "whatsits".

 

[pRoFiT]

The band itself is made of spring steel so that it snaps back after contraction.

The braking material is 'brake pad material' (semi-metallic, organic, or ceramic materials) that is bonded to the steel band. It's not 'foamy stuff' by any stretch of the imagination but a hard, semi flexible material.

Bike chain? Bicycle chain or motorcycle chain? Stay away from bicycle chain--too weak and made for....bicycles not engine powered "whatsits".

Thanks hellion, where were you when i started my krazy kart design. Now i think i will have mix #35, #40 and bike chain for steering!

Agreed though. Dont use bike chain unless its an electric bike? no this is diy GO KARTS not diy-E-bikes.

I would like to see what custom brake pads look like though?

 

[CatmanDobbins]

Thanks for the help all. I'm learning a ton.

Does anyone have an answer to the axle question though? If I am using two short, dead axles for the back wheels, couldn't they be made of galvanized pipe without worrying about longevity too much? I was told that a live axle setup using this will make the pipe bend and it won't last long, but now the pipe isn't spinning and all it is really doing is acting as an axis of rotation for the wheel.

What ya think?

Also, I had no idea that the chain was weaker on a bike than on a go kart. That's really good info, thanks Hellion.

I think, if I can, I'm gonna go with 8:1 ratio on the kart because I want more acceleration/torgue at low speeds as opposed to top speed on this. Also, I want to carry a lot of weight.

 

[mckutzy]

Don't use a pipe for an axle... Get some proper keyed shafting and use that.. Using anything like pipe will cause a failure quickly... As anything done to secure the brakes and drive sprocket will weaken it significantly...

 

[pRoFiT]

I would say get some steel. drop the galvanized pipe. It smokes bad when welding on and can kill, or so i've been told.

If you want a dead axle, then a couple bolts will work for the axles. I always see a large bolt on the drive side. Do some dead axle research and you will see what i mean.

If you are going the cheap route then a dead axle with a paddle brake is probably cheapest and simplest way.

This guy has the cheap brake system you can see in his first post. http://www.diygokarts.com/vb/showthread.php?t=15933 even though he wants to replace it

 

[Flyinhillbilly]

Thanks for the help all. I'm learning a ton.

Does anyone have an answer to the axle question though? If I am using two short, dead axles for the back wheels, couldn't they be made of galvanized pipe without worrying about longevity too much? I was told that a live axle setup using this will make the pipe bend and it won't last long,

I want to carry a lot of weight.

Nuff said. Just buy and axle or keyed shaft.

 

[CatmanDobbins]

I would say get some steel. drop the galvanized pipe. It smokes bad when welding on and can kill, or so i've been told.

If you want a dead axle, then a couple bolts will work for the axles. I always see a large bolt on the drive side. Do some dead axle research and you will see what i mean.

If you are going the cheap route then a dead axle with a paddle brake is probably cheapest and simplest way.

This guy has the cheap brake system you can see in his first post. http://www.diygokarts.com/vb/showthread.php?t=15933 even though he wants to replace it


Thanks for the help, I don't have a welder, but from what other people have said it's not a good idea anyway. The problem is that I have hubs that are 1 inch bore. I don't know where I would get one inch bore bolts you know? Maybe they have them at an industrial supply shop? Also, the pictures that are on that post are kind of confusing. The kart isn't using a brake that just brushes against the tire is it? That might be devastating to the kart no? I looked up paddle brakes and they seem to be the same as band brakes. Any way you can help is appreciated!